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Fixed- and adaptive-codebook gains

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Vladimir Voroshilov 2009-06-05 01:55:06 +07:00 committed by Michael Niedermayer
parent 7fadc0151c
commit 0a3337883f
2 changed files with 40 additions and 0 deletions
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7
libavcodec/g729data.h
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@ -307,6 +307,13 @@ static const int16_t cb_ma_predictor_sum_inv[2][10] = { /* (3.12) */
{ 9202, 7320, 6788, 7738, 8170, 8154, 8856, 8818, 8366, 8544}
};
/**
* MA prediction coefficients (3.9.1 of G.729, near Equation 69)
*/
static const uint16_t ma_prediction_coeff[4] = { /* (0.13) */
5571, 4751, 2785, 1556
};
/**
* initial LSP coefficients belongs to virtual frame preceding the
* first frame of the stream

33
libavcodec/g729dec.c
View File

@ -29,6 +29,7 @@
#include "avcodec.h"
#include "libavutil/avutil.h"
#include "get_bits.h"
#include "dsputil.h"
#include "g729.h"
#include "lsp.h"
@ -71,6 +72,11 @@
*/
#define SHARP_MAX 13017
/**
* MR_ENERGY (mean removed energy) = mean_energy + 10 * log10(2^26 * subframe_size) in (7.13)
*/
#define MR_ENERGY 1018156
typedef enum {
FORMAT_G729_8K = 0,
FORMAT_G729D_6K4,
@ -87,6 +93,8 @@ typedef struct {
} G729FormatDescription;
typedef struct {
DSPContext dsp;
int pitch_delay_int_prev; ///< integer part of previous subframe's pitch delay (4.1.3)
/// (2.13) LSP quantizer outputs
@ -97,6 +105,14 @@ typedef struct {
int16_t lsp_buf[2][10]; ///< (0.15) LSP coefficients (previous and current frames) (3.2.5)
int16_t *lsp[2]; ///< pointers to lsp_buf
int16_t quant_energy[4]; ///< (5.10) past quantized energy
/// (1.14) pitch gain of previous subframe
int16_t gain_pitch;
/// (14.1) gain code from previous subframe
int16_t gain_code;
uint16_t rand_value; ///< random number generator value (4.4.4)
int ma_predictor_prev; ///< switched MA predictor of LSP quantizer from last good frame
} G729Context;
@ -228,6 +244,12 @@ static av_cold int decoder_init(AVCodecContext * avctx)
/* random seed initialization */
ctx->rand_value = 21845;
/* quantized prediction error */
for(i=0; i<4; i++)
ctx->quant_energy[i] = -14336; // -14 in (5.10)
dsputil_init(&ctx->dsp, avctx);
return 0;
}
@ -306,6 +328,8 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
FFSWAP(int16_t*, ctx->lsp[1], ctx->lsp[0]);
for (i = 0; i < 2; i++) {
int gain_corr_factor;
uint8_t ac_index; ///< adaptive codebook index
uint8_t pulses_signs; ///< fixed-codebook vector pulse signs
int fc_indexes; ///< fixed-codebook indexes
@ -389,6 +413,15 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
gain_corr_factor = cb_gain_1st_8k[gc_1st_index][1] +
cb_gain_2nd_8k[gc_2nd_index][1];
/* Decode the fixed-codebook gain. */
ctx->gain_code = ff_acelp_decode_gain_code(&ctx->dsp, gain_corr_factor,
fc, MR_ENERGY,
ctx->quant_energy,
ma_prediction_coeff,
SUBFRAME_SIZE, 4);
}
ff_acelp_update_past_gain(ctx->quant_energy, gain_corr_factor, 2, frame_erasure);
ff_acelp_weighted_vector_sum(ctx->exc + i * SUBFRAME_SIZE,
ctx->exc + i * SUBFRAME_SIZE, fc,
(!voicing && frame_erasure) ? 0 : ctx->gain_pitch,