Chiebot-Mirror
/
FFmpeg
mirror of https://github.com/FFmpeg/FFmpeg.git
8
0
Fork 0
Code Issues Projects Releases Wiki Activity

Add G.729D decoder

Browse Source
pull/2/head
Vladimir Voroshilov 17 years ago committed by Michael Niedermayer
parent b7c7fc3359
commit e610c5f383
2 changed files with 137 additions and 1 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 28
      libavcodec/g729data.h
  2. 110
      libavcodec/g729dec.c

28
libavcodec/g729data.h
Unescape View File

@ -351,4 +351,32 @@ static const uint16_t ma_prediction_coeff[4] = { /* (0.13) */
static const int16_t lsp_init[10]= { /* (0.15) */
30000, 26000, 21000, 15000, 8000, 0, -8000,-15000,-21000,-26000
};
/**
* additional "phase" post-processing filter impulse response (D.6.2 of G.729)
*
* Table contains three impulse responses, correspond to
* different amounts of spreading.
*/
static const int16_t phase_filter[3][40] =
{
{ // maximum spreading (for noise-like segments)
14690, 11518, 1268, -2762, -5672, 7514, -36, -2808, -3041, 4823,
2952, -8425, 3785, 1455, 2179, -8638, 8051, -2104, -1455, 777,
1108, -2386, 2254, -364, -675, -2104, 6046, -5682, 1072, 3123,
-5059, 5312, -2330, -3729, 6924, -3890, 675, -1776, 29, 10145,
},
{ // medium spreading
30274, 3831, -4037, 2972, -1049, -1003, 2477, -3044, 2815, -2232,
1753, -1612, 1714, -1776, 1543, -1009, 429, -170, 472, -1265,
2176, -2707, 2523, -1622, 344, 826, -1530, 1724, -1658, 1701,
-2064, 2644, -3061, 2897, -1979, 557, 780, -1370, 842, 655,
},
{ // no spreading (for voiced speech)
32767, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
}
};
#endif /* AVCODEC_G729DATA_H */

110
libavcodec/g729dec.c
Unescape View File

@ -81,6 +81,10 @@
*/
#define MR_ENERGY 1018156
#define DECISION_NOISE 0
#define DECISION_INTERMEDIATE 1
#define DECISION_VOICE 2
typedef enum {
FORMAT_G729_8K = 0,
FORMAT_G729D_6K4,
@ -124,6 +128,10 @@ typedef struct {
/// (14.1) gain code from current and previous subframe
int16_t past_gain_code[2];
/// voice decision on previous subframe (0-noise, 1-intermediate, 2-voice), G.729D
int16_t voice_decision;
int16_t onset; ///< detected onset level (0-2)
int16_t was_periodic; ///< whether previous frame was declared as periodic or not (4.4)
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
@ -230,6 +238,85 @@ static void lsf_restore_from_previous(int16_t* lsfq,
}
}
/**
* Constructs new excitation signal and applies phase filter to it
* @param out[out] constructed speech signal
* @param in original excitation signal
* @param fc_cur (2.13) original fixed-codebook vector
* @param gain_code (14.1) gain code
* @param subframe_size length of the subframe
*/
void g729d_get_new_exc(
int16_t* out,
const int16_t* in,
const int16_t* fc_cur,
int dstate,
int gain_code,
int subframe_size)
{
int i;
int16_t fc_new[SUBFRAME_SIZE];
ff_celp_convolve_circ(fc_new, fc_cur, phase_filter[dstate], subframe_size);
for(i=0; i<subframe_size; i++)
{
out[i] = in[i];
out[i] -= (gain_code * fc_cur[i] + 0x2000) >> 14;
out[i] += (gain_code * fc_new[i] + 0x2000) >> 14;
}
}
/**
* Makes decision about onset in current subframe
* @param past_onset decision result of previous subframe
* @param past_gain_code gain code of current and previous subframe
*
* @return onset decision result for current subframe
*/
int g729d_onset_decision(int past_onset, const int16_t* past_gain_code)
{
if((past_gain_code[0] >> 1) > past_gain_code[1])
return 2;
else
return FFMAX(past_onset-1, 0);
}
/**
* Makes decision about voice presence in current subframe
* @param onset onset level
* @param prev_voice_decision voice decision result from previous subframe
* @param past_gain_pitch pitch gain of current and previous subframes
*
* @return voice decision result for current subframe
*/
static int16_t g729d_voice_decision(int onset, int prev_voice_decision, const int16_t* past_gain_pitch)
{
int i, low_gain_pitch_cnt, voice_decision;
if(past_gain_pitch[0] >= 14745) // 0.9
voice_decision = DECISION_VOICE;
else if (past_gain_pitch[0] <= 9830) // 0.6
voice_decision = DECISION_NOISE;
else
voice_decision = DECISION_INTERMEDIATE;
for(i=0, low_gain_pitch_cnt=0; i<6; i++)
if(past_gain_pitch[i] < 9830)
low_gain_pitch_cnt++;
if(low_gain_pitch_cnt > 2 && !onset)
voice_decision = DECISION_NOISE;
if(!onset && voice_decision > prev_voice_decision + 1)
voice_decision--;
if(onset && voice_decision < DECISION_VOICE)
voice_decision++;
return voice_decision;
}
static av_cold int decoder_init(AVCodecContext * avctx)
{
G729Context* ctx = avctx->priv_data;
@ -302,6 +389,9 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
if (buf_size == 10) {
packet_type = FORMAT_G729_8K;
format = format_g729_8k;
//Reset voice decision
ctx->onset = 0;
ctx->voice_decision = DECISION_VOICE;
av_log(avctx, AV_LOG_DEBUG, "Packet type: %s\n", "G.729 @ 8kbit/s");
} else if (buf_size == 8) {
packet_type = FORMAT_G729D_6K4;
@ -497,11 +587,29 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
SUBFRAME_SIZE,
10,
1,
0x800)) {
0x800))
/* Overflow occured, downscale excitation signal... */
for (j = 0; j < 2 * SUBFRAME_SIZE + PITCH_DELAY_MAX + INTERPOL_LEN; j++)
ctx->exc_base[j] >>= 2;
/* ... and make synthesis again. */
if (packet_type == FORMAT_G729D_6K4) {
int16_t exc_new[SUBFRAME_SIZE];
ctx->onset = g729d_onset_decision(ctx->onset, ctx->past_gain_code);
ctx->voice_decision = g729d_voice_decision(ctx->onset, ctx->voice_decision, ctx->past_gain_pitch);
g729d_get_new_exc(exc_new, ctx->exc + i * SUBFRAME_SIZE, fc, ctx->voice_decision, ctx->past_gain_code[0], SUBFRAME_SIZE);
ff_celp_lp_synthesis_filter(
synth+10,
&lp[i][1],
exc_new,
SUBFRAME_SIZE,
10,
0,
0x800);
} else {
ff_celp_lp_synthesis_filter(
synth+10,
&lp[i][1],

Write Preview
Loading…
Cancel
Save