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ffmpeg/libavcodec/ratecontrol.c

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/*
* Rate control for video encoders
*
* Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <math.h>
#include "common.h"
#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"
#undef NDEBUG // allways check asserts, the speed effect is far too small to disable them
#include <assert.h>
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
#ifndef M_E
#define M_E 2.718281828
#endif
static int init_pass2(MpegEncContext *s);
static double get_qscale(MpegEncContext *s, RateControlEntry *rce, double rate_factor, int frame_num);
void ff_write_pass1_stats(MpegEncContext *s){
sprintf(s->avctx->stats_out, "in:%d out:%d type:%d q:%f itex:%d ptex:%d mv:%d misc:%d fcode:%d bcode:%d mc-var:%d var:%d icount:%d;\n",
s->picture_number, s->input_picture_number - s->max_b_frames, s->pict_type,
s->frame_qscale, s->i_tex_bits, s->p_tex_bits, s->mv_bits, s->misc_bits,
s->f_code, s->b_code, s->mc_mb_var_sum, s->mb_var_sum, s->i_count);
}
int ff_rate_control_init(MpegEncContext *s)
{
RateControlContext *rcc= &s->rc_context;
int i;
emms_c();
for(i=0; i<5; i++){
rcc->pred[i].coeff= 7.0;
rcc->pred[i].count= 1.0;
rcc->pred[i].decay= 0.4;
rcc->i_cplx_sum [i]=
rcc->p_cplx_sum [i]=
rcc->mv_bits_sum[i]=
rcc->qscale_sum [i]=
rcc->frame_count[i]= 1; // 1 is better cuz of 1/0 and such
rcc->last_qscale_for[i]=5;
}
rcc->buffer_index= s->avctx->rc_buffer_size/2;
if(s->flags&CODEC_FLAG_PASS2){
int i;
char *p;
/* find number of pics */
p= s->avctx->stats_in;
for(i=-1; p; i++){
p= strchr(p+1, ';');
}
i+= s->max_b_frames;
rcc->entry = (RateControlEntry*)av_mallocz(i*sizeof(RateControlEntry));
rcc->num_entries= i;
/* init all to skiped p frames (with b frames we might have a not encoded frame at the end FIXME) */
for(i=0; i<rcc->num_entries; i++){
RateControlEntry *rce= &rcc->entry[i];
rce->pict_type= rce->new_pict_type=P_TYPE;
rce->qscale= rce->new_qscale=2;
rce->misc_bits= s->mb_num + 10;
rce->mb_var_sum= s->mb_num*100;
}
/* read stats */
p= s->avctx->stats_in;
for(i=0; i<rcc->num_entries - s->max_b_frames; i++){
RateControlEntry *rce;
int picture_number;
int e;
char *next;
next= strchr(p, ';');
if(next){
(*next)=0; //sscanf in unbelieavle slow on looong strings //FIXME copy / dont write
next++;
}
e= sscanf(p, " in:%d ", &picture_number);
assert(picture_number >= 0);
assert(picture_number < rcc->num_entries);
rce= &rcc->entry[picture_number];
e+=sscanf(p, " in:%*d out:%*d type:%d q:%f itex:%d ptex:%d mv:%d misc:%d fcode:%d bcode:%d mc-var:%d var:%d icount:%d",
&rce->pict_type, &rce->qscale, &rce->i_tex_bits, &rce->p_tex_bits, &rce->mv_bits, &rce->misc_bits,
&rce->f_code, &rce->b_code, &rce->mc_mb_var_sum, &rce->mb_var_sum, &rce->i_count);
if(e!=12){
fprintf(stderr, "statistics are damaged at line %d, parser out=%d\n", i, e);
return -1;
}
p= next;
}
if(init_pass2(s) < 0) return -1;
}
if(!(s->flags&CODEC_FLAG_PASS2)){
rcc->short_term_qsum=0.001;
rcc->short_term_qcount=0.001;
rcc->pass1_rc_eq_output_sum= 0.001;
rcc->pass1_wanted_bits=0.001;
/* init stuff with the user specified complexity */
if(s->avctx->rc_initial_cplx){
for(i=0; i<60*30; i++){
double bits= s->avctx->rc_initial_cplx * (i/10000.0 + 1.0)*s->mb_num;
RateControlEntry rce;
double q;
if (i%((s->gop_size+3)/4)==0) rce.pict_type= I_TYPE;
else if(i%(s->max_b_frames+1)) rce.pict_type= B_TYPE;
else rce.pict_type= P_TYPE;
rce.new_pict_type= rce.pict_type;
rce.mc_mb_var_sum= bits*s->mb_num/100000;
rce.mb_var_sum = s->mb_num;
rce.qscale = 2;
rce.f_code = 2;
rce.b_code = 1;
rce.misc_bits= 1;
if(s->pict_type== I_TYPE){
rce.i_count = s->mb_num;
rce.i_tex_bits= bits;
rce.p_tex_bits= 0;
rce.mv_bits= 0;
}else{
rce.i_count = 0; //FIXME we do know this approx
rce.i_tex_bits= 0;
rce.p_tex_bits= bits*0.9;
rce.mv_bits= bits*0.1;
}
rcc->i_cplx_sum [rce.pict_type] += rce.i_tex_bits*rce.qscale;
rcc->p_cplx_sum [rce.pict_type] += rce.p_tex_bits*rce.qscale;
rcc->mv_bits_sum[rce.pict_type] += rce.mv_bits;
rcc->frame_count[rce.pict_type] ++;
bits= rce.i_tex_bits + rce.p_tex_bits;
q= get_qscale(s, &rce, rcc->pass1_wanted_bits/rcc->pass1_rc_eq_output_sum, i);
rcc->pass1_wanted_bits+= s->bit_rate/(s->frame_rate / (double)FRAME_RATE_BASE);
}
}
}
return 0;
}
void ff_rate_control_uninit(MpegEncContext *s)
{
RateControlContext *rcc= &s->rc_context;
emms_c();
av_freep(&rcc->entry);
}
static inline double qp2bits(RateControlEntry *rce, double qp){
if(qp<=0.0){
fprintf(stderr, "qp<=0.0\n");
}
return rce->qscale * (double)(rce->i_tex_bits + rce->p_tex_bits+1)/ qp;
}
static inline double bits2qp(RateControlEntry *rce, double bits){
if(bits<0.9){
fprintf(stderr, "bits<0.9\n");
}
return rce->qscale * (double)(rce->i_tex_bits + rce->p_tex_bits+1)/ bits;
}
static void update_rc_buffer(MpegEncContext *s, int frame_size){
RateControlContext *rcc= &s->rc_context;
const double fps= (double)s->frame_rate / FRAME_RATE_BASE;
const double buffer_size= s->avctx->rc_buffer_size;
const double min_rate= s->avctx->rc_min_rate/fps;
const double max_rate= s->avctx->rc_max_rate/fps;
if(buffer_size){
rcc->buffer_index-= frame_size;
if(rcc->buffer_index < buffer_size/2 /*FIXME /2 */ || min_rate==0){
rcc->buffer_index+= max_rate;
if(rcc->buffer_index >= buffer_size)
rcc->buffer_index= buffer_size-1;
}else{
rcc->buffer_index+= min_rate;
}
if(rcc->buffer_index < 0)
fprintf(stderr, "rc buffer underflow\n");
if(rcc->buffer_index >= s->avctx->rc_buffer_size)
fprintf(stderr, "rc buffer overflow\n");
}
}
/**
* modifies the bitrate curve from pass1 for one frame
*/
static double get_qscale(MpegEncContext *s, RateControlEntry *rce, double rate_factor, int frame_num){
RateControlContext *rcc= &s->rc_context;
double q, bits;
const int pict_type= rce->new_pict_type;
const double mb_num= s->mb_num;
int i;
double const_values[]={
M_PI,
M_E,
rce->i_tex_bits*rce->qscale,
rce->p_tex_bits*rce->qscale,
(rce->i_tex_bits + rce->p_tex_bits)*(double)rce->qscale,
rce->mv_bits/mb_num,
rce->pict_type == B_TYPE ? (rce->f_code + rce->b_code)*0.5 : rce->f_code,
rce->i_count/mb_num,
rce->mc_mb_var_sum/mb_num,
rce->mb_var_sum/mb_num,
rce->pict_type == I_TYPE,
rce->pict_type == P_TYPE,
rce->pict_type == B_TYPE,
rcc->qscale_sum[pict_type] / (double)rcc->frame_count[pict_type],
s->qcompress,
/* rcc->last_qscale_for[I_TYPE],
rcc->last_qscale_for[P_TYPE],
rcc->last_qscale_for[B_TYPE],
rcc->next_non_b_qscale,*/
rcc->i_cplx_sum[I_TYPE] / (double)rcc->frame_count[I_TYPE],
rcc->i_cplx_sum[P_TYPE] / (double)rcc->frame_count[P_TYPE],
rcc->p_cplx_sum[P_TYPE] / (double)rcc->frame_count[P_TYPE],
rcc->p_cplx_sum[B_TYPE] / (double)rcc->frame_count[B_TYPE],
(rcc->i_cplx_sum[pict_type] + rcc->p_cplx_sum[pict_type]) / (double)rcc->frame_count[pict_type],
0
};
char *const_names[]={
"PI",
"E",
"iTex",
"pTex",
"tex",
"mv",
"fCode",
"iCount",
"mcVar",
"var",
"isI",
"isP",
"isB",
"avgQP",
"qComp",
/* "lastIQP",
"lastPQP",
"lastBQP",
"nextNonBQP",*/
"avgIITex",
"avgPITex",
"avgPPTex",
"avgBPTex",
"avgTex",
NULL
};
static double (*func1[])(void *, double)={
bits2qp,
qp2bits,
NULL
};
char *func1_names[]={
"bits2qp",
"qp2bits",
NULL
};
bits= ff_eval(s->avctx->rc_eq, const_values, const_names, func1, func1_names, NULL, NULL, rce);
rcc->pass1_rc_eq_output_sum+= bits;
bits*=rate_factor;
if(bits<0.0) bits=0.0;
bits+= 1.0; //avoid 1/0 issues
/* user override */
for(i=0; i<s->avctx->rc_override_count; i++){
RcOverride *rco= s->avctx->rc_override;
if(rco[i].start_frame > frame_num) continue;
if(rco[i].end_frame < frame_num) continue;
if(rco[i].qscale)
bits= qp2bits(rce, rco[i].qscale); //FIXME move at end to really force it?
else
bits*= rco[i].quality_factor;
}
q= bits2qp(rce, bits);
/* I/B difference */
if (pict_type==I_TYPE && s->avctx->i_quant_factor<0.0)
q= -q*s->avctx->i_quant_factor + s->avctx->i_quant_offset;
else if(pict_type==B_TYPE && s->avctx->b_quant_factor<0.0)
q= -q*s->avctx->b_quant_factor + s->avctx->b_quant_offset;
return q;
}
static double get_diff_limited_q(MpegEncContext *s, RateControlEntry *rce, double q){
RateControlContext *rcc= &s->rc_context;
AVCodecContext *a= s->avctx;
const int pict_type= rce->new_pict_type;
const double last_p_q = rcc->last_qscale_for[P_TYPE];
const double last_non_b_q= rcc->last_qscale_for[rcc->last_non_b_pict_type];
if (pict_type==I_TYPE && (a->i_quant_factor>0.0 || rcc->last_non_b_pict_type==P_TYPE))
q= last_p_q *ABS(a->i_quant_factor) + a->i_quant_offset;
else if(pict_type==B_TYPE && a->b_quant_factor>0.0)
q= last_non_b_q* a->b_quant_factor + a->b_quant_offset;
/* last qscale / qdiff stuff */
if(rcc->last_non_b_pict_type==pict_type || pict_type!=I_TYPE){
double last_q= rcc->last_qscale_for[pict_type];
if (q > last_q + a->max_qdiff) q= last_q + a->max_qdiff;
else if(q < last_q - a->max_qdiff) q= last_q - a->max_qdiff;
}
rcc->last_qscale_for[pict_type]= q; //Note we cant do that after blurring
if(pict_type!=B_TYPE)
rcc->last_non_b_pict_type= pict_type;
return q;
}
/**
* gets the qmin & qmax for pict_type
*/
static void get_qminmax(int *qmin_ret, int *qmax_ret, MpegEncContext *s, int pict_type){
int qmin= s->qmin;
int qmax= s->qmax;
if(pict_type==B_TYPE){
qmin= (int)(qmin*ABS(s->avctx->b_quant_factor)+s->avctx->b_quant_offset + 0.5);
qmax= (int)(qmax*ABS(s->avctx->b_quant_factor)+s->avctx->b_quant_offset + 0.5);
}else if(pict_type==I_TYPE){
qmin= (int)(qmin*ABS(s->avctx->i_quant_factor)+s->avctx->i_quant_offset + 0.5);
qmax= (int)(qmax*ABS(s->avctx->i_quant_factor)+s->avctx->i_quant_offset + 0.5);
}
if(qmin<1) qmin=1;
if(qmin==1 && s->qmin>1) qmin=2; //avoid qmin=1 unless the user wants qmin=1
if(qmin<3 && s->max_qcoeff<=128 && pict_type==I_TYPE) qmin=3; //reduce cliping problems
if(qmax>31) qmax=31;
if(qmax<=qmin) qmax= qmin= (qmax+qmin+1)>>1;
*qmin_ret= qmin;
*qmax_ret= qmax;
}
static double modify_qscale(MpegEncContext *s, RateControlEntry *rce, double q, int frame_num){
RateControlContext *rcc= &s->rc_context;
int qmin, qmax;
double bits;
const int pict_type= rce->new_pict_type;
const double buffer_size= s->avctx->rc_buffer_size;
const double min_rate= s->avctx->rc_min_rate;
const double max_rate= s->avctx->rc_max_rate;
get_qminmax(&qmin, &qmax, s, pict_type);
/* modulation */
if(s->avctx->rc_qmod_freq && frame_num%s->avctx->rc_qmod_freq==0 && pict_type==P_TYPE)
q*= s->avctx->rc_qmod_amp;
bits= qp2bits(rce, q);
//printf("q:%f\n", q);
/* buffer overflow/underflow protection */
if(buffer_size){
double expected_size= rcc->buffer_index;
if(min_rate){
double d= 2*(buffer_size - expected_size)/buffer_size;
if(d>1.0) d=1.0;
else if(d<0.0001) d=0.0001;
q*= pow(d, 1.0/s->avctx->rc_buffer_aggressivity);
q= MIN(q, bits2qp(rce, MAX((min_rate - buffer_size + rcc->buffer_index)*2, 1)));
}
if(max_rate){
double d= 2*expected_size/buffer_size;
if(d>1.0) d=1.0;
else if(d<0.0001) d=0.0001;
q/= pow(d, 1.0/s->avctx->rc_buffer_aggressivity);
q= MAX(q, bits2qp(rce, MAX(rcc->buffer_index/2, 1)));
}
}
//printf("q:%f max:%f min:%f size:%f index:%d bits:%f agr:%f\n", q,max_rate, min_rate, buffer_size, rcc->buffer_index, bits, s->avctx->rc_buffer_aggressivity);
if(s->avctx->rc_qsquish==0.0 || qmin==qmax){
if (q<qmin) q=qmin;
else if(q>qmax) q=qmax;
}else{
double min2= log(qmin);
double max2= log(qmax);
q= log(q);
q= (q - min2)/(max2-min2) - 0.5;
q*= -4.0;
q= 1.0/(1.0 + exp(q));
q= q*(max2-min2) + min2;
q= exp(q);
}
return q;
}
//----------------------------------
// 1 Pass Code
static double predict_size(Predictor *p, double q, double var)
{
return p->coeff*var / (q*p->count);
}
static double predict_qp(Predictor *p, double size, double var)
{
//printf("coeff:%f, count:%f, var:%f, size:%f//\n", p->coeff, p->count, var, size);
return p->coeff*var / (size*p->count);
}
static void update_predictor(Predictor *p, double q, double var, double size)
{
double new_coeff= size*q / (var + 1);
if(var<10) return;
p->count*= p->decay;
p->coeff*= p->decay;
p->count++;
p->coeff+= new_coeff;
}
static void adaptive_quantization(MpegEncContext *s, double q){
int i;
const float lumi_masking= s->avctx->lumi_masking / (128.0*128.0);
const float dark_masking= s->avctx->dark_masking / (128.0*128.0);
const float temp_cplx_masking= s->avctx->temporal_cplx_masking;
const float spatial_cplx_masking = s->avctx->spatial_cplx_masking;
const float p_masking = s->avctx->p_masking;
float bits_sum= 0.0;
float cplx_sum= 0.0;
float cplx_tab[s->mb_num];
float bits_tab[s->mb_num];
const int qmin= 2; //s->avctx->mb_qmin;
const int qmax= 31; //s->avctx->mb_qmax;
for(i=0; i<s->mb_num; i++){
float temp_cplx= sqrt(s->mc_mb_var[i]);
float spat_cplx= sqrt(s->mb_var[i]);
const int lumi= s->mb_mean[i];
float bits, cplx, factor;
if(spat_cplx < q/3) spat_cplx= q/3; //FIXME finetune
if(temp_cplx < q/3) temp_cplx= q/3; //FIXME finetune
if((s->mb_type[i]&MB_TYPE_INTRA)){//FIXME hq mode
cplx= spat_cplx;
factor= 1.0 + p_masking;
}else{
cplx= temp_cplx;
factor= pow(temp_cplx, - temp_cplx_masking);
}
factor*=pow(spat_cplx, - spatial_cplx_masking);
if(lumi>127)
factor*= (1.0 - (lumi-128)*(lumi-128)*lumi_masking);
else
factor*= (1.0 - (lumi-128)*(lumi-128)*dark_masking);
if(factor<0.00001) factor= 0.00001;
bits= cplx*factor;
cplx_sum+= cplx;
bits_sum+= bits;
cplx_tab[i]= cplx;
bits_tab[i]= bits;
}
/* handle qmin/qmax cliping */
if(s->flags&CODEC_FLAG_NORMALIZE_AQP){
for(i=0; i<s->mb_num; i++){
float newq= q*cplx_tab[i]/bits_tab[i];
newq*= bits_sum/cplx_sum;
if (newq > qmax){
bits_sum -= bits_tab[i];
cplx_sum -= cplx_tab[i]*q/qmax;
}
else if(newq < qmin){
bits_sum -= bits_tab[i];
cplx_sum -= cplx_tab[i]*q/qmin;
}
}
}
for(i=0; i<s->mb_num; i++){
float newq= q*cplx_tab[i]/bits_tab[i];
int intq;
if(s->flags&CODEC_FLAG_NORMALIZE_AQP){
newq*= bits_sum/cplx_sum;
}
if(i && ABS(s->qscale_table[i-1] - newq)<0.75)
intq= s->qscale_table[i-1];
else
intq= (int)(newq + 0.5);
if (intq > qmax) intq= qmax;
else if(intq < qmin) intq= qmin;
//if(i%s->mb_width==0) printf("\n");
//printf("%2d%3d ", intq, ff_sqrt(s->mc_mb_var[i]));
s->qscale_table[i]= intq;
}
}
float ff_rate_estimate_qscale(MpegEncContext *s)
{
float q;
int qmin, qmax;
float br_compensation;
double diff;
double short_term_q;
double fps;
int picture_number= s->picture_number;
int64_t wanted_bits;
RateControlContext *rcc= &s->rc_context;
RateControlEntry local_rce, *rce;
double bits;
double rate_factor;
int var;
const int pict_type= s->pict_type;
emms_c();
get_qminmax(&qmin, &qmax, s, pict_type);
fps= (double)s->frame_rate / FRAME_RATE_BASE;
//printf("input_pic_num:%d pic_num:%d frame_rate:%d\n", s->input_picture_number, s->picture_number, s->frame_rate);
/* update predictors */
if(picture_number>2){
const int last_var= s->last_pict_type == I_TYPE ? rcc->last_mb_var_sum : rcc->last_mc_mb_var_sum;
update_predictor(&rcc->pred[s->last_pict_type], rcc->last_qscale, sqrt(last_var), s->frame_bits);
}
if(s->flags&CODEC_FLAG_PASS2){
assert(picture_number>=0);
assert(picture_number<rcc->num_entries);
rce= &rcc->entry[picture_number];
wanted_bits= rce->expected_bits;
}else{
rce= &local_rce;
wanted_bits= (uint64_t)(s->bit_rate*(double)picture_number/fps);
}
diff= s->total_bits - wanted_bits;
br_compensation= (s->bit_rate_tolerance - diff)/s->bit_rate_tolerance;
if(br_compensation<=0.0) br_compensation=0.001;
var= pict_type == I_TYPE ? s->mb_var_sum : s->mc_mb_var_sum;
if(s->flags&CODEC_FLAG_PASS2){
if(pict_type!=I_TYPE)
assert(pict_type == rce->new_pict_type);
q= rce->new_qscale / br_compensation;
//printf("%f %f %f last:%d var:%d type:%d//\n", q, rce->new_qscale, br_compensation, s->frame_bits, var, pict_type);
}else{
rce->pict_type=
rce->new_pict_type= pict_type;
rce->mc_mb_var_sum= s->mc_mb_var_sum;
rce->mb_var_sum = s-> mb_var_sum;
rce->qscale = 2;
rce->f_code = s->f_code;
rce->b_code = s->b_code;
rce->misc_bits= 1;
if(picture_number>0)
update_rc_buffer(s, s->frame_bits);
bits= predict_size(&rcc->pred[pict_type], rce->qscale, sqrt(var));
if(pict_type== I_TYPE){
rce->i_count = s->mb_num;
rce->i_tex_bits= bits;
rce->p_tex_bits= 0;
rce->mv_bits= 0;
}else{
rce->i_count = 0; //FIXME we do know this approx
rce->i_tex_bits= 0;
rce->p_tex_bits= bits*0.9;
rce->mv_bits= bits*0.1;
}
rcc->i_cplx_sum [pict_type] += rce->i_tex_bits*rce->qscale;
rcc->p_cplx_sum [pict_type] += rce->p_tex_bits*rce->qscale;
rcc->mv_bits_sum[pict_type] += rce->mv_bits;
rcc->frame_count[pict_type] ++;
bits= rce->i_tex_bits + rce->p_tex_bits;
rate_factor= rcc->pass1_wanted_bits/rcc->pass1_rc_eq_output_sum * br_compensation;
q= get_qscale(s, rce, rate_factor, picture_number);
assert(q>0.0);
//printf("%f ", q);
q= get_diff_limited_q(s, rce, q);
//printf("%f ", q);
assert(q>0.0);
if(pict_type==P_TYPE || s->intra_only){ //FIXME type dependant blur like in 2-pass
rcc->short_term_qsum*=s->qblur;
rcc->short_term_qcount*=s->qblur;
rcc->short_term_qsum+= q;
rcc->short_term_qcount++;
//printf("%f ", q);
q= short_term_q= rcc->short_term_qsum/rcc->short_term_qcount;
//printf("%f ", q);
}
assert(q>0.0);
q= modify_qscale(s, rce, q, picture_number);
rcc->pass1_wanted_bits+= s->bit_rate/fps;
assert(q>0.0);
}
//printf("qmin:%d, qmax:%d, q:%f\n", qmin, qmax, q);
if (q<qmin) q=qmin;
else if(q>qmax) q=qmax;
// printf("%f %d %d %d\n", q, picture_number, (int)wanted_bits, (int)s->total_bits);
//printf("%f %f %f\n", q, br_compensation, short_term_q);
//printf("q:%d diff:%d comp:%f st_q:%f last_size:%d type:%d\n", qscale, (int)diff, br_compensation,
// short_term_q, s->frame_bits, pict_type);
//printf("%d %d\n", s->bit_rate, (int)fps);
if(s->adaptive_quant)
adaptive_quantization(s, q);
else
q= (int)(q + 0.5);
rcc->last_qscale= q;
rcc->last_mc_mb_var_sum= s->mc_mb_var_sum;
rcc->last_mb_var_sum= s->mb_var_sum;
return q;
}
//----------------------------------------------
// 2-Pass code
static int init_pass2(MpegEncContext *s)
{
RateControlContext *rcc= &s->rc_context;
int i;
double fps= (double)s->frame_rate / FRAME_RATE_BASE;
double complexity[5]={0,0,0,0,0}; // aproximate bits at quant=1
double avg_quantizer[5];
uint64_t const_bits[5]={0,0,0,0,0}; // quantizer idependant bits
uint64_t available_bits[5];
uint64_t all_const_bits;
uint64_t all_available_bits= (uint64_t)(s->bit_rate*(double)rcc->num_entries/fps);
double rate_factor=0;
double step;
int last_i_frame=-10000000;
const int filter_size= (int)(s->qblur*4) | 1;
double expected_bits;
double *qscale, *blured_qscale;
/* find complexity & const_bits & decide the pict_types */
for(i=0; i<rcc->num_entries; i++){
RateControlEntry *rce= &rcc->entry[i];
if(s->b_frame_strategy==0 || s->max_b_frames==0){
rce->new_pict_type= rce->pict_type;
}else{
int j;
int next_non_b_type=P_TYPE;
switch(rce->pict_type){
case I_TYPE:
if(i-last_i_frame>s->gop_size/2){ //FIXME this is not optimal
rce->new_pict_type= I_TYPE;
last_i_frame= i;
}else{
rce->new_pict_type= P_TYPE; // will be caught by the scene detection anyway
}
break;
case P_TYPE:
rce->new_pict_type= P_TYPE;
break;
case B_TYPE:
for(j=i+1; j<i+s->max_b_frames+2 && j<rcc->num_entries; j++){
if(rcc->entry[j].pict_type != B_TYPE){
next_non_b_type= rcc->entry[j].pict_type;
break;
}
}
if(next_non_b_type==I_TYPE)
rce->new_pict_type= P_TYPE;
else
rce->new_pict_type= B_TYPE;
break;
}
}
rcc->i_cplx_sum [rce->pict_type] += rce->i_tex_bits*rce->qscale;
rcc->p_cplx_sum [rce->pict_type] += rce->p_tex_bits*rce->qscale;
rcc->mv_bits_sum[rce->pict_type] += rce->mv_bits;
rcc->frame_count[rce->pict_type] ++;
complexity[rce->new_pict_type]+= (rce->i_tex_bits+ rce->p_tex_bits)*(double)rce->qscale;
const_bits[rce->new_pict_type]+= rce->mv_bits + rce->misc_bits;
}
all_const_bits= const_bits[I_TYPE] + const_bits[P_TYPE] + const_bits[B_TYPE];
if(all_available_bits < all_const_bits){
fprintf(stderr, "requested bitrate is to low\n");
return -1;
}
/* find average quantizers */
avg_quantizer[P_TYPE]=0;
for(step=256*256; step>0.0000001; step*=0.5){
double expected_bits=0;
avg_quantizer[P_TYPE]+= step;
avg_quantizer[I_TYPE]= avg_quantizer[P_TYPE]*ABS(s->avctx->i_quant_factor) + s->avctx->i_quant_offset;
avg_quantizer[B_TYPE]= avg_quantizer[P_TYPE]*ABS(s->avctx->b_quant_factor) + s->avctx->b_quant_offset;
expected_bits=
+ all_const_bits
+ complexity[I_TYPE]/avg_quantizer[I_TYPE]
+ complexity[P_TYPE]/avg_quantizer[P_TYPE]
+ complexity[B_TYPE]/avg_quantizer[B_TYPE];
if(expected_bits < all_available_bits) avg_quantizer[P_TYPE]-= step;
//printf("%f %lld %f\n", expected_bits, all_available_bits, avg_quantizer[P_TYPE]);
}
//printf("qp_i:%f, qp_p:%f, qp_b:%f\n", avg_quantizer[I_TYPE],avg_quantizer[P_TYPE],avg_quantizer[B_TYPE]);
for(i=0; i<5; i++){
available_bits[i]= const_bits[i] + complexity[i]/avg_quantizer[i];
}
//printf("%lld %lld %lld %lld\n", available_bits[I_TYPE], available_bits[P_TYPE], available_bits[B_TYPE], all_available_bits);
qscale= malloc(sizeof(double)*rcc->num_entries);
blured_qscale= malloc(sizeof(double)*rcc->num_entries);
for(step=256*256; step>0.0000001; step*=0.5){
expected_bits=0;
rate_factor+= step;
rcc->buffer_index= s->avctx->rc_buffer_size/2;
/* find qscale */
for(i=0; i<rcc->num_entries; i++){
qscale[i]= get_qscale(s, &rcc->entry[i], rate_factor, i);
}
assert(filter_size%2==1);
/* fixed I/B QP relative to P mode */
for(i=rcc->num_entries-1; i>=0; i--){
RateControlEntry *rce= &rcc->entry[i];
qscale[i]= get_diff_limited_q(s, rce, qscale[i]);
}
/* smooth curve */
for(i=0; i<rcc->num_entries; i++){
RateControlEntry *rce= &rcc->entry[i];
const int pict_type= rce->new_pict_type;
int j;
double q=0.0, sum=0.0;
for(j=0; j<filter_size; j++){
int index= i+j-filter_size/2;
double d= index-i;
double coeff= s->qblur==0 ? 1.0 : exp(-d*d/(s->qblur * s->qblur));
if(index < 0 || index >= rcc->num_entries) continue;
if(pict_type != rcc->entry[index].new_pict_type) continue;
q+= qscale[index] * coeff;
sum+= coeff;
}
blured_qscale[i]= q/sum;
}
/* find expected bits */
for(i=0; i<rcc->num_entries; i++){
RateControlEntry *rce= &rcc->entry[i];
double bits;
rce->new_qscale= modify_qscale(s, rce, blured_qscale[i], i);
bits= qp2bits(rce, rce->new_qscale) + rce->mv_bits + rce->misc_bits;
//printf("%d %f\n", rce->new_bits, blured_qscale[i]);
update_rc_buffer(s, bits);
rce->expected_bits= expected_bits;
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;
}
free(qscale);
free(blured_qscale);
if(abs(expected_bits/all_available_bits - 1.0) > 0.01 ){
fprintf(stderr, "Error: 2pass curve failed to converge\n");
return -1;
}
return 0;
}
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