[FFmpeg-cvslog] r15901 - in trunk/libavcodec: qcelpdata.h qcelpdec.c
vitor
subversion
Fri Nov 21 19:39:17 CET 2008
Author: vitor
Date: Fri Nov 21 19:39:16 2008
New Revision: 15901
Log:
More OKed parts of the QCELP decoder
patch by Kenan Gillet, kenan.gillet gmail com
Modified:
trunk/libavcodec/qcelpdata.h
trunk/libavcodec/qcelpdec.c
Modified: trunk/libavcodec/qcelpdata.h
==============================================================================
--- trunk/libavcodec/qcelpdata.h (original)
+++ trunk/libavcodec/qcelpdata.h Fri Nov 21 19:39:16 2008
@@ -391,6 +391,16 @@ static const qcelp_vector * const qcelp_
#define QCELP_SCALE 8192.
/**
+ * the upper boundary of the clipping, depends on QCELP_SCALE
+ */
+#define QCELP_CLIP_UPPER_BOUND (8191.75/8192.)
+
+/**
+ * the lower boundary of the clipping, depends on QCELP_SCALE
+ */
+#define QCELP_CLIP_LOWER_BOUND -1.
+
+/**
* table for computing Ga (decoded linear codebook gain magnitude)
*
* @note The table could fit in int16_t in x*8 form, but it seems
@@ -470,7 +480,7 @@ static const int8_t qcelp_rate_half_code
/**
* sqrt(1.887) is the maximum of the pseudorandom
* white sequence used to generate the scaled codebook
- * vector for framerate 1/4.
+ * vector for bitrate 1/4.
*
* TIA/EIA/IS-733 2.4.8.1.2
*/
@@ -478,7 +488,7 @@ static const int8_t qcelp_rate_half_code
/**
* table for impulse response of BPF used to filter
- * the white excitation for framerate 1/4 synthesis
+ * the white excitation for bitrate 1/4 synthesis
*
* Only half the tables are needed because of symmetry.
*
@@ -490,4 +500,20 @@ static const double qcelp_rnd_fir_coefs[
-9.918777e-2, 3.749518e-2, 8.985137e-1
};
+/**
+ * This spread factor is used, for bitrate 1/8 and I_F_Q,
+ * to force the LSP frequencies to be at least 80 Hz apart.
+ *
+ * TIA/EIA/IS-733 2.4.3.3.2
+ */
+#define QCELP_LSP_SPREAD_FACTOR 0.02
+
+/**
+ * predictor coefficient for the conversion of LSP codes
+ * to LSP frequencies for 1/8 and I_F_Q
+ *
+ * TIA/EIA/IS-733 2.4.3.2.7-2
+ */
+#define QCELP_LSP_OCTAVE_PREDICTOR 29.0/32
+
#endif /* AVCODEC_QCELPDATA_H */
Modified: trunk/libavcodec/qcelpdec.c
==============================================================================
--- trunk/libavcodec/qcelpdec.c (original)
+++ trunk/libavcodec/qcelpdec.c Fri Nov 21 19:39:16 2008
@@ -69,6 +69,116 @@ static av_cold int qcelp_decode_init(AVC
}
/**
+ * Decodes the 10 quantized LSP frequencies from the LSPV/LSP
+ * transmission codes of any bitrate and checks for badly received packets.
+ *
+ * @param q the context
+ * @param lspf line spectral pair frequencies
+ *
+ * @return 0 on success, -1 if the packet is badly received
+ *
+ * TIA/EIA/IS-733 2.4.3.2.6.2-2, 2.4.8.7.3
+ */
+static int decode_lspf(QCELPContext *q,
+ float *lspf) {
+ int i;
+ float tmp_lspf;
+
+ if (q->bitrate == RATE_OCTAVE ||
+ q->bitrate == I_F_Q) {
+ float smooth;
+ const float *predictors = (q->prev_bitrate != RATE_OCTAVE &&
+ q->prev_bitrate != I_F_Q ? q->prev_lspf
+ : q->predictor_lspf);
+
+ if (q->bitrate == RATE_OCTAVE) {
+ q->octave_count++;
+
+ for (i = 0; i < 10; i++) {
+ q->predictor_lspf[i] =
+ lspf[i] = (q->lspv[i] ? QCELP_LSP_SPREAD_FACTOR
+ : -QCELP_LSP_SPREAD_FACTOR)
+ + predictors[i] * QCELP_LSP_OCTAVE_PREDICTOR
+ + (i + 1) * ((1 - QCELP_LSP_OCTAVE_PREDICTOR)/11);
+ }
+ smooth = (q->octave_count < 10 ? .875 : 0.1);
+ } else {
+ float erasure_coeff = QCELP_LSP_OCTAVE_PREDICTOR;
+
+ assert(q->bitrate == I_F_Q);
+
+ if (q->erasure_count > 1)
+ erasure_coeff *= (q->erasure_count < 4 ? 0.9 : 0.7);
+
+ for (i = 0; i < 10; i++) {
+ q->predictor_lspf[i] =
+ lspf[i] = (i + 1) * ( 1 - erasure_coeff)/11
+ + erasure_coeff * predictors[i];
+ }
+ smooth = 0.125;
+ }
+
+ // Check the stability of the LSP frequencies.
+ lspf[0] = FFMAX(lspf[0], QCELP_LSP_SPREAD_FACTOR);
+ for (i = 1; i < 10; i++)
+ lspf[i] = FFMAX(lspf[i], (lspf[i-1] + QCELP_LSP_SPREAD_FACTOR));
+
+ lspf[9] = FFMIN(lspf[9], (1.0 - QCELP_LSP_SPREAD_FACTOR));
+ for (i = 9; i > 0; i--)
+ lspf[i-1] = FFMIN(lspf[i-1], (lspf[i] - QCELP_LSP_SPREAD_FACTOR));
+
+ // Low-pass filter the LSP frequencies.
+ weighted_vector_sumf(lspf, lspf, q->prev_lspf, smooth, 1.0 - smooth, 10);
+ } else {
+ q->octave_count = 0;
+
+ tmp_lspf = 0.;
+ for (i = 0; i < 5 ; i++) {
+ lspf[2*i+0] = tmp_lspf += qcelp_lspvq[i][q->lspv[i]][0] * 0.0001;
+ lspf[2*i+1] = tmp_lspf += qcelp_lspvq[i][q->lspv[i]][1] * 0.0001;
+ }
+
+ // Check for badly received packets.
+ if (q->bitrate == RATE_QUARTER) {
+ if (lspf[9] <= .70 || lspf[9] >= .97)
+ return -1;
+ for (i = 3; i < 10; i++)
+ if (fabs(lspf[i] - lspf[i-2]) < .08)
+ return -1;
+ } else {
+ if (lspf[9] <= .66 || lspf[9] >= .985)
+ return -1;
+ for (i = 4; i < 10; i++)
+ if (fabs(lspf[i] - lspf[i-4]) < .0931)
+ return -1;
+ }
+ }
+ return 0;
+}
+
+/**
+ * If the received packet is Rate 1/4 a further sanity check is made of the codebook gain.
+ *
+ * @param cbgain the unpacked cbgain array
+ * @return -1 if the sanity check fails, 0 otherwise
+ *
+ * TIA/EIA/IS-733 2.4.8.7.3
+ */
+static int codebook_sanity_check_for_rate_quarter(const uint8_t *cbgain) {
+ int i, prev_diff=0;
+
+ for (i = 1; i < 5; i++) {
+ int diff = cbgain[i] - cbgain[i-1];
+ if (FFABS(diff) > 10)
+ return -1;
+ else if (FFABS(diff - prev_diff) > 12)
+ return -1;
+ prev_diff = diff;
+ }
+ return 0;
+}
+
+/**
* Computes the scaled codebook vector Cdn From INDEX and GAIN
* for all rates.
*
@@ -96,7 +206,7 @@ static void compute_svector(const QCELPC
uint16_t cbseed, cindex;
float *rnd, tmp_gain, fir_filter_value;
- switch (q->framerate) {
+ switch (q->bitrate) {
case RATE_FULL:
for (i = 0; i < 16; i++) {
tmp_gain = gain[i] * QCELP_RATE_FULL_CODEBOOK_RATIO;
@@ -248,7 +358,7 @@ static const float *do_pitchfilter(float
/**
* Interpolates LSP frequencies and computes LPC coefficients
- * for a given framerate & pitch subframe.
+ * for a given bitrate & pitch subframe.
*
* TIA/EIA/IS-733 2.4.3.3.4
*
@@ -263,9 +373,9 @@ void interpolate_lpc(QCELPContext *q, co
float interpolated_lspf[10];
float weight;
- if(q->framerate >= RATE_QUARTER)
+ if(q->bitrate >= RATE_QUARTER)
weight = 0.25 * (subframe_num + 1);
- else if(q->framerate == RATE_OCTAVE && !subframe_num)
+ else if(q->bitrate == RATE_OCTAVE && !subframe_num)
weight = 0.625;
else
weight = 1.0;
@@ -275,11 +385,11 @@ void interpolate_lpc(QCELPContext *q, co
weighted_vector_sumf(interpolated_lspf, curr_lspf, q->prev_lspf,
weight, 1.0 - weight, 10);
qcelp_lspf2lpc(interpolated_lspf, lpc);
- }else if(q->framerate >= RATE_QUARTER || (q->framerate == I_F_Q && !subframe_num))
+ }else if(q->bitrate >= RATE_QUARTER || (q->bitrate == I_F_Q && !subframe_num))
qcelp_lspf2lpc(curr_lspf, lpc);
}
-static int buf_size2framerate(const int buf_size)
+static int buf_size2bitrate(const int buf_size)
{
switch(buf_size)
{
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