[FFmpeg-cvslog] r26206 - in trunk/libavcodec: Makefile ac3enc.c ac3enc_fixed.c ac3enc_fixed.h
jbr
subversion
Mon Jan 3 17:08:56 CET 2011
Author: jbr
Date: Mon Jan 3 17:08:56 2011
New Revision: 26206
Log:
Move fixed-point parts of the AC-3 encoder to separate files.
Added:
trunk/libavcodec/ac3enc_fixed.c
- copied, changed from r26205, trunk/libavcodec/ac3enc.c
trunk/libavcodec/ac3enc_fixed.h
- copied, changed from r26205, trunk/libavcodec/ac3enc.c
Modified:
trunk/libavcodec/Makefile
trunk/libavcodec/ac3enc.c
Modified: trunk/libavcodec/Makefile
==============================================================================
--- trunk/libavcodec/Makefile Mon Jan 3 13:43:48 2011 (r26205)
+++ trunk/libavcodec/Makefile Mon Jan 3 17:08:56 2011 (r26206)
@@ -54,7 +54,7 @@ OBJS-$(CONFIG_AAC_ENCODER) +
mpeg4audio.o
OBJS-$(CONFIG_AASC_DECODER) += aasc.o msrledec.o
OBJS-$(CONFIG_AC3_DECODER) += ac3dec.o ac3dec_data.o ac3.o
-OBJS-$(CONFIG_AC3_ENCODER) += ac3enc.o ac3tab.o ac3.o
+OBJS-$(CONFIG_AC3_ENCODER) += ac3enc_fixed.o ac3tab.o ac3.o
OBJS-$(CONFIG_ALAC_DECODER) += alac.o
OBJS-$(CONFIG_ALAC_ENCODER) += alacenc.o
OBJS-$(CONFIG_ALS_DECODER) += alsdec.o bgmc.o mpeg4audio.o
Modified: trunk/libavcodec/ac3enc.c
==============================================================================
--- trunk/libavcodec/ac3enc.c Mon Jan 3 13:43:48 2011 (r26205)
+++ trunk/libavcodec/ac3enc.c Mon Jan 3 17:08:56 2011 (r26206)
@@ -43,33 +43,9 @@
/** Scale a float value by 2^bits and convert to an integer. */
#define SCALE_FLOAT(a, bits) lrintf((a) * (float)(1 << (bits)))
-typedef int16_t SampleType;
-typedef int32_t CoefType;
-
-#define SCALE_COEF(a) (a)
-
-/** Scale a float value by 2^15, convert to an integer, and clip to range -32767..32767. */
-#define FIX15(a) av_clip(SCALE_FLOAT(a, 15), -32767, 32767)
+#include "ac3enc_fixed.h"
-/**
- * Compex number.
- * Used in fixed-point MDCT calculation.
- */
-typedef struct IComplex {
- int16_t re,im;
-} IComplex;
-
-typedef struct AC3MDCTContext {
- const int16_t *window; ///< MDCT window function
- int nbits; ///< log2(transform size)
- int16_t *costab; ///< FFT cos table
- int16_t *sintab; ///< FFT sin table
- int16_t *xcos1; ///< MDCT cos table
- int16_t *xsin1; ///< MDCT sin table
- int16_t *rot_tmp; ///< temp buffer for pre-rotated samples
- IComplex *cplx_tmp; ///< temp buffer for complex pre-rotated samples
-} AC3MDCTContext;
/**
* Data for a single audio block.
@@ -154,6 +130,21 @@ typedef struct AC3EncodeContext {
} AC3EncodeContext;
+/* prototypes for functions in ac3enc_fixed.c */
+
+static av_cold void mdct_end(AC3MDCTContext *mdct);
+
+static av_cold int mdct_init(AVCodecContext *avctx, AC3MDCTContext *mdct,
+ int nbits);
+
+static void mdct512(AC3MDCTContext *mdct, CoefType *out, SampleType *in);
+
+static void apply_window(SampleType *output, const SampleType *input,
+ const SampleType *window, int n);
+
+static int normalize_samples(AC3EncodeContext *s);
+
+
/**
* LUT for number of exponent groups.
* exponent_group_tab[exponent strategy-1][number of coefficients]
@@ -234,291 +225,6 @@ static void deinterleave_input_samples(A
/**
- * Finalize MDCT and free allocated memory.
- */
-static av_cold void mdct_end(AC3MDCTContext *mdct)
-{
- mdct->nbits = 0;
- av_freep(&mdct->costab);
- av_freep(&mdct->sintab);
- av_freep(&mdct->xcos1);
- av_freep(&mdct->xsin1);
- av_freep(&mdct->rot_tmp);
- av_freep(&mdct->cplx_tmp);
-}
-
-
-/**
- * Initialize FFT tables.
- * @param ln log2(FFT size)
- */
-static av_cold int fft_init(AVCodecContext *avctx, AC3MDCTContext *mdct, int ln)
-{
- int i, n, n2;
- float alpha;
-
- n = 1 << ln;
- n2 = n >> 1;
-
- FF_ALLOC_OR_GOTO(avctx, mdct->costab, n2 * sizeof(*mdct->costab), fft_alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, mdct->sintab, n2 * sizeof(*mdct->sintab), fft_alloc_fail);
-
- for (i = 0; i < n2; i++) {
- alpha = 2.0 * M_PI * i / n;
- mdct->costab[i] = FIX15(cos(alpha));
- mdct->sintab[i] = FIX15(sin(alpha));
- }
-
- return 0;
-fft_alloc_fail:
- mdct_end(mdct);
- return AVERROR(ENOMEM);
-}
-
-
-/**
- * Initialize MDCT tables.
- * @param nbits log2(MDCT size)
- */
-static av_cold int mdct_init(AVCodecContext *avctx, AC3MDCTContext *mdct,
- int nbits)
-{
- int i, n, n4, ret;
-
- n = 1 << nbits;
- n4 = n >> 2;
-
- mdct->nbits = nbits;
-
- ret = fft_init(avctx, mdct, nbits - 2);
- if (ret)
- return ret;
-
- mdct->window = ff_ac3_window;
-
- FF_ALLOC_OR_GOTO(avctx, mdct->xcos1, n4 * sizeof(*mdct->xcos1), mdct_alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, mdct->xsin1, n4 * sizeof(*mdct->xsin1), mdct_alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, mdct->rot_tmp, n * sizeof(*mdct->rot_tmp), mdct_alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, mdct->cplx_tmp, n4 * sizeof(*mdct->cplx_tmp), mdct_alloc_fail);
-
- for (i = 0; i < n4; i++) {
- float alpha = 2.0 * M_PI * (i + 1.0 / 8.0) / n;
- mdct->xcos1[i] = FIX15(-cos(alpha));
- mdct->xsin1[i] = FIX15(-sin(alpha));
- }
-
- return 0;
-mdct_alloc_fail:
- mdct_end(mdct);
- return AVERROR(ENOMEM);
-}
-
-
-/** Butterfly op */
-#define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
-{ \
- int ax, ay, bx, by; \
- bx = pre1; \
- by = pim1; \
- ax = qre1; \
- ay = qim1; \
- pre = (bx + ax) >> 1; \
- pim = (by + ay) >> 1; \
- qre = (bx - ax) >> 1; \
- qim = (by - ay) >> 1; \
-}
-
-
-/** Complex multiply */
-#define CMUL(pre, pim, are, aim, bre, bim) \
-{ \
- pre = (MUL16(are, bre) - MUL16(aim, bim)) >> 15; \
- pim = (MUL16(are, bim) + MUL16(bre, aim)) >> 15; \
-}
-
-
-/**
- * Calculate a 2^n point complex FFT on 2^ln points.
- * @param z complex input/output samples
- * @param ln log2(FFT size)
- */
-static void fft(AC3MDCTContext *mdct, IComplex *z, int ln)
-{
- int j, l, np, np2;
- int nblocks, nloops;
- register IComplex *p,*q;
- int tmp_re, tmp_im;
-
- np = 1 << ln;
-
- /* reverse */
- for (j = 0; j < np; j++) {
- int k = av_reverse[j] >> (8 - ln);
- if (k < j)
- FFSWAP(IComplex, z[k], z[j]);
- }
-
- /* pass 0 */
-
- p = &z[0];
- j = np >> 1;
- do {
- BF(p[0].re, p[0].im, p[1].re, p[1].im,
- p[0].re, p[0].im, p[1].re, p[1].im);
- p += 2;
- } while (--j);
-
- /* pass 1 */
-
- p = &z[0];
- j = np >> 2;
- do {
- BF(p[0].re, p[0].im, p[2].re, p[2].im,
- p[0].re, p[0].im, p[2].re, p[2].im);
- BF(p[1].re, p[1].im, p[3].re, p[3].im,
- p[1].re, p[1].im, p[3].im, -p[3].re);
- p+=4;
- } while (--j);
-
- /* pass 2 .. ln-1 */
-
- nblocks = np >> 3;
- nloops = 1 << 2;
- np2 = np >> 1;
- do {
- p = z;
- q = z + nloops;
- for (j = 0; j < nblocks; j++) {
- BF(p->re, p->im, q->re, q->im,
- p->re, p->im, q->re, q->im);
- p++;
- q++;
- for(l = nblocks; l < np2; l += nblocks) {
- CMUL(tmp_re, tmp_im, mdct->costab[l], -mdct->sintab[l], q->re, q->im);
- BF(p->re, p->im, q->re, q->im,
- p->re, p->im, tmp_re, tmp_im);
- p++;
- q++;
- }
- p += nloops;
- q += nloops;
- }
- nblocks = nblocks >> 1;
- nloops = nloops << 1;
- } while (nblocks);
-}
-
-
-/**
- * Calculate a 512-point MDCT
- * @param out 256 output frequency coefficients
- * @param in 512 windowed input audio samples
- */
-static void mdct512(AC3MDCTContext *mdct, int32_t *out, int16_t *in)
-{
- int i, re, im, n, n2, n4;
- int16_t *rot = mdct->rot_tmp;
- IComplex *x = mdct->cplx_tmp;
-
- n = 1 << mdct->nbits;
- n2 = n >> 1;
- n4 = n >> 2;
-
- /* shift to simplify computations */
- for (i = 0; i <n4; i++)
- rot[i] = -in[i + 3*n4];
- memcpy(&rot[n4], &in[0], 3*n4*sizeof(*in));
-
- /* pre rotation */
- for (i = 0; i < n4; i++) {
- re = ((int)rot[ 2*i] - (int)rot[ n-1-2*i]) >> 1;
- im = -((int)rot[n2+2*i] - (int)rot[n2-1-2*i]) >> 1;
- CMUL(x[i].re, x[i].im, re, im, -mdct->xcos1[i], mdct->xsin1[i]);
- }
-
- fft(mdct, x, mdct->nbits - 2);
-
- /* post rotation */
- for (i = 0; i < n4; i++) {
- re = x[i].re;
- im = x[i].im;
- CMUL(out[n2-1-2*i], out[2*i], re, im, mdct->xsin1[i], mdct->xcos1[i]);
- }
-}
-
-
-/**
- * Apply KBD window to input samples prior to MDCT.
- */
-static void apply_window(int16_t *output, const int16_t *input,
- const int16_t *window, int n)
-{
- int i;
- int n2 = n >> 1;
-
- for (i = 0; i < n2; i++) {
- output[i] = MUL16(input[i], window[i]) >> 15;
- output[n-i-1] = MUL16(input[n-i-1], window[i]) >> 15;
- }
-}
-
-
-/**
- * Calculate the log2() of the maximum absolute value in an array.
- * @param tab input array
- * @param n number of values in the array
- * @return log2(max(abs(tab[])))
- */
-static int log2_tab(int16_t *tab, int n)
-{
- int i, v;
-
- v = 0;
- for (i = 0; i < n; i++)
- v |= abs(tab[i]);
-
- return av_log2(v);
-}
-
-
-/**
- * Left-shift each value in an array by a specified amount.
- * @param tab input array
- * @param n number of values in the array
- * @param lshift left shift amount. a negative value means right shift.
- */
-static void lshift_tab(int16_t *tab, int n, int lshift)
-{
- int i;
-
- if (lshift > 0) {
- for (i = 0; i < n; i++)
- tab[i] <<= lshift;
- } else if (lshift < 0) {
- lshift = -lshift;
- for (i = 0; i < n; i++)
- tab[i] >>= lshift;
- }
-}
-
-
-/**
- * Normalize the input samples to use the maximum available precision.
- * This assumes signed 16-bit input samples. Exponents are reduced by 9 to
- * match the 24-bit internal precision for MDCT coefficients.
- *
- * @return exponent shift
- */
-static int normalize_samples(AC3EncodeContext *s)
-{
- int v = 14 - log2_tab(s->windowed_samples, AC3_WINDOW_SIZE);
- v = FFMAX(0, v);
- lshift_tab(s->windowed_samples, AC3_WINDOW_SIZE, v);
- return v - 9;
-}
-
-
-/**
* Apply the MDCT to input samples to generate frequency coefficients.
* This applies the KBD window and normalizes the input to reduce precision
* loss due to fixed-point calculations.
@@ -1982,113 +1688,3 @@ init_fail:
ac3_encode_close(avctx);
return ret;
}
-
-
-#ifdef TEST
-/*************************************************************************/
-/* TEST */
-
-#include "libavutil/lfg.h"
-
-#define MDCT_NBITS 9
-#define MDCT_SAMPLES (1 << MDCT_NBITS)
-#define FN (MDCT_SAMPLES/4)
-
-
-static void fft_test(AC3MDCTContext *mdct, AVLFG *lfg)
-{
- IComplex in[FN], in1[FN];
- int k, n, i;
- float sum_re, sum_im, a;
-
- for (i = 0; i < FN; i++) {
- in[i].re = av_lfg_get(lfg) % 65535 - 32767;
- in[i].im = av_lfg_get(lfg) % 65535 - 32767;
- in1[i] = in[i];
- }
- fft(mdct, in, 7);
-
- /* do it by hand */
- for (k = 0; k < FN; k++) {
- sum_re = 0;
- sum_im = 0;
- for (n = 0; n < FN; n++) {
- a = -2 * M_PI * (n * k) / FN;
- sum_re += in1[n].re * cos(a) - in1[n].im * sin(a);
- sum_im += in1[n].re * sin(a) + in1[n].im * cos(a);
- }
- av_log(NULL, AV_LOG_DEBUG, "%3d: %6d,%6d %6.0f,%6.0f\n",
- k, in[k].re, in[k].im, sum_re / FN, sum_im / FN);
- }
-}
-
-
-static void mdct_test(AC3MDCTContext *mdct, AVLFG *lfg)
-{
- int16_t input[MDCT_SAMPLES];
- int32_t output[AC3_MAX_COEFS];
- float input1[MDCT_SAMPLES];
- float output1[AC3_MAX_COEFS];
- float s, a, err, e, emax;
- int i, k, n;
-
- for (i = 0; i < MDCT_SAMPLES; i++) {
- input[i] = (av_lfg_get(lfg) % 65535 - 32767) * 9 / 10;
- input1[i] = input[i];
- }
-
- mdct512(mdct, output, input);
-
- /* do it by hand */
- for (k = 0; k < AC3_MAX_COEFS; k++) {
- s = 0;
- for (n = 0; n < MDCT_SAMPLES; n++) {
- a = (2*M_PI*(2*n+1+MDCT_SAMPLES/2)*(2*k+1) / (4 * MDCT_SAMPLES));
- s += input1[n] * cos(a);
- }
- output1[k] = -2 * s / MDCT_SAMPLES;
- }
-
- err = 0;
- emax = 0;
- for (i = 0; i < AC3_MAX_COEFS; i++) {
- av_log(NULL, AV_LOG_DEBUG, "%3d: %7d %7.0f\n", i, output[i], output1[i]);
- e = output[i] - output1[i];
- if (e > emax)
- emax = e;
- err += e * e;
- }
- av_log(NULL, AV_LOG_DEBUG, "err2=%f emax=%f\n", err / AC3_MAX_COEFS, emax);
-}
-
-
-int main(void)
-{
- AVLFG lfg;
- AC3MDCTContext mdct;
-
- mdct.avctx = NULL;
- av_log_set_level(AV_LOG_DEBUG);
- mdct_init(&mdct, 9);
-
- fft_test(&mdct, &lfg);
- mdct_test(&mdct, &lfg);
-
- return 0;
-}
-#endif /* TEST */
-
-
-AVCodec ac3_encoder = {
- "ac3",
- AVMEDIA_TYPE_AUDIO,
- CODEC_ID_AC3,
- sizeof(AC3EncodeContext),
- ac3_encode_init,
- ac3_encode_frame,
- ac3_encode_close,
- NULL,
- .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
- .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
- .channel_layouts = ac3_channel_layouts,
-};
Copied and modified: trunk/libavcodec/ac3enc_fixed.c (from r26205, trunk/libavcodec/ac3enc.c)
==============================================================================
--- trunk/libavcodec/ac3enc.c Mon Jan 3 13:43:48 2011 (r26205, copy source)
+++ trunk/libavcodec/ac3enc_fixed.c Mon Jan 3 17:08:56 2011 (r26206)
@@ -23,217 +23,17 @@
/**
* @file
- * The simplest AC-3 encoder.
+ * fixed-point AC-3 encoder.
*/
-//#define DEBUG
-
-#include "libavcore/audioconvert.h"
-#include "libavutil/crc.h"
-#include "avcodec.h"
-#include "put_bits.h"
-#include "dsputil.h"
-#include "ac3.h"
-#include "audioconvert.h"
-
-
-/** Maximum number of exponent groups. +1 for separate DC exponent. */
-#define AC3_MAX_EXP_GROUPS 85
-
-/** Scale a float value by 2^bits and convert to an integer. */
-#define SCALE_FLOAT(a, bits) lrintf((a) * (float)(1 << (bits)))
-
-typedef int16_t SampleType;
-typedef int32_t CoefType;
+#include "ac3enc.c"
-#define SCALE_COEF(a) (a)
/** Scale a float value by 2^15, convert to an integer, and clip to range -32767..32767. */
#define FIX15(a) av_clip(SCALE_FLOAT(a, 15), -32767, 32767)
/**
- * Compex number.
- * Used in fixed-point MDCT calculation.
- */
-typedef struct IComplex {
- int16_t re,im;
-} IComplex;
-
-typedef struct AC3MDCTContext {
- const int16_t *window; ///< MDCT window function
- int nbits; ///< log2(transform size)
- int16_t *costab; ///< FFT cos table
- int16_t *sintab; ///< FFT sin table
- int16_t *xcos1; ///< MDCT cos table
- int16_t *xsin1; ///< MDCT sin table
- int16_t *rot_tmp; ///< temp buffer for pre-rotated samples
- IComplex *cplx_tmp; ///< temp buffer for complex pre-rotated samples
-} AC3MDCTContext;
-
-/**
- * Data for a single audio block.
- */
-typedef struct AC3Block {
- uint8_t **bap; ///< bit allocation pointers (bap)
- CoefType **mdct_coef; ///< MDCT coefficients
- uint8_t **exp; ///< original exponents
- uint8_t **grouped_exp; ///< grouped exponents
- int16_t **psd; ///< psd per frequency bin
- int16_t **band_psd; ///< psd per critical band
- int16_t **mask; ///< masking curve
- uint16_t **qmant; ///< quantized mantissas
- uint8_t exp_strategy[AC3_MAX_CHANNELS]; ///< exponent strategies
- int8_t exp_shift[AC3_MAX_CHANNELS]; ///< exponent shift values
-} AC3Block;
-
-/**
- * AC-3 encoder private context.
- */
-typedef struct AC3EncodeContext {
- PutBitContext pb; ///< bitstream writer context
- DSPContext dsp;
- AC3MDCTContext mdct; ///< MDCT context
-
- AC3Block blocks[AC3_MAX_BLOCKS]; ///< per-block info
-
- int bitstream_id; ///< bitstream id (bsid)
- int bitstream_mode; ///< bitstream mode (bsmod)
-
- int bit_rate; ///< target bit rate, in bits-per-second
- int sample_rate; ///< sampling frequency, in Hz
-
- int frame_size_min; ///< minimum frame size in case rounding is necessary
- int frame_size; ///< current frame size in bytes
- int frame_size_code; ///< frame size code (frmsizecod)
- uint16_t crc_inv[2];
- int bits_written; ///< bit count (used to avg. bitrate)
- int samples_written; ///< sample count (used to avg. bitrate)
-
- int fbw_channels; ///< number of full-bandwidth channels (nfchans)
- int channels; ///< total number of channels (nchans)
- int lfe_on; ///< indicates if there is an LFE channel (lfeon)
- int lfe_channel; ///< channel index of the LFE channel
- int channel_mode; ///< channel mode (acmod)
- const uint8_t *channel_map; ///< channel map used to reorder channels
-
- int cutoff; ///< user-specified cutoff frequency, in Hz
- int bandwidth_code[AC3_MAX_CHANNELS]; ///< bandwidth code (0 to 60) (chbwcod)
- int nb_coefs[AC3_MAX_CHANNELS];
-
- /* bitrate allocation control */
- int slow_gain_code; ///< slow gain code (sgaincod)
- int slow_decay_code; ///< slow decay code (sdcycod)
- int fast_decay_code; ///< fast decay code (fdcycod)
- int db_per_bit_code; ///< dB/bit code (dbpbcod)
- int floor_code; ///< floor code (floorcod)
- AC3BitAllocParameters bit_alloc; ///< bit allocation parameters
- int coarse_snr_offset; ///< coarse SNR offsets (csnroffst)
- int fast_gain_code[AC3_MAX_CHANNELS]; ///< fast gain codes (signal-to-mask ratio) (fgaincod)
- int fine_snr_offset[AC3_MAX_CHANNELS]; ///< fine SNR offsets (fsnroffst)
- int frame_bits_fixed; ///< number of non-coefficient bits for fixed parameters
- int frame_bits; ///< all frame bits except exponents and mantissas
- int exponent_bits; ///< number of bits used for exponents
-
- /* mantissa encoding */
- int mant1_cnt, mant2_cnt, mant4_cnt; ///< mantissa counts for bap=1,2,4
- uint16_t *qmant1_ptr, *qmant2_ptr, *qmant4_ptr; ///< mantissa pointers for bap=1,2,4
-
- SampleType **planar_samples;
- uint8_t *bap_buffer;
- uint8_t *bap1_buffer;
- CoefType *mdct_coef_buffer;
- uint8_t *exp_buffer;
- uint8_t *grouped_exp_buffer;
- int16_t *psd_buffer;
- int16_t *band_psd_buffer;
- int16_t *mask_buffer;
- uint16_t *qmant_buffer;
-
- DECLARE_ALIGNED(16, SampleType, windowed_samples)[AC3_WINDOW_SIZE];
-} AC3EncodeContext;
-
-
-/**
- * LUT for number of exponent groups.
- * exponent_group_tab[exponent strategy-1][number of coefficients]
- */
-static uint8_t exponent_group_tab[3][256];
-
-
-/**
- * List of supported channel layouts.
- */
-static const int64_t ac3_channel_layouts[] = {
- AV_CH_LAYOUT_MONO,
- AV_CH_LAYOUT_STEREO,
- AV_CH_LAYOUT_2_1,
- AV_CH_LAYOUT_SURROUND,
- AV_CH_LAYOUT_2_2,
- AV_CH_LAYOUT_QUAD,
- AV_CH_LAYOUT_4POINT0,
- AV_CH_LAYOUT_5POINT0,
- AV_CH_LAYOUT_5POINT0_BACK,
- (AV_CH_LAYOUT_MONO | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_STEREO | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_2_1 | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_SURROUND | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_2_2 | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_QUAD | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_4POINT0 | AV_CH_LOW_FREQUENCY),
- AV_CH_LAYOUT_5POINT1,
- AV_CH_LAYOUT_5POINT1_BACK,
- 0
-};
-
-
-/**
- * Adjust the frame size to make the average bit rate match the target bit rate.
- * This is only needed for 11025, 22050, and 44100 sample rates.
- */
-static void adjust_frame_size(AC3EncodeContext *s)
-{
- while (s->bits_written >= s->bit_rate && s->samples_written >= s->sample_rate) {
- s->bits_written -= s->bit_rate;
- s->samples_written -= s->sample_rate;
- }
- s->frame_size = s->frame_size_min +
- 2 * (s->bits_written * s->sample_rate < s->samples_written * s->bit_rate);
- s->bits_written += s->frame_size * 8;
- s->samples_written += AC3_FRAME_SIZE;
-}
-
-
-/**
- * Deinterleave input samples.
- * Channels are reordered from FFmpeg's default order to AC-3 order.
- */
-static void deinterleave_input_samples(AC3EncodeContext *s,
- const SampleType *samples)
-{
- int ch, i;
-
- /* deinterleave and remap input samples */
- for (ch = 0; ch < s->channels; ch++) {
- const SampleType *sptr;
- int sinc;
-
- /* copy last 256 samples of previous frame to the start of the current frame */
- memcpy(&s->planar_samples[ch][0], &s->planar_samples[ch][AC3_FRAME_SIZE],
- AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0]));
-
- /* deinterleave */
- sinc = s->channels;
- sptr = samples + s->channel_map[ch];
- for (i = AC3_BLOCK_SIZE; i < AC3_FRAME_SIZE+AC3_BLOCK_SIZE; i++) {
- s->planar_samples[ch][i] = *sptr;
- sptr += sinc;
- }
- }
-}
-
-
-/**
* Finalize MDCT and free allocated memory.
*/
static av_cold void mdct_end(AC3MDCTContext *mdct)
@@ -518,1472 +318,6 @@ static int normalize_samples(AC3EncodeCo
}
-/**
- * Apply the MDCT to input samples to generate frequency coefficients.
- * This applies the KBD window and normalizes the input to reduce precision
- * loss due to fixed-point calculations.
- */
-static void apply_mdct(AC3EncodeContext *s)
-{
- int blk, ch;
-
- for (ch = 0; ch < s->channels; ch++) {
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- const SampleType *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE];
-
- apply_window(s->windowed_samples, input_samples, s->mdct.window, AC3_WINDOW_SIZE);
-
- block->exp_shift[ch] = normalize_samples(s);
-
- mdct512(&s->mdct, block->mdct_coef[ch], s->windowed_samples);
- }
- }
-}
-
-
-/**
- * Initialize exponent tables.
- */
-static av_cold void exponent_init(AC3EncodeContext *s)
-{
- int i;
- for (i = 73; i < 256; i++) {
- exponent_group_tab[0][i] = (i - 1) / 3;
- exponent_group_tab[1][i] = (i + 2) / 6;
- exponent_group_tab[2][i] = (i + 8) / 12;
- }
- /* LFE */
- exponent_group_tab[0][7] = 2;
-}
-
-
-/**
- * Extract exponents from the MDCT coefficients.
- * This takes into account the normalization that was done to the input samples
- * by adjusting the exponents by the exponent shift values.
- */
-static void extract_exponents(AC3EncodeContext *s)
-{
- int blk, ch, i;
-
- for (ch = 0; ch < s->channels; ch++) {
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- for (i = 0; i < AC3_MAX_COEFS; i++) {
- int e;
- int v = abs(SCALE_COEF(block->mdct_coef[ch][i]));
- if (v == 0)
- e = 24;
- else {
- e = 23 - av_log2(v) + block->exp_shift[ch];
- if (e >= 24) {
- e = 24;
- block->mdct_coef[ch][i] = 0;
- }
- }
- block->exp[ch][i] = e;
- }
- }
- }
-}
-
-
-/**
- * Exponent Difference Threshold.
- * New exponents are sent if their SAD exceed this number.
- */
-#define EXP_DIFF_THRESHOLD 1000
-
-
-/**
- * Calculate exponent strategies for all blocks in a single channel.
- */
-static void compute_exp_strategy_ch(AC3EncodeContext *s, uint8_t *exp_strategy,
- uint8_t **exp)
-{
- int blk, blk1;
- int exp_diff;
-
- /* estimate if the exponent variation & decide if they should be
- reused in the next frame */
- exp_strategy[0] = EXP_NEW;
- for (blk = 1; blk < AC3_MAX_BLOCKS; blk++) {
- exp_diff = s->dsp.sad[0](NULL, exp[blk], exp[blk-1], 16, 16);
- if (exp_diff > EXP_DIFF_THRESHOLD)
- exp_strategy[blk] = EXP_NEW;
- else
- exp_strategy[blk] = EXP_REUSE;
- }
- emms_c();
-
- /* now select the encoding strategy type : if exponents are often
- recoded, we use a coarse encoding */
- blk = 0;
- while (blk < AC3_MAX_BLOCKS) {
- blk1 = blk + 1;
- while (blk1 < AC3_MAX_BLOCKS && exp_strategy[blk1] == EXP_REUSE)
- blk1++;
- switch (blk1 - blk) {
- case 1: exp_strategy[blk] = EXP_D45; break;
- case 2:
- case 3: exp_strategy[blk] = EXP_D25; break;
- default: exp_strategy[blk] = EXP_D15; break;
- }
- blk = blk1;
- }
-}
-
-
-/**
- * Calculate exponent strategies for all channels.
- * Array arrangement is reversed to simplify the per-channel calculation.
- */
-static void compute_exp_strategy(AC3EncodeContext *s)
-{
- uint8_t *exp1[AC3_MAX_CHANNELS][AC3_MAX_BLOCKS];
- uint8_t exp_str1[AC3_MAX_CHANNELS][AC3_MAX_BLOCKS];
- int ch, blk;
-
- for (ch = 0; ch < s->fbw_channels; ch++) {
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- exp1[ch][blk] = s->blocks[blk].exp[ch];
- exp_str1[ch][blk] = s->blocks[blk].exp_strategy[ch];
- }
-
- compute_exp_strategy_ch(s, exp_str1[ch], exp1[ch]);
-
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++)
- s->blocks[blk].exp_strategy[ch] = exp_str1[ch][blk];
- }
- if (s->lfe_on) {
- ch = s->lfe_channel;
- s->blocks[0].exp_strategy[ch] = EXP_D15;
- for (blk = 1; blk < AC3_MAX_BLOCKS; blk++)
- s->blocks[blk].exp_strategy[ch] = EXP_REUSE;
- }
-}
-
-
-/**
- * Set each encoded exponent in a block to the minimum of itself and the
- * exponent in the same frequency bin of a following block.
- * exp[i] = min(exp[i], exp1[i]
- */
-static void exponent_min(uint8_t *exp, uint8_t *exp1, int n)
-{
- int i;
- for (i = 0; i < n; i++) {
- if (exp1[i] < exp[i])
- exp[i] = exp1[i];
- }
-}
-
-
-/**
- * Update the exponents so that they are the ones the decoder will decode.
- */
-static void encode_exponents_blk_ch(uint8_t *exp, int nb_exps, int exp_strategy)
-{
- int nb_groups, i, k;
-
- nb_groups = exponent_group_tab[exp_strategy-1][nb_exps] * 3;
-
- /* for each group, compute the minimum exponent */
- switch(exp_strategy) {
- case EXP_D25:
- for (i = 1, k = 1; i <= nb_groups; i++) {
- uint8_t exp_min = exp[k];
- if (exp[k+1] < exp_min)
- exp_min = exp[k+1];
- exp[i] = exp_min;
- k += 2;
- }
- break;
- case EXP_D45:
- for (i = 1, k = 1; i <= nb_groups; i++) {
- uint8_t exp_min = exp[k];
- if (exp[k+1] < exp_min)
- exp_min = exp[k+1];
- if (exp[k+2] < exp_min)
- exp_min = exp[k+2];
- if (exp[k+3] < exp_min)
- exp_min = exp[k+3];
- exp[i] = exp_min;
- k += 4;
- }
- break;
- }
-
- /* constraint for DC exponent */
- if (exp[0] > 15)
- exp[0] = 15;
-
- /* decrease the delta between each groups to within 2 so that they can be
- differentially encoded */
- for (i = 1; i <= nb_groups; i++)
- exp[i] = FFMIN(exp[i], exp[i-1] + 2);
- i--;
- while (--i >= 0)
- exp[i] = FFMIN(exp[i], exp[i+1] + 2);
-
- /* now we have the exponent values the decoder will see */
- switch (exp_strategy) {
- case EXP_D25:
- for (i = nb_groups, k = nb_groups * 2; i > 0; i--) {
- uint8_t exp1 = exp[i];
- exp[k--] = exp1;
- exp[k--] = exp1;
- }
- break;
- case EXP_D45:
- for (i = nb_groups, k = nb_groups * 4; i > 0; i--) {
- exp[k] = exp[k-1] = exp[k-2] = exp[k-3] = exp[i];
- k -= 4;
- }
- break;
- }
-}
-
-
-/**
- * Encode exponents from original extracted form to what the decoder will see.
- * This copies and groups exponents based on exponent strategy and reduces
- * deltas between adjacent exponent groups so that they can be differentially
- * encoded.
- */
-static void encode_exponents(AC3EncodeContext *s)
-{
- int blk, blk1, blk2, ch;
- AC3Block *block, *block1, *block2;
-
- for (ch = 0; ch < s->channels; ch++) {
- blk = 0;
- block = &s->blocks[0];
- while (blk < AC3_MAX_BLOCKS) {
- blk1 = blk + 1;
- block1 = block + 1;
- /* for the EXP_REUSE case we select the min of the exponents */
- while (blk1 < AC3_MAX_BLOCKS && block1->exp_strategy[ch] == EXP_REUSE) {
- exponent_min(block->exp[ch], block1->exp[ch], s->nb_coefs[ch]);
- blk1++;
- block1++;
- }
- encode_exponents_blk_ch(block->exp[ch], s->nb_coefs[ch],
- block->exp_strategy[ch]);
- /* copy encoded exponents for reuse case */
- block2 = block + 1;
- for (blk2 = blk+1; blk2 < blk1; blk2++, block2++) {
- memcpy(block2->exp[ch], block->exp[ch],
- s->nb_coefs[ch] * sizeof(uint8_t));
- }
- blk = blk1;
- block = block1;
- }
- }
-}
-
-
-/**
- * Group exponents.
- * 3 delta-encoded exponents are in each 7-bit group. The number of groups
- * varies depending on exponent strategy and bandwidth.
- */
-static void group_exponents(AC3EncodeContext *s)
-{
- int blk, ch, i;
- int group_size, nb_groups, bit_count;
- uint8_t *p;
- int delta0, delta1, delta2;
- int exp0, exp1;
-
- bit_count = 0;
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- for (ch = 0; ch < s->channels; ch++) {
- if (block->exp_strategy[ch] == EXP_REUSE) {
- continue;
- }
- group_size = block->exp_strategy[ch] + (block->exp_strategy[ch] == EXP_D45);
- nb_groups = exponent_group_tab[block->exp_strategy[ch]-1][s->nb_coefs[ch]];
- bit_count += 4 + (nb_groups * 7);
- p = block->exp[ch];
-
- /* DC exponent */
- exp1 = *p++;
- block->grouped_exp[ch][0] = exp1;
-
- /* remaining exponents are delta encoded */
- for (i = 1; i <= nb_groups; i++) {
- /* merge three delta in one code */
- exp0 = exp1;
- exp1 = p[0];
- p += group_size;
- delta0 = exp1 - exp0 + 2;
-
- exp0 = exp1;
- exp1 = p[0];
- p += group_size;
- delta1 = exp1 - exp0 + 2;
-
- exp0 = exp1;
- exp1 = p[0];
- p += group_size;
- delta2 = exp1 - exp0 + 2;
-
- block->grouped_exp[ch][i] = ((delta0 * 5 + delta1) * 5) + delta2;
- }
- }
- }
-
- s->exponent_bits = bit_count;
-}
-
-
-/**
- * Calculate final exponents from the supplied MDCT coefficients and exponent shift.
- * Extract exponents from MDCT coefficients, calculate exponent strategies,
- * and encode final exponents.
- */
-static void process_exponents(AC3EncodeContext *s)
-{
- extract_exponents(s);
-
- compute_exp_strategy(s);
-
- encode_exponents(s);
-
- group_exponents(s);
-}
-
-
-/**
- * Count frame bits that are based solely on fixed parameters.
- * This only has to be run once when the encoder is initialized.
- */
-static void count_frame_bits_fixed(AC3EncodeContext *s)
-{
- static const int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
- int blk;
- int frame_bits;
-
- /* assumptions:
- * no dynamic range codes
- * no channel coupling
- * no rematrixing
- * bit allocation parameters do not change between blocks
- * SNR offsets do not change between blocks
- * no delta bit allocation
- * no skipped data
- * no auxilliary data
- */
-
- /* header size */
- frame_bits = 65;
- frame_bits += frame_bits_inc[s->channel_mode];
-
- /* audio blocks */
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- frame_bits += s->fbw_channels * 2 + 2; /* blksw * c, dithflag * c, dynrnge, cplstre */
- if (s->channel_mode == AC3_CHMODE_STEREO) {
- frame_bits++; /* rematstr */
- if (!blk)
- frame_bits += 4;
- }
- frame_bits += 2 * s->fbw_channels; /* chexpstr[2] * c */
- if (s->lfe_on)
- frame_bits++; /* lfeexpstr */
- frame_bits++; /* baie */
- frame_bits++; /* snr */
- frame_bits += 2; /* delta / skip */
- }
- frame_bits++; /* cplinu for block 0 */
- /* bit alloc info */
- /* sdcycod[2], fdcycod[2], sgaincod[2], dbpbcod[2], floorcod[3] */
- /* csnroffset[6] */
- /* (fsnoffset[4] + fgaincod[4]) * c */
- frame_bits += 2*4 + 3 + 6 + s->channels * (4 + 3);
-
- /* auxdatae, crcrsv */
- frame_bits += 2;
-
- /* CRC */
- frame_bits += 16;
-
- s->frame_bits_fixed = frame_bits;
-}
-
-
-/**
- * Initialize bit allocation.
- * Set default parameter codes and calculate parameter values.
- */
-static void bit_alloc_init(AC3EncodeContext *s)
-{
- int ch;
-
- /* init default parameters */
- s->slow_decay_code = 2;
- s->fast_decay_code = 1;
- s->slow_gain_code = 1;
- s->db_per_bit_code = 3;
- s->floor_code = 4;
- for (ch = 0; ch < s->channels; ch++)
- s->fast_gain_code[ch] = 4;
-
- /* initial snr offset */
- s->coarse_snr_offset = 40;
-
- /* compute real values */
- /* currently none of these values change during encoding, so we can just
- set them once at initialization */
- s->bit_alloc.slow_decay = ff_ac3_slow_decay_tab[s->slow_decay_code] >> s->bit_alloc.sr_shift;
- s->bit_alloc.fast_decay = ff_ac3_fast_decay_tab[s->fast_decay_code] >> s->bit_alloc.sr_shift;
- s->bit_alloc.slow_gain = ff_ac3_slow_gain_tab[s->slow_gain_code];
- s->bit_alloc.db_per_bit = ff_ac3_db_per_bit_tab[s->db_per_bit_code];
- s->bit_alloc.floor = ff_ac3_floor_tab[s->floor_code];
-
- count_frame_bits_fixed(s);
-}
-
-
-/**
- * Count the bits used to encode the frame, minus exponents and mantissas.
- * Bits based on fixed parameters have already been counted, so now we just
- * have to add the bits based on parameters that change during encoding.
- */
-static void count_frame_bits(AC3EncodeContext *s)
-{
- int blk, ch;
- int frame_bits = 0;
-
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- uint8_t *exp_strategy = s->blocks[blk].exp_strategy;
- for (ch = 0; ch < s->fbw_channels; ch++) {
- if (exp_strategy[ch] != EXP_REUSE)
- frame_bits += 6 + 2; /* chbwcod[6], gainrng[2] */
- }
- }
- s->frame_bits = s->frame_bits_fixed + frame_bits;
-}
-
-
-/**
- * Calculate the number of bits needed to encode a set of mantissas.
- */
-static int compute_mantissa_size(int mant_cnt[5], uint8_t *bap, int nb_coefs)
-{
- int bits, b, i;
-
- bits = 0;
- for (i = 0; i < nb_coefs; i++) {
- b = bap[i];
- if (b <= 4) {
- // bap=1 to bap=4 will be counted in compute_mantissa_size_final
- mant_cnt[b]++;
- } else if (b <= 13) {
- // bap=5 to bap=13 use (bap-1) bits
- bits += b - 1;
- } else {
- // bap=14 uses 14 bits and bap=15 uses 16 bits
- bits += (b == 14) ? 14 : 16;
- }
- }
- return bits;
-}
-
-
-/**
- * Finalize the mantissa bit count by adding in the grouped mantissas.
- */
-static int compute_mantissa_size_final(int mant_cnt[5])
-{
- // bap=1 : 3 mantissas in 5 bits
- int bits = (mant_cnt[1] / 3) * 5;
- // bap=2 : 3 mantissas in 7 bits
- // bap=4 : 2 mantissas in 7 bits
- bits += ((mant_cnt[2] / 3) + (mant_cnt[4] >> 1)) * 7;
- // bap=3 : each mantissa is 3 bits
- bits += mant_cnt[3] * 3;
- return bits;
-}
-
-
-/**
- * Calculate masking curve based on the final exponents.
- * Also calculate the power spectral densities to use in future calculations.
- */
-static void bit_alloc_masking(AC3EncodeContext *s)
-{
- int blk, ch;
-
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- for (ch = 0; ch < s->channels; ch++) {
- /* We only need psd and mask for calculating bap.
- Since we currently do not calculate bap when exponent
- strategy is EXP_REUSE we do not need to calculate psd or mask. */
- if (block->exp_strategy[ch] != EXP_REUSE) {
- ff_ac3_bit_alloc_calc_psd(block->exp[ch], 0,
- s->nb_coefs[ch],
- block->psd[ch], block->band_psd[ch]);
- ff_ac3_bit_alloc_calc_mask(&s->bit_alloc, block->band_psd[ch],
- 0, s->nb_coefs[ch],
- ff_ac3_fast_gain_tab[s->fast_gain_code[ch]],
- ch == s->lfe_channel,
- DBA_NONE, 0, NULL, NULL, NULL,
- block->mask[ch]);
- }
- }
- }
-}
-
-
-/**
- * Ensure that bap for each block and channel point to the current bap_buffer.
- * They may have been switched during the bit allocation search.
- */
-static void reset_block_bap(AC3EncodeContext *s)
-{
- int blk, ch;
- if (s->blocks[0].bap[0] == s->bap_buffer)
- return;
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- for (ch = 0; ch < s->channels; ch++) {
- s->blocks[blk].bap[ch] = &s->bap_buffer[AC3_MAX_COEFS * (blk * s->channels + ch)];
- }
- }
-}
-
-
-/**
- * Run the bit allocation with a given SNR offset.
- * This calculates the bit allocation pointers that will be used to determine
- * the quantization of each mantissa.
- * @return the number of bits needed for mantissas if the given SNR offset is
- * is used.
- */
-static int bit_alloc(AC3EncodeContext *s, int snr_offset)
-{
- int blk, ch;
- int mantissa_bits;
- int mant_cnt[5];
-
- snr_offset = (snr_offset - 240) << 2;
-
- reset_block_bap(s);
- mantissa_bits = 0;
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- // initialize grouped mantissa counts. these are set so that they are
- // padded to the next whole group size when bits are counted in
- // compute_mantissa_size_final
- mant_cnt[0] = mant_cnt[3] = 0;
- mant_cnt[1] = mant_cnt[2] = 2;
- mant_cnt[4] = 1;
- for (ch = 0; ch < s->channels; ch++) {
- /* Currently the only bit allocation parameters which vary across
- blocks within a frame are the exponent values. We can take
- advantage of that by reusing the bit allocation pointers
- whenever we reuse exponents. */
- if (block->exp_strategy[ch] == EXP_REUSE) {
- memcpy(block->bap[ch], s->blocks[blk-1].bap[ch], AC3_MAX_COEFS);
- } else {
- ff_ac3_bit_alloc_calc_bap(block->mask[ch], block->psd[ch], 0,
- s->nb_coefs[ch], snr_offset,
- s->bit_alloc.floor, ff_ac3_bap_tab,
- block->bap[ch]);
- }
- mantissa_bits += compute_mantissa_size(mant_cnt, block->bap[ch], s->nb_coefs[ch]);
- }
- mantissa_bits += compute_mantissa_size_final(mant_cnt);
- }
- return mantissa_bits;
-}
-
-
-/**
- * Constant bitrate bit allocation search.
- * Find the largest SNR offset that will allow data to fit in the frame.
- */
-static int cbr_bit_allocation(AC3EncodeContext *s)
-{
- int ch;
- int bits_left;
- int snr_offset, snr_incr;
-
- bits_left = 8 * s->frame_size - (s->frame_bits + s->exponent_bits);
-
- snr_offset = s->coarse_snr_offset << 4;
-
- /* if previous frame SNR offset was 1023, check if current frame can also
- use SNR offset of 1023. if so, skip the search. */
- if ((snr_offset | s->fine_snr_offset[0]) == 1023) {
- if (bit_alloc(s, 1023) <= bits_left)
- return 0;
- }
-
- while (snr_offset >= 0 &&
- bit_alloc(s, snr_offset) > bits_left) {
- snr_offset -= 64;
- }
- if (snr_offset < 0)
- return AVERROR(EINVAL);
-
- FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
- for (snr_incr = 64; snr_incr > 0; snr_incr >>= 2) {
- while (snr_offset + snr_incr <= 1023 &&
- bit_alloc(s, snr_offset + snr_incr) <= bits_left) {
- snr_offset += snr_incr;
- FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
- }
- }
- FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
- reset_block_bap(s);
-
- s->coarse_snr_offset = snr_offset >> 4;
- for (ch = 0; ch < s->channels; ch++)
- s->fine_snr_offset[ch] = snr_offset & 0xF;
-
- return 0;
-}
-
-
-/**
- * Downgrade exponent strategies to reduce the bits used by the exponents.
- * This is a fallback for when bit allocation fails with the normal exponent
- * strategies. Each time this function is run it only downgrades the
- * strategy in 1 channel of 1 block.
- * @return non-zero if downgrade was unsuccessful
- */
-static int downgrade_exponents(AC3EncodeContext *s)
-{
- int ch, blk;
-
- for (ch = 0; ch < s->fbw_channels; ch++) {
- for (blk = AC3_MAX_BLOCKS-1; blk >= 0; blk--) {
- if (s->blocks[blk].exp_strategy[ch] == EXP_D15) {
- s->blocks[blk].exp_strategy[ch] = EXP_D25;
- return 0;
- }
- }
- }
- for (ch = 0; ch < s->fbw_channels; ch++) {
- for (blk = AC3_MAX_BLOCKS-1; blk >= 0; blk--) {
- if (s->blocks[blk].exp_strategy[ch] == EXP_D25) {
- s->blocks[blk].exp_strategy[ch] = EXP_D45;
- return 0;
- }
- }
- }
- for (ch = 0; ch < s->fbw_channels; ch++) {
- /* block 0 cannot reuse exponents, so only downgrade D45 to REUSE if
- the block number > 0 */
- for (blk = AC3_MAX_BLOCKS-1; blk > 0; blk--) {
- if (s->blocks[blk].exp_strategy[ch] > EXP_REUSE) {
- s->blocks[blk].exp_strategy[ch] = EXP_REUSE;
- return 0;
- }
- }
- }
- return -1;
-}
-
-
-/**
- * Reduce the bandwidth to reduce the number of bits used for a given SNR offset.
- * This is a second fallback for when bit allocation still fails after exponents
- * have been downgraded.
- * @return non-zero if bandwidth reduction was unsuccessful
- */
-static int reduce_bandwidth(AC3EncodeContext *s, int min_bw_code)
-{
- int ch;
-
- if (s->bandwidth_code[0] > min_bw_code) {
- for (ch = 0; ch < s->fbw_channels; ch++) {
- s->bandwidth_code[ch]--;
- s->nb_coefs[ch] = s->bandwidth_code[ch] * 3 + 73;
- }
- return 0;
- }
- return -1;
-}
-
-
-/**
- * Perform bit allocation search.
- * Finds the SNR offset value that maximizes quality and fits in the specified
- * frame size. Output is the SNR offset and a set of bit allocation pointers
- * used to quantize the mantissas.
- */
-static int compute_bit_allocation(AC3EncodeContext *s)
-{
- int ret;
-
- count_frame_bits(s);
-
- bit_alloc_masking(s);
-
- ret = cbr_bit_allocation(s);
- while (ret) {
- /* fallback 1: downgrade exponents */
- if (!downgrade_exponents(s)) {
- extract_exponents(s);
- encode_exponents(s);
- group_exponents(s);
- ret = compute_bit_allocation(s);
- continue;
- }
-
- /* fallback 2: reduce bandwidth */
- /* only do this if the user has not specified a specific cutoff
- frequency */
- if (!s->cutoff && !reduce_bandwidth(s, 0)) {
- process_exponents(s);
- ret = compute_bit_allocation(s);
- continue;
- }
-
- /* fallbacks were not enough... */
- break;
- }
-
- return ret;
-}
-
-
-/**
- * Symmetric quantization on 'levels' levels.
- */
-static inline int sym_quant(int c, int e, int levels)
-{
- int v;
-
- if (c >= 0) {
- v = (levels * (c << e)) >> 24;
- v = (v + 1) >> 1;
- v = (levels >> 1) + v;
- } else {
- v = (levels * ((-c) << e)) >> 24;
- v = (v + 1) >> 1;
- v = (levels >> 1) - v;
- }
- assert(v >= 0 && v < levels);
- return v;
-}
-
-
-/**
- * Asymmetric quantization on 2^qbits levels.
- */
-static inline int asym_quant(int c, int e, int qbits)
-{
- int lshift, m, v;
-
- lshift = e + qbits - 24;
- if (lshift >= 0)
- v = c << lshift;
- else
- v = c >> (-lshift);
- /* rounding */
- v = (v + 1) >> 1;
- m = (1 << (qbits-1));
- if (v >= m)
- v = m - 1;
- assert(v >= -m);
- return v & ((1 << qbits)-1);
-}
-
-
-/**
- * Quantize a set of mantissas for a single channel in a single block.
- */
-static void quantize_mantissas_blk_ch(AC3EncodeContext *s, CoefType *mdct_coef,
- int8_t exp_shift, uint8_t *exp,
- uint8_t *bap, uint16_t *qmant, int n)
-{
- int i;
-
- for (i = 0; i < n; i++) {
- int v;
- int c = SCALE_COEF(mdct_coef[i]);
- int e = exp[i] - exp_shift;
- int b = bap[i];
- switch (b) {
- case 0:
- v = 0;
- break;
- case 1:
- v = sym_quant(c, e, 3);
- switch (s->mant1_cnt) {
- case 0:
- s->qmant1_ptr = &qmant[i];
- v = 9 * v;
- s->mant1_cnt = 1;
- break;
- case 1:
- *s->qmant1_ptr += 3 * v;
- s->mant1_cnt = 2;
- v = 128;
- break;
- default:
- *s->qmant1_ptr += v;
- s->mant1_cnt = 0;
- v = 128;
- break;
- }
- break;
- case 2:
- v = sym_quant(c, e, 5);
- switch (s->mant2_cnt) {
- case 0:
- s->qmant2_ptr = &qmant[i];
- v = 25 * v;
- s->mant2_cnt = 1;
- break;
- case 1:
- *s->qmant2_ptr += 5 * v;
- s->mant2_cnt = 2;
- v = 128;
- break;
- default:
- *s->qmant2_ptr += v;
- s->mant2_cnt = 0;
- v = 128;
- break;
- }
- break;
- case 3:
- v = sym_quant(c, e, 7);
- break;
- case 4:
- v = sym_quant(c, e, 11);
- switch (s->mant4_cnt) {
- case 0:
- s->qmant4_ptr = &qmant[i];
- v = 11 * v;
- s->mant4_cnt = 1;
- break;
- default:
- *s->qmant4_ptr += v;
- s->mant4_cnt = 0;
- v = 128;
- break;
- }
- break;
- case 5:
- v = sym_quant(c, e, 15);
- break;
- case 14:
- v = asym_quant(c, e, 14);
- break;
- case 15:
- v = asym_quant(c, e, 16);
- break;
- default:
- v = asym_quant(c, e, b - 1);
- break;
- }
- qmant[i] = v;
- }
-}
-
-
-/**
- * Quantize mantissas using coefficients, exponents, and bit allocation pointers.
- */
-static void quantize_mantissas(AC3EncodeContext *s)
-{
- int blk, ch;
-
-
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- s->mant1_cnt = s->mant2_cnt = s->mant4_cnt = 0;
- s->qmant1_ptr = s->qmant2_ptr = s->qmant4_ptr = NULL;
-
- for (ch = 0; ch < s->channels; ch++) {
- quantize_mantissas_blk_ch(s, block->mdct_coef[ch], block->exp_shift[ch],
- block->exp[ch], block->bap[ch],
- block->qmant[ch], s->nb_coefs[ch]);
- }
- }
-}
-
-
-/**
- * Write the AC-3 frame header to the output bitstream.
- */
-static void output_frame_header(AC3EncodeContext *s)
-{
- put_bits(&s->pb, 16, 0x0b77); /* frame header */
- put_bits(&s->pb, 16, 0); /* crc1: will be filled later */
- put_bits(&s->pb, 2, s->bit_alloc.sr_code);
- put_bits(&s->pb, 6, s->frame_size_code + (s->frame_size - s->frame_size_min) / 2);
- put_bits(&s->pb, 5, s->bitstream_id);
- put_bits(&s->pb, 3, s->bitstream_mode);
- put_bits(&s->pb, 3, s->channel_mode);
- if ((s->channel_mode & 0x01) && s->channel_mode != AC3_CHMODE_MONO)
- put_bits(&s->pb, 2, 1); /* XXX -4.5 dB */
- if (s->channel_mode & 0x04)
- put_bits(&s->pb, 2, 1); /* XXX -6 dB */
- if (s->channel_mode == AC3_CHMODE_STEREO)
- put_bits(&s->pb, 2, 0); /* surround not indicated */
- put_bits(&s->pb, 1, s->lfe_on); /* LFE */
- put_bits(&s->pb, 5, 31); /* dialog norm: -31 db */
- put_bits(&s->pb, 1, 0); /* no compression control word */
- put_bits(&s->pb, 1, 0); /* no lang code */
- put_bits(&s->pb, 1, 0); /* no audio production info */
- put_bits(&s->pb, 1, 0); /* no copyright */
- put_bits(&s->pb, 1, 1); /* original bitstream */
- put_bits(&s->pb, 1, 0); /* no time code 1 */
- put_bits(&s->pb, 1, 0); /* no time code 2 */
- put_bits(&s->pb, 1, 0); /* no additional bit stream info */
-}
-
-
-/**
- * Write one audio block to the output bitstream.
- */
-static void output_audio_block(AC3EncodeContext *s, int block_num)
-{
- int ch, i, baie, rbnd;
- AC3Block *block = &s->blocks[block_num];
-
- /* block switching */
- for (ch = 0; ch < s->fbw_channels; ch++)
- put_bits(&s->pb, 1, 0);
-
- /* dither flags */
- for (ch = 0; ch < s->fbw_channels; ch++)
- put_bits(&s->pb, 1, 1);
-
- /* dynamic range codes */
- put_bits(&s->pb, 1, 0);
-
- /* channel coupling */
- if (!block_num) {
- put_bits(&s->pb, 1, 1); /* coupling strategy present */
- put_bits(&s->pb, 1, 0); /* no coupling strategy */
- } else {
- put_bits(&s->pb, 1, 0); /* no new coupling strategy */
- }
-
- /* stereo rematrixing */
- if (s->channel_mode == AC3_CHMODE_STEREO) {
- if (!block_num) {
- /* first block must define rematrixing (rematstr) */
- put_bits(&s->pb, 1, 1);
-
- /* dummy rematrixing rematflg(1:4)=0 */
- for (rbnd = 0; rbnd < 4; rbnd++)
- put_bits(&s->pb, 1, 0);
- } else {
- /* no matrixing (but should be used in the future) */
- put_bits(&s->pb, 1, 0);
- }
- }
-
- /* exponent strategy */
- for (ch = 0; ch < s->fbw_channels; ch++)
- put_bits(&s->pb, 2, block->exp_strategy[ch]);
- if (s->lfe_on)
- put_bits(&s->pb, 1, block->exp_strategy[s->lfe_channel]);
-
- /* bandwidth */
- for (ch = 0; ch < s->fbw_channels; ch++) {
- if (block->exp_strategy[ch] != EXP_REUSE)
- put_bits(&s->pb, 6, s->bandwidth_code[ch]);
- }
-
- /* exponents */
- for (ch = 0; ch < s->channels; ch++) {
- int nb_groups;
-
- if (block->exp_strategy[ch] == EXP_REUSE)
- continue;
-
- /* DC exponent */
- put_bits(&s->pb, 4, block->grouped_exp[ch][0]);
-
- /* exponent groups */
- nb_groups = exponent_group_tab[block->exp_strategy[ch]-1][s->nb_coefs[ch]];
- for (i = 1; i <= nb_groups; i++)
- put_bits(&s->pb, 7, block->grouped_exp[ch][i]);
-
- /* gain range info */
- if (ch != s->lfe_channel)
- put_bits(&s->pb, 2, 0);
- }
-
- /* bit allocation info */
- baie = (block_num == 0);
- put_bits(&s->pb, 1, baie);
- if (baie) {
- put_bits(&s->pb, 2, s->slow_decay_code);
- put_bits(&s->pb, 2, s->fast_decay_code);
- put_bits(&s->pb, 2, s->slow_gain_code);
- put_bits(&s->pb, 2, s->db_per_bit_code);
- put_bits(&s->pb, 3, s->floor_code);
- }
-
- /* snr offset */
- put_bits(&s->pb, 1, baie);
- if (baie) {
- put_bits(&s->pb, 6, s->coarse_snr_offset);
- for (ch = 0; ch < s->channels; ch++) {
- put_bits(&s->pb, 4, s->fine_snr_offset[ch]);
- put_bits(&s->pb, 3, s->fast_gain_code[ch]);
- }
- }
-
- put_bits(&s->pb, 1, 0); /* no delta bit allocation */
- put_bits(&s->pb, 1, 0); /* no data to skip */
-
- /* mantissas */
- for (ch = 0; ch < s->channels; ch++) {
- int b, q;
- for (i = 0; i < s->nb_coefs[ch]; i++) {
- q = block->qmant[ch][i];
- b = block->bap[ch][i];
- switch (b) {
- case 0: break;
- case 1: if (q != 128) put_bits(&s->pb, 5, q); break;
- case 2: if (q != 128) put_bits(&s->pb, 7, q); break;
- case 3: put_bits(&s->pb, 3, q); break;
- case 4: if (q != 128) put_bits(&s->pb, 7, q); break;
- case 14: put_bits(&s->pb, 14, q); break;
- case 15: put_bits(&s->pb, 16, q); break;
- default: put_bits(&s->pb, b-1, q); break;
- }
- }
- }
-}
-
-
-/** CRC-16 Polynomial */
-#define CRC16_POLY ((1 << 0) | (1 << 2) | (1 << 15) | (1 << 16))
-
-
-static unsigned int mul_poly(unsigned int a, unsigned int b, unsigned int poly)
-{
- unsigned int c;
-
- c = 0;
- while (a) {
- if (a & 1)
- c ^= b;
- a = a >> 1;
- b = b << 1;
- if (b & (1 << 16))
- b ^= poly;
- }
- return c;
-}
-
-
-static unsigned int pow_poly(unsigned int a, unsigned int n, unsigned int poly)
-{
- unsigned int r;
- r = 1;
- while (n) {
- if (n & 1)
- r = mul_poly(r, a, poly);
- a = mul_poly(a, a, poly);
- n >>= 1;
- }
- return r;
-}
-
-
-/**
- * Fill the end of the frame with 0's and compute the two CRCs.
- */
-static void output_frame_end(AC3EncodeContext *s)
-{
- const AVCRC *crc_ctx = av_crc_get_table(AV_CRC_16_ANSI);
- int frame_size_58, pad_bytes, crc1, crc2_partial, crc2, crc_inv;
- uint8_t *frame;
-
- frame_size_58 = ((s->frame_size >> 2) + (s->frame_size >> 4)) << 1;
-
- /* pad the remainder of the frame with zeros */
- flush_put_bits(&s->pb);
- frame = s->pb.buf;
- pad_bytes = s->frame_size - (put_bits_ptr(&s->pb) - frame) - 2;
- assert(pad_bytes >= 0);
- if (pad_bytes > 0)
- memset(put_bits_ptr(&s->pb), 0, pad_bytes);
-
- /* compute crc1 */
- /* this is not so easy because it is at the beginning of the data... */
- crc1 = av_bswap16(av_crc(crc_ctx, 0, frame + 4, frame_size_58 - 4));
- crc_inv = s->crc_inv[s->frame_size > s->frame_size_min];
- crc1 = mul_poly(crc_inv, crc1, CRC16_POLY);
- AV_WB16(frame + 2, crc1);
-
- /* compute crc2 */
- crc2_partial = av_crc(crc_ctx, 0, frame + frame_size_58,
- s->frame_size - frame_size_58 - 3);
- crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
- /* ensure crc2 does not match sync word by flipping crcrsv bit if needed */
- if (crc2 == 0x770B) {
- frame[s->frame_size - 3] ^= 0x1;
- crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
- }
- crc2 = av_bswap16(crc2);
- AV_WB16(frame + s->frame_size - 2, crc2);
-}
-
-
-/**
- * Write the frame to the output bitstream.
- */
-static void output_frame(AC3EncodeContext *s, unsigned char *frame)
-{
- int blk;
-
- init_put_bits(&s->pb, frame, AC3_MAX_CODED_FRAME_SIZE);
-
- output_frame_header(s);
-
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++)
- output_audio_block(s, blk);
-
- output_frame_end(s);
-}
-
-
-/**
- * Encode a single AC-3 frame.
- */
-static int ac3_encode_frame(AVCodecContext *avctx, unsigned char *frame,
- int buf_size, void *data)
-{
- AC3EncodeContext *s = avctx->priv_data;
- const SampleType *samples = data;
- int ret;
-
- if (s->bit_alloc.sr_code == 1)
- adjust_frame_size(s);
-
- deinterleave_input_samples(s, samples);
-
- apply_mdct(s);
-
- process_exponents(s);
-
- ret = compute_bit_allocation(s);
- if (ret) {
- av_log(avctx, AV_LOG_ERROR, "Bit allocation failed. Try increasing the bitrate.\n");
- return ret;
- }
-
- quantize_mantissas(s);
-
- output_frame(s, frame);
-
- return s->frame_size;
-}
-
-
-/**
- * Finalize encoding and free any memory allocated by the encoder.
- */
-static av_cold int ac3_encode_close(AVCodecContext *avctx)
-{
- int blk, ch;
- AC3EncodeContext *s = avctx->priv_data;
-
- for (ch = 0; ch < s->channels; ch++)
- av_freep(&s->planar_samples[ch]);
- av_freep(&s->planar_samples);
- av_freep(&s->bap_buffer);
- av_freep(&s->bap1_buffer);
- av_freep(&s->mdct_coef_buffer);
- av_freep(&s->exp_buffer);
- av_freep(&s->grouped_exp_buffer);
- av_freep(&s->psd_buffer);
- av_freep(&s->band_psd_buffer);
- av_freep(&s->mask_buffer);
- av_freep(&s->qmant_buffer);
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- av_freep(&block->bap);
- av_freep(&block->mdct_coef);
- av_freep(&block->exp);
- av_freep(&block->grouped_exp);
- av_freep(&block->psd);
- av_freep(&block->band_psd);
- av_freep(&block->mask);
- av_freep(&block->qmant);
- }
-
- mdct_end(&s->mdct);
-
- av_freep(&avctx->coded_frame);
- return 0;
-}
-
-
-/**
- * Set channel information during initialization.
- */
-static av_cold int set_channel_info(AC3EncodeContext *s, int channels,
- int64_t *channel_layout)
-{
- int ch_layout;
-
- if (channels < 1 || channels > AC3_MAX_CHANNELS)
- return AVERROR(EINVAL);
- if ((uint64_t)*channel_layout > 0x7FF)
- return AVERROR(EINVAL);
- ch_layout = *channel_layout;
- if (!ch_layout)
- ch_layout = avcodec_guess_channel_layout(channels, CODEC_ID_AC3, NULL);
- if (av_get_channel_layout_nb_channels(ch_layout) != channels)
- return AVERROR(EINVAL);
-
- s->lfe_on = !!(ch_layout & AV_CH_LOW_FREQUENCY);
- s->channels = channels;
- s->fbw_channels = channels - s->lfe_on;
- s->lfe_channel = s->lfe_on ? s->fbw_channels : -1;
- if (s->lfe_on)
- ch_layout -= AV_CH_LOW_FREQUENCY;
-
- switch (ch_layout) {
- case AV_CH_LAYOUT_MONO: s->channel_mode = AC3_CHMODE_MONO; break;
- case AV_CH_LAYOUT_STEREO: s->channel_mode = AC3_CHMODE_STEREO; break;
- case AV_CH_LAYOUT_SURROUND: s->channel_mode = AC3_CHMODE_3F; break;
- case AV_CH_LAYOUT_2_1: s->channel_mode = AC3_CHMODE_2F1R; break;
- case AV_CH_LAYOUT_4POINT0: s->channel_mode = AC3_CHMODE_3F1R; break;
- case AV_CH_LAYOUT_QUAD:
- case AV_CH_LAYOUT_2_2: s->channel_mode = AC3_CHMODE_2F2R; break;
- case AV_CH_LAYOUT_5POINT0:
- case AV_CH_LAYOUT_5POINT0_BACK: s->channel_mode = AC3_CHMODE_3F2R; break;
- default:
- return AVERROR(EINVAL);
- }
-
- s->channel_map = ff_ac3_enc_channel_map[s->channel_mode][s->lfe_on];
- *channel_layout = ch_layout;
- if (s->lfe_on)
- *channel_layout |= AV_CH_LOW_FREQUENCY;
-
- return 0;
-}
-
-
-static av_cold int validate_options(AVCodecContext *avctx, AC3EncodeContext *s)
-{
- int i, ret;
-
- /* validate channel layout */
- if (!avctx->channel_layout) {
- av_log(avctx, AV_LOG_WARNING, "No channel layout specified. The "
- "encoder will guess the layout, but it "
- "might be incorrect.\n");
- }
- ret = set_channel_info(s, avctx->channels, &avctx->channel_layout);
- if (ret) {
- av_log(avctx, AV_LOG_ERROR, "invalid channel layout\n");
- return ret;
- }
-
- /* validate sample rate */
- for (i = 0; i < 9; i++) {
- if ((ff_ac3_sample_rate_tab[i / 3] >> (i % 3)) == avctx->sample_rate)
- break;
- }
- if (i == 9) {
- av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");
- return AVERROR(EINVAL);
- }
- s->sample_rate = avctx->sample_rate;
- s->bit_alloc.sr_shift = i % 3;
- s->bit_alloc.sr_code = i / 3;
-
- /* validate bit rate */
- for (i = 0; i < 19; i++) {
- if ((ff_ac3_bitrate_tab[i] >> s->bit_alloc.sr_shift)*1000 == avctx->bit_rate)
- break;
- }
- if (i == 19) {
- av_log(avctx, AV_LOG_ERROR, "invalid bit rate\n");
- return AVERROR(EINVAL);
- }
- s->bit_rate = avctx->bit_rate;
- s->frame_size_code = i << 1;
-
- /* validate cutoff */
- if (avctx->cutoff < 0) {
- av_log(avctx, AV_LOG_ERROR, "invalid cutoff frequency\n");
- return AVERROR(EINVAL);
- }
- s->cutoff = avctx->cutoff;
- if (s->cutoff > (s->sample_rate >> 1))
- s->cutoff = s->sample_rate >> 1;
-
- return 0;
-}
-
-
-/**
- * Set bandwidth for all channels.
- * The user can optionally supply a cutoff frequency. Otherwise an appropriate
- * default value will be used.
- */
-static av_cold void set_bandwidth(AC3EncodeContext *s)
-{
- int ch, bw_code;
-
- if (s->cutoff) {
- /* calculate bandwidth based on user-specified cutoff frequency */
- int fbw_coeffs;
- fbw_coeffs = s->cutoff * 2 * AC3_MAX_COEFS / s->sample_rate;
- bw_code = av_clip((fbw_coeffs - 73) / 3, 0, 60);
- } else {
- /* use default bandwidth setting */
- /* XXX: should compute the bandwidth according to the frame
- size, so that we avoid annoying high frequency artifacts */
- bw_code = 50;
- }
-
- /* set number of coefficients for each channel */
- for (ch = 0; ch < s->fbw_channels; ch++) {
- s->bandwidth_code[ch] = bw_code;
- s->nb_coefs[ch] = bw_code * 3 + 73;
- }
- if (s->lfe_on)
- s->nb_coefs[s->lfe_channel] = 7; /* LFE channel always has 7 coefs */
-}
-
-
-static av_cold int allocate_buffers(AVCodecContext *avctx)
-{
- int blk, ch;
- AC3EncodeContext *s = avctx->priv_data;
-
- FF_ALLOC_OR_GOTO(avctx, s->planar_samples, s->channels * sizeof(*s->planar_samples),
- alloc_fail);
- for (ch = 0; ch < s->channels; ch++) {
- FF_ALLOCZ_OR_GOTO(avctx, s->planar_samples[ch],
- (AC3_FRAME_SIZE+AC3_BLOCK_SIZE) * sizeof(**s->planar_samples),
- alloc_fail);
- }
- FF_ALLOC_OR_GOTO(avctx, s->bap_buffer, AC3_MAX_BLOCKS * s->channels *
- AC3_MAX_COEFS * sizeof(*s->bap_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->bap1_buffer, AC3_MAX_BLOCKS * s->channels *
- AC3_MAX_COEFS * sizeof(*s->bap1_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->mdct_coef_buffer, AC3_MAX_BLOCKS * s->channels *
- AC3_MAX_COEFS * sizeof(*s->mdct_coef_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->exp_buffer, AC3_MAX_BLOCKS * s->channels *
- AC3_MAX_COEFS * sizeof(*s->exp_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->grouped_exp_buffer, AC3_MAX_BLOCKS * s->channels *
- 128 * sizeof(*s->grouped_exp_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->psd_buffer, AC3_MAX_BLOCKS * s->channels *
- AC3_MAX_COEFS * sizeof(*s->psd_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->band_psd_buffer, AC3_MAX_BLOCKS * s->channels *
- 64 * sizeof(*s->band_psd_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->mask_buffer, AC3_MAX_BLOCKS * s->channels *
- 64 * sizeof(*s->mask_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->qmant_buffer, AC3_MAX_BLOCKS * s->channels *
- AC3_MAX_COEFS * sizeof(*s->qmant_buffer), alloc_fail);
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- FF_ALLOC_OR_GOTO(avctx, block->bap, s->channels * sizeof(*block->bap),
- alloc_fail);
- FF_ALLOCZ_OR_GOTO(avctx, block->mdct_coef, s->channels * sizeof(*block->mdct_coef),
- alloc_fail);
- FF_ALLOCZ_OR_GOTO(avctx, block->exp, s->channels * sizeof(*block->exp),
- alloc_fail);
- FF_ALLOCZ_OR_GOTO(avctx, block->grouped_exp, s->channels * sizeof(*block->grouped_exp),
- alloc_fail);
- FF_ALLOCZ_OR_GOTO(avctx, block->psd, s->channels * sizeof(*block->psd),
- alloc_fail);
- FF_ALLOCZ_OR_GOTO(avctx, block->band_psd, s->channels * sizeof(*block->band_psd),
- alloc_fail);
- FF_ALLOCZ_OR_GOTO(avctx, block->mask, s->channels * sizeof(*block->mask),
- alloc_fail);
- FF_ALLOCZ_OR_GOTO(avctx, block->qmant, s->channels * sizeof(*block->qmant),
- alloc_fail);
-
- for (ch = 0; ch < s->channels; ch++) {
- block->bap[ch] = &s->bap_buffer [AC3_MAX_COEFS * (blk * s->channels + ch)];
- block->mdct_coef[ch] = &s->mdct_coef_buffer [AC3_MAX_COEFS * (blk * s->channels + ch)];
- block->exp[ch] = &s->exp_buffer [AC3_MAX_COEFS * (blk * s->channels + ch)];
- block->grouped_exp[ch] = &s->grouped_exp_buffer[128 * (blk * s->channels + ch)];
- block->psd[ch] = &s->psd_buffer [AC3_MAX_COEFS * (blk * s->channels + ch)];
- block->band_psd[ch] = &s->band_psd_buffer [64 * (blk * s->channels + ch)];
- block->mask[ch] = &s->mask_buffer [64 * (blk * s->channels + ch)];
- block->qmant[ch] = &s->qmant_buffer [AC3_MAX_COEFS * (blk * s->channels + ch)];
- }
- }
-
- return 0;
-alloc_fail:
- return AVERROR(ENOMEM);
-}
-
-
-/**
- * Initialize the encoder.
- */
-static av_cold int ac3_encode_init(AVCodecContext *avctx)
-{
- AC3EncodeContext *s = avctx->priv_data;
- int ret, frame_size_58;
-
- avctx->frame_size = AC3_FRAME_SIZE;
-
- ac3_common_init();
-
- ret = validate_options(avctx, s);
- if (ret)
- return ret;
-
- s->bitstream_id = 8 + s->bit_alloc.sr_shift;
- s->bitstream_mode = 0; /* complete main audio service */
-
- s->frame_size_min = 2 * ff_ac3_frame_size_tab[s->frame_size_code][s->bit_alloc.sr_code];
- s->bits_written = 0;
- s->samples_written = 0;
- s->frame_size = s->frame_size_min;
-
- /* calculate crc_inv for both possible frame sizes */
- frame_size_58 = (( s->frame_size >> 2) + ( s->frame_size >> 4)) << 1;
- s->crc_inv[0] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
- if (s->bit_alloc.sr_code == 1) {
- frame_size_58 = (((s->frame_size+2) >> 2) + ((s->frame_size+2) >> 4)) << 1;
- s->crc_inv[1] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
- }
-
- set_bandwidth(s);
-
- exponent_init(s);
-
- bit_alloc_init(s);
-
- ret = mdct_init(avctx, &s->mdct, 9);
- if (ret)
- goto init_fail;
-
- ret = allocate_buffers(avctx);
- if (ret)
- goto init_fail;
-
- avctx->coded_frame= avcodec_alloc_frame();
-
- dsputil_init(&s->dsp, avctx);
-
- return 0;
-init_fail:
- ac3_encode_close(avctx);
- return ret;
-}
-
-
#ifdef TEST
/*************************************************************************/
/* TEST */
Copied and modified: trunk/libavcodec/ac3enc_fixed.h (from r26205, trunk/libavcodec/ac3enc.c)
==============================================================================
--- trunk/libavcodec/ac3enc.c Mon Jan 3 13:43:48 2011 (r26205, copy source)
+++ trunk/libavcodec/ac3enc_fixed.h Mon Jan 3 17:08:56 2011 (r26206)
@@ -23,34 +23,20 @@
/**
* @file
- * The simplest AC-3 encoder.
+ * fixed-point AC-3 encoder header.
*/
-//#define DEBUG
-
-#include "libavcore/audioconvert.h"
-#include "libavutil/crc.h"
-#include "avcodec.h"
-#include "put_bits.h"
-#include "dsputil.h"
-#include "ac3.h"
-#include "audioconvert.h"
-
+#ifndef AVCODEC_AC3ENC_FIXED_H
+#define AVCODEC_AC3ENC_FIXED_H
-/** Maximum number of exponent groups. +1 for separate DC exponent. */
-#define AC3_MAX_EXP_GROUPS 85
+#include <stdint.h>
-/** Scale a float value by 2^bits and convert to an integer. */
-#define SCALE_FLOAT(a, bits) lrintf((a) * (float)(1 << (bits)))
typedef int16_t SampleType;
typedef int32_t CoefType;
#define SCALE_COEF(a) (a)
-/** Scale a float value by 2^15, convert to an integer, and clip to range -32767..32767. */
-#define FIX15(a) av_clip(SCALE_FLOAT(a, 15), -32767, 32767)
-
/**
* Compex number.
@@ -71,2024 +57,4 @@ typedef struct AC3MDCTContext {
IComplex *cplx_tmp; ///< temp buffer for complex pre-rotated samples
} AC3MDCTContext;
-/**
- * Data for a single audio block.
- */
-typedef struct AC3Block {
- uint8_t **bap; ///< bit allocation pointers (bap)
- CoefType **mdct_coef; ///< MDCT coefficients
- uint8_t **exp; ///< original exponents
- uint8_t **grouped_exp; ///< grouped exponents
- int16_t **psd; ///< psd per frequency bin
- int16_t **band_psd; ///< psd per critical band
- int16_t **mask; ///< masking curve
- uint16_t **qmant; ///< quantized mantissas
- uint8_t exp_strategy[AC3_MAX_CHANNELS]; ///< exponent strategies
- int8_t exp_shift[AC3_MAX_CHANNELS]; ///< exponent shift values
-} AC3Block;
-
-/**
- * AC-3 encoder private context.
- */
-typedef struct AC3EncodeContext {
- PutBitContext pb; ///< bitstream writer context
- DSPContext dsp;
- AC3MDCTContext mdct; ///< MDCT context
-
- AC3Block blocks[AC3_MAX_BLOCKS]; ///< per-block info
-
- int bitstream_id; ///< bitstream id (bsid)
- int bitstream_mode; ///< bitstream mode (bsmod)
-
- int bit_rate; ///< target bit rate, in bits-per-second
- int sample_rate; ///< sampling frequency, in Hz
-
- int frame_size_min; ///< minimum frame size in case rounding is necessary
- int frame_size; ///< current frame size in bytes
- int frame_size_code; ///< frame size code (frmsizecod)
- uint16_t crc_inv[2];
- int bits_written; ///< bit count (used to avg. bitrate)
- int samples_written; ///< sample count (used to avg. bitrate)
-
- int fbw_channels; ///< number of full-bandwidth channels (nfchans)
- int channels; ///< total number of channels (nchans)
- int lfe_on; ///< indicates if there is an LFE channel (lfeon)
- int lfe_channel; ///< channel index of the LFE channel
- int channel_mode; ///< channel mode (acmod)
- const uint8_t *channel_map; ///< channel map used to reorder channels
-
- int cutoff; ///< user-specified cutoff frequency, in Hz
- int bandwidth_code[AC3_MAX_CHANNELS]; ///< bandwidth code (0 to 60) (chbwcod)
- int nb_coefs[AC3_MAX_CHANNELS];
-
- /* bitrate allocation control */
- int slow_gain_code; ///< slow gain code (sgaincod)
- int slow_decay_code; ///< slow decay code (sdcycod)
- int fast_decay_code; ///< fast decay code (fdcycod)
- int db_per_bit_code; ///< dB/bit code (dbpbcod)
- int floor_code; ///< floor code (floorcod)
- AC3BitAllocParameters bit_alloc; ///< bit allocation parameters
- int coarse_snr_offset; ///< coarse SNR offsets (csnroffst)
- int fast_gain_code[AC3_MAX_CHANNELS]; ///< fast gain codes (signal-to-mask ratio) (fgaincod)
- int fine_snr_offset[AC3_MAX_CHANNELS]; ///< fine SNR offsets (fsnroffst)
- int frame_bits_fixed; ///< number of non-coefficient bits for fixed parameters
- int frame_bits; ///< all frame bits except exponents and mantissas
- int exponent_bits; ///< number of bits used for exponents
-
- /* mantissa encoding */
- int mant1_cnt, mant2_cnt, mant4_cnt; ///< mantissa counts for bap=1,2,4
- uint16_t *qmant1_ptr, *qmant2_ptr, *qmant4_ptr; ///< mantissa pointers for bap=1,2,4
-
- SampleType **planar_samples;
- uint8_t *bap_buffer;
- uint8_t *bap1_buffer;
- CoefType *mdct_coef_buffer;
- uint8_t *exp_buffer;
- uint8_t *grouped_exp_buffer;
- int16_t *psd_buffer;
- int16_t *band_psd_buffer;
- int16_t *mask_buffer;
- uint16_t *qmant_buffer;
-
- DECLARE_ALIGNED(16, SampleType, windowed_samples)[AC3_WINDOW_SIZE];
-} AC3EncodeContext;
-
-
-/**
- * LUT for number of exponent groups.
- * exponent_group_tab[exponent strategy-1][number of coefficients]
- */
-static uint8_t exponent_group_tab[3][256];
-
-
-/**
- * List of supported channel layouts.
- */
-static const int64_t ac3_channel_layouts[] = {
- AV_CH_LAYOUT_MONO,
- AV_CH_LAYOUT_STEREO,
- AV_CH_LAYOUT_2_1,
- AV_CH_LAYOUT_SURROUND,
- AV_CH_LAYOUT_2_2,
- AV_CH_LAYOUT_QUAD,
- AV_CH_LAYOUT_4POINT0,
- AV_CH_LAYOUT_5POINT0,
- AV_CH_LAYOUT_5POINT0_BACK,
- (AV_CH_LAYOUT_MONO | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_STEREO | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_2_1 | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_SURROUND | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_2_2 | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_QUAD | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_4POINT0 | AV_CH_LOW_FREQUENCY),
- AV_CH_LAYOUT_5POINT1,
- AV_CH_LAYOUT_5POINT1_BACK,
- 0
-};
-
-
-/**
- * Adjust the frame size to make the average bit rate match the target bit rate.
- * This is only needed for 11025, 22050, and 44100 sample rates.
- */
-static void adjust_frame_size(AC3EncodeContext *s)
-{
- while (s->bits_written >= s->bit_rate && s->samples_written >= s->sample_rate) {
- s->bits_written -= s->bit_rate;
- s->samples_written -= s->sample_rate;
- }
- s->frame_size = s->frame_size_min +
- 2 * (s->bits_written * s->sample_rate < s->samples_written * s->bit_rate);
- s->bits_written += s->frame_size * 8;
- s->samples_written += AC3_FRAME_SIZE;
-}
-
-
-/**
- * Deinterleave input samples.
- * Channels are reordered from FFmpeg's default order to AC-3 order.
- */
-static void deinterleave_input_samples(AC3EncodeContext *s,
- const SampleType *samples)
-{
- int ch, i;
-
- /* deinterleave and remap input samples */
- for (ch = 0; ch < s->channels; ch++) {
- const SampleType *sptr;
- int sinc;
-
- /* copy last 256 samples of previous frame to the start of the current frame */
- memcpy(&s->planar_samples[ch][0], &s->planar_samples[ch][AC3_FRAME_SIZE],
- AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0]));
-
- /* deinterleave */
- sinc = s->channels;
- sptr = samples + s->channel_map[ch];
- for (i = AC3_BLOCK_SIZE; i < AC3_FRAME_SIZE+AC3_BLOCK_SIZE; i++) {
- s->planar_samples[ch][i] = *sptr;
- sptr += sinc;
- }
- }
-}
-
-
-/**
- * Finalize MDCT and free allocated memory.
- */
-static av_cold void mdct_end(AC3MDCTContext *mdct)
-{
- mdct->nbits = 0;
- av_freep(&mdct->costab);
- av_freep(&mdct->sintab);
- av_freep(&mdct->xcos1);
- av_freep(&mdct->xsin1);
- av_freep(&mdct->rot_tmp);
- av_freep(&mdct->cplx_tmp);
-}
-
-
-/**
- * Initialize FFT tables.
- * @param ln log2(FFT size)
- */
-static av_cold int fft_init(AVCodecContext *avctx, AC3MDCTContext *mdct, int ln)
-{
- int i, n, n2;
- float alpha;
-
- n = 1 << ln;
- n2 = n >> 1;
-
- FF_ALLOC_OR_GOTO(avctx, mdct->costab, n2 * sizeof(*mdct->costab), fft_alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, mdct->sintab, n2 * sizeof(*mdct->sintab), fft_alloc_fail);
-
- for (i = 0; i < n2; i++) {
- alpha = 2.0 * M_PI * i / n;
- mdct->costab[i] = FIX15(cos(alpha));
- mdct->sintab[i] = FIX15(sin(alpha));
- }
-
- return 0;
-fft_alloc_fail:
- mdct_end(mdct);
- return AVERROR(ENOMEM);
-}
-
-
-/**
- * Initialize MDCT tables.
- * @param nbits log2(MDCT size)
- */
-static av_cold int mdct_init(AVCodecContext *avctx, AC3MDCTContext *mdct,
- int nbits)
-{
- int i, n, n4, ret;
-
- n = 1 << nbits;
- n4 = n >> 2;
-
- mdct->nbits = nbits;
-
- ret = fft_init(avctx, mdct, nbits - 2);
- if (ret)
- return ret;
-
- mdct->window = ff_ac3_window;
-
- FF_ALLOC_OR_GOTO(avctx, mdct->xcos1, n4 * sizeof(*mdct->xcos1), mdct_alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, mdct->xsin1, n4 * sizeof(*mdct->xsin1), mdct_alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, mdct->rot_tmp, n * sizeof(*mdct->rot_tmp), mdct_alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, mdct->cplx_tmp, n4 * sizeof(*mdct->cplx_tmp), mdct_alloc_fail);
-
- for (i = 0; i < n4; i++) {
- float alpha = 2.0 * M_PI * (i + 1.0 / 8.0) / n;
- mdct->xcos1[i] = FIX15(-cos(alpha));
- mdct->xsin1[i] = FIX15(-sin(alpha));
- }
-
- return 0;
-mdct_alloc_fail:
- mdct_end(mdct);
- return AVERROR(ENOMEM);
-}
-
-
-/** Butterfly op */
-#define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
-{ \
- int ax, ay, bx, by; \
- bx = pre1; \
- by = pim1; \
- ax = qre1; \
- ay = qim1; \
- pre = (bx + ax) >> 1; \
- pim = (by + ay) >> 1; \
- qre = (bx - ax) >> 1; \
- qim = (by - ay) >> 1; \
-}
-
-
-/** Complex multiply */
-#define CMUL(pre, pim, are, aim, bre, bim) \
-{ \
- pre = (MUL16(are, bre) - MUL16(aim, bim)) >> 15; \
- pim = (MUL16(are, bim) + MUL16(bre, aim)) >> 15; \
-}
-
-
-/**
- * Calculate a 2^n point complex FFT on 2^ln points.
- * @param z complex input/output samples
- * @param ln log2(FFT size)
- */
-static void fft(AC3MDCTContext *mdct, IComplex *z, int ln)
-{
- int j, l, np, np2;
- int nblocks, nloops;
- register IComplex *p,*q;
- int tmp_re, tmp_im;
-
- np = 1 << ln;
-
- /* reverse */
- for (j = 0; j < np; j++) {
- int k = av_reverse[j] >> (8 - ln);
- if (k < j)
- FFSWAP(IComplex, z[k], z[j]);
- }
-
- /* pass 0 */
-
- p = &z[0];
- j = np >> 1;
- do {
- BF(p[0].re, p[0].im, p[1].re, p[1].im,
- p[0].re, p[0].im, p[1].re, p[1].im);
- p += 2;
- } while (--j);
-
- /* pass 1 */
-
- p = &z[0];
- j = np >> 2;
- do {
- BF(p[0].re, p[0].im, p[2].re, p[2].im,
- p[0].re, p[0].im, p[2].re, p[2].im);
- BF(p[1].re, p[1].im, p[3].re, p[3].im,
- p[1].re, p[1].im, p[3].im, -p[3].re);
- p+=4;
- } while (--j);
-
- /* pass 2 .. ln-1 */
-
- nblocks = np >> 3;
- nloops = 1 << 2;
- np2 = np >> 1;
- do {
- p = z;
- q = z + nloops;
- for (j = 0; j < nblocks; j++) {
- BF(p->re, p->im, q->re, q->im,
- p->re, p->im, q->re, q->im);
- p++;
- q++;
- for(l = nblocks; l < np2; l += nblocks) {
- CMUL(tmp_re, tmp_im, mdct->costab[l], -mdct->sintab[l], q->re, q->im);
- BF(p->re, p->im, q->re, q->im,
- p->re, p->im, tmp_re, tmp_im);
- p++;
- q++;
- }
- p += nloops;
- q += nloops;
- }
- nblocks = nblocks >> 1;
- nloops = nloops << 1;
- } while (nblocks);
-}
-
-
-/**
- * Calculate a 512-point MDCT
- * @param out 256 output frequency coefficients
- * @param in 512 windowed input audio samples
- */
-static void mdct512(AC3MDCTContext *mdct, int32_t *out, int16_t *in)
-{
- int i, re, im, n, n2, n4;
- int16_t *rot = mdct->rot_tmp;
- IComplex *x = mdct->cplx_tmp;
-
- n = 1 << mdct->nbits;
- n2 = n >> 1;
- n4 = n >> 2;
-
- /* shift to simplify computations */
- for (i = 0; i <n4; i++)
- rot[i] = -in[i + 3*n4];
- memcpy(&rot[n4], &in[0], 3*n4*sizeof(*in));
-
- /* pre rotation */
- for (i = 0; i < n4; i++) {
- re = ((int)rot[ 2*i] - (int)rot[ n-1-2*i]) >> 1;
- im = -((int)rot[n2+2*i] - (int)rot[n2-1-2*i]) >> 1;
- CMUL(x[i].re, x[i].im, re, im, -mdct->xcos1[i], mdct->xsin1[i]);
- }
-
- fft(mdct, x, mdct->nbits - 2);
-
- /* post rotation */
- for (i = 0; i < n4; i++) {
- re = x[i].re;
- im = x[i].im;
- CMUL(out[n2-1-2*i], out[2*i], re, im, mdct->xsin1[i], mdct->xcos1[i]);
- }
-}
-
-
-/**
- * Apply KBD window to input samples prior to MDCT.
- */
-static void apply_window(int16_t *output, const int16_t *input,
- const int16_t *window, int n)
-{
- int i;
- int n2 = n >> 1;
-
- for (i = 0; i < n2; i++) {
- output[i] = MUL16(input[i], window[i]) >> 15;
- output[n-i-1] = MUL16(input[n-i-1], window[i]) >> 15;
- }
-}
-
-
-/**
- * Calculate the log2() of the maximum absolute value in an array.
- * @param tab input array
- * @param n number of values in the array
- * @return log2(max(abs(tab[])))
- */
-static int log2_tab(int16_t *tab, int n)
-{
- int i, v;
-
- v = 0;
- for (i = 0; i < n; i++)
- v |= abs(tab[i]);
-
- return av_log2(v);
-}
-
-
-/**
- * Left-shift each value in an array by a specified amount.
- * @param tab input array
- * @param n number of values in the array
- * @param lshift left shift amount. a negative value means right shift.
- */
-static void lshift_tab(int16_t *tab, int n, int lshift)
-{
- int i;
-
- if (lshift > 0) {
- for (i = 0; i < n; i++)
- tab[i] <<= lshift;
- } else if (lshift < 0) {
- lshift = -lshift;
- for (i = 0; i < n; i++)
- tab[i] >>= lshift;
- }
-}
-
-
-/**
- * Normalize the input samples to use the maximum available precision.
- * This assumes signed 16-bit input samples. Exponents are reduced by 9 to
- * match the 24-bit internal precision for MDCT coefficients.
- *
- * @return exponent shift
- */
-static int normalize_samples(AC3EncodeContext *s)
-{
- int v = 14 - log2_tab(s->windowed_samples, AC3_WINDOW_SIZE);
- v = FFMAX(0, v);
- lshift_tab(s->windowed_samples, AC3_WINDOW_SIZE, v);
- return v - 9;
-}
-
-
-/**
- * Apply the MDCT to input samples to generate frequency coefficients.
- * This applies the KBD window and normalizes the input to reduce precision
- * loss due to fixed-point calculations.
- */
-static void apply_mdct(AC3EncodeContext *s)
-{
- int blk, ch;
-
- for (ch = 0; ch < s->channels; ch++) {
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- const SampleType *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE];
-
- apply_window(s->windowed_samples, input_samples, s->mdct.window, AC3_WINDOW_SIZE);
-
- block->exp_shift[ch] = normalize_samples(s);
-
- mdct512(&s->mdct, block->mdct_coef[ch], s->windowed_samples);
- }
- }
-}
-
-
-/**
- * Initialize exponent tables.
- */
-static av_cold void exponent_init(AC3EncodeContext *s)
-{
- int i;
- for (i = 73; i < 256; i++) {
- exponent_group_tab[0][i] = (i - 1) / 3;
- exponent_group_tab[1][i] = (i + 2) / 6;
- exponent_group_tab[2][i] = (i + 8) / 12;
- }
- /* LFE */
- exponent_group_tab[0][7] = 2;
-}
-
-
-/**
- * Extract exponents from the MDCT coefficients.
- * This takes into account the normalization that was done to the input samples
- * by adjusting the exponents by the exponent shift values.
- */
-static void extract_exponents(AC3EncodeContext *s)
-{
- int blk, ch, i;
-
- for (ch = 0; ch < s->channels; ch++) {
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- for (i = 0; i < AC3_MAX_COEFS; i++) {
- int e;
- int v = abs(SCALE_COEF(block->mdct_coef[ch][i]));
- if (v == 0)
- e = 24;
- else {
- e = 23 - av_log2(v) + block->exp_shift[ch];
- if (e >= 24) {
- e = 24;
- block->mdct_coef[ch][i] = 0;
- }
- }
- block->exp[ch][i] = e;
- }
- }
- }
-}
-
-
-/**
- * Exponent Difference Threshold.
- * New exponents are sent if their SAD exceed this number.
- */
-#define EXP_DIFF_THRESHOLD 1000
-
-
-/**
- * Calculate exponent strategies for all blocks in a single channel.
- */
-static void compute_exp_strategy_ch(AC3EncodeContext *s, uint8_t *exp_strategy,
- uint8_t **exp)
-{
- int blk, blk1;
- int exp_diff;
-
- /* estimate if the exponent variation & decide if they should be
- reused in the next frame */
- exp_strategy[0] = EXP_NEW;
- for (blk = 1; blk < AC3_MAX_BLOCKS; blk++) {
- exp_diff = s->dsp.sad[0](NULL, exp[blk], exp[blk-1], 16, 16);
- if (exp_diff > EXP_DIFF_THRESHOLD)
- exp_strategy[blk] = EXP_NEW;
- else
- exp_strategy[blk] = EXP_REUSE;
- }
- emms_c();
-
- /* now select the encoding strategy type : if exponents are often
- recoded, we use a coarse encoding */
- blk = 0;
- while (blk < AC3_MAX_BLOCKS) {
- blk1 = blk + 1;
- while (blk1 < AC3_MAX_BLOCKS && exp_strategy[blk1] == EXP_REUSE)
- blk1++;
- switch (blk1 - blk) {
- case 1: exp_strategy[blk] = EXP_D45; break;
- case 2:
- case 3: exp_strategy[blk] = EXP_D25; break;
- default: exp_strategy[blk] = EXP_D15; break;
- }
- blk = blk1;
- }
-}
-
-
-/**
- * Calculate exponent strategies for all channels.
- * Array arrangement is reversed to simplify the per-channel calculation.
- */
-static void compute_exp_strategy(AC3EncodeContext *s)
-{
- uint8_t *exp1[AC3_MAX_CHANNELS][AC3_MAX_BLOCKS];
- uint8_t exp_str1[AC3_MAX_CHANNELS][AC3_MAX_BLOCKS];
- int ch, blk;
-
- for (ch = 0; ch < s->fbw_channels; ch++) {
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- exp1[ch][blk] = s->blocks[blk].exp[ch];
- exp_str1[ch][blk] = s->blocks[blk].exp_strategy[ch];
- }
-
- compute_exp_strategy_ch(s, exp_str1[ch], exp1[ch]);
-
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++)
- s->blocks[blk].exp_strategy[ch] = exp_str1[ch][blk];
- }
- if (s->lfe_on) {
- ch = s->lfe_channel;
- s->blocks[0].exp_strategy[ch] = EXP_D15;
- for (blk = 1; blk < AC3_MAX_BLOCKS; blk++)
- s->blocks[blk].exp_strategy[ch] = EXP_REUSE;
- }
-}
-
-
-/**
- * Set each encoded exponent in a block to the minimum of itself and the
- * exponent in the same frequency bin of a following block.
- * exp[i] = min(exp[i], exp1[i]
- */
-static void exponent_min(uint8_t *exp, uint8_t *exp1, int n)
-{
- int i;
- for (i = 0; i < n; i++) {
- if (exp1[i] < exp[i])
- exp[i] = exp1[i];
- }
-}
-
-
-/**
- * Update the exponents so that they are the ones the decoder will decode.
- */
-static void encode_exponents_blk_ch(uint8_t *exp, int nb_exps, int exp_strategy)
-{
- int nb_groups, i, k;
-
- nb_groups = exponent_group_tab[exp_strategy-1][nb_exps] * 3;
-
- /* for each group, compute the minimum exponent */
- switch(exp_strategy) {
- case EXP_D25:
- for (i = 1, k = 1; i <= nb_groups; i++) {
- uint8_t exp_min = exp[k];
- if (exp[k+1] < exp_min)
- exp_min = exp[k+1];
- exp[i] = exp_min;
- k += 2;
- }
- break;
- case EXP_D45:
- for (i = 1, k = 1; i <= nb_groups; i++) {
- uint8_t exp_min = exp[k];
- if (exp[k+1] < exp_min)
- exp_min = exp[k+1];
- if (exp[k+2] < exp_min)
- exp_min = exp[k+2];
- if (exp[k+3] < exp_min)
- exp_min = exp[k+3];
- exp[i] = exp_min;
- k += 4;
- }
- break;
- }
-
- /* constraint for DC exponent */
- if (exp[0] > 15)
- exp[0] = 15;
-
- /* decrease the delta between each groups to within 2 so that they can be
- differentially encoded */
- for (i = 1; i <= nb_groups; i++)
- exp[i] = FFMIN(exp[i], exp[i-1] + 2);
- i--;
- while (--i >= 0)
- exp[i] = FFMIN(exp[i], exp[i+1] + 2);
-
- /* now we have the exponent values the decoder will see */
- switch (exp_strategy) {
- case EXP_D25:
- for (i = nb_groups, k = nb_groups * 2; i > 0; i--) {
- uint8_t exp1 = exp[i];
- exp[k--] = exp1;
- exp[k--] = exp1;
- }
- break;
- case EXP_D45:
- for (i = nb_groups, k = nb_groups * 4; i > 0; i--) {
- exp[k] = exp[k-1] = exp[k-2] = exp[k-3] = exp[i];
- k -= 4;
- }
- break;
- }
-}
-
-
-/**
- * Encode exponents from original extracted form to what the decoder will see.
- * This copies and groups exponents based on exponent strategy and reduces
- * deltas between adjacent exponent groups so that they can be differentially
- * encoded.
- */
-static void encode_exponents(AC3EncodeContext *s)
-{
- int blk, blk1, blk2, ch;
- AC3Block *block, *block1, *block2;
-
- for (ch = 0; ch < s->channels; ch++) {
- blk = 0;
- block = &s->blocks[0];
- while (blk < AC3_MAX_BLOCKS) {
- blk1 = blk + 1;
- block1 = block + 1;
- /* for the EXP_REUSE case we select the min of the exponents */
- while (blk1 < AC3_MAX_BLOCKS && block1->exp_strategy[ch] == EXP_REUSE) {
- exponent_min(block->exp[ch], block1->exp[ch], s->nb_coefs[ch]);
- blk1++;
- block1++;
- }
- encode_exponents_blk_ch(block->exp[ch], s->nb_coefs[ch],
- block->exp_strategy[ch]);
- /* copy encoded exponents for reuse case */
- block2 = block + 1;
- for (blk2 = blk+1; blk2 < blk1; blk2++, block2++) {
- memcpy(block2->exp[ch], block->exp[ch],
- s->nb_coefs[ch] * sizeof(uint8_t));
- }
- blk = blk1;
- block = block1;
- }
- }
-}
-
-
-/**
- * Group exponents.
- * 3 delta-encoded exponents are in each 7-bit group. The number of groups
- * varies depending on exponent strategy and bandwidth.
- */
-static void group_exponents(AC3EncodeContext *s)
-{
- int blk, ch, i;
- int group_size, nb_groups, bit_count;
- uint8_t *p;
- int delta0, delta1, delta2;
- int exp0, exp1;
-
- bit_count = 0;
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- for (ch = 0; ch < s->channels; ch++) {
- if (block->exp_strategy[ch] == EXP_REUSE) {
- continue;
- }
- group_size = block->exp_strategy[ch] + (block->exp_strategy[ch] == EXP_D45);
- nb_groups = exponent_group_tab[block->exp_strategy[ch]-1][s->nb_coefs[ch]];
- bit_count += 4 + (nb_groups * 7);
- p = block->exp[ch];
-
- /* DC exponent */
- exp1 = *p++;
- block->grouped_exp[ch][0] = exp1;
-
- /* remaining exponents are delta encoded */
- for (i = 1; i <= nb_groups; i++) {
- /* merge three delta in one code */
- exp0 = exp1;
- exp1 = p[0];
- p += group_size;
- delta0 = exp1 - exp0 + 2;
-
- exp0 = exp1;
- exp1 = p[0];
- p += group_size;
- delta1 = exp1 - exp0 + 2;
-
- exp0 = exp1;
- exp1 = p[0];
- p += group_size;
- delta2 = exp1 - exp0 + 2;
-
- block->grouped_exp[ch][i] = ((delta0 * 5 + delta1) * 5) + delta2;
- }
- }
- }
-
- s->exponent_bits = bit_count;
-}
-
-
-/**
- * Calculate final exponents from the supplied MDCT coefficients and exponent shift.
- * Extract exponents from MDCT coefficients, calculate exponent strategies,
- * and encode final exponents.
- */
-static void process_exponents(AC3EncodeContext *s)
-{
- extract_exponents(s);
-
- compute_exp_strategy(s);
-
- encode_exponents(s);
-
- group_exponents(s);
-}
-
-
-/**
- * Count frame bits that are based solely on fixed parameters.
- * This only has to be run once when the encoder is initialized.
- */
-static void count_frame_bits_fixed(AC3EncodeContext *s)
-{
- static const int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
- int blk;
- int frame_bits;
-
- /* assumptions:
- * no dynamic range codes
- * no channel coupling
- * no rematrixing
- * bit allocation parameters do not change between blocks
- * SNR offsets do not change between blocks
- * no delta bit allocation
- * no skipped data
- * no auxilliary data
- */
-
- /* header size */
- frame_bits = 65;
- frame_bits += frame_bits_inc[s->channel_mode];
-
- /* audio blocks */
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- frame_bits += s->fbw_channels * 2 + 2; /* blksw * c, dithflag * c, dynrnge, cplstre */
- if (s->channel_mode == AC3_CHMODE_STEREO) {
- frame_bits++; /* rematstr */
- if (!blk)
- frame_bits += 4;
- }
- frame_bits += 2 * s->fbw_channels; /* chexpstr[2] * c */
- if (s->lfe_on)
- frame_bits++; /* lfeexpstr */
- frame_bits++; /* baie */
- frame_bits++; /* snr */
- frame_bits += 2; /* delta / skip */
- }
- frame_bits++; /* cplinu for block 0 */
- /* bit alloc info */
- /* sdcycod[2], fdcycod[2], sgaincod[2], dbpbcod[2], floorcod[3] */
- /* csnroffset[6] */
- /* (fsnoffset[4] + fgaincod[4]) * c */
- frame_bits += 2*4 + 3 + 6 + s->channels * (4 + 3);
-
- /* auxdatae, crcrsv */
- frame_bits += 2;
-
- /* CRC */
- frame_bits += 16;
-
- s->frame_bits_fixed = frame_bits;
-}
-
-
-/**
- * Initialize bit allocation.
- * Set default parameter codes and calculate parameter values.
- */
-static void bit_alloc_init(AC3EncodeContext *s)
-{
- int ch;
-
- /* init default parameters */
- s->slow_decay_code = 2;
- s->fast_decay_code = 1;
- s->slow_gain_code = 1;
- s->db_per_bit_code = 3;
- s->floor_code = 4;
- for (ch = 0; ch < s->channels; ch++)
- s->fast_gain_code[ch] = 4;
-
- /* initial snr offset */
- s->coarse_snr_offset = 40;
-
- /* compute real values */
- /* currently none of these values change during encoding, so we can just
- set them once at initialization */
- s->bit_alloc.slow_decay = ff_ac3_slow_decay_tab[s->slow_decay_code] >> s->bit_alloc.sr_shift;
- s->bit_alloc.fast_decay = ff_ac3_fast_decay_tab[s->fast_decay_code] >> s->bit_alloc.sr_shift;
- s->bit_alloc.slow_gain = ff_ac3_slow_gain_tab[s->slow_gain_code];
- s->bit_alloc.db_per_bit = ff_ac3_db_per_bit_tab[s->db_per_bit_code];
- s->bit_alloc.floor = ff_ac3_floor_tab[s->floor_code];
-
- count_frame_bits_fixed(s);
-}
-
-
-/**
- * Count the bits used to encode the frame, minus exponents and mantissas.
- * Bits based on fixed parameters have already been counted, so now we just
- * have to add the bits based on parameters that change during encoding.
- */
-static void count_frame_bits(AC3EncodeContext *s)
-{
- int blk, ch;
- int frame_bits = 0;
-
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- uint8_t *exp_strategy = s->blocks[blk].exp_strategy;
- for (ch = 0; ch < s->fbw_channels; ch++) {
- if (exp_strategy[ch] != EXP_REUSE)
- frame_bits += 6 + 2; /* chbwcod[6], gainrng[2] */
- }
- }
- s->frame_bits = s->frame_bits_fixed + frame_bits;
-}
-
-
-/**
- * Calculate the number of bits needed to encode a set of mantissas.
- */
-static int compute_mantissa_size(int mant_cnt[5], uint8_t *bap, int nb_coefs)
-{
- int bits, b, i;
-
- bits = 0;
- for (i = 0; i < nb_coefs; i++) {
- b = bap[i];
- if (b <= 4) {
- // bap=1 to bap=4 will be counted in compute_mantissa_size_final
- mant_cnt[b]++;
- } else if (b <= 13) {
- // bap=5 to bap=13 use (bap-1) bits
- bits += b - 1;
- } else {
- // bap=14 uses 14 bits and bap=15 uses 16 bits
- bits += (b == 14) ? 14 : 16;
- }
- }
- return bits;
-}
-
-
-/**
- * Finalize the mantissa bit count by adding in the grouped mantissas.
- */
-static int compute_mantissa_size_final(int mant_cnt[5])
-{
- // bap=1 : 3 mantissas in 5 bits
- int bits = (mant_cnt[1] / 3) * 5;
- // bap=2 : 3 mantissas in 7 bits
- // bap=4 : 2 mantissas in 7 bits
- bits += ((mant_cnt[2] / 3) + (mant_cnt[4] >> 1)) * 7;
- // bap=3 : each mantissa is 3 bits
- bits += mant_cnt[3] * 3;
- return bits;
-}
-
-
-/**
- * Calculate masking curve based on the final exponents.
- * Also calculate the power spectral densities to use in future calculations.
- */
-static void bit_alloc_masking(AC3EncodeContext *s)
-{
- int blk, ch;
-
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- for (ch = 0; ch < s->channels; ch++) {
- /* We only need psd and mask for calculating bap.
- Since we currently do not calculate bap when exponent
- strategy is EXP_REUSE we do not need to calculate psd or mask. */
- if (block->exp_strategy[ch] != EXP_REUSE) {
- ff_ac3_bit_alloc_calc_psd(block->exp[ch], 0,
- s->nb_coefs[ch],
- block->psd[ch], block->band_psd[ch]);
- ff_ac3_bit_alloc_calc_mask(&s->bit_alloc, block->band_psd[ch],
- 0, s->nb_coefs[ch],
- ff_ac3_fast_gain_tab[s->fast_gain_code[ch]],
- ch == s->lfe_channel,
- DBA_NONE, 0, NULL, NULL, NULL,
- block->mask[ch]);
- }
- }
- }
-}
-
-
-/**
- * Ensure that bap for each block and channel point to the current bap_buffer.
- * They may have been switched during the bit allocation search.
- */
-static void reset_block_bap(AC3EncodeContext *s)
-{
- int blk, ch;
- if (s->blocks[0].bap[0] == s->bap_buffer)
- return;
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- for (ch = 0; ch < s->channels; ch++) {
- s->blocks[blk].bap[ch] = &s->bap_buffer[AC3_MAX_COEFS * (blk * s->channels + ch)];
- }
- }
-}
-
-
-/**
- * Run the bit allocation with a given SNR offset.
- * This calculates the bit allocation pointers that will be used to determine
- * the quantization of each mantissa.
- * @return the number of bits needed for mantissas if the given SNR offset is
- * is used.
- */
-static int bit_alloc(AC3EncodeContext *s, int snr_offset)
-{
- int blk, ch;
- int mantissa_bits;
- int mant_cnt[5];
-
- snr_offset = (snr_offset - 240) << 2;
-
- reset_block_bap(s);
- mantissa_bits = 0;
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- // initialize grouped mantissa counts. these are set so that they are
- // padded to the next whole group size when bits are counted in
- // compute_mantissa_size_final
- mant_cnt[0] = mant_cnt[3] = 0;
- mant_cnt[1] = mant_cnt[2] = 2;
- mant_cnt[4] = 1;
- for (ch = 0; ch < s->channels; ch++) {
- /* Currently the only bit allocation parameters which vary across
- blocks within a frame are the exponent values. We can take
- advantage of that by reusing the bit allocation pointers
- whenever we reuse exponents. */
- if (block->exp_strategy[ch] == EXP_REUSE) {
- memcpy(block->bap[ch], s->blocks[blk-1].bap[ch], AC3_MAX_COEFS);
- } else {
- ff_ac3_bit_alloc_calc_bap(block->mask[ch], block->psd[ch], 0,
- s->nb_coefs[ch], snr_offset,
- s->bit_alloc.floor, ff_ac3_bap_tab,
- block->bap[ch]);
- }
- mantissa_bits += compute_mantissa_size(mant_cnt, block->bap[ch], s->nb_coefs[ch]);
- }
- mantissa_bits += compute_mantissa_size_final(mant_cnt);
- }
- return mantissa_bits;
-}
-
-
-/**
- * Constant bitrate bit allocation search.
- * Find the largest SNR offset that will allow data to fit in the frame.
- */
-static int cbr_bit_allocation(AC3EncodeContext *s)
-{
- int ch;
- int bits_left;
- int snr_offset, snr_incr;
-
- bits_left = 8 * s->frame_size - (s->frame_bits + s->exponent_bits);
-
- snr_offset = s->coarse_snr_offset << 4;
-
- /* if previous frame SNR offset was 1023, check if current frame can also
- use SNR offset of 1023. if so, skip the search. */
- if ((snr_offset | s->fine_snr_offset[0]) == 1023) {
- if (bit_alloc(s, 1023) <= bits_left)
- return 0;
- }
-
- while (snr_offset >= 0 &&
- bit_alloc(s, snr_offset) > bits_left) {
- snr_offset -= 64;
- }
- if (snr_offset < 0)
- return AVERROR(EINVAL);
-
- FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
- for (snr_incr = 64; snr_incr > 0; snr_incr >>= 2) {
- while (snr_offset + snr_incr <= 1023 &&
- bit_alloc(s, snr_offset + snr_incr) <= bits_left) {
- snr_offset += snr_incr;
- FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
- }
- }
- FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
- reset_block_bap(s);
-
- s->coarse_snr_offset = snr_offset >> 4;
- for (ch = 0; ch < s->channels; ch++)
- s->fine_snr_offset[ch] = snr_offset & 0xF;
-
- return 0;
-}
-
-
-/**
- * Downgrade exponent strategies to reduce the bits used by the exponents.
- * This is a fallback for when bit allocation fails with the normal exponent
- * strategies. Each time this function is run it only downgrades the
- * strategy in 1 channel of 1 block.
- * @return non-zero if downgrade was unsuccessful
- */
-static int downgrade_exponents(AC3EncodeContext *s)
-{
- int ch, blk;
-
- for (ch = 0; ch < s->fbw_channels; ch++) {
- for (blk = AC3_MAX_BLOCKS-1; blk >= 0; blk--) {
- if (s->blocks[blk].exp_strategy[ch] == EXP_D15) {
- s->blocks[blk].exp_strategy[ch] = EXP_D25;
- return 0;
- }
- }
- }
- for (ch = 0; ch < s->fbw_channels; ch++) {
- for (blk = AC3_MAX_BLOCKS-1; blk >= 0; blk--) {
- if (s->blocks[blk].exp_strategy[ch] == EXP_D25) {
- s->blocks[blk].exp_strategy[ch] = EXP_D45;
- return 0;
- }
- }
- }
- for (ch = 0; ch < s->fbw_channels; ch++) {
- /* block 0 cannot reuse exponents, so only downgrade D45 to REUSE if
- the block number > 0 */
- for (blk = AC3_MAX_BLOCKS-1; blk > 0; blk--) {
- if (s->blocks[blk].exp_strategy[ch] > EXP_REUSE) {
- s->blocks[blk].exp_strategy[ch] = EXP_REUSE;
- return 0;
- }
- }
- }
- return -1;
-}
-
-
-/**
- * Reduce the bandwidth to reduce the number of bits used for a given SNR offset.
- * This is a second fallback for when bit allocation still fails after exponents
- * have been downgraded.
- * @return non-zero if bandwidth reduction was unsuccessful
- */
-static int reduce_bandwidth(AC3EncodeContext *s, int min_bw_code)
-{
- int ch;
-
- if (s->bandwidth_code[0] > min_bw_code) {
- for (ch = 0; ch < s->fbw_channels; ch++) {
- s->bandwidth_code[ch]--;
- s->nb_coefs[ch] = s->bandwidth_code[ch] * 3 + 73;
- }
- return 0;
- }
- return -1;
-}
-
-
-/**
- * Perform bit allocation search.
- * Finds the SNR offset value that maximizes quality and fits in the specified
- * frame size. Output is the SNR offset and a set of bit allocation pointers
- * used to quantize the mantissas.
- */
-static int compute_bit_allocation(AC3EncodeContext *s)
-{
- int ret;
-
- count_frame_bits(s);
-
- bit_alloc_masking(s);
-
- ret = cbr_bit_allocation(s);
- while (ret) {
- /* fallback 1: downgrade exponents */
- if (!downgrade_exponents(s)) {
- extract_exponents(s);
- encode_exponents(s);
- group_exponents(s);
- ret = compute_bit_allocation(s);
- continue;
- }
-
- /* fallback 2: reduce bandwidth */
- /* only do this if the user has not specified a specific cutoff
- frequency */
- if (!s->cutoff && !reduce_bandwidth(s, 0)) {
- process_exponents(s);
- ret = compute_bit_allocation(s);
- continue;
- }
-
- /* fallbacks were not enough... */
- break;
- }
-
- return ret;
-}
-
-
-/**
- * Symmetric quantization on 'levels' levels.
- */
-static inline int sym_quant(int c, int e, int levels)
-{
- int v;
-
- if (c >= 0) {
- v = (levels * (c << e)) >> 24;
- v = (v + 1) >> 1;
- v = (levels >> 1) + v;
- } else {
- v = (levels * ((-c) << e)) >> 24;
- v = (v + 1) >> 1;
- v = (levels >> 1) - v;
- }
- assert(v >= 0 && v < levels);
- return v;
-}
-
-
-/**
- * Asymmetric quantization on 2^qbits levels.
- */
-static inline int asym_quant(int c, int e, int qbits)
-{
- int lshift, m, v;
-
- lshift = e + qbits - 24;
- if (lshift >= 0)
- v = c << lshift;
- else
- v = c >> (-lshift);
- /* rounding */
- v = (v + 1) >> 1;
- m = (1 << (qbits-1));
- if (v >= m)
- v = m - 1;
- assert(v >= -m);
- return v & ((1 << qbits)-1);
-}
-
-
-/**
- * Quantize a set of mantissas for a single channel in a single block.
- */
-static void quantize_mantissas_blk_ch(AC3EncodeContext *s, CoefType *mdct_coef,
- int8_t exp_shift, uint8_t *exp,
- uint8_t *bap, uint16_t *qmant, int n)
-{
- int i;
-
- for (i = 0; i < n; i++) {
- int v;
- int c = SCALE_COEF(mdct_coef[i]);
- int e = exp[i] - exp_shift;
- int b = bap[i];
- switch (b) {
- case 0:
- v = 0;
- break;
- case 1:
- v = sym_quant(c, e, 3);
- switch (s->mant1_cnt) {
- case 0:
- s->qmant1_ptr = &qmant[i];
- v = 9 * v;
- s->mant1_cnt = 1;
- break;
- case 1:
- *s->qmant1_ptr += 3 * v;
- s->mant1_cnt = 2;
- v = 128;
- break;
- default:
- *s->qmant1_ptr += v;
- s->mant1_cnt = 0;
- v = 128;
- break;
- }
- break;
- case 2:
- v = sym_quant(c, e, 5);
- switch (s->mant2_cnt) {
- case 0:
- s->qmant2_ptr = &qmant[i];
- v = 25 * v;
- s->mant2_cnt = 1;
- break;
- case 1:
- *s->qmant2_ptr += 5 * v;
- s->mant2_cnt = 2;
- v = 128;
- break;
- default:
- *s->qmant2_ptr += v;
- s->mant2_cnt = 0;
- v = 128;
- break;
- }
- break;
- case 3:
- v = sym_quant(c, e, 7);
- break;
- case 4:
- v = sym_quant(c, e, 11);
- switch (s->mant4_cnt) {
- case 0:
- s->qmant4_ptr = &qmant[i];
- v = 11 * v;
- s->mant4_cnt = 1;
- break;
- default:
- *s->qmant4_ptr += v;
- s->mant4_cnt = 0;
- v = 128;
- break;
- }
- break;
- case 5:
- v = sym_quant(c, e, 15);
- break;
- case 14:
- v = asym_quant(c, e, 14);
- break;
- case 15:
- v = asym_quant(c, e, 16);
- break;
- default:
- v = asym_quant(c, e, b - 1);
- break;
- }
- qmant[i] = v;
- }
-}
-
-
-/**
- * Quantize mantissas using coefficients, exponents, and bit allocation pointers.
- */
-static void quantize_mantissas(AC3EncodeContext *s)
-{
- int blk, ch;
-
-
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- s->mant1_cnt = s->mant2_cnt = s->mant4_cnt = 0;
- s->qmant1_ptr = s->qmant2_ptr = s->qmant4_ptr = NULL;
-
- for (ch = 0; ch < s->channels; ch++) {
- quantize_mantissas_blk_ch(s, block->mdct_coef[ch], block->exp_shift[ch],
- block->exp[ch], block->bap[ch],
- block->qmant[ch], s->nb_coefs[ch]);
- }
- }
-}
-
-
-/**
- * Write the AC-3 frame header to the output bitstream.
- */
-static void output_frame_header(AC3EncodeContext *s)
-{
- put_bits(&s->pb, 16, 0x0b77); /* frame header */
- put_bits(&s->pb, 16, 0); /* crc1: will be filled later */
- put_bits(&s->pb, 2, s->bit_alloc.sr_code);
- put_bits(&s->pb, 6, s->frame_size_code + (s->frame_size - s->frame_size_min) / 2);
- put_bits(&s->pb, 5, s->bitstream_id);
- put_bits(&s->pb, 3, s->bitstream_mode);
- put_bits(&s->pb, 3, s->channel_mode);
- if ((s->channel_mode & 0x01) && s->channel_mode != AC3_CHMODE_MONO)
- put_bits(&s->pb, 2, 1); /* XXX -4.5 dB */
- if (s->channel_mode & 0x04)
- put_bits(&s->pb, 2, 1); /* XXX -6 dB */
- if (s->channel_mode == AC3_CHMODE_STEREO)
- put_bits(&s->pb, 2, 0); /* surround not indicated */
- put_bits(&s->pb, 1, s->lfe_on); /* LFE */
- put_bits(&s->pb, 5, 31); /* dialog norm: -31 db */
- put_bits(&s->pb, 1, 0); /* no compression control word */
- put_bits(&s->pb, 1, 0); /* no lang code */
- put_bits(&s->pb, 1, 0); /* no audio production info */
- put_bits(&s->pb, 1, 0); /* no copyright */
- put_bits(&s->pb, 1, 1); /* original bitstream */
- put_bits(&s->pb, 1, 0); /* no time code 1 */
- put_bits(&s->pb, 1, 0); /* no time code 2 */
- put_bits(&s->pb, 1, 0); /* no additional bit stream info */
-}
-
-
-/**
- * Write one audio block to the output bitstream.
- */
-static void output_audio_block(AC3EncodeContext *s, int block_num)
-{
- int ch, i, baie, rbnd;
- AC3Block *block = &s->blocks[block_num];
-
- /* block switching */
- for (ch = 0; ch < s->fbw_channels; ch++)
- put_bits(&s->pb, 1, 0);
-
- /* dither flags */
- for (ch = 0; ch < s->fbw_channels; ch++)
- put_bits(&s->pb, 1, 1);
-
- /* dynamic range codes */
- put_bits(&s->pb, 1, 0);
-
- /* channel coupling */
- if (!block_num) {
- put_bits(&s->pb, 1, 1); /* coupling strategy present */
- put_bits(&s->pb, 1, 0); /* no coupling strategy */
- } else {
- put_bits(&s->pb, 1, 0); /* no new coupling strategy */
- }
-
- /* stereo rematrixing */
- if (s->channel_mode == AC3_CHMODE_STEREO) {
- if (!block_num) {
- /* first block must define rematrixing (rematstr) */
- put_bits(&s->pb, 1, 1);
-
- /* dummy rematrixing rematflg(1:4)=0 */
- for (rbnd = 0; rbnd < 4; rbnd++)
- put_bits(&s->pb, 1, 0);
- } else {
- /* no matrixing (but should be used in the future) */
- put_bits(&s->pb, 1, 0);
- }
- }
-
- /* exponent strategy */
- for (ch = 0; ch < s->fbw_channels; ch++)
- put_bits(&s->pb, 2, block->exp_strategy[ch]);
- if (s->lfe_on)
- put_bits(&s->pb, 1, block->exp_strategy[s->lfe_channel]);
-
- /* bandwidth */
- for (ch = 0; ch < s->fbw_channels; ch++) {
- if (block->exp_strategy[ch] != EXP_REUSE)
- put_bits(&s->pb, 6, s->bandwidth_code[ch]);
- }
-
- /* exponents */
- for (ch = 0; ch < s->channels; ch++) {
- int nb_groups;
-
- if (block->exp_strategy[ch] == EXP_REUSE)
- continue;
-
- /* DC exponent */
- put_bits(&s->pb, 4, block->grouped_exp[ch][0]);
-
- /* exponent groups */
- nb_groups = exponent_group_tab[block->exp_strategy[ch]-1][s->nb_coefs[ch]];
- for (i = 1; i <= nb_groups; i++)
- put_bits(&s->pb, 7, block->grouped_exp[ch][i]);
-
- /* gain range info */
- if (ch != s->lfe_channel)
- put_bits(&s->pb, 2, 0);
- }
-
- /* bit allocation info */
- baie = (block_num == 0);
- put_bits(&s->pb, 1, baie);
- if (baie) {
- put_bits(&s->pb, 2, s->slow_decay_code);
- put_bits(&s->pb, 2, s->fast_decay_code);
- put_bits(&s->pb, 2, s->slow_gain_code);
- put_bits(&s->pb, 2, s->db_per_bit_code);
- put_bits(&s->pb, 3, s->floor_code);
- }
-
- /* snr offset */
- put_bits(&s->pb, 1, baie);
- if (baie) {
- put_bits(&s->pb, 6, s->coarse_snr_offset);
- for (ch = 0; ch < s->channels; ch++) {
- put_bits(&s->pb, 4, s->fine_snr_offset[ch]);
- put_bits(&s->pb, 3, s->fast_gain_code[ch]);
- }
- }
-
- put_bits(&s->pb, 1, 0); /* no delta bit allocation */
- put_bits(&s->pb, 1, 0); /* no data to skip */
-
- /* mantissas */
- for (ch = 0; ch < s->channels; ch++) {
- int b, q;
- for (i = 0; i < s->nb_coefs[ch]; i++) {
- q = block->qmant[ch][i];
- b = block->bap[ch][i];
- switch (b) {
- case 0: break;
- case 1: if (q != 128) put_bits(&s->pb, 5, q); break;
- case 2: if (q != 128) put_bits(&s->pb, 7, q); break;
- case 3: put_bits(&s->pb, 3, q); break;
- case 4: if (q != 128) put_bits(&s->pb, 7, q); break;
- case 14: put_bits(&s->pb, 14, q); break;
- case 15: put_bits(&s->pb, 16, q); break;
- default: put_bits(&s->pb, b-1, q); break;
- }
- }
- }
-}
-
-
-/** CRC-16 Polynomial */
-#define CRC16_POLY ((1 << 0) | (1 << 2) | (1 << 15) | (1 << 16))
-
-
-static unsigned int mul_poly(unsigned int a, unsigned int b, unsigned int poly)
-{
- unsigned int c;
-
- c = 0;
- while (a) {
- if (a & 1)
- c ^= b;
- a = a >> 1;
- b = b << 1;
- if (b & (1 << 16))
- b ^= poly;
- }
- return c;
-}
-
-
-static unsigned int pow_poly(unsigned int a, unsigned int n, unsigned int poly)
-{
- unsigned int r;
- r = 1;
- while (n) {
- if (n & 1)
- r = mul_poly(r, a, poly);
- a = mul_poly(a, a, poly);
- n >>= 1;
- }
- return r;
-}
-
-
-/**
- * Fill the end of the frame with 0's and compute the two CRCs.
- */
-static void output_frame_end(AC3EncodeContext *s)
-{
- const AVCRC *crc_ctx = av_crc_get_table(AV_CRC_16_ANSI);
- int frame_size_58, pad_bytes, crc1, crc2_partial, crc2, crc_inv;
- uint8_t *frame;
-
- frame_size_58 = ((s->frame_size >> 2) + (s->frame_size >> 4)) << 1;
-
- /* pad the remainder of the frame with zeros */
- flush_put_bits(&s->pb);
- frame = s->pb.buf;
- pad_bytes = s->frame_size - (put_bits_ptr(&s->pb) - frame) - 2;
- assert(pad_bytes >= 0);
- if (pad_bytes > 0)
- memset(put_bits_ptr(&s->pb), 0, pad_bytes);
-
- /* compute crc1 */
- /* this is not so easy because it is at the beginning of the data... */
- crc1 = av_bswap16(av_crc(crc_ctx, 0, frame + 4, frame_size_58 - 4));
- crc_inv = s->crc_inv[s->frame_size > s->frame_size_min];
- crc1 = mul_poly(crc_inv, crc1, CRC16_POLY);
- AV_WB16(frame + 2, crc1);
-
- /* compute crc2 */
- crc2_partial = av_crc(crc_ctx, 0, frame + frame_size_58,
- s->frame_size - frame_size_58 - 3);
- crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
- /* ensure crc2 does not match sync word by flipping crcrsv bit if needed */
- if (crc2 == 0x770B) {
- frame[s->frame_size - 3] ^= 0x1;
- crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
- }
- crc2 = av_bswap16(crc2);
- AV_WB16(frame + s->frame_size - 2, crc2);
-}
-
-
-/**
- * Write the frame to the output bitstream.
- */
-static void output_frame(AC3EncodeContext *s, unsigned char *frame)
-{
- int blk;
-
- init_put_bits(&s->pb, frame, AC3_MAX_CODED_FRAME_SIZE);
-
- output_frame_header(s);
-
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++)
- output_audio_block(s, blk);
-
- output_frame_end(s);
-}
-
-
-/**
- * Encode a single AC-3 frame.
- */
-static int ac3_encode_frame(AVCodecContext *avctx, unsigned char *frame,
- int buf_size, void *data)
-{
- AC3EncodeContext *s = avctx->priv_data;
- const SampleType *samples = data;
- int ret;
-
- if (s->bit_alloc.sr_code == 1)
- adjust_frame_size(s);
-
- deinterleave_input_samples(s, samples);
-
- apply_mdct(s);
-
- process_exponents(s);
-
- ret = compute_bit_allocation(s);
- if (ret) {
- av_log(avctx, AV_LOG_ERROR, "Bit allocation failed. Try increasing the bitrate.\n");
- return ret;
- }
-
- quantize_mantissas(s);
-
- output_frame(s, frame);
-
- return s->frame_size;
-}
-
-
-/**
- * Finalize encoding and free any memory allocated by the encoder.
- */
-static av_cold int ac3_encode_close(AVCodecContext *avctx)
-{
- int blk, ch;
- AC3EncodeContext *s = avctx->priv_data;
-
- for (ch = 0; ch < s->channels; ch++)
- av_freep(&s->planar_samples[ch]);
- av_freep(&s->planar_samples);
- av_freep(&s->bap_buffer);
- av_freep(&s->bap1_buffer);
- av_freep(&s->mdct_coef_buffer);
- av_freep(&s->exp_buffer);
- av_freep(&s->grouped_exp_buffer);
- av_freep(&s->psd_buffer);
- av_freep(&s->band_psd_buffer);
- av_freep(&s->mask_buffer);
- av_freep(&s->qmant_buffer);
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- av_freep(&block->bap);
- av_freep(&block->mdct_coef);
- av_freep(&block->exp);
- av_freep(&block->grouped_exp);
- av_freep(&block->psd);
- av_freep(&block->band_psd);
- av_freep(&block->mask);
- av_freep(&block->qmant);
- }
-
- mdct_end(&s->mdct);
-
- av_freep(&avctx->coded_frame);
- return 0;
-}
-
-
-/**
- * Set channel information during initialization.
- */
-static av_cold int set_channel_info(AC3EncodeContext *s, int channels,
- int64_t *channel_layout)
-{
- int ch_layout;
-
- if (channels < 1 || channels > AC3_MAX_CHANNELS)
- return AVERROR(EINVAL);
- if ((uint64_t)*channel_layout > 0x7FF)
- return AVERROR(EINVAL);
- ch_layout = *channel_layout;
- if (!ch_layout)
- ch_layout = avcodec_guess_channel_layout(channels, CODEC_ID_AC3, NULL);
- if (av_get_channel_layout_nb_channels(ch_layout) != channels)
- return AVERROR(EINVAL);
-
- s->lfe_on = !!(ch_layout & AV_CH_LOW_FREQUENCY);
- s->channels = channels;
- s->fbw_channels = channels - s->lfe_on;
- s->lfe_channel = s->lfe_on ? s->fbw_channels : -1;
- if (s->lfe_on)
- ch_layout -= AV_CH_LOW_FREQUENCY;
-
- switch (ch_layout) {
- case AV_CH_LAYOUT_MONO: s->channel_mode = AC3_CHMODE_MONO; break;
- case AV_CH_LAYOUT_STEREO: s->channel_mode = AC3_CHMODE_STEREO; break;
- case AV_CH_LAYOUT_SURROUND: s->channel_mode = AC3_CHMODE_3F; break;
- case AV_CH_LAYOUT_2_1: s->channel_mode = AC3_CHMODE_2F1R; break;
- case AV_CH_LAYOUT_4POINT0: s->channel_mode = AC3_CHMODE_3F1R; break;
- case AV_CH_LAYOUT_QUAD:
- case AV_CH_LAYOUT_2_2: s->channel_mode = AC3_CHMODE_2F2R; break;
- case AV_CH_LAYOUT_5POINT0:
- case AV_CH_LAYOUT_5POINT0_BACK: s->channel_mode = AC3_CHMODE_3F2R; break;
- default:
- return AVERROR(EINVAL);
- }
-
- s->channel_map = ff_ac3_enc_channel_map[s->channel_mode][s->lfe_on];
- *channel_layout = ch_layout;
- if (s->lfe_on)
- *channel_layout |= AV_CH_LOW_FREQUENCY;
-
- return 0;
-}
-
-
-static av_cold int validate_options(AVCodecContext *avctx, AC3EncodeContext *s)
-{
- int i, ret;
-
- /* validate channel layout */
- if (!avctx->channel_layout) {
- av_log(avctx, AV_LOG_WARNING, "No channel layout specified. The "
- "encoder will guess the layout, but it "
- "might be incorrect.\n");
- }
- ret = set_channel_info(s, avctx->channels, &avctx->channel_layout);
- if (ret) {
- av_log(avctx, AV_LOG_ERROR, "invalid channel layout\n");
- return ret;
- }
-
- /* validate sample rate */
- for (i = 0; i < 9; i++) {
- if ((ff_ac3_sample_rate_tab[i / 3] >> (i % 3)) == avctx->sample_rate)
- break;
- }
- if (i == 9) {
- av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");
- return AVERROR(EINVAL);
- }
- s->sample_rate = avctx->sample_rate;
- s->bit_alloc.sr_shift = i % 3;
- s->bit_alloc.sr_code = i / 3;
-
- /* validate bit rate */
- for (i = 0; i < 19; i++) {
- if ((ff_ac3_bitrate_tab[i] >> s->bit_alloc.sr_shift)*1000 == avctx->bit_rate)
- break;
- }
- if (i == 19) {
- av_log(avctx, AV_LOG_ERROR, "invalid bit rate\n");
- return AVERROR(EINVAL);
- }
- s->bit_rate = avctx->bit_rate;
- s->frame_size_code = i << 1;
-
- /* validate cutoff */
- if (avctx->cutoff < 0) {
- av_log(avctx, AV_LOG_ERROR, "invalid cutoff frequency\n");
- return AVERROR(EINVAL);
- }
- s->cutoff = avctx->cutoff;
- if (s->cutoff > (s->sample_rate >> 1))
- s->cutoff = s->sample_rate >> 1;
-
- return 0;
-}
-
-
-/**
- * Set bandwidth for all channels.
- * The user can optionally supply a cutoff frequency. Otherwise an appropriate
- * default value will be used.
- */
-static av_cold void set_bandwidth(AC3EncodeContext *s)
-{
- int ch, bw_code;
-
- if (s->cutoff) {
- /* calculate bandwidth based on user-specified cutoff frequency */
- int fbw_coeffs;
- fbw_coeffs = s->cutoff * 2 * AC3_MAX_COEFS / s->sample_rate;
- bw_code = av_clip((fbw_coeffs - 73) / 3, 0, 60);
- } else {
- /* use default bandwidth setting */
- /* XXX: should compute the bandwidth according to the frame
- size, so that we avoid annoying high frequency artifacts */
- bw_code = 50;
- }
-
- /* set number of coefficients for each channel */
- for (ch = 0; ch < s->fbw_channels; ch++) {
- s->bandwidth_code[ch] = bw_code;
- s->nb_coefs[ch] = bw_code * 3 + 73;
- }
- if (s->lfe_on)
- s->nb_coefs[s->lfe_channel] = 7; /* LFE channel always has 7 coefs */
-}
-
-
-static av_cold int allocate_buffers(AVCodecContext *avctx)
-{
- int blk, ch;
- AC3EncodeContext *s = avctx->priv_data;
-
- FF_ALLOC_OR_GOTO(avctx, s->planar_samples, s->channels * sizeof(*s->planar_samples),
- alloc_fail);
- for (ch = 0; ch < s->channels; ch++) {
- FF_ALLOCZ_OR_GOTO(avctx, s->planar_samples[ch],
- (AC3_FRAME_SIZE+AC3_BLOCK_SIZE) * sizeof(**s->planar_samples),
- alloc_fail);
- }
- FF_ALLOC_OR_GOTO(avctx, s->bap_buffer, AC3_MAX_BLOCKS * s->channels *
- AC3_MAX_COEFS * sizeof(*s->bap_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->bap1_buffer, AC3_MAX_BLOCKS * s->channels *
- AC3_MAX_COEFS * sizeof(*s->bap1_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->mdct_coef_buffer, AC3_MAX_BLOCKS * s->channels *
- AC3_MAX_COEFS * sizeof(*s->mdct_coef_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->exp_buffer, AC3_MAX_BLOCKS * s->channels *
- AC3_MAX_COEFS * sizeof(*s->exp_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->grouped_exp_buffer, AC3_MAX_BLOCKS * s->channels *
- 128 * sizeof(*s->grouped_exp_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->psd_buffer, AC3_MAX_BLOCKS * s->channels *
- AC3_MAX_COEFS * sizeof(*s->psd_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->band_psd_buffer, AC3_MAX_BLOCKS * s->channels *
- 64 * sizeof(*s->band_psd_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->mask_buffer, AC3_MAX_BLOCKS * s->channels *
- 64 * sizeof(*s->mask_buffer), alloc_fail);
- FF_ALLOC_OR_GOTO(avctx, s->qmant_buffer, AC3_MAX_BLOCKS * s->channels *
- AC3_MAX_COEFS * sizeof(*s->qmant_buffer), alloc_fail);
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- AC3Block *block = &s->blocks[blk];
- FF_ALLOC_OR_GOTO(avctx, block->bap, s->channels * sizeof(*block->bap),
- alloc_fail);
- FF_ALLOCZ_OR_GOTO(avctx, block->mdct_coef, s->channels * sizeof(*block->mdct_coef),
- alloc_fail);
- FF_ALLOCZ_OR_GOTO(avctx, block->exp, s->channels * sizeof(*block->exp),
- alloc_fail);
- FF_ALLOCZ_OR_GOTO(avctx, block->grouped_exp, s->channels * sizeof(*block->grouped_exp),
- alloc_fail);
- FF_ALLOCZ_OR_GOTO(avctx, block->psd, s->channels * sizeof(*block->psd),
- alloc_fail);
- FF_ALLOCZ_OR_GOTO(avctx, block->band_psd, s->channels * sizeof(*block->band_psd),
- alloc_fail);
- FF_ALLOCZ_OR_GOTO(avctx, block->mask, s->channels * sizeof(*block->mask),
- alloc_fail);
- FF_ALLOCZ_OR_GOTO(avctx, block->qmant, s->channels * sizeof(*block->qmant),
- alloc_fail);
-
- for (ch = 0; ch < s->channels; ch++) {
- block->bap[ch] = &s->bap_buffer [AC3_MAX_COEFS * (blk * s->channels + ch)];
- block->mdct_coef[ch] = &s->mdct_coef_buffer [AC3_MAX_COEFS * (blk * s->channels + ch)];
- block->exp[ch] = &s->exp_buffer [AC3_MAX_COEFS * (blk * s->channels + ch)];
- block->grouped_exp[ch] = &s->grouped_exp_buffer[128 * (blk * s->channels + ch)];
- block->psd[ch] = &s->psd_buffer [AC3_MAX_COEFS * (blk * s->channels + ch)];
- block->band_psd[ch] = &s->band_psd_buffer [64 * (blk * s->channels + ch)];
- block->mask[ch] = &s->mask_buffer [64 * (blk * s->channels + ch)];
- block->qmant[ch] = &s->qmant_buffer [AC3_MAX_COEFS * (blk * s->channels + ch)];
- }
- }
-
- return 0;
-alloc_fail:
- return AVERROR(ENOMEM);
-}
-
-
-/**
- * Initialize the encoder.
- */
-static av_cold int ac3_encode_init(AVCodecContext *avctx)
-{
- AC3EncodeContext *s = avctx->priv_data;
- int ret, frame_size_58;
-
- avctx->frame_size = AC3_FRAME_SIZE;
-
- ac3_common_init();
-
- ret = validate_options(avctx, s);
- if (ret)
- return ret;
-
- s->bitstream_id = 8 + s->bit_alloc.sr_shift;
- s->bitstream_mode = 0; /* complete main audio service */
-
- s->frame_size_min = 2 * ff_ac3_frame_size_tab[s->frame_size_code][s->bit_alloc.sr_code];
- s->bits_written = 0;
- s->samples_written = 0;
- s->frame_size = s->frame_size_min;
-
- /* calculate crc_inv for both possible frame sizes */
- frame_size_58 = (( s->frame_size >> 2) + ( s->frame_size >> 4)) << 1;
- s->crc_inv[0] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
- if (s->bit_alloc.sr_code == 1) {
- frame_size_58 = (((s->frame_size+2) >> 2) + ((s->frame_size+2) >> 4)) << 1;
- s->crc_inv[1] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
- }
-
- set_bandwidth(s);
-
- exponent_init(s);
-
- bit_alloc_init(s);
-
- ret = mdct_init(avctx, &s->mdct, 9);
- if (ret)
- goto init_fail;
-
- ret = allocate_buffers(avctx);
- if (ret)
- goto init_fail;
-
- avctx->coded_frame= avcodec_alloc_frame();
-
- dsputil_init(&s->dsp, avctx);
-
- return 0;
-init_fail:
- ac3_encode_close(avctx);
- return ret;
-}
-
-
-#ifdef TEST
-/*************************************************************************/
-/* TEST */
-
-#include "libavutil/lfg.h"
-
-#define MDCT_NBITS 9
-#define MDCT_SAMPLES (1 << MDCT_NBITS)
-#define FN (MDCT_SAMPLES/4)
-
-
-static void fft_test(AC3MDCTContext *mdct, AVLFG *lfg)
-{
- IComplex in[FN], in1[FN];
- int k, n, i;
- float sum_re, sum_im, a;
-
- for (i = 0; i < FN; i++) {
- in[i].re = av_lfg_get(lfg) % 65535 - 32767;
- in[i].im = av_lfg_get(lfg) % 65535 - 32767;
- in1[i] = in[i];
- }
- fft(mdct, in, 7);
-
- /* do it by hand */
- for (k = 0; k < FN; k++) {
- sum_re = 0;
- sum_im = 0;
- for (n = 0; n < FN; n++) {
- a = -2 * M_PI * (n * k) / FN;
- sum_re += in1[n].re * cos(a) - in1[n].im * sin(a);
- sum_im += in1[n].re * sin(a) + in1[n].im * cos(a);
- }
- av_log(NULL, AV_LOG_DEBUG, "%3d: %6d,%6d %6.0f,%6.0f\n",
- k, in[k].re, in[k].im, sum_re / FN, sum_im / FN);
- }
-}
-
-
-static void mdct_test(AC3MDCTContext *mdct, AVLFG *lfg)
-{
- int16_t input[MDCT_SAMPLES];
- int32_t output[AC3_MAX_COEFS];
- float input1[MDCT_SAMPLES];
- float output1[AC3_MAX_COEFS];
- float s, a, err, e, emax;
- int i, k, n;
-
- for (i = 0; i < MDCT_SAMPLES; i++) {
- input[i] = (av_lfg_get(lfg) % 65535 - 32767) * 9 / 10;
- input1[i] = input[i];
- }
-
- mdct512(mdct, output, input);
-
- /* do it by hand */
- for (k = 0; k < AC3_MAX_COEFS; k++) {
- s = 0;
- for (n = 0; n < MDCT_SAMPLES; n++) {
- a = (2*M_PI*(2*n+1+MDCT_SAMPLES/2)*(2*k+1) / (4 * MDCT_SAMPLES));
- s += input1[n] * cos(a);
- }
- output1[k] = -2 * s / MDCT_SAMPLES;
- }
-
- err = 0;
- emax = 0;
- for (i = 0; i < AC3_MAX_COEFS; i++) {
- av_log(NULL, AV_LOG_DEBUG, "%3d: %7d %7.0f\n", i, output[i], output1[i]);
- e = output[i] - output1[i];
- if (e > emax)
- emax = e;
- err += e * e;
- }
- av_log(NULL, AV_LOG_DEBUG, "err2=%f emax=%f\n", err / AC3_MAX_COEFS, emax);
-}
-
-
-int main(void)
-{
- AVLFG lfg;
- AC3MDCTContext mdct;
-
- mdct.avctx = NULL;
- av_log_set_level(AV_LOG_DEBUG);
- mdct_init(&mdct, 9);
-
- fft_test(&mdct, &lfg);
- mdct_test(&mdct, &lfg);
-
- return 0;
-}
-#endif /* TEST */
-
-
-AVCodec ac3_encoder = {
- "ac3",
- AVMEDIA_TYPE_AUDIO,
- CODEC_ID_AC3,
- sizeof(AC3EncodeContext),
- ac3_encode_init,
- ac3_encode_frame,
- ac3_encode_close,
- NULL,
- .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
- .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
- .channel_layouts = ac3_channel_layouts,
-};
+#endif /* AVCODEC_AC3ENC_FIXED_H */
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