[SCM] libav/experimental: ADPCM: trellis quantization
siretart at users.alioth.debian.org
siretart at users.alioth.debian.org
Sun Jun 30 15:47:57 UTC 2013
The following commit has been merged in the experimental branch:
commit 696d6889d2a0b98954799075292f885de83e151f
Author: Loren Merritt <lorenm at u.washington.edu>
Date: Sat Jun 3 19:04:56 2006 +0000
ADPCM: trellis quantization
Originally committed as revision 5451 to svn://svn.ffmpeg.org/ffmpeg/trunk
diff --git a/libavcodec/adpcm.c b/libavcodec/adpcm.c
index 3382834..22a710d 100644
--- a/libavcodec/adpcm.c
+++ b/libavcodec/adpcm.c
@@ -257,6 +257,177 @@ static inline unsigned char adpcm_yamaha_compress_sample(ADPCMChannelStatus *c,
return nibble;
}
+typedef struct TrellisPath {
+ int nibble;
+ int prev;
+} TrellisPath;
+
+typedef struct TrellisNode {
+ uint32_t ssd;
+ int path;
+ int sample1;
+ int sample2;
+ int step;
+} TrellisNode;
+
+static void adpcm_compress_trellis(AVCodecContext *avctx, const short *samples,
+ uint8_t *dst, ADPCMChannelStatus *c, int n)
+{
+#define FREEZE_INTERVAL 128
+ //FIXME 6% faster if frontier is a compile-time constant
+ const int frontier = 1 << avctx->trellis;
+ const int stride = avctx->channels;
+ const int version = avctx->codec->id;
+ const int max_paths = frontier*FREEZE_INTERVAL;
+ TrellisPath paths[max_paths], *p;
+ TrellisNode node_buf[2][frontier];
+ TrellisNode *nodep_buf[2][frontier];
+ TrellisNode **nodes = nodep_buf[0]; // nodes[] is always sorted by .ssd
+ TrellisNode **nodes_next = nodep_buf[1];
+ int pathn = 0, froze = -1, i, j, k;
+
+ assert(!(max_paths&(max_paths-1)));
+
+ memset(nodep_buf, 0, sizeof(nodep_buf));
+ nodes[0] = &node_buf[1][0];
+ nodes[0]->ssd = 0;
+ nodes[0]->path = 0;
+ nodes[0]->step = c->step_index;
+ nodes[0]->sample1 = c->sample1;
+ nodes[0]->sample2 = c->sample2;
+ if(version == CODEC_ID_ADPCM_IMA_WAV)
+ nodes[0]->sample1 = c->prev_sample;
+ if(version == CODEC_ID_ADPCM_MS)
+ nodes[0]->step = c->idelta;
+ if(version == CODEC_ID_ADPCM_YAMAHA) {
+ if(c->step == 0) {
+ nodes[0]->step = 127;
+ nodes[0]->sample1 = 0;
+ } else {
+ nodes[0]->step = c->step;
+ nodes[0]->sample1 = c->predictor;
+ }
+ }
+
+ for(i=0; i<n; i++) {
+ TrellisNode *t = node_buf[i&1];
+ TrellisNode **u;
+ int sample = samples[i*stride];
+ memset(nodes_next, 0, frontier*sizeof(TrellisNode*));
+ for(j=0; j<frontier && nodes[j]; j++) {
+ // higher j have higher ssd already, so they're unlikely to use a suboptimal next sample too
+ const int range = (j < frontier/2) ? 1 : 0;
+ const int step = nodes[j]->step;
+ int nidx;
+ if(version == CODEC_ID_ADPCM_MS) {
+ const int predictor = ((nodes[j]->sample1 * c->coeff1) + (nodes[j]->sample2 * c->coeff2)) / 256;
+ const int div = (sample - predictor) / step;
+ const int nmin = clip(div-range, -8, 6);
+ const int nmax = clip(div+range, -7, 7);
+ for(nidx=nmin; nidx<=nmax; nidx++) {
+ const int nibble = nidx & 0xf;
+ int dec_sample = predictor + nidx * step;
+#define STORE_NODE(NAME, STEP_INDEX)\
+ int d;\
+ uint32_t ssd;\
+ CLAMP_TO_SHORT(dec_sample);\
+ d = sample - dec_sample;\
+ ssd = nodes[j]->ssd + d*d;\
+ if(nodes_next[frontier-1] && ssd >= nodes_next[frontier-1]->ssd)\
+ continue;\
+ /* Collapse any two states with the same previous sample value. \
+ * One could also distinguish states by step and by 2nd to last
+ * sample, but the effects of that are negligible. */\
+ for(k=0; k<frontier && nodes_next[k]; k++) {\
+ if(dec_sample == nodes_next[k]->sample1) {\
+ assert(ssd >= nodes_next[k]->ssd);\
+ goto next_##NAME;\
+ }\
+ }\
+ for(k=0; k<frontier; k++) {\
+ if(!nodes_next[k] || ssd < nodes_next[k]->ssd) {\
+ TrellisNode *u = nodes_next[frontier-1];\
+ if(!u) {\
+ assert(pathn < max_paths);\
+ u = t++;\
+ u->path = pathn++;\
+ }\
+ u->ssd = ssd;\
+ u->step = STEP_INDEX;\
+ u->sample2 = nodes[j]->sample1;\
+ u->sample1 = dec_sample;\
+ paths[u->path].nibble = nibble;\
+ paths[u->path].prev = nodes[j]->path;\
+ memmove(&nodes_next[k+1], &nodes_next[k], (frontier-k-1)*sizeof(TrellisNode*));\
+ nodes_next[k] = u;\
+ break;\
+ }\
+ }\
+ next_##NAME:;
+ STORE_NODE(ms, FFMAX(16, (AdaptationTable[nibble] * step) >> 8));
+ }
+ } else if(version == CODEC_ID_ADPCM_IMA_WAV) {
+#define LOOP_NODES(NAME, STEP_TABLE, STEP_INDEX)\
+ const int predictor = nodes[j]->sample1;\
+ const int div = (sample - predictor) * 4 / STEP_TABLE;\
+ int nmin = clip(div-range, -7, 6);\
+ int nmax = clip(div+range, -6, 7);\
+ if(nmin<=0) nmin--; /* distinguish -0 from +0 */\
+ if(nmax<0) nmax--;\
+ for(nidx=nmin; nidx<=nmax; nidx++) {\
+ const int nibble = nidx<0 ? 7-nidx : nidx;\
+ int dec_sample = predictor + (STEP_TABLE * yamaha_difflookup[nibble]) / 8;\
+ STORE_NODE(NAME, STEP_INDEX);\
+ }
+ LOOP_NODES(ima, step_table[step], clip(step + index_table[nibble], 0, 88));
+ } else { //CODEC_ID_ADPCM_YAMAHA
+ LOOP_NODES(yamaha, step, clip((step * yamaha_indexscale[nibble]) >> 8, 127, 24567));
+#undef LOOP_NODES
+#undef STORE_NODE
+ }
+ }
+
+ u = nodes;
+ nodes = nodes_next;
+ nodes_next = u;
+
+ // prevent overflow
+ if(nodes[0]->ssd > (1<<28)) {
+ for(j=1; j<frontier && nodes[j]; j++)
+ nodes[j]->ssd -= nodes[0]->ssd;
+ nodes[0]->ssd = 0;
+ }
+
+ // merge old paths to save memory
+ if(i == froze + FREEZE_INTERVAL) {
+ p = &paths[nodes[0]->path];
+ for(k=i; k>froze; k--) {
+ dst[k] = p->nibble;
+ p = &paths[p->prev];
+ }
+ froze = i;
+ pathn = 0;
+ // other nodes might use paths that don't coincide with the frozen one.
+ // checking which nodes do so is too slow, so just kill them all.
+ // this also slightly improves quality, but I don't know why.
+ memset(nodes+1, 0, (frontier-1)*sizeof(TrellisNode*));
+ }
+ }
+
+ p = &paths[nodes[0]->path];
+ for(i=n-1; i>froze; i--) {
+ dst[i] = p->nibble;
+ p = &paths[p->prev];
+ }
+
+ c->predictor = nodes[0]->sample1;
+ c->sample1 = nodes[0]->sample1;
+ c->sample2 = nodes[0]->sample2;
+ c->step_index = nodes[0]->step;
+ c->step = nodes[0]->step;
+ c->idelta = nodes[0]->step;
+}
+
static int adpcm_encode_frame(AVCodecContext *avctx,
unsigned char *frame, int buf_size, void *data)
{
@@ -293,6 +464,24 @@ static int adpcm_encode_frame(AVCodecContext *avctx,
}
/* stereo: 4 bytes (8 samples) for left, 4 bytes for right, 4 bytes left, ... */
+ if(avctx->trellis > 0) {
+ uint8_t buf[2][n*8];
+ adpcm_compress_trellis(avctx, samples, buf[0], &c->status[0], n*8);
+ if(avctx->channels == 2)
+ adpcm_compress_trellis(avctx, samples+1, buf[1], &c->status[1], n*8);
+ for(i=0; i<n; i++) {
+ *dst++ = buf[0][8*i+0] | (buf[0][8*i+1] << 4);
+ *dst++ = buf[0][8*i+2] | (buf[0][8*i+3] << 4);
+ *dst++ = buf[0][8*i+4] | (buf[0][8*i+5] << 4);
+ *dst++ = buf[0][8*i+6] | (buf[0][8*i+7] << 4);
+ if (avctx->channels == 2) {
+ *dst++ = buf[1][8*i+0] | (buf[1][8*i+1] << 4);
+ *dst++ = buf[1][8*i+2] | (buf[1][8*i+3] << 4);
+ *dst++ = buf[1][8*i+4] | (buf[1][8*i+5] << 4);
+ *dst++ = buf[1][8*i+6] | (buf[1][8*i+7] << 4);
+ }
+ }
+ } else
for (; n>0; n--) {
*dst = adpcm_ima_compress_sample(&c->status[0], samples[0]) & 0x0F;
*dst |= (adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels]) << 4) & 0xF0;
@@ -352,6 +541,21 @@ static int adpcm_encode_frame(AVCodecContext *avctx,
*dst++ = c->status[i].sample2 >> 8;
}
+ if(avctx->trellis > 0) {
+ int n = avctx->block_align - 7*avctx->channels;
+ uint8_t buf[2][n];
+ if(avctx->channels == 1) {
+ n *= 2;
+ adpcm_compress_trellis(avctx, samples, buf[0], &c->status[0], n);
+ for(i=0; i<n; i+=2)
+ *dst++ = (buf[0][i] << 4) | buf[0][i+1];
+ } else {
+ adpcm_compress_trellis(avctx, samples, buf[0], &c->status[0], n);
+ adpcm_compress_trellis(avctx, samples+1, buf[1], &c->status[1], n);
+ for(i=0; i<n; i++)
+ *dst++ = (buf[0][i] << 4) | buf[1][i];
+ }
+ } else
for(i=7*avctx->channels; i<avctx->block_align; i++) {
int nibble;
nibble = adpcm_ms_compress_sample(&c->status[ 0], *samples++)<<4;
@@ -361,6 +565,20 @@ static int adpcm_encode_frame(AVCodecContext *avctx,
break;
case CODEC_ID_ADPCM_YAMAHA:
n = avctx->frame_size / 2;
+ if(avctx->trellis > 0) {
+ uint8_t buf[2][n*2];
+ n *= 2;
+ if(avctx->channels == 1) {
+ adpcm_compress_trellis(avctx, samples, buf[0], &c->status[0], n);
+ for(i=0; i<n; i+=2)
+ *dst++ = buf[0][i] | (buf[0][i+1] << 4);
+ } else {
+ adpcm_compress_trellis(avctx, samples, buf[0], &c->status[0], n);
+ adpcm_compress_trellis(avctx, samples+1, buf[1], &c->status[1], n);
+ for(i=0; i<n; i++)
+ *dst++ = buf[0][i] | (buf[1][i] << 4);
+ }
+ } else
for (; n>0; n--) {
for(i = 0; i < avctx->channels; i++) {
int nibble;
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index ce66439..830c4fa 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -720,7 +720,7 @@ static AVOption options[]={
{"refs", NULL, OFFSET(refs), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"chromaoffset", NULL, OFFSET(chromaoffset), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"bframebias", NULL, OFFSET(bframebias), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
-{"trellis", NULL, OFFSET(trellis), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
+{"trellis", NULL, OFFSET(trellis), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|A|E},
{"directpred", NULL, OFFSET(directpred), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX, V|E},
{"bpyramid", NULL, 0, FF_OPT_TYPE_CONST, CODEC_FLAG2_BPYRAMID, INT_MIN, INT_MAX, V|E, "flags2"},
{"wpred", NULL, 0, FF_OPT_TYPE_CONST, CODEC_FLAG2_WPRED, INT_MIN, INT_MAX, V|E, "flags2"},
--
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