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Synthesis filter

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This commit is contained in:
Vladimir Voroshilov 2009-06-05 11:11:54 +07:00 committed by Michael Niedermayer
parent 4920a1a913
commit b7c7fc3359
1 changed files with 41 additions and 0 deletions
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41
libavcodec/g729dec.c
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@ -34,6 +34,7 @@
#include "g729.h"
#include "lsp.h"
#include "celp_math.h"
#include "celp_filters.h"
#include "acelp_filters.h"
#include "acelp_pitch_delay.h"
#include "acelp_vectors.h"
@ -57,6 +58,9 @@
*/
#define LSFQ_DIFF_MIN 321
/// interpolation filter length
#define INTERPOL_LEN 11
/**
* minimum gain pitch value (3.8, Equation 47)
* 0.2 in (1.14)
@ -111,6 +115,9 @@ typedef struct {
int16_t quant_energy[4]; ///< (5.10) past quantized energy
/// previous speech data for LP synthesis filter
int16_t syn_filter_data[10];
/// (1.14) pitch gain of current and five previous subframes
int16_t past_gain_pitch[6];
@ -283,6 +290,8 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
int pitch_delay_int; // pitch delay, integer part
int pitch_delay_3x; // pitch delay, multiplied by 3
int16_t fc[SUBFRAME_SIZE]; // fixed-codebook vector
int16_t synth[SUBFRAME_SIZE+10]; // fixed-codebook vector
int j;
int is_periodic = 0; // whether one of the subframes is declared as periodic or not
if (*data_size < SUBFRAME_SIZE << 2) {
@ -476,10 +485,42 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
( ctx->was_periodic && frame_erasure) ? 0 : ctx->past_gain_code[0],
1 << 13, 14, SUBFRAME_SIZE);
memcpy(synth, ctx->syn_filter_data, 10 * sizeof(int16_t));
/* Temporary synth buffer is required since filter needs additional space at top of buffer and, thus,
synthesis can not be done directly to output buffer. This buffer will be reused by future
postprocessing filters. */
if (ff_celp_lp_synthesis_filter(
synth+10,
&lp[i][1],
ctx->exc + i * SUBFRAME_SIZE,
SUBFRAME_SIZE,
10,
1,
0x800)) {
/* Overflow occured, downscale excitation signal... */
for (j = 0; j < 2 * SUBFRAME_SIZE + PITCH_DELAY_MAX + INTERPOL_LEN; j++)
ctx->exc_base[j] >>= 2;
ff_celp_lp_synthesis_filter(
synth+10,
&lp[i][1],
ctx->exc + i * SUBFRAME_SIZE,
SUBFRAME_SIZE,
10,
0,
0x800);
}
/* Save data (without postfilter) for use in next subframe. */
memcpy(ctx->syn_filter_data, synth+SUBFRAME_SIZE, 10 * sizeof(int16_t));
if (frame_erasure)
ctx->pitch_delay_int_prev = FFMIN(ctx->pitch_delay_int_prev + 1, PITCH_DELAY_MAX);
else
ctx->pitch_delay_int_prev = pitch_delay_int;
/* Dumb. Will be replaced by high-pass filter */
memcpy(out_frame + i * SUBFRAME_SIZE, synth + 10, SUBFRAME_SIZE * sizeof(int16_t));
}
ctx->was_periodic = is_periodic;