[FFmpeg-cvslog] Add G.729D decoder
Vladimir Voroshilov
git at videolan.org
Sat Sep 24 21:17:03 CEST 2011
ffmpeg | branch: master | Vladimir Voroshilov <voroshil at gmail.com> | Wed Sep 3 23:47:58 2008 +0700| [e610c5f383f31e55a672961f1e671d83328c36b1] | committer: Michael Niedermayer
Add G.729D decoder
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e610c5f383f31e55a672961f1e671d83328c36b1
---
libavcodec/g729data.h | 28 ++++++++++++
libavcodec/g729dec.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 137 insertions(+), 1 deletions(-)
diff --git a/libavcodec/g729data.h b/libavcodec/g729data.h
index c36be40..2509c39 100644
--- a/libavcodec/g729data.h
+++ b/libavcodec/g729data.h
@@ -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 */
diff --git a/libavcodec/g729dec.c b/libavcodec/g729dec.c
index c1d0905..5fc2167 100644
--- a/libavcodec/g729dec.c
+++ b/libavcodec/g729dec.c
@@ -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],
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