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g722: Add a trellis encoder
The structure is largely based on the trellis encoder in adpcm.c. Originally committed as revision 25866 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Martin Storsjö
parent
699b317f59
commit
c6fe83a3e0
@ -43,6 +43,8 @@
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#define PREV_SAMPLES_BUF_SIZE 1024
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#define FREEZE_INTERVAL 128
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typedef struct {
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int16_t prev_samples[PREV_SAMPLES_BUF_SIZE]; ///< memory of past decoded samples
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int prev_samples_pos; ///< the number of values in prev_samples
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@ -61,6 +63,17 @@ typedef struct {
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int16_t log_factor; ///< delayed 2-logarithmic quantizer factor
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int16_t scale_factor; ///< delayed quantizer scale factor
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} band[2];
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struct TrellisNode {
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struct G722Band state;
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uint32_t ssd;
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int path;
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} *node_buf[2], **nodep_buf[2];
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struct TrellisPath {
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int value;
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int prev;
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} *paths[2];
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} G722Context;
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@ -216,6 +229,29 @@ static av_cold int g722_init(AVCodecContext * avctx)
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if (avctx->lowres)
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avctx->sample_rate /= 2;
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if (avctx->trellis) {
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int frontier = 1 << avctx->trellis;
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int max_paths = frontier * FREEZE_INTERVAL;
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int i;
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for (i = 0; i < 2; i++) {
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c->paths[i] = av_mallocz(max_paths * sizeof(**c->paths));
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c->node_buf[i] = av_mallocz(2 * frontier * sizeof(**c->node_buf));
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c->nodep_buf[i] = av_mallocz(2 * frontier * sizeof(**c->nodep_buf));
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}
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}
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return 0;
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}
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static av_cold int g722_close(AVCodecContext *avctx)
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{
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G722Context *c = avctx->priv_data;
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int i;
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for (i = 0; i < 2; i++) {
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av_freep(&c->paths[i]);
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av_freep(&c->node_buf[i]);
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av_freep(&c->nodep_buf[i]);
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}
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return 0;
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}
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@ -351,6 +387,164 @@ static inline int encode_low(const struct G722Band* state, int xlow)
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return (diff < 0 ? (i < 2 ? 63 : 33) : 61) - i;
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}
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static int g722_encode_trellis(AVCodecContext *avctx,
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uint8_t *dst, int buf_size, void *data)
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{
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G722Context *c = avctx->priv_data;
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const int16_t *samples = data;
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int i, j, k;
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int frontier = 1 << avctx->trellis;
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struct TrellisNode **nodes[2];
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struct TrellisNode **nodes_next[2];
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int pathn[2] = {0, 0}, froze = -1;
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struct TrellisPath *p[2];
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for (i = 0; i < 2; i++) {
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nodes[i] = c->nodep_buf[i];
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nodes_next[i] = c->nodep_buf[i] + frontier;
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memset(c->nodep_buf[i], 0, 2 * frontier * sizeof(*c->nodep_buf));
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nodes[i][0] = c->node_buf[i] + frontier;
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nodes[i][0]->ssd = 0;
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nodes[i][0]->path = 0;
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nodes[i][0]->state = c->band[i];
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}
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for (i = 0; i < buf_size >> 1; i++) {
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int xlow, xhigh;
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struct TrellisNode *next[2];
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int heap_pos[2] = {0, 0};
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for (j = 0; j < 2; j++) {
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next[j] = c->node_buf[j] + frontier*(i & 1);
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memset(nodes_next[j], 0, frontier * sizeof(**nodes_next));
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}
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filter_samples(c, &samples[2*i], &xlow, &xhigh);
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for (j = 0; j < frontier && nodes[0][j]; j++) {
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/* Only k >> 2 affects the future adaptive state, therefore testing
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* small steps that don't change k >> 2 is useless, the orignal
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* value from encode_low is better than them. Since we step k
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* in steps of 4, make sure range is a multiple of 4, so that
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* we don't miss the original value from encode_low. */
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int range = j < frontier/2 ? 4 : 0;
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struct TrellisNode *cur_node = nodes[0][j];
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int ilow = encode_low(&cur_node->state, xlow);
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for (k = ilow - range; k <= ilow + range && k <= 63; k += 4) {
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int decoded, dec_diff, pos;
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uint32_t ssd;
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struct TrellisNode* node;
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if (k < 0)
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continue;
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decoded = av_clip((cur_node->state.scale_factor *
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low_inv_quant6[k] >> 10)
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+ cur_node->state.s_predictor, -16384, 16383);
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dec_diff = xlow - decoded;
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#define STORE_NODE(index, UPDATE, VALUE)\
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ssd = cur_node->ssd + dec_diff*dec_diff;\
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/* Check for wraparound. Using 64 bit ssd counters would \
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* be simpler, but is slower on x86 32 bit. */\
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if (ssd < cur_node->ssd)\
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continue;\
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if (heap_pos[index] < frontier) {\
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pos = heap_pos[index]++;\
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assert(pathn[index] < FREEZE_INTERVAL * frontier);\
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node = nodes_next[index][pos] = next[index]++;\
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node->path = pathn[index]++;\
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} else {\
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/* Try to replace one of the leaf nodes with the new \
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* one, but not always testing the same leaf position */\
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pos = (frontier>>1) + (heap_pos[index] & ((frontier>>1) - 1));\
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if (ssd >= nodes_next[index][pos]->ssd)\
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continue;\
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heap_pos[index]++;\
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node = nodes_next[index][pos];\
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}\
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node->ssd = ssd;\
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node->state = cur_node->state;\
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UPDATE;\
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c->paths[index][node->path].value = VALUE;\
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c->paths[index][node->path].prev = cur_node->path;\
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/* Sift the newly inserted node up in the heap to restore \
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* the heap property */\
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while (pos > 0) {\
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int parent = (pos - 1) >> 1;\
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if (nodes_next[index][parent]->ssd <= ssd)\
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break;\
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FFSWAP(struct TrellisNode*, nodes_next[index][parent],\
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nodes_next[index][pos]);\
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pos = parent;\
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}
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STORE_NODE(0, update_low_predictor(&node->state, k >> 2), k);
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}
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}
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for (j = 0; j < frontier && nodes[1][j]; j++) {
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int ihigh;
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struct TrellisNode *cur_node = nodes[1][j];
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/* We don't try to get any initial guess for ihigh via
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* encode_high - since there's only 4 possible values, test
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* them all. Testing all of these gives a much, much larger
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* gain than testing a larger range around ilow. */
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for (ihigh = 0; ihigh < 4; ihigh++) {
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int dhigh, decoded, dec_diff, pos;
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uint32_t ssd;
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struct TrellisNode* node;
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dhigh = cur_node->state.scale_factor *
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high_inv_quant[ihigh] >> 10;
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decoded = av_clip(dhigh + cur_node->state.s_predictor,
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-16384, 16383);
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dec_diff = xhigh - decoded;
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STORE_NODE(1, update_high_predictor(&node->state, dhigh, ihigh), ihigh);
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}
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}
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for (j = 0; j < 2; j++) {
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FFSWAP(struct TrellisNode**, nodes[j], nodes_next[j]);
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if (nodes[j][0]->ssd > (1 << 16)) {
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for (k = 1; k < frontier && nodes[j][k]; k++)
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nodes[j][k]->ssd -= nodes[j][0]->ssd;
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nodes[j][0]->ssd = 0;
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}
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}
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if (i == froze + FREEZE_INTERVAL) {
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p[0] = &c->paths[0][nodes[0][0]->path];
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p[1] = &c->paths[1][nodes[1][0]->path];
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for (j = i; j > froze; j--) {
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dst[j] = p[1]->value << 6 | p[0]->value;
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p[0] = &c->paths[0][p[0]->prev];
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p[1] = &c->paths[1][p[1]->prev];
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}
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froze = i;
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pathn[0] = pathn[1] = 0;
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memset(nodes[0] + 1, 0, (frontier - 1)*sizeof(**nodes));
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memset(nodes[1] + 1, 0, (frontier - 1)*sizeof(**nodes));
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}
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}
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p[0] = &c->paths[0][nodes[0][0]->path];
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p[1] = &c->paths[1][nodes[1][0]->path];
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for (j = i; j > froze; j--) {
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dst[j] = p[1]->value << 6 | p[0]->value;
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p[0] = &c->paths[0][p[0]->prev];
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p[1] = &c->paths[1][p[1]->prev];
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}
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c->band[0] = nodes[0][0]->state;
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c->band[1] = nodes[1][0]->state;
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return i;
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}
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static int g722_encode_frame(AVCodecContext *avctx,
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uint8_t *dst, int buf_size, void *data)
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{
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@ -358,6 +552,9 @@ static int g722_encode_frame(AVCodecContext *avctx,
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const int16_t *samples = data;
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int i;
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if (avctx->trellis)
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return g722_encode_trellis(avctx, dst, buf_size, data);
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for (i = 0; i < buf_size >> 1; i++) {
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int xlow, xhigh, ihigh, ilow;
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filter_samples(c, &samples[2*i], &xlow, &xhigh);
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@ -377,6 +574,7 @@ AVCodec adpcm_g722_encoder = {
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.id = CODEC_ID_ADPCM_G722,
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.priv_data_size = sizeof(G722Context),
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.init = g722_init,
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.close = g722_close,
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.encode = g722_encode_frame,
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.long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"),
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.sample_fmts = (enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
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