mpegvideo_enc.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

        return -1;
    }

    if(avctx->rc_max_rate && avctx->rc_max_rate == avctx->bit_rate && avctx->rc_max_rate != avctx->rc_min_rate){
        av_log(avctx, AV_LOG_INFO, "impossible bitrate constraints, this will fail\n");
    }

    if(avctx->rc_buffer_size && avctx->bit_rate*av_q2d(avctx->time_base) > avctx->rc_buffer_size){
        av_log(avctx, AV_LOG_ERROR, "VBV buffer too small for bitrate\n");
        return -1;
    }

    if(avctx->bit_rate*av_q2d(avctx->time_base) > avctx->bit_rate_tolerance){
        av_log(avctx, AV_LOG_ERROR, "bitrate tolerance too small for bitrate\n");
        return -1;
    }

    if(   s->avctx->rc_max_rate && s->avctx->rc_min_rate == s->avctx->rc_max_rate
       && (s->codec_id == CODEC_ID_MPEG1VIDEO || s->codec_id == CODEC_ID_MPEG2VIDEO)
       && 90000LL * (avctx->rc_buffer_size-1) > s->avctx->rc_max_rate*0xFFFFLL){

        av_log(avctx, AV_LOG_INFO, "Warning vbv_delay will be set to 0xFFFF (=VBR) as the specified vbv buffer is too large for the given bitrate!\n");
    }

    if((s->flags & CODEC_FLAG_4MV) && s->codec_id != CODEC_ID_MPEG4
       && s->codec_id != CODEC_ID_H263 && s->codec_id != CODEC_ID_H263P && s->codec_id != CODEC_ID_FLV1){
        av_log(avctx, AV_LOG_ERROR, "4MV not supported by codec\n");
        return -1;
    }

    if(s->obmc && s->avctx->mb_decision != FF_MB_DECISION_SIMPLE){
        av_log(avctx, AV_LOG_ERROR, "OBMC is only supported with simple mb decision\n");
        return -1;
    }

    if(s->obmc && s->codec_id != CODEC_ID_H263 && s->codec_id != CODEC_ID_H263P){
        av_log(avctx, AV_LOG_ERROR, "OBMC is only supported with H263(+)\n");
        return -1;
    }

    if(s->quarter_sample && s->codec_id != CODEC_ID_MPEG4){
        av_log(avctx, AV_LOG_ERROR, "qpel not supported by codec\n");
        return -1;
    }

    if(s->data_partitioning && s->codec_id != CODEC_ID_MPEG4){
        av_log(avctx, AV_LOG_ERROR, "data partitioning not supported by codec\n");
        return -1;
    }

    if(s->max_b_frames && s->codec_id != CODEC_ID_MPEG4 && s->codec_id != CODEC_ID_MPEG1VIDEO && s->codec_id != CODEC_ID_MPEG2VIDEO){
        av_log(avctx, AV_LOG_ERROR, "b frames not supported by codec\n");
        return -1;
    }

    if((s->flags & (CODEC_FLAG_INTERLACED_DCT|CODEC_FLAG_INTERLACED_ME|CODEC_FLAG_ALT_SCAN))
       && s->codec_id != CODEC_ID_MPEG4 && s->codec_id != CODEC_ID_MPEG2VIDEO){
        av_log(avctx, AV_LOG_ERROR, "interlacing not supported by codec\n");
        return -1;
    }

    if(s->mpeg_quant && s->codec_id != CODEC_ID_MPEG4){ //FIXME mpeg2 uses that too
        av_log(avctx, AV_LOG_ERROR, "mpeg2 style quantization not supported by codec\n");
        return -1;
    }

    if((s->flags & CODEC_FLAG_CBP_RD) && !(s->flags & CODEC_FLAG_TRELLIS_QUANT)){
        av_log(avctx, AV_LOG_ERROR, "CBP RD needs trellis quant\n");
        return -1;
    }

    if((s->flags & CODEC_FLAG_QP_RD) && s->avctx->mb_decision != FF_MB_DECISION_RD){
        av_log(avctx, AV_LOG_ERROR, "QP RD needs mbd=2\n");
        return -1;
    }

    if(s->avctx->scenechange_threshold < 1000000000 && (s->flags & CODEC_FLAG_CLOSED_GOP)){
        av_log(avctx, AV_LOG_ERROR, "closed gop with scene change detection arent supported yet, set threshold to 1000000000\n");
        return -1;
    }

    if((s->flags2 & CODEC_FLAG2_INTRA_VLC) && s->codec_id != CODEC_ID_MPEG2VIDEO){
        av_log(avctx, AV_LOG_ERROR, "intra vlc table not supported by codec\n");
        return -1;
    }

    if(s->flags & CODEC_FLAG_LOW_DELAY){
        if (s->codec_id != CODEC_ID_MPEG2VIDEO && s->codec_id != CODEC_ID_MPEG1VIDEO){
            av_log(avctx, AV_LOG_ERROR, "low delay forcing is only available for mpeg1/2\n");
            return -1;
        }
        if (s->max_b_frames != 0){
            av_log(avctx, AV_LOG_ERROR, "b frames cannot be used with low delay\n");
            return -1;
        }
    }

    if(s->q_scale_type == 1){
        if(s->codec_id != CODEC_ID_MPEG2VIDEO){
            av_log(avctx, AV_LOG_ERROR, "non linear quant is only available for mpeg2\n");
            return -1;
        }
        if(avctx->qmax > 12){
            av_log(avctx, AV_LOG_ERROR, "non linear quant only supports qmax <= 12 currently\n");
            return -1;
        }
    }

    if(s->avctx->thread_count > 1 && s->codec_id != CODEC_ID_MPEG4
       && s->codec_id != CODEC_ID_MPEG1VIDEO && s->codec_id != CODEC_ID_MPEG2VIDEO
       && (s->codec_id != CODEC_ID_H263P || !(s->flags & CODEC_FLAG_H263P_SLICE_STRUCT))){
        av_log(avctx, AV_LOG_ERROR, "multi threaded encoding not supported by codec\n");
        return -1;
    }

    if(s->avctx->thread_count > 1)
        s->rtp_mode= 1;

    if(!avctx->time_base.den || !avctx->time_base.num){
        av_log(avctx, AV_LOG_ERROR, "framerate not set\n");
        return -1;
    }

    i= (INT_MAX/2+128)>>8;
    if(avctx->me_threshold >= i){
        av_log(avctx, AV_LOG_ERROR, "me_threshold too large, max is %d\n", i - 1);
        return -1;
    }
    if(avctx->mb_threshold >= i){
        av_log(avctx, AV_LOG_ERROR, "mb_threshold too large, max is %d\n", i - 1);
        return -1;
    }

    if(avctx->b_frame_strategy && (avctx->flags&CODEC_FLAG_PASS2)){
        av_log(avctx, AV_LOG_INFO, "notice: b_frame_strategy only affects the first pass\n");
        avctx->b_frame_strategy = 0;
    }

    i= ff_gcd(avctx->time_base.den, avctx->time_base.num);
    if(i > 1){
        av_log(avctx, AV_LOG_INFO, "removing common factors from framerate\n");
        avctx->time_base.den /= i;
        avctx->time_base.num /= i;
//        return -1;
    }

    if(s->codec_id==CODEC_ID_MJPEG){
        s->intra_quant_bias= 1<<(QUANT_BIAS_SHIFT-1); //(a + x/2)/x
        s->inter_quant_bias= 0;
    }else if(s->mpeg_quant || s->codec_id==CODEC_ID_MPEG1VIDEO || s->codec_id==CODEC_ID_MPEG2VIDEO){
        s->intra_quant_bias= 3<<(QUANT_BIAS_SHIFT-3); //(a + x*3/8)/x
        s->inter_quant_bias= 0;
    }else{
        s->intra_quant_bias=0;
        s->inter_quant_bias=-(1<<(QUANT_BIAS_SHIFT-2)); //(a - x/4)/x
    }

    if(avctx->intra_quant_bias != FF_DEFAULT_QUANT_BIAS)
        s->intra_quant_bias= avctx->intra_quant_bias;
    if(avctx->inter_quant_bias != FF_DEFAULT_QUANT_BIAS)
        s->inter_quant_bias= avctx->inter_quant_bias;

    avcodec_get_chroma_sub_sample(avctx->pix_fmt, &chroma_h_shift, &chroma_v_shift);

    if(avctx->codec_id == CODEC_ID_MPEG4 && s->avctx->time_base.den > (1<<16)-1){
        av_log(avctx, AV_LOG_ERROR, "timebase not supported by mpeg 4 standard\n");
        return -1;
    }
    s->time_increment_bits = av_log2(s->avctx->time_base.den - 1) + 1;

    switch(avctx->codec->id) {
    case CODEC_ID_MPEG1VIDEO:
        s->out_format = FMT_MPEG1;
        s->low_delay= !!(s->flags & CODEC_FLAG_LOW_DELAY);
        avctx->delay= s->low_delay ? 0 : (s->max_b_frames + 1);
        break;
    case CODEC_ID_MPEG2VIDEO:
        s->out_format = FMT_MPEG1;
        s->low_delay= !!(s->flags & CODEC_FLAG_LOW_DELAY);
        avctx->delay= s->low_delay ? 0 : (s->max_b_frames + 1);
        s->rtp_mode= 1;
        break;
    case CODEC_ID_LJPEG:
    case CODEC_ID_MJPEG:
        s->out_format = FMT_MJPEG;
        s->intra_only = 1; /* force intra only for jpeg */
        s->mjpeg_vsample[0] = 2;
        s->mjpeg_vsample[1] = 2>>chroma_v_shift;
        s->mjpeg_vsample[2] = 2>>chroma_v_shift;
        s->mjpeg_hsample[0] = 2;
        s->mjpeg_hsample[1] = 2>>chroma_h_shift;
        s->mjpeg_hsample[2] = 2>>chroma_h_shift;
        if (!(ENABLE_MJPEG_ENCODER || ENABLE_LJPEG_ENCODER)
            || ff_mjpeg_encode_init(s) < 0)
            return -1;
        avctx->delay=0;
        s->low_delay=1;
        break;
    case CODEC_ID_H261:
        if (!ENABLE_H261_ENCODER)  return -1;
        if (ff_h261_get_picture_format(s->width, s->height) < 0) {
            av_log(avctx, AV_LOG_ERROR, "The specified picture size of %dx%d is not valid for the H.261 codec.\nValid sizes are 176x144, 352x288\n", s->width, s->height);
            return -1;
        }
        s->out_format = FMT_H261;
        avctx->delay=0;
        s->low_delay=1;
        break;
    case CODEC_ID_H263:
        if (!ENABLE_H263_ENCODER)  return -1;
        if (h263_get_picture_format(s->width, s->height) == 7) {
            av_log(avctx, AV_LOG_INFO, "The specified picture size of %dx%d is not valid for the H.263 codec.\nValid sizes are 128x96, 176x144, 352x288, 704x576, and 1408x1152. Try H.263+.\n", s->width, s->height);
            return -1;
        }
        s->out_format = FMT_H263;
        s->obmc= (avctx->flags & CODEC_FLAG_OBMC) ? 1:0;
        avctx->delay=0;
        s->low_delay=1;
        break;
    case CODEC_ID_H263P:
        s->out_format = FMT_H263;
        s->h263_plus = 1;
        /* Fx */
        s->umvplus = (avctx->flags & CODEC_FLAG_H263P_UMV) ? 1:0;
        s->h263_aic= (avctx->flags & CODEC_FLAG_AC_PRED) ? 1:0;
        s->modified_quant= s->h263_aic;
        s->alt_inter_vlc= (avctx->flags & CODEC_FLAG_H263P_AIV) ? 1:0;
        s->obmc= (avctx->flags & CODEC_FLAG_OBMC) ? 1:0;
        s->loop_filter= (avctx->flags & CODEC_FLAG_LOOP_FILTER) ? 1:0;
        s->unrestricted_mv= s->obmc || s->loop_filter || s->umvplus;
        s->h263_slice_structured= (s->flags & CODEC_FLAG_H263P_SLICE_STRUCT) ? 1:0;

        /* /Fx */
        /* These are just to be sure */
        avctx->delay=0;
        s->low_delay=1;
        break;
    case CODEC_ID_FLV1:
        s->out_format = FMT_H263;
        s->h263_flv = 2; /* format = 1; 11-bit codes */
        s->unrestricted_mv = 1;
        s->rtp_mode=0; /* don't allow GOB */
        avctx->delay=0;
        s->low_delay=1;
        break;
    case CODEC_ID_RV10:
        s->out_format = FMT_H263;
        avctx->delay=0;
        s->low_delay=1;
        break;
    case CODEC_ID_RV20:
        s->out_format = FMT_H263;
        avctx->delay=0;
        s->low_delay=1;
        s->modified_quant=1;
        s->h263_aic=1;
        s->h263_plus=1;
        s->loop_filter=1;
        s->unrestricted_mv= s->obmc || s->loop_filter || s->umvplus;
        break;
    case CODEC_ID_MPEG4:
        s->out_format = FMT_H263;
        s->h263_pred = 1;
        s->unrestricted_mv = 1;
        s->low_delay= s->max_b_frames ? 0 : 1;
        avctx->delay= s->low_delay ? 0 : (s->max_b_frames + 1);
        break;
    case CODEC_ID_MSMPEG4V1:
        s->out_format = FMT_H263;
        s->h263_msmpeg4 = 1;
        s->h263_pred = 1;
        s->unrestricted_mv = 1;
        s->msmpeg4_version= 1;
        avctx->delay=0;
        s->low_delay=1;
        break;
    case CODEC_ID_MSMPEG4V2:
        s->out_format = FMT_H263;
        s->h263_msmpeg4 = 1;
        s->h263_pred = 1;
        s->unrestricted_mv = 1;
        s->msmpeg4_version= 2;
        avctx->delay=0;
        s->low_delay=1;
        break;
    case CODEC_ID_MSMPEG4V3:
        s->out_format = FMT_H263;
        s->h263_msmpeg4 = 1;
        s->h263_pred = 1;
        s->unrestricted_mv = 1;
        s->msmpeg4_version= 3;
        s->flipflop_rounding=1;
        avctx->delay=0;
        s->low_delay=1;
        break;
    case CODEC_ID_WMV1:
        s->out_format = FMT_H263;
        s->h263_msmpeg4 = 1;
        s->h263_pred = 1;
        s->unrestricted_mv = 1;
        s->msmpeg4_version= 4;
        s->flipflop_rounding=1;
        avctx->delay=0;
        s->low_delay=1;
        break;
    case CODEC_ID_WMV2:
        s->out_format = FMT_H263;
        s->h263_msmpeg4 = 1;
        s->h263_pred = 1;
        s->unrestricted_mv = 1;
        s->msmpeg4_version= 5;
        s->flipflop_rounding=1;
        avctx->delay=0;
        s->low_delay=1;
        break;
    default:
        return -1;
    }

    avctx->has_b_frames= !s->low_delay;

    s->encoding = 1;

    /* init */
    if (MPV_common_init(s) < 0)
        return -1;

    if(!s->dct_quantize)
        s->dct_quantize = dct_quantize_c;
    if(!s->denoise_dct)
        s->denoise_dct = denoise_dct_c;
    s->fast_dct_quantize = s->dct_quantize;
    if(s->flags & CODEC_FLAG_TRELLIS_QUANT)
        s->dct_quantize = dct_quantize_trellis_c;

    if((ENABLE_H263P_ENCODER || ENABLE_RV20_ENCODER) && s->modified_quant)
        s->chroma_qscale_table= ff_h263_chroma_qscale_table;
    s->progressive_frame=
    s->progressive_sequence= !(avctx->flags & (CODEC_FLAG_INTERLACED_DCT|CODEC_FLAG_INTERLACED_ME|CODEC_FLAG_ALT_SCAN));
    s->quant_precision=5;