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second pass encoding changes:

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- warn rather than fail when specified bitrate need not be used
- fail with a useful message when specified bitrate is too low
- print potentially useful information if verbose

patch based mostly on suggestions from Michael Niedermayer and Loren Merritt

Originally committed as revision 6176 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Corey Hickey 2006-09-05 15:46:06 +00:00
parent 157cba3bdb
commit 577cd173e3
1 changed files with 39 additions and 6 deletions
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45
libavcodec/ratecontrol.c
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@ -790,7 +790,7 @@ static int init_pass2(MpegEncContext *s)
{
RateControlContext *rcc= &s->rc_context;
AVCodecContext *a= s->avctx;
int i;
int i, toobig;
double fps= 1/av_q2d(s->avctx->time_base);
double complexity[5]={0,0,0,0,0}; // aproximate bits at quant=1
uint64_t const_bits[5]={0,0,0,0,0}; // quantizer idependant bits
@ -801,7 +801,7 @@ static int init_pass2(MpegEncContext *s)
//int last_i_frame=-10000000;
const int filter_size= (int)(a->qblur*4) | 1;
double expected_bits;
double *qscale, *blured_qscale;
double *qscale, *blured_qscale, qscale_sum;
/* find complexity & const_bits & decide the pict_types */
for(i=0; i<rcc->num_entries; i++){
@ -825,6 +825,7 @@ static int init_pass2(MpegEncContext *s)
qscale= av_malloc(sizeof(double)*rcc->num_entries);
blured_qscale= av_malloc(sizeof(double)*rcc->num_entries);
toobig = 0;
for(step=256*256; step>0.0000001; step*=0.5){
expected_bits=0;
@ -878,14 +879,46 @@ static int init_pass2(MpegEncContext *s)
expected_bits += bits;
}
// printf("%f %d %f\n", expected_bits, (int)all_available_bits, rate_factor);
if(expected_bits > all_available_bits) rate_factor-= step;
/*
av_log(s->avctx, AV_LOG_INFO,
"expected_bits: %f all_available_bits: %d rate_factor: %f\n",
expected_bits, (int)all_available_bits, rate_factor);
*/
if(expected_bits > all_available_bits) {
rate_factor-= step;
++toobig;
}
}
av_free(qscale);
av_free(blured_qscale);
if(fabs(expected_bits/all_available_bits - 1.0) > 0.01 ){
av_log(s->avctx, AV_LOG_ERROR, "Error: 2pass curve failed to converge\n");
/* check bitrate calculations and print info */
qscale_sum = 0.0;
for(i=0; i<rcc->num_entries; i++){
/* av_log(s->avctx, AV_LOG_DEBUG, "[lavc rc] entry[%d].new_qscale = %.3f qp = %.3f\n",
i, rcc->entry[i].new_qscale, rcc->entry[i].new_qscale / FF_QP2LAMBDA); */
qscale_sum += clip(rcc->entry[i].new_qscale / FF_QP2LAMBDA, s->avctx->qmin, s->avctx->qmax);
}
assert(toobig <= 40);
av_log(s->avctx, AV_LOG_DEBUG,
"[lavc rc] requested bitrate: %d bps expected bitrate: %d bps\n",
s->bit_rate,
(int)(expected_bits / ((double)all_available_bits/s->bit_rate)));
av_log(s->avctx, AV_LOG_DEBUG,
"[lavc rc] estimated target average qp: %.3f\n",
(float)qscale_sum / rcc->num_entries);
if (toobig == 0) {
av_log(s->avctx, AV_LOG_INFO,
"[lavc rc] Using all of requested bitrate is not "
"necessary for this video with these parameters.\n");
} else if (toobig == 40) {
av_log(s->avctx, AV_LOG_ERROR,
"[lavc rc] Error: bitrate too low for this video "
"with these parameters.\n");
return -1;
} else if (fabs(expected_bits/all_available_bits - 1.0) > 0.01) {
av_log(s->avctx, AV_LOG_ERROR,
"[lavc rc] Error: 2pass curve failed to converge\n");
return -1;
}