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aacenc: Only trellis over a column of 61 scalefactors (reduced from 256).

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This still provides plenty of dynamic range, makes every move legal, and greatly reduces the search space.

Originally committed as revision 23317 to svn://svn.ffmpeg.org/ffmpeg/trunk
oldabi
Alex Converse 15 years ago
parent 05e659ef83
commit 144c5e3dd2
1 changed files with 52 additions and 26 deletions
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  1. 78
      libavcodec/aaccoder.c

78
libavcodec/aaccoder.c
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@ -30,6 +30,7 @@
* add sane pulse detection
***********************************/
#include <float.h>
#include "avcodec.h"
#include "put_bits.h"
#include "aac.h"
@ -462,12 +463,10 @@ static void codebook_trellis_rate(AACEncContext *s, SingleChannelElement *sce,
typedef struct TrellisPath {
float cost;
int prev;
int min_val;
int max_val;
} TrellisPath;
#define TRELLIS_STAGES 121
#define TRELLIS_STATES 256
#define TRELLIS_STATES (SCALE_MAX_DIFF+1)
static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
SingleChannelElement *sce,
@ -480,19 +479,56 @@ static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
int bandaddr[TRELLIS_STAGES];
int minq;
float mincost;
float q0f = FLT_MAX, q1f = 0.0f, qnrgf = 0.0f;
int q0, q1, qcnt = 0;
for (i = 0; i < 1024; i++) {
float t = fabsf(sce->coeffs[i]);
if (t > 0.0f) {
q0f = FFMIN(q0f, t);
q1f = FFMAX(q1f, t);
qnrgf += t*t;
qcnt++;
}
}
if (!qcnt) {
memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
memset(sce->zeroes, 1, sizeof(sce->zeroes));
return;
}
//minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
q0 = av_clip_uint8(log2(q0f)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
//maximum scalefactor index is when maximum coefficient after quantizing is still not zero
q1 = av_clip_uint8(log2(q1f)*4 + 6 + SCALE_ONE_POS - SCALE_DIV_512);
//av_log(NULL, AV_LOG_ERROR, "q0 %d, q1 %d\n", q0, q1);
if (q1 - q0 > 60) {
int q0low = q0;
int q1high = q1;
//minimum scalefactor index is when maximum nonzero coefficient after quantizing is not clipped
int qnrg = av_clip_uint8(log2(sqrt(qnrgf/qcnt))*4 - 31 + SCALE_ONE_POS - SCALE_DIV_512);
q1 = qnrg + 30;
q0 = qnrg - 30;
//av_log(NULL, AV_LOG_ERROR, "q0 %d, q1 %d\n", q0, q1);
if (q0 < q0low) {
q1 += q0low - q0;
q0 = q0low;
} else if (q1 > q1high) {
q0 -= q1 - q1high;
q1 = q1high;
}
}
//av_log(NULL, AV_LOG_ERROR, "q0 %d, q1 %d\n", q0, q1);
for (i = 0; i < TRELLIS_STATES; i++) {
paths[0][i].cost = 0.0f;
paths[0][i].prev = -1;
paths[0][i].min_val = i;
paths[0][i].max_val = i;
}
for (j = 1; j < TRELLIS_STAGES; j++) {
for (i = 0; i < TRELLIS_STATES; i++) {
paths[j][i].cost = INFINITY;
paths[j][i].prev = -2;
paths[j][i].min_val = INT_MAX;
paths[j][i].max_val = 0;
}
}
idx = 1;
@ -529,6 +565,8 @@ static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
minscale = av_clip_uint8(log2(qmin)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
//maximum scalefactor index is when maximum coefficient after quantizing is still not zero
maxscale = av_clip_uint8(log2(qmax)*4 + 6 + SCALE_ONE_POS - SCALE_DIV_512);
minscale = av_clip(minscale - q0, 0, TRELLIS_STATES - 1);
maxscale = av_clip(maxscale - q0, 0, TRELLIS_STATES);
for (q = minscale; q < maxscale; q++) {
float dists[12], dist;
memset(dists, 0, sizeof(dists));
@ -537,52 +575,40 @@ static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
int cb;
for (cb = 0; cb <= ESC_BT; cb++)
dists[cb] += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g],
q, cb, lambda / band->threshold, INFINITY, NULL);
q + q0, cb, lambda / band->threshold, INFINITY, NULL);
}
dist = dists[0];
for (i = 1; i <= ESC_BT; i++)
dist = FFMIN(dist, dists[i]);
minrd = FFMIN(minrd, dist);
for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, TRELLIS_STATES); i++) {
for (i = 0; i < q1 - q0; i++) {
float cost;
int minv, maxv;
if (isinf(paths[idx - 1][i].cost))
continue;
cost = paths[idx - 1][i].cost + dist
+ ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
minv = FFMIN(paths[idx - 1][i].min_val, q);
maxv = FFMAX(paths[idx - 1][i].max_val, q);
if (cost < paths[idx][q].cost && maxv-minv < SCALE_MAX_DIFF) {
if (cost < paths[idx][q].cost) {
paths[idx][q].cost = cost;
paths[idx][q].prev = i;
paths[idx][q].min_val = minv;
paths[idx][q].max_val = maxv;
}
}
}
} else {
for (q = 0; q < TRELLIS_STATES; q++) {
for (q = 0; q < q1 - q0; q++) {
if (!isinf(paths[idx - 1][q].cost)) {
paths[idx][q].cost = paths[idx - 1][q].cost + 1;
paths[idx][q].prev = q;
paths[idx][q].min_val = FFMIN(paths[idx - 1][q].min_val, q);
paths[idx][q].max_val = FFMAX(paths[idx - 1][q].max_val, q);
continue;
}
for (i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, TRELLIS_STATES); i++) {
for (i = 0; i < q1 - q0; i++) {
float cost;
int minv, maxv;
if (isinf(paths[idx - 1][i].cost))
continue;
cost = paths[idx - 1][i].cost + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
minv = FFMIN(paths[idx - 1][i].min_val, q);
maxv = FFMAX(paths[idx - 1][i].max_val, q);
if (cost < paths[idx][q].cost && maxv-minv < SCALE_MAX_DIFF) {
if (cost < paths[idx][q].cost) {
paths[idx][q].cost = cost;
paths[idx][q].prev = i;
paths[idx][q].min_val = minv;
paths[idx][q].max_val = maxv;
}
}
}
@ -602,7 +628,7 @@ static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
}
}
while (idx) {
sce->sf_idx[bandaddr[idx]] = minq;
sce->sf_idx[bandaddr[idx]] = minq + q0;
minq = paths[idx][minq].prev;
idx--;
}

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