Function encode_frame

libavcodec/snow.c:3700–3975

}

static int encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){
    SnowContext *s = avctx->priv_data;
    RangeCoder * const c= &s->c;
    AVFrame *pict = data;
    const int width= s->avctx->width;
    const int height= s->avctx->height;
    int level, orientation, plane_index, i, y;
    uint8_t rc_header_bak[sizeof(s->header_state)];
    uint8_t rc_block_bak[sizeof(s->block_state)];

    ff_init_range_encoder(c, buf, buf_size);
    ff_build_rac_states(c, 0.05*(1LL<<32), 256-8);

    for(i=0; i<3; i++){
        int shift= !!i;
        for(y=0; y<(height>>shift); y++)
            memcpy(&s->input_picture.data[i][y * s->input_picture.linesize[i]],
                   &pict->data[i][y * pict->linesize[i]],
                   width>>shift);
    }
    s->new_picture = *pict;

    s->m.picture_number= avctx->frame_number;
    if(avctx->flags&CODEC_FLAG_PASS2){
        s->m.pict_type =
        pict->pict_type= s->m.rc_context.entry[avctx->frame_number].new_pict_type;
        s->keyframe= pict->pict_type==FF_I_TYPE;
        if(!(avctx->flags&CODEC_FLAG_QSCALE)) {
            pict->quality= ff_rate_estimate_qscale(&s->m, 0);
            if (pict->quality < 0)
                return -1;
        }
    }else{
        s->keyframe= avctx->gop_size==0 || avctx->frame_number % avctx->gop_size == 0;
        s->m.pict_type=
        pict->pict_type= s->keyframe ? FF_I_TYPE : FF_P_TYPE;
    }

    if(s->pass1_rc && avctx->frame_number == 0)
        pict->quality= 2*FF_QP2LAMBDA;
    if(pict->quality){
        s->qlog= qscale2qlog(pict->quality);
        s->lambda = pict->quality * 3/2;
    }
    if(s->qlog < 0 || (!pict->quality && (avctx->flags & CODEC_FLAG_QSCALE))){
        s->qlog= LOSSLESS_QLOG;
        s->lambda = 0;
    }//else keep previous frame's qlog until after motion estimation

    frame_start(s);

    s->m.current_picture_ptr= &s->m.current_picture;
    s->m.last_picture.pts= s->m.current_picture.pts;
    s->m.current_picture.pts= pict->pts;
    if(pict->pict_type == FF_P_TYPE){
        int block_width = (width +15)>>4;
        int block_height= (height+15)>>4;
        int stride= s->current_picture.linesize[0];