[FFmpeg-devel] [PATCH 2/2] libavcodec: Implementation of AC3 fixed point decoder

Nedeljko Babic nbabic at mips.com
Thu Feb 28 16:10:31 CET 2013


Signed-off-by: Nedeljko Babic <nbabic at mips.com>
---
 libavcodec/Makefile       |    3 +-
 libavcodec/ac3.h          |   62 ++++++++++++--
 libavcodec/ac3dec.c       |  206 +++++++++++++++++++++++++++------------------
 libavcodec/ac3dec.h       |   39 +++++----
 libavcodec/ac3dec_fixed.c |  166 ++++++++++++++++++++++++++++++++++++
 libavcodec/ac3dec_float.c |   77 +++++++++++++++++
 libavcodec/ac3dsp.c       |   26 ++++++
 libavcodec/ac3dsp.h       |    2 +
 libavcodec/allcodecs.c    |    1 +
 libavcodec/kbdwin.c       |   23 +++++
 libavcodec/kbdwin.h       |    1 +
 libavutil/Makefile        |    1 +
 libavutil/fixed_dsp.c     |   73 ++++++++++++++++
 libavutil/fixed_dsp.h     |   81 ++++++++++++++++++
 14 files changed, 653 insertions(+), 108 deletions(-)
 create mode 100644 libavcodec/ac3dec_fixed.c
 create mode 100644 libavcodec/ac3dec_float.c
 create mode 100644 libavutil/fixed_dsp.c
 create mode 100644 libavutil/fixed_dsp.h

diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 95f1c0c..9402fac 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -89,7 +89,8 @@ OBJS-$(CONFIG_AAC_ENCODER)             += aacenc.o aaccoder.o    \
                                           psymodel.o iirfilter.o \
                                           mpeg4audio.o kbdwin.o
 OBJS-$(CONFIG_AASC_DECODER)            += aasc.o msrledec.o
-OBJS-$(CONFIG_AC3_DECODER)             += ac3dec.o ac3dec_data.o ac3.o kbdwin.o
+OBJS-$(CONFIG_AC3_DECODER)             += ac3dec_float.o ac3dec_data.o ac3.o kbdwin.o
+OBJS-$(CONFIG_AC3FIXED_DECODER)        += ac3dec_fixed.o ac3dec_data.o ac3.o kbdwin.o
 OBJS-$(CONFIG_AC3_ENCODER)             += ac3enc_float.o ac3enc.o ac3tab.o \
                                           ac3.o kbdwin.o
 OBJS-$(CONFIG_AC3_FIXED_ENCODER)       += ac3enc_fixed.o ac3enc.o ac3tab.o ac3.o
diff --git a/libavcodec/ac3.h b/libavcodec/ac3.h
index e609bb5..adf68a3 100644
--- a/libavcodec/ac3.h
+++ b/libavcodec/ac3.h
@@ -51,16 +51,60 @@
 #define EXP_D25   2
 #define EXP_D45   3
 
+#ifndef CONFIG_AC3_FIXED
+#define CONFIG_AC3_FIXED 0
+#endif
+
+#if CONFIG_AC3_FIXED
+
+#define CONFIG_FFT_FLOAT 0
+
+#define FIXR(a)                 ((int)((a) * 0 + 0.5))
+#define FIXR12(a)               ((int)((a) * 4096 + 0.5))
+#define FIXR15(a)               ((int)((a) * 32768 + 0.5))
+#define ROUND15(x)              ((x) + 16384) >> 15
+
+#define AC3_RENAME(x)           x ## _fixed
+#define AC3_NORM(norm)          (1<<24)/(norm)
+#define AC3_MUL(a,b)            ((((int64_t) (a)) * (b))>>12)
+#define AC3_DYNAMIC_RANGE(x)    (x)
+#define AC3_SPX_BLEND(x)        (x)
+#define AC3_DYNAMIC_RANGE1      0
+
+#define INTFLOAT                int
+#define SHORTFLOAT              int16_t
+
+#else /* CONFIG_AC3_FIXED */
+
+#define FIXR(x)                 ((float)(x))
+#define FIXR12(x)               ((float)(x))
+#define FIXR15(x)               ((float)(x))
+#define ROUND15(x)              (x)
+
+#define AC3_RENAME(x)           x
+#define AC3_NORM(norm)          (1.0f/(norm))
+#define AC3_MUL(a,b)            ((a) * (b))
+#define AC3_DYNAMIC_RANGE(x)    ((dynamic_range_tab[x] - 1.0) * s->drc_scale) + 1.0
+#define AC3_SPX_BLEND(x)        (x)* (1.0f/32)
+#define AC3_DYNAMIC_RANGE1      1.0f
+
+#define INTFLOAT                float
+#define SHORTFLOAT              float
+
+#endif /* CONFIG_AC3_FIXED */
+
+#define AC3_LEVEL(x)            ROUND15((x) * FIXR15(0.7071067811865476))
+
 /* pre-defined gain values */
-#define LEVEL_PLUS_3DB          1.4142135623730950
-#define LEVEL_PLUS_1POINT5DB    1.1892071150027209
-#define LEVEL_MINUS_1POINT5DB   0.8408964152537145
-#define LEVEL_MINUS_3DB         0.7071067811865476
-#define LEVEL_MINUS_4POINT5DB   0.5946035575013605
-#define LEVEL_MINUS_6DB         0.5000000000000000
-#define LEVEL_MINUS_9DB         0.3535533905932738
-#define LEVEL_ZERO              0.0000000000000000
-#define LEVEL_ONE               1.0000000000000000
+#define LEVEL_PLUS_3DB          FIXR12(1.4142135623730950)
+#define LEVEL_PLUS_1POINT5DB    FIXR12(1.1892071150027209)
+#define LEVEL_MINUS_1POINT5DB   FIXR12(0.8408964152537145)
+#define LEVEL_MINUS_3DB         FIXR12(0.7071067811865476)
+#define LEVEL_MINUS_4POINT5DB   FIXR12(0.5946035575013605)
+#define LEVEL_MINUS_6DB         FIXR12(0.5000000000000000)
+#define LEVEL_MINUS_9DB         FIXR12(0.3535533905932738)
+#define LEVEL_ZERO              FIXR12(0.0000000000000000)
+#define LEVEL_ONE               FIXR12(1.0000000000000000)
 
 /** Delta bit allocation strategy */
 typedef enum {
diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c
index 5dde004..6b49fb5 100644
--- a/libavcodec/ac3dec.c
+++ b/libavcodec/ac3dec.c
@@ -64,7 +64,7 @@ static const uint8_t quantization_tab[16] = {
 static float dynamic_range_tab[256];
 
 /** Adjustments in dB gain */
-static const float gain_levels[9] = {
+static const INTFLOAT AC3_RENAME(gain_levels)[9] = {
     LEVEL_PLUS_3DB,
     LEVEL_PLUS_1POINT5DB,
     LEVEL_ONE,
@@ -168,14 +168,22 @@ static av_cold int ac3_decode_init(AVCodecContext *avctx)
     ac3_tables_init();
     ff_mdct_init(&s->imdct_256, 8, 1, 1.0);
     ff_mdct_init(&s->imdct_512, 9, 1, 1.0);
-    ff_kbd_window_init(s->window, 5.0, 256);
+    AC3_RENAME(ff_kbd_window_init)(s->window, 5.0, 256);
     ff_dsputil_init(&s->dsp, avctx);
+#if CONFIG_AC3_FIXED
+    avpriv_fixed_dsp_init(&s->fdsp, avctx->flags & CODEC_FLAG_BITEXACT);
+#else
     avpriv_float_dsp_init(&s->fdsp, avctx->flags & CODEC_FLAG_BITEXACT);
+#endif
     ff_ac3dsp_init(&s->ac3dsp, avctx->flags & CODEC_FLAG_BITEXACT);
     ff_fmt_convert_init(&s->fmt_conv, avctx);
     av_lfg_init(&s->dith_state, 0);
 
+#if CONFIG_AC3_FIXED
+    avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
+#else
     avctx->sample_fmt = AV_SAMPLE_FMT_FLTP;
+#endif
 
     /* allow downmixing to stereo or mono */
     if (avctx->channels > 0 && avctx->request_channels > 0 &&
@@ -301,20 +309,20 @@ static int parse_frame_header(AC3DecodeContext *s)
 static void set_downmix_coeffs(AC3DecodeContext *s)
 {
     int i;
-    float cmix = gain_levels[s->  center_mix_level];
-    float smix = gain_levels[s->surround_mix_level];
-    float norm0, norm1;
+    SHORTFLOAT cmix = AC3_RENAME(gain_levels)[s->  center_mix_level];
+    SHORTFLOAT smix = AC3_RENAME(gain_levels)[s->surround_mix_level];
+    INTFLOAT norm0, norm1;
 
     for (i = 0; i < s->fbw_channels; i++) {
-        s->downmix_coeffs[i][0] = gain_levels[ac3_default_coeffs[s->channel_mode][i][0]];
-        s->downmix_coeffs[i][1] = gain_levels[ac3_default_coeffs[s->channel_mode][i][1]];
+        s->downmix_coeffs[i][0] = AC3_RENAME(gain_levels)[ac3_default_coeffs[s->channel_mode][i][0]];
+        s->downmix_coeffs[i][1] = AC3_RENAME(gain_levels)[ac3_default_coeffs[s->channel_mode][i][1]];
     }
     if (s->channel_mode > 1 && s->channel_mode & 1) {
         s->downmix_coeffs[1][0] = s->downmix_coeffs[1][1] = cmix;
     }
     if (s->channel_mode == AC3_CHMODE_2F1R || s->channel_mode == AC3_CHMODE_3F1R) {
         int nf = s->channel_mode - 2;
-        s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf][1] = smix * LEVEL_MINUS_3DB;
+        s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf][1] = AC3_LEVEL(smix);
     }
     if (s->channel_mode == AC3_CHMODE_2F2R || s->channel_mode == AC3_CHMODE_3F2R) {
         int nf = s->channel_mode - 4;
@@ -322,22 +330,23 @@ static void set_downmix_coeffs(AC3DecodeContext *s)
     }
 
     /* renormalize */
-    norm0 = norm1 = 0.0;
+    norm0 = norm1 = FIXR(0.0);
     for (i = 0; i < s->fbw_channels; i++) {
         norm0 += s->downmix_coeffs[i][0];
         norm1 += s->downmix_coeffs[i][1];
     }
-    norm0 = 1.0f / norm0;
-    norm1 = 1.0f / norm1;
+
+    norm0 = AC3_NORM(norm0);
+    norm1 = AC3_NORM(norm1);
+
     for (i = 0; i < s->fbw_channels; i++) {
-        s->downmix_coeffs[i][0] *= norm0;
-        s->downmix_coeffs[i][1] *= norm1;
+        s->downmix_coeffs[i][0] = (SHORTFLOAT)AC3_MUL(s->downmix_coeffs[i][0],norm0);
+        s->downmix_coeffs[i][1] = (SHORTFLOAT)AC3_MUL(s->downmix_coeffs[i][1],norm1);
     }
 
     if (s->output_mode == AC3_CHMODE_MONO) {
         for (i = 0; i < s->fbw_channels; i++)
-            s->downmix_coeffs[i][0] = (s->downmix_coeffs[i][0] +
-                                       s->downmix_coeffs[i][1]) * LEVEL_MINUS_3DB;
+            s->downmix_coeffs[i][0] = AC3_LEVEL(s->downmix_coeffs[i][0] + s->downmix_coeffs[i][1]);
     }
 }
 
@@ -601,23 +610,54 @@ static inline void do_imdct(AC3DecodeContext *s, int channels)
     for (ch = 1; ch <= channels; ch++) {
         if (s->block_switch[ch]) {
             int i;
-            float *x = s->tmp_output + 128;
+            FFTSample *x = s->tmp_output + 128;
             for (i = 0; i < 128; i++)
                 x[i] = s->transform_coeffs[ch][2 * i];
             s->imdct_256.imdct_half(&s->imdct_256, s->tmp_output, x);
-            s->fdsp.vector_fmul_window(s->outptr[ch - 1], s->delay[ch - 1],
+            s->fdsp.AC3_RENAME(vector_fmul_window)(s->outptr[ch - 1], s->delay[ch - 1],
                                        s->tmp_output, s->window, 128);
             for (i = 0; i < 128; i++)
                 x[i] = s->transform_coeffs[ch][2 * i + 1];
             s->imdct_256.imdct_half(&s->imdct_256, s->delay[ch - 1], x);
         } else {
             s->imdct_512.imdct_half(&s->imdct_512, s->tmp_output, s->transform_coeffs[ch]);
-            s->fdsp.vector_fmul_window(s->outptr[ch - 1], s->delay[ch - 1],
+            s->fdsp.AC3_RENAME(vector_fmul_window)(s->outptr[ch - 1], s->delay[ch - 1],
                                        s->tmp_output, s->window, 128);
-            memcpy(s->delay[ch - 1], s->tmp_output + 128, 128 * sizeof(float));
+            memcpy(s->delay[ch - 1], s->tmp_output + 128, 128 * sizeof(FFTSample));
+        }
+    }
+}
+
+/**
+ * Downmix samples from original signal to stereo or mono (this is for 16-bit samples
+ * and fixed point decoder - original (for 32-bit samples) is in ac3dsp.c).
+ */
+#if CONFIG_AC3_FIXED
+static void ac3_downmix_c_fixed16(int16_t **samples, int16_t (*matrix)[2],
+                      int out_ch, int in_ch, int len)
+{
+    int i, j;
+    int v0, v1;
+    if (out_ch == 2) {
+        for (i = 0; i < len; i++) {
+            v0 = v1 = 0;
+            for (j = 0; j < in_ch; j++) {
+                v0 += samples[j][i] * matrix[j][0];
+                v1 += samples[j][i] * matrix[j][1];
+            }
+            samples[0][i] = (v0+2048)>>12;
+            samples[1][i] = (v1+2048)>>12;
+        }
+    } else if (out_ch == 1) {
+        for (i = 0; i < len; i++) {
+            v0 = 0;
+            for (j = 0; j < in_ch; j++)
+                v0 += samples[j][i] * matrix[j][0];
+            samples[0][i] = (v0+2048)>>12;
         }
     }
 }
+#endif
 
 /**
  * Upmix delay samples from stereo to original channel layout.
@@ -747,10 +787,9 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
     i = !s->channel_mode;
     do {
         if (get_bits1(gbc)) {
-            s->dynamic_range[i] = ((dynamic_range_tab[get_bits(gbc, 8)] - 1.0) *
-                                  s->drc_scale) + 1.0;
+            s->dynamic_range[i] = AC3_DYNAMIC_RANGE(get_bits(gbc, 8));
         } else if (blk == 0) {
-            s->dynamic_range[i] = 1.0f;
+            s->dynamic_range[i] = AC3_DYNAMIC_RANGE1;
         }
     } while (i--);
 
@@ -776,6 +815,10 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
             if (start_subband > 7)
                 start_subband += start_subband - 7;
             end_subband    = get_bits(gbc, 3) + 5;
+#if CONFIG_AC3_FIXED
+            s->spx_dst_end_freq = end_freq_inv_tab[end_subband];
+            end_subband += 5;
+#endif
             if (end_subband   > 7)
                 end_subband   += end_subband   - 7;
             dst_start_freq = dst_start_freq * 12 + 25;
@@ -796,7 +839,9 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
 
             s->spx_dst_start_freq = dst_start_freq;
             s->spx_src_start_freq = src_start_freq;
+#if !CONFIG_AC3_FIXED
             s->spx_dst_end_freq   = dst_end_freq;
+#endif
 
             decode_band_structure(gbc, blk, s->eac3, 0,
                                   start_subband, end_subband,
@@ -816,18 +861,40 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
         for (ch = 1; ch <= fbw_channels; ch++) {
             if (s->channel_uses_spx[ch]) {
                 if (s->first_spx_coords[ch] || get_bits1(gbc)) {
-                    float spx_blend;
+                    INTFLOAT spx_blend;
                     int bin, master_spx_coord;
 
                     s->first_spx_coords[ch] = 0;
-                    spx_blend = get_bits(gbc, 5) * (1.0f/32);
+                    spx_blend = AC3_SPX_BLEND(get_bits(gbc, 5));
                     master_spx_coord = get_bits(gbc, 2) * 3;
 
                     bin = s->spx_src_start_freq;
                     for (bnd = 0; bnd < s->num_spx_bands; bnd++) {
                         int bandsize;
                         int spx_coord_exp, spx_coord_mant;
-                        float nratio, sblend, nblend, spx_coord;
+                        INTFLOAT nratio, sblend, nblend;
+#if CONFIG_AC3_FIXED
+                        int64_t accu;
+                        /* calculate blending factors */
+                        bandsize = s->spx_band_sizes[bnd];
+                        accu = (int64_t)((bin << 23) + (bandsize << 22)) * s->spx_dst_end_freq;
+                        nratio = (int)(accu >> 32);
+                        nratio -= spx_blend << 18;
+
+                        if (nratio < 0) {
+                            nblend = 0;
+                            sblend = 0x800000;
+                        } else if (nratio > 0x7fffff) {
+                            nblend = 0x800000;
+                            sblend = 0;
+                        } else {
+                            nblend = ac3_fixed_sqrt(nratio);
+                            accu = (int64_t)nblend * 1859775393;
+                            nblend = (int)((accu + (1<<29)) >> 30);
+                            sblend = ac3_fixed_sqrt(0x800000 - nratio);
+                        }
+#else
+                        float spx_coord;
 
                         /* calculate blending factors */
                         bandsize = s->spx_band_sizes[bnd];
@@ -836,6 +903,7 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
                         nblend = sqrtf(3.0f * nratio); // noise is scaled by sqrt(3)
                                                        // to give unity variance
                         sblend = sqrtf(1.0f - nratio);
+#endif
                         bin += bandsize;
 
                         /* decode spx coordinates */
@@ -844,11 +912,18 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
                         if (spx_coord_exp == 15) spx_coord_mant <<= 1;
                         else                     spx_coord_mant += 4;
                         spx_coord_mant <<= (25 - spx_coord_exp - master_spx_coord);
-                        spx_coord = spx_coord_mant * (1.0f / (1 << 23));
 
                         /* multiply noise and signal blending factors by spx coordinate */
+#if CONFIG_AC3_FIXED
+                        accu = (int64_t)nblend * spx_coord_mant;
+                        s->spx_noise_blend[ch][bnd]  = (int)((accu + (1<<22)) >> 23);
+                        accu = (int64_t)sblend * spx_coord_mant;
+                        s->spx_signal_blend[ch][bnd] = (int)((accu + (1<<22)) >> 23);
+#else
+                        spx_coord = spx_coord_mant * (1.0f / (1 << 23));
                         s->spx_noise_blend [ch][bnd] = nblend * spx_coord;
                         s->spx_signal_blend[ch][bnd] = sblend * spx_coord;
+#endif
                     }
                 }
             } else {
@@ -1203,6 +1278,17 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
     if (s->channel_mode == AC3_CHMODE_STEREO)
         do_rematrixing(s);
 
+#if CONFIG_AC3_FIXED
+    for (ch = 1; ch <= s->channels; ch++) {
+        int gain;
+        if(s->channel_mode == AC3_CHMODE_DUALMONO) {
+            gain = s->dynamic_range[2-ch];
+        } else {
+            gain = s->dynamic_range[0];
+        }
+        scale_coefs(s->transform_coeffs[ch], s->fixed_coeffs[ch], gain, 256);
+    }
+#else
     /* apply scaling to coefficients (headroom, dynrng) */
     for (ch = 1; ch <= s->channels; ch++) {
         float gain = 1.0 / 4194304.0f;
@@ -1214,6 +1300,7 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
         s->fmt_conv.int32_to_float_fmul_scalar(s->transform_coeffs[ch],
                                                s->fixed_coeffs[ch], gain, 256);
     }
+#endif
 
     /* apply spectral extension to high frequency bins */
     if (s->spx_in_use && CONFIG_EAC3_DECODER) {
@@ -1235,23 +1322,26 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
         }
 
         do_imdct(s, s->channels);
-
         if (downmix_output) {
+#if CONFIG_AC3_FIXED
+            ac3_downmix_c_fixed16(s->outptr, s->downmix_coeffs,
+                              s->out_channels, s->fbw_channels, 256);
+#else
             s->ac3dsp.downmix(s->outptr, s->downmix_coeffs,
                               s->out_channels, s->fbw_channels, 256);
+#endif
         }
     } else {
         if (downmix_output) {
-            s->ac3dsp.downmix(s->xcfptr + 1, s->downmix_coeffs,
+            s->ac3dsp.AC3_RENAME(downmix)(s->xcfptr + 1, s->downmix_coeffs,
                               s->out_channels, s->fbw_channels, 256);
         }
 
         if (downmix_output && !s->downmixed) {
             s->downmixed = 1;
-            s->ac3dsp.downmix(s->dlyptr, s->downmix_coeffs, s->out_channels,
+            s->ac3dsp.AC3_RENAME(downmix)(s->dlyptr, s->downmix_coeffs, s->out_channels,
                               s->fbw_channels, 128);
         }
-
         do_imdct(s, s->out_channels);
     }
 
@@ -1270,7 +1360,7 @@ static int ac3_decode_frame(AVCodecContext * avctx, void *data,
     AC3DecodeContext *s = avctx->priv_data;
     int blk, ch, err, ret;
     const uint8_t *channel_map;
-    const float *output[AC3_MAX_CHANNELS];
+    const SHORTFLOAT *output[AC3_MAX_CHANNELS];
 
     /* copy input buffer to decoder context to avoid reading past the end
        of the buffer, which can be caused by a damaged input stream. */
@@ -1353,8 +1443,8 @@ static int ac3_decode_frame(AVCodecContext * avctx, void *data,
         avctx->channels       = s->out_channels;
         avctx->channel_layout = s->channel_layout;
 
-        s->loro_center_mix_level   = gain_levels[s->  center_mix_level];
-        s->loro_surround_mix_level = gain_levels[s->surround_mix_level];
+        s->loro_center_mix_level   = AC3_RENAME(gain_levels)[s->  center_mix_level];
+        s->loro_surround_mix_level = AC3_RENAME(gain_levels)[s->surround_mix_level];
         s->ltrt_center_mix_level   = LEVEL_MINUS_3DB;
         s->ltrt_surround_mix_level = LEVEL_MINUS_3DB;
         /* set downmixing coefficients if needed */
@@ -1388,7 +1478,7 @@ static int ac3_decode_frame(AVCodecContext * avctx, void *data,
     }
     for (ch = 0; ch < s->channels; ch++) {
         if (ch < s->out_channels)
-            s->outptr[channel_map[ch]] = (float *)frame->data[ch];
+            s->outptr[channel_map[ch]] = (SHORTFLOAT *)frame->data[ch];
     }
     for (blk = 0; blk < s->num_blocks; blk++) {
         if (!err && decode_audio_block(s, blk)) {
@@ -1397,7 +1487,7 @@ static int ac3_decode_frame(AVCodecContext * avctx, void *data,
         }
         if (err)
             for (ch = 0; ch < s->out_channels; ch++)
-                memcpy(((float*)frame->data[ch]) + AC3_BLOCK_SIZE*blk, output[ch], 1024);
+                memcpy(((SHORTFLOAT*)frame->data[ch]) + AC3_BLOCK_SIZE*blk, output[ch], 1024);
         for (ch = 0; ch < s->out_channels; ch++)
             output[ch] = s->outptr[channel_map[ch]];
         for (ch = 0; ch < s->out_channels; ch++) {
@@ -1442,49 +1532,3 @@ static const AVOption options[] = {
 
     { NULL},
 };
-
-static const AVClass ac3_decoder_class = {
-    .class_name = "AC3 decoder",
-    .item_name  = av_default_item_name,
-    .option     = options,
-    .version    = LIBAVUTIL_VERSION_INT,
-};
-
-AVCodec ff_ac3_decoder = {
-    .name           = "ac3",
-    .type           = AVMEDIA_TYPE_AUDIO,
-    .id             = AV_CODEC_ID_AC3,
-    .priv_data_size = sizeof (AC3DecodeContext),
-    .init           = ac3_decode_init,
-    .close          = ac3_decode_end,
-    .decode         = ac3_decode_frame,
-    .capabilities   = CODEC_CAP_DR1,
-    .long_name      = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
-    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
-                                                      AV_SAMPLE_FMT_NONE },
-    .priv_class     = &ac3_decoder_class,
-};
-
-#if CONFIG_EAC3_DECODER
-static const AVClass eac3_decoder_class = {
-    .class_name = "E-AC3 decoder",
-    .item_name  = av_default_item_name,
-    .option     = options,
-    .version    = LIBAVUTIL_VERSION_INT,
-};
-
-AVCodec ff_eac3_decoder = {
-    .name           = "eac3",
-    .type           = AVMEDIA_TYPE_AUDIO,
-    .id             = AV_CODEC_ID_EAC3,
-    .priv_data_size = sizeof (AC3DecodeContext),
-    .init           = ac3_decode_init,
-    .close          = ac3_decode_end,
-    .decode         = ac3_decode_frame,
-    .capabilities   = CODEC_CAP_DR1,
-    .long_name      = NULL_IF_CONFIG_SMALL("ATSC A/52B (AC-3, E-AC-3)"),
-    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
-                                                      AV_SAMPLE_FMT_NONE },
-    .priv_class     = &eac3_decoder_class,
-};
-#endif
diff --git a/libavcodec/ac3dec.h b/libavcodec/ac3dec.h
index 6c99ef6..e6a2e62 100644
--- a/libavcodec/ac3dec.h
+++ b/libavcodec/ac3dec.h
@@ -51,6 +51,7 @@
 #define AVCODEC_AC3DEC_H
 
 #include "libavutil/float_dsp.h"
+#include "libavutil/fixed_dsp.h"
 #include "libavutil/lfg.h"
 #include "ac3.h"
 #include "ac3dsp.h"
@@ -90,10 +91,10 @@ typedef struct AC3DecodeContext {
 ///@}
 
     int preferred_stereo_downmix;
-    float ltrt_center_mix_level;
-    float ltrt_surround_mix_level;
-    float loro_center_mix_level;
-    float loro_surround_mix_level;
+    SHORTFLOAT ltrt_center_mix_level;
+    SHORTFLOAT ltrt_surround_mix_level;
+    SHORTFLOAT loro_center_mix_level;
+    SHORTFLOAT loro_surround_mix_level;
 
 ///@name Frame syntax parameters
     int snr_offset_strategy;                ///< SNR offset strategy                    (snroffststr)
@@ -130,8 +131,8 @@ typedef struct AC3DecodeContext {
     int num_spx_bands;                          ///< number of spx bands                    (nspxbnds)
     uint8_t spx_band_sizes[SPX_MAX_BANDS];      ///< number of bins in each spx band
     uint8_t first_spx_coords[AC3_MAX_CHANNELS]; ///< first spx coordinates states           (firstspxcos)
-    float spx_noise_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS]; ///< spx noise blending factor  (nblendfact)
-    float spx_signal_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS];///< spx signal blending factor (sblendfact)
+    INTFLOAT spx_noise_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS]; ///< spx noise blending factor  (nblendfact)
+    INTFLOAT spx_signal_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS];///< spx signal blending factor (sblendfact)
 ///@}
 
 ///@name Adaptive hybrid transform
@@ -143,15 +144,15 @@ typedef struct AC3DecodeContext {
     int fbw_channels;                           ///< number of full-bandwidth channels
     int channels;                               ///< number of total channels
     int lfe_ch;                                 ///< index of LFE channel
-    float downmix_coeffs[AC3_MAX_CHANNELS][2];  ///< stereo downmix coefficients
+    SHORTFLOAT downmix_coeffs[AC3_MAX_CHANNELS][2];  ///< stereo downmix coefficients
     int downmixed;                              ///< indicates if coeffs are currently downmixed
     int output_mode;                            ///< output channel configuration
     int out_channels;                           ///< number of output channels
 ///@}
 
 ///@name Dynamic range
-    float dynamic_range[2];                 ///< dynamic range
-    float drc_scale;                        ///< percentage of dynamic range compression to be applied
+    INTFLOAT dynamic_range[2];                 ///< dynamic range
+    INTFLOAT drc_scale;                        ///< percentage of dynamic range compression to be applied
 ///@}
 
 ///@name Bandwidth
@@ -199,22 +200,26 @@ typedef struct AC3DecodeContext {
 
 ///@name Optimization
     DSPContext dsp;                         ///< for optimization
+#if CONFIG_AC3_FIXED
+    AVFixedDSPContext fdsp;
+#else
     AVFloatDSPContext fdsp;
+#endif
     AC3DSPContext ac3dsp;
     FmtConvertContext fmt_conv;             ///< optimized conversion functions
 ///@}
 
-    float *outptr[AC3_MAX_CHANNELS];
-    float *xcfptr[AC3_MAX_CHANNELS];
-    float *dlyptr[AC3_MAX_CHANNELS];
+    SHORTFLOAT *outptr[AC3_MAX_CHANNELS];
+    INTFLOAT *xcfptr[AC3_MAX_CHANNELS];
+    INTFLOAT *dlyptr[AC3_MAX_CHANNELS];
 
 ///@name Aligned arrays
     DECLARE_ALIGNED(16, int,   fixed_coeffs)[AC3_MAX_CHANNELS][AC3_MAX_COEFS];       ///< fixed-point transform coefficients
-    DECLARE_ALIGNED(32, float, transform_coeffs)[AC3_MAX_CHANNELS][AC3_MAX_COEFS];   ///< transform coefficients
-    DECLARE_ALIGNED(32, float, delay)[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE];             ///< delay - added to the next block
-    DECLARE_ALIGNED(32, float, window)[AC3_BLOCK_SIZE];                              ///< window coefficients
-    DECLARE_ALIGNED(32, float, tmp_output)[AC3_BLOCK_SIZE];                          ///< temporary storage for output before windowing
-    DECLARE_ALIGNED(32, float, output)[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE];            ///< output after imdct transform and windowing
+    DECLARE_ALIGNED(32, INTFLOAT, transform_coeffs)[AC3_MAX_CHANNELS][AC3_MAX_COEFS];   ///< transform coefficients
+    DECLARE_ALIGNED(32, INTFLOAT, delay)[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE];             ///< delay - added to the next block
+    DECLARE_ALIGNED(32, INTFLOAT, window)[AC3_BLOCK_SIZE];                              ///< window coefficients
+    DECLARE_ALIGNED(32, INTFLOAT, tmp_output)[AC3_BLOCK_SIZE];                          ///< temporary storage for output before windowing
+    DECLARE_ALIGNED(32, SHORTFLOAT, output)[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE];            ///< output after imdct transform and windowing
     DECLARE_ALIGNED(32, uint8_t, input_buffer)[AC3_FRAME_BUFFER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE]; ///< temp buffer to prevent overread
 ///@}
 } AC3DecodeContext;
diff --git a/libavcodec/ac3dec_fixed.c b/libavcodec/ac3dec_fixed.c
new file mode 100644
index 0000000..e8373d9
--- /dev/null
+++ b/libavcodec/ac3dec_fixed.c
@@ -0,0 +1,166 @@
+/*
+ * Copyright (c) 2012
+ *      MIPS Technologies, Inc., California.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the MIPS Technologies, Inc., nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE MIPS TECHNOLOGIES, INC. ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE MIPS TECHNOLOGIES, INC. BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * Author:  Stanislav Ocovaj (socovaj at mips.com)
+ *
+ * AC3 fixed-point decoder for MIPS platforms
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#define CONFIG_FFT_FLOAT 0
+#define CONFIG_AC3_FIXED 1
+#define CONFIG_FFT_FIXED_32 1
+#include "ac3dec.h"
+
+
+/**
+ * Table for center mix levels
+ * reference: Section 5.4.2.4 cmixlev
+ */
+static const uint8_t center_levels[4] = { 4, 5, 6, 5 };
+
+/**
+ * Table for surround mix levels
+ * reference: Section 5.4.2.5 surmixlev
+ */
+static const uint8_t surround_levels[4] = { 4, 6, 7, 6 };
+
+int end_freq_inv_tab[8] =
+{
+    50529027, 44278013, 39403370, 32292987, 27356480, 23729101, 20951060, 18755316
+};
+
+static void scale_coefs (
+    int32_t *dst,
+    const int *src,
+    int dynrng,
+    int len)
+{
+    int i, shift, round;
+    int16_t mul;
+    int temp, temp1, temp2, temp3, temp4, temp5, temp6, temp7;
+
+    mul = (dynrng & 0x1f) + 0x20;
+    shift = 4 - ((dynrng << 24) >> 29);
+    round = 1 << (shift-1);
+    for (i=0; i<len; i+=8) {
+
+        temp = src[i] * mul;
+        temp1 = src[i+1] * mul;
+        temp = temp + round;
+        temp2 = src[i+2] * mul;
+
+        temp1 = temp1 + round;
+        dst[i] = temp >> shift;
+        temp3 = src[i+3] * mul;
+        temp2 = temp2 + round;
+
+        dst[i+1] = temp1 >> shift;
+        temp4 = src[i + 4] * mul;
+        temp3 = temp3 + round;
+        dst[i+2] = temp2 >> shift;
+
+        temp5 = src[i+5] * mul;
+        temp4 = temp4 + round;
+        dst[i+3] = temp3 >> shift;
+        temp6 = src[i+6] * mul;
+
+        dst[i+4] = temp4 >> shift;
+        temp5 = temp5 + round;
+        temp7 = src[i+7] * mul;
+        temp6 = temp6 + round;
+
+        dst[i+5] = temp5 >> shift;
+        temp7 = temp7 + round;
+        dst[i+6] = temp6 >> shift;
+        dst[i+7] = temp7 >> shift;
+
+    }
+}
+
+static int ac3_fixed_sqrt(int x)
+{
+    int retval;
+    int bit_mask;
+    int guess;
+    int square;
+    int   i;
+    long long accu;
+
+        retval = 0;
+        bit_mask = 0x400000;
+
+        for (i=0; i<23; i++){
+            guess = retval + bit_mask;
+            accu = (long long)guess * guess;
+            square = (int)(accu >> 23);
+            if (x >= square)
+                retval += bit_mask;
+            bit_mask >>= 1;
+        }
+    return retval;
+}
+
+#include "ac3dec.c"
+
+static const AVClass ac3_decoder_class = {
+    .class_name = "Fixed-Point AC-3 Decoder",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+AVCodec ff_ac3fixed_decoder = {
+    .name           = "ac3fixed",
+    .type           = AVMEDIA_TYPE_AUDIO,
+    .id             = CODEC_ID_AC3,
+    .priv_data_size = sizeof (AC3DecodeContext),
+    .init           = ac3_decode_init,
+    .close          = ac3_decode_end,
+    .decode         = ac3_decode_frame,
+    .capabilities   = CODEC_CAP_DR1,
+    .long_name      = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
+    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
+                                                      AV_SAMPLE_FMT_NONE },
+    .priv_class     = &ac3_decoder_class,
+};
diff --git a/libavcodec/ac3dec_float.c b/libavcodec/ac3dec_float.c
new file mode 100644
index 0000000..aebf243
--- /dev/null
+++ b/libavcodec/ac3dec_float.c
@@ -0,0 +1,77 @@
+/*
+ * AC-3 Audio Decoder
+ * This code was developed as part of Google Summer of Code 2006.
+ * E-AC-3 support was added as part of Google Summer of Code 2007.
+ *
+ * Copyright (c) 2006 Kartikey Mahendra BHATT (bhattkm at gmail dot com)
+ * Copyright (c) 2007-2008 Bartlomiej Wolowiec <bartek.wolowiec at gmail.com>
+ * Copyright (c) 2007 Justin Ruggles <justin.ruggles at gmail.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * Upmix delay samples from stereo to original channel layout.
+ */
+#include "ac3dec.h"
+#include "ac3dec.c"
+
+static const AVClass ac3_decoder_class = {
+    .class_name = "AC3 decoder",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+AVCodec ff_ac3_decoder = {
+    .name           = "ac3",
+    .type           = AVMEDIA_TYPE_AUDIO,
+    .id             = AV_CODEC_ID_AC3,
+    .priv_data_size = sizeof (AC3DecodeContext),
+    .init           = ac3_decode_init,
+    .close          = ac3_decode_end,
+    .decode         = ac3_decode_frame,
+    .capabilities   = CODEC_CAP_DR1,
+    .long_name      = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
+    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
+                                                      AV_SAMPLE_FMT_NONE },
+    .priv_class     = &ac3_decoder_class,
+};
+
+#if CONFIG_EAC3_DECODER
+static const AVClass eac3_decoder_class = {
+    .class_name = "E-AC3 decoder",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+AVCodec ff_eac3_decoder = {
+    .name           = "eac3",
+    .type           = AVMEDIA_TYPE_AUDIO,
+    .id             = AV_CODEC_ID_EAC3,
+    .priv_data_size = sizeof (AC3DecodeContext),
+    .init           = ac3_decode_init,
+    .close          = ac3_decode_end,
+    .decode         = ac3_decode_frame,
+    .capabilities   = CODEC_CAP_DR1,
+    .long_name      = NULL_IF_CONFIG_SMALL("ATSC A/52B (AC-3, E-AC-3)"),
+    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
+                                                      AV_SAMPLE_FMT_NONE },
+    .priv_class     = &eac3_decoder_class,
+};
+#endif
diff --git a/libavcodec/ac3dsp.c b/libavcodec/ac3dsp.c
index 6df3a68..7176928 100644
--- a/libavcodec/ac3dsp.c
+++ b/libavcodec/ac3dsp.c
@@ -239,6 +239,31 @@ static void ac3_downmix_c(float **samples, float (*matrix)[2],
     }
 }
 
+static void ac3_downmix_c_fixed(int32_t **samples, int16_t (*matrix)[2],
+                      int out_ch, int in_ch, int len)
+{
+    int i, j;
+    int64_t v0, v1;
+    if (out_ch == 2) {
+        for (i = 0; i < len; i++) {
+            v0 = v1 = 0;
+            for (j = 0; j < in_ch; j++) {
+                v0 += (int64_t)samples[j][i] * matrix[j][0];
+                v1 += (int64_t)samples[j][i] * matrix[j][1];
+            }
+            samples[0][i] = (v0+2048)>>12;
+            samples[1][i] = (v1+2048)>>12;
+        }
+    } else if (out_ch == 1) {
+        for (i = 0; i < len; i++) {
+            v0 = 0;
+            for (j = 0; j < in_ch; j++)
+                v0 += (int64_t)samples[j][i] * matrix[j][0];
+            samples[0][i] = (v0+2048)>>12;
+        }
+    }
+}
+
 av_cold void ff_ac3dsp_init(AC3DSPContext *c, int bit_exact)
 {
     c->ac3_exponent_min = ac3_exponent_min_c;
@@ -253,6 +278,7 @@ av_cold void ff_ac3dsp_init(AC3DSPContext *c, int bit_exact)
     c->sum_square_butterfly_int32 = ac3_sum_square_butterfly_int32_c;
     c->sum_square_butterfly_float = ac3_sum_square_butterfly_float_c;
     c->downmix = ac3_downmix_c;
+    c->downmix_fixed = ac3_downmix_c_fixed;
 
     if (ARCH_ARM)
         ff_ac3dsp_init_arm(c, bit_exact);
diff --git a/libavcodec/ac3dsp.h b/libavcodec/ac3dsp.h
index bafbc89..8ec4a69 100644
--- a/libavcodec/ac3dsp.h
+++ b/libavcodec/ac3dsp.h
@@ -134,6 +134,8 @@ typedef struct AC3DSPContext {
 
     void (*downmix)(float **samples, float (*matrix)[2], int out_ch,
                     int in_ch, int len);
+    void (*downmix_fixed)(int32_t **samples, int16_t (*matrix)[2], int out_ch,
+                    int in_ch, int len);
 } AC3DSPContext;
 
 void ff_ac3dsp_init    (AC3DSPContext *c, int bit_exact);
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index 584446f..a7794bc 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -309,6 +309,7 @@ void avcodec_register_all(void)
     REGISTER_DECODER(AAC_LATM,          aac_latm);
     REGISTER_ENCDEC (AC3,               ac3);
     REGISTER_ENCODER(AC3_FIXED,         ac3_fixed);
+    REGISTER_DECODER(AC3FIXED,          ac3fixed);
     REGISTER_ENCDEC (ALAC,              alac);
     REGISTER_DECODER(ALS,               als);
     REGISTER_DECODER(AMRNB,             amrnb);
diff --git a/libavcodec/kbdwin.c b/libavcodec/kbdwin.c
index 5a62e9d..c6cdabc 100644
--- a/libavcodec/kbdwin.c
+++ b/libavcodec/kbdwin.c
@@ -45,3 +45,26 @@ av_cold void ff_kbd_window_init(float *window, float alpha, int n)
    for (i = 0; i < n; i++)
        window[i] = sqrt(local_window[i] / sum);
 }
+
+av_cold void ff_kbd_window_init_fixed(int32_t *window, float alpha, int n)
+{
+    int i, j;
+    double sum = 0.0, bessel, tmp;
+    double local_window[FF_KBD_WINDOW_MAX];
+    double alpha2 = (alpha * M_PI / n) * (alpha * M_PI / n);
+
+    av_assert0(n <= FF_KBD_WINDOW_MAX);
+
+    for (i = 0; i < n; i++) {
+        tmp = i * (n - i) * alpha2;
+        bessel = 1.0;
+        for (j = BESSEL_I0_ITER; j > 0; j--)
+            bessel = bessel * tmp / (j * j) + 1;
+        sum += bessel;
+        local_window[i] = sum;
+    }
+
+    sum++;
+    for (i = 0; i < n; i++)
+       window[i] = (int)floor(2147483648.0 * sqrt(local_window[i] / sum) + 0.5);
+}
diff --git a/libavcodec/kbdwin.h b/libavcodec/kbdwin.h
index 4b93975..2e02e10 100644
--- a/libavcodec/kbdwin.h
+++ b/libavcodec/kbdwin.h
@@ -31,5 +31,6 @@
  * @param   n       size of half window, max FF_KBD_WINDOW_MAX
  */
 void ff_kbd_window_init(float *window, float alpha, int n);
+void ff_kbd_window_init_fixed(int32_t *window, float alpha, int n);
 
 #endif /* AVCODEC_KBDWIN_H */
diff --git a/libavutil/Makefile b/libavutil/Makefile
index 544c33f..bda2445 100644
--- a/libavutil/Makefile
+++ b/libavutil/Makefile
@@ -73,6 +73,7 @@ OBJS = adler32.o                                                        \
        fifo.o                                                           \
        file.o                                                           \
        float_dsp.o                                                      \
+       fixed_dsp.o                                                      \
        hmac.o                                                           \
        imgutils.o                                                       \
        intfloat_readwrite.o                                             \
diff --git a/libavutil/fixed_dsp.c b/libavutil/fixed_dsp.c
new file mode 100644
index 0000000..d3c4db6
--- /dev/null
+++ b/libavutil/fixed_dsp.c
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2012
+ *      MIPS Technologies, Inc., California.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the MIPS Technologies, Inc., nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE MIPS TECHNOLOGIES, INC. ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE MIPS TECHNOLOGIES, INC. BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * Author:  Nedeljko Babic (nbabic at mips.com)
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "fixed_dsp.h"
+#include "common.h"
+
+static void vector_fmul_window_fixed_c(int16_t *dst, const int32_t *src0,
+                                       const int32_t *src1, const int32_t *win, int len)
+{
+    int32_t s0, s1, wi, wj, i,j;
+
+    dst += len;
+    win += len;
+    src0+= len;
+
+    for (i=-len, j=len-1; i<0; i++, j--) {
+        s0 = src0[i];
+        s1 = src1[j];
+        wi = win[i];
+        wj = win[j];
+        dst[i] = av_clip_int16_c(((((int64_t)s0*wj - (int64_t)s1*wi + 0x40000000) >> 31) + 0x80) >> 8);
+        dst[j] = av_clip_int16_c(((((int64_t)s0*wi + (int64_t)s1*wj + 0x40000000) >> 31) + 0x80) >> 8);
+    }
+}
+
+void avpriv_fixed_dsp_init(AVFixedDSPContext *fdsp, int bit_exact)
+{
+    fdsp->vector_fmul_window_fixed = vector_fmul_window_fixed_c;
+}
diff --git a/libavutil/fixed_dsp.h b/libavutil/fixed_dsp.h
new file mode 100644
index 0000000..66bc104
--- /dev/null
+++ b/libavutil/fixed_dsp.h
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2012
+ *      MIPS Technologies, Inc., California.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the MIPS Technologies, Inc., nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE MIPS TECHNOLOGIES, INC. ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE MIPS TECHNOLOGIES, INC. BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * Author:  Nedeljko Babic (nbabic at mips.com)
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVUTIL_FIXED_DSP_H
+#define AVUTIL_FIXED_DSP_H
+
+#include <stdint.h>
+
+typedef struct AVFixedDSPContext {
+    /**
+     * Overlap/add with window function.
+     * Used primarily by MDCT-based audio codecs.
+     * Source and destination vectors must overlap exactly or not at all.
+     *
+     * @param dst  result vector
+     *             constraints: 16-byte aligned
+     * @param src0 first source vector
+     *             constraints: 16-byte aligned
+     * @param src1 second source vector
+     *             constraints: 16-byte aligned
+     * @param win  half-window vector
+     *             constraints: 16-byte aligned
+     * @param len  length of vector
+     *             constraints: multiple of 4
+     */
+    void (*vector_fmul_window_fixed)(int16_t *dst, const int32_t *src0, const int32_t *src1, const int32_t *win, int len);
+} AVFixedDSPContext;
+
+/**
+ * Initialize a fixed DSP context.
+ *
+ * @param fdsp    fixed DSP context
+ * @param strict  setting to non-zero avoids using functions which may not be IEEE-754 compliant
+ */
+void avpriv_fixed_dsp_init(AVFixedDSPContext *fdsp, int strict);
+
+#endif /* AVUTIL_FIXED_DSP_H */
-- 
1.7.3.4



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