vc1.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

    srcU = s->last_picture.data[1] + uvsrc_y * s->uvlinesize + uvsrc_x;
    srcV = s->last_picture.data[2] + uvsrc_y * s->uvlinesize + uvsrc_x;
    if(v->rangeredfrm || (v->mv_mode == MV_PMODE_INTENSITY_COMP)
       || (unsigned)uvsrc_x > (s->h_edge_pos >> 1) - 9
       || (unsigned)uvsrc_y > (s->v_edge_pos >> 1) - 9){
        ff_emulated_edge_mc(s->edge_emu_buffer     , srcU, s->uvlinesize, 8+1, 8+1,
                            uvsrc_x, uvsrc_y, s->h_edge_pos >> 1, s->v_edge_pos >> 1);
        ff_emulated_edge_mc(s->edge_emu_buffer + 16, srcV, s->uvlinesize, 8+1, 8+1,
                            uvsrc_x, uvsrc_y, s->h_edge_pos >> 1, s->v_edge_pos >> 1);
        srcU = s->edge_emu_buffer;
        srcV = s->edge_emu_buffer + 16;

        /* if we deal with range reduction we need to scale source blocks */
        if(v->rangeredfrm) {
            int i, j;
            uint8_t *src, *src2;

            src = srcU; src2 = srcV;
            for(j = 0; j < 9; j++) {
                for(i = 0; i < 9; i++) {
                    src[i] = ((src[i] - 128) >> 1) + 128;
                    src2[i] = ((src2[i] - 128) >> 1) + 128;
                }
                src += s->uvlinesize;
                src2 += s->uvlinesize;
            }
        }
        /* if we deal with intensity compensation we need to scale source blocks */
        if(v->mv_mode == MV_PMODE_INTENSITY_COMP) {
            int i, j;
            uint8_t *src, *src2;

            src = srcU; src2 = srcV;
            for(j = 0; j < 9; j++) {
                for(i = 0; i < 9; i++) {
                    src[i] = v->lutuv[src[i]];
                    src2[i] = v->lutuv[src2[i]];
                }
                src += s->uvlinesize;
                src2 += s->uvlinesize;
            }
        }
    }

    /* Chroma MC always uses qpel bilinear */
    uvdxy = ((uvmy & 3) << 2) | (uvmx & 3);
    uvmx = (uvmx&3)<<1;
    uvmy = (uvmy&3)<<1;
    if(!v->rnd){
        dsp->put_h264_chroma_pixels_tab[0](s->dest[1], srcU, s->uvlinesize, 8, uvmx, uvmy);
        dsp->put_h264_chroma_pixels_tab[0](s->dest[2], srcV, s->uvlinesize, 8, uvmx, uvmy);
    }else{
        dsp->put_no_rnd_h264_chroma_pixels_tab[0](s->dest[1], srcU, s->uvlinesize, 8, uvmx, uvmy);
        dsp->put_no_rnd_h264_chroma_pixels_tab[0](s->dest[2], srcV, s->uvlinesize, 8, uvmx, uvmy);
    }
}

static int decode_sequence_header_adv(VC1Context *v, GetBitContext *gb);

/**
 * Decode Simple/Main Profiles sequence header
 * @see Figure 7-8, p16-17
 * @param avctx Codec context
 * @param gb GetBit context initialized from Codec context extra_data
 * @return Status
 */
static int decode_sequence_header(AVCodecContext *avctx, GetBitContext *gb)
{
    VC1Context *v = avctx->priv_data;

    av_log(avctx, AV_LOG_DEBUG, "Header: %0X\n", show_bits(gb, 32));
    v->profile = get_bits(gb, 2);
    if (v->profile == PROFILE_COMPLEX)
    {
        av_log(avctx, AV_LOG_ERROR, "WMV3 Complex Profile is not fully supported\n");
    }

    if (v->profile == PROFILE_ADVANCED)
    {
        return decode_sequence_header_adv(v, gb);
    }
    else
    {
        v->res_sm = get_bits(gb, 2); //reserved
        if (v->res_sm)
        {
            av_log(avctx, AV_LOG_ERROR,
                   "Reserved RES_SM=%i is forbidden\n", v->res_sm);
            return -1;
        }
    }

    // (fps-2)/4 (->30)
    v->frmrtq_postproc = get_bits(gb, 3); //common
    // (bitrate-32kbps)/64kbps
    v->bitrtq_postproc = get_bits(gb, 5); //common
    v->s.loop_filter = get_bits1(gb); //common
    if(v->s.loop_filter == 1 && v->profile == PROFILE_SIMPLE)
    {
        av_log(avctx, AV_LOG_ERROR,
               "LOOPFILTER shell not be enabled in simple profile\n");
    }

    v->res_x8 = get_bits1(gb); //reserved
    if (v->res_x8)
    {
        av_log(avctx, AV_LOG_ERROR,
               "1 for reserved RES_X8 is forbidden\n");
        //return -1;
    }
    v->multires = get_bits1(gb);
    v->res_fasttx = get_bits1(gb);
    if (!v->res_fasttx)
    {
        av_log(avctx, AV_LOG_ERROR,
               "0 for reserved RES_FASTTX is forbidden\n");
        //return -1;
    }

    v->fastuvmc =  get_bits1(gb); //common
    if (!v->profile && !v->fastuvmc)
    {
        av_log(avctx, AV_LOG_ERROR,
               "FASTUVMC unavailable in Simple Profile\n");
        return -1;
    }
    v->extended_mv =  get_bits1(gb); //common
    if (!v->profile && v->extended_mv)
    {
        av_log(avctx, AV_LOG_ERROR,
               "Extended MVs unavailable in Simple Profile\n");
        return -1;
    }
    v->dquant =  get_bits(gb, 2); //common
    v->vstransform =  get_bits1(gb); //common

    v->res_transtab = get_bits1(gb);
    if (v->res_transtab)
    {
        av_log(avctx, AV_LOG_ERROR,
               "1 for reserved RES_TRANSTAB is forbidden\n");
        return -1;
    }

    v->overlap = get_bits1(gb); //common

    v->s.resync_marker = get_bits1(gb);
    v->rangered = get_bits1(gb);
    if (v->rangered && v->profile == PROFILE_SIMPLE)
    {
        av_log(avctx, AV_LOG_INFO,
               "RANGERED should be set to 0 in simple profile\n");
    }

    v->s.max_b_frames = avctx->max_b_frames = get_bits(gb, 3); //common
    v->quantizer_mode = get_bits(gb, 2); //common

    v->finterpflag = get_bits1(gb); //common
    v->res_rtm_flag = get_bits1(gb); //reserved
    if (!v->res_rtm_flag)
    {
//            av_log(avctx, AV_LOG_ERROR,
//                   "0 for reserved RES_RTM_FLAG is forbidden\n");
        av_log(avctx, AV_LOG_ERROR,
               "Old WMV3 version detected, only I-frames will be decoded\n");
        //return -1;
    }
    //TODO: figure out what they mean (always 0x402F)
    if(!v->res_fasttx) skip_bits(gb, 16);
    av_log(avctx, AV_LOG_DEBUG,
               "Profile %i:\nfrmrtq_postproc=%i, bitrtq_postproc=%i\n"
               "LoopFilter=%i, MultiRes=%i, FastUVMC=%i, Extended MV=%i\n"
               "Rangered=%i, VSTransform=%i, Overlap=%i, SyncMarker=%i\n"
               "DQuant=%i, Quantizer mode=%i, Max B frames=%i\n",
               v->profile, v->frmrtq_postproc, v->bitrtq_postproc,
               v->s.loop_filter, v->multires, v->fastuvmc, v->extended_mv,
               v->rangered, v->vstransform, v->overlap, v->s.resync_marker,
               v->dquant, v->quantizer_mode, avctx->max_b_frames
               );
    return 0;
}

static int decode_sequence_header_adv(VC1Context *v, GetBitContext *gb)
{
    v->res_rtm_flag = 1;
    v->level = get_bits(gb, 3);
    if(v->level >= 5)
    {
        av_log(v->s.avctx, AV_LOG_ERROR, "Reserved LEVEL %i\n",v->level);
    }
    v->chromaformat = get_bits(gb, 2);
    if (v->chromaformat != 1)
    {
        av_log(v->s.avctx, AV_LOG_ERROR,
               "Only 4:2:0 chroma format supported\n");
        return -1;
    }

    // (fps-2)/4 (->30)
    v->frmrtq_postproc = get_bits(gb, 3); //common
    // (bitrate-32kbps)/64kbps
    v->bitrtq_postproc = get_bits(gb, 5); //common
    v->postprocflag = get_bits1(gb); //common

    v->s.avctx->coded_width = (get_bits(gb, 12) + 1) << 1;
    v->s.avctx->coded_height = (get_bits(gb, 12) + 1) << 1;
    v->s.avctx->width = v->s.avctx->coded_width;
    v->s.avctx->height = v->s.avctx->coded_height;
    v->broadcast = get_bits1(gb);
    v->interlace = get_bits1(gb);
    v->tfcntrflag = get_bits1(gb);
    v->finterpflag = get_bits1(gb);
    skip_bits1(gb); // reserved

    v->s.h_edge_pos = v->s.avctx->coded_width;
    v->s.v_edge_pos = v->s.avctx->coded_height;

    av_log(v->s.avctx, AV_LOG_DEBUG,
               "Advanced Profile level %i:\nfrmrtq_postproc=%i, bitrtq_postproc=%i\n"
               "LoopFilter=%i, ChromaFormat=%i, Pulldown=%i, Interlace: %i\n"
               "TFCTRflag=%i, FINTERPflag=%i\n",
               v->level, v->frmrtq_postproc, v->bitrtq_postproc,
               v->s.loop_filter, v->chromaformat, v->broadcast, v->interlace,
               v->tfcntrflag, v->finterpflag
               );

    v->psf = get_bits1(gb);
    if(v->psf) { //PsF, 6.1.13
        av_log(v->s.avctx, AV_LOG_ERROR, "Progressive Segmented Frame mode: not supported (yet)\n");
        return -1;
    }
    v->s.max_b_frames = v->s.avctx->max_b_frames = 7;
    if(get_bits1(gb)) { //Display Info - decoding is not affected by it
        int w, h, ar = 0;
        av_log(v->s.avctx, AV_LOG_DEBUG, "Display extended info:\n");
        v->s.avctx->width  = v->s.width  = w = get_bits(gb, 14) + 1;
        v->s.avctx->height = v->s.height = h = get_bits(gb, 14) + 1;
        av_log(v->s.avctx, AV_LOG_DEBUG, "Display dimensions: %ix%i\n", w, h);
        if(get_bits1(gb))
            ar = get_bits(gb, 4);
        if(ar && ar < 14){
            v->s.avctx->sample_aspect_ratio = ff_vc1_pixel_aspect[ar];
        }else if(ar == 15){
            w = get_bits(gb, 8);
            h = get_bits(gb, 8);
            v->s.avctx->sample_aspect_ratio = (AVRational){w, h};
        }

        if(get_bits1(gb)){ //framerate stuff
            if(get_bits1(gb)) {
                v->s.avctx->time_base.num = 32;
                v->s.avctx->time_base.den = get_bits(gb, 16) + 1;
            } else {
                int nr, dr;
                nr = get_bits(gb, 8);
                dr = get_bits(gb, 4);
                if(nr && nr < 8 && dr && dr < 3){
                    v->s.avctx->time_base.num = ff_vc1_fps_dr[dr - 1];
                    v->s.avctx->time_base.den = ff_vc1_fps_nr[nr - 1] * 1000;
                }
            }
        }

        if(get_bits1(gb)){
            v->color_prim = get_bits(gb, 8);
            v->transfer_char = get_bits(gb, 8);
            v->matrix_coef = get_bits(gb, 8);
        }
    }

    v->hrd_param_flag = get_bits1(gb);
    if(v->hrd_param_flag) {
        int i;
        v->hrd_num_leaky_buckets = get_bits(gb, 5);
        skip_bits(gb, 4); //bitrate exponent
        skip_bits(gb, 4); //buffer size exponent
        for(i = 0; i < v->hrd_num_leaky_buckets; i++) {
            skip_bits(gb, 16); //hrd_rate[n]
            skip_bits(gb, 16); //hrd_buffer[n]
        }
    }
    return 0;
}

static int decode_entry_point(AVCodecContext *avctx, GetBitContext *gb)
{
    VC1Context *v = avctx->priv_data;
    int i, blink, clentry, refdist;

    av_log(avctx, AV_LOG_DEBUG, "Entry point: %08X\n", show_bits_long(gb, 32));
    blink = get_bits1(gb); // broken link
    clentry = get_bits1(gb); // closed entry
    v->panscanflag = get_bits1(gb);
    refdist = get_bits1(gb); // refdist flag
    v->s.loop_filter = get_bits1(gb);
    v->fastuvmc = get_bits1(gb);
    v->extended_mv = get_bits1(gb);
    v->dquant = get_bits(gb, 2);
    v->vstransform = get_bits1(gb);
    v->overlap = get_bits1(gb);
    v->quantizer_mode = get_bits(gb, 2);

    if(v->hrd_param_flag){
        for(i = 0; i < v->hrd_num_leaky_buckets; i++) {
            skip_bits(gb, 8); //hrd_full[n]
        }
    }

    if(get_bits1(gb)){
        avctx->coded_width = (get_bits(gb, 12)+1)<<1;
        avctx->coded_height = (get_bits(gb, 12)+1)<<1;
    }
    if(v->extended_mv)
        v->extended_dmv = get_bits1(gb);
    if(get_bits1(gb)) {
        av_log(avctx, AV_LOG_ERROR, "Luma scaling is not supported, expect wrong picture\n");
        skip_bits(gb, 3); // Y range, ignored for now
    }
    if(get_bits1(gb)) {
        av_log(avctx, AV_LOG_ERROR, "Chroma scaling is not supported, expect wrong picture\n");
        skip_bits(gb, 3); // UV range, ignored for now
    }

    av_log(avctx, AV_LOG_DEBUG, "Entry point info:\n"
        "BrokenLink=%i, ClosedEntry=%i, PanscanFlag=%i\n"
        "RefDist=%i, Postproc=%i, FastUVMC=%i, ExtMV=%i\n"
        "DQuant=%i, VSTransform=%i, Overlap=%i, Qmode=%i\n",
        blink, clentry, v->panscanflag, refdist, v->s.loop_filter,
        v->fastuvmc, v->extended_mv, v->dquant, v->vstransform, v->overlap, v->quantizer_mode);

    return 0;
}

static int vc1_parse_frame_header(VC1Context *v, GetBitContext* gb)
{
    int pqindex, lowquant, status;

    if(v->finterpflag) v->interpfrm = get_bits1(gb);
    skip_bits(gb, 2); //framecnt unused
    v->rangeredfrm = 0;
    if (v->rangered) v->rangeredfrm = get_bits1(gb);
    v->s.pict_type = get_bits1(gb);
    if (v->s.avctx->max_b_frames) {
        if (!v->s.pict_type) {
            if (get_bits1(gb)) v->s.pict_type = I_TYPE;
            else v->s.pict_type = B_TYPE;
        } else v->s.pict_type = P_TYPE;
    } else v->s.pict_type = v->s.pict_type ? P_TYPE : I_TYPE;

    v->bi_type = 0;
    if(v->s.pict_type == B_TYPE) {
        v->bfraction = get_vlc2(gb, ff_vc1_bfraction_vlc.table, VC1_BFRACTION_VLC_BITS, 1);
        v->bfraction = ff_vc1_bfraction_lut[v->bfraction];