ratecontrol.c

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.10平台上编译为嵌入式图形界面操作系统。

/*
 * Rate control for video encoders
 *
 * Copyright (c) 2002 Michael Niedermayer <[e-mail]>
 *
 * 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
 */

/**
 * @file ratecontrol.c
 * Rate control for video encoders.
 */ 

#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_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:%d 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->current_picture.quality, s->i_tex_bits, s->p_tex_bits, s->mv_bits, s->misc_bits, 
            s->f_code, s->b_code, s->current_picture.mc_mb_var_sum, s->current_picture.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= FF_QP2LAMBDA * 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]=FF_QP2LAMBDA * 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=FF_QP2LAMBDA * 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){
                av_log(s->avctx, AV_LOG_ERROR, "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   = FF_QP2LAMBDA * 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->avctx->frame_rate / (double)s->avctx->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){
        av_log(NULL, AV_LOG_ERROR, "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){
        av_log(NULL, AV_LOG_ERROR, "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->avctx->frame_rate / (double)s->avctx->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)
            av_log(s->avctx, AV_LOG_ERROR, "rc buffer underflow\n");
        if(rcc->buffer_index >= s->avctx->rc_buffer_size)
            av_log(s->avctx, AV_LOG_ERROR, "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
    };
    static const 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)={
        (void *)bits2qp,
        (void *)qp2bits,
        NULL
    };
    static const 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];
        const int maxdiff= FF_QP2LAMBDA * a->max_qdiff;

        if     (q > last_q + maxdiff) q= last_q + maxdiff;
        else if(q < last_q - maxdiff) q= last_q - maxdiff;
    }

    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->avctx->lmin;                                                       
    int qmax= s->avctx->lmax;
    
    assert(qmin <= 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);
    }

    qmin= clip(qmin, 1, FF_LAMBDA_MAX);
    qmax= clip(qmax, 1, FF_LAMBDA_MAX);

    if(qmax<qmin) qmax= qmin;
    
    *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= FFMIN(q, bits2qp(rce, FFMAX((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);