vc9.c

ffmpeg源码分析

                 vc9_norm2_bits, 1, 1,
                 vc9_norm2_codes, 1, 1, 1);
        INIT_VLC(&vc9_norm6_vlc, VC9_NORM6_VLC_BITS, 64,
                 vc9_norm6_bits, 1, 1,
                 vc9_norm6_codes, 2, 2, 1);
        INIT_VLC(&vc9_imode_vlc, VC9_IMODE_VLC_BITS, 7,
                 vc9_imode_bits, 1, 1,
                 vc9_imode_codes, 1, 1, 1);
        for (i=0; i<3; i++)
        {
            INIT_VLC(&vc9_ttmb_vlc[i], VC9_TTMB_VLC_BITS, 16,
                     vc9_ttmb_bits[i], 1, 1,
                     vc9_ttmb_codes[i], 2, 2, 1);
            INIT_VLC(&vc9_ttblk_vlc[i], VC9_TTBLK_VLC_BITS, 8,
                     vc9_ttblk_bits[i], 1, 1,
                     vc9_ttblk_codes[i], 1, 1, 1);
            INIT_VLC(&vc9_subblkpat_vlc[i], VC9_SUBBLKPAT_VLC_BITS, 15,
                     vc9_subblkpat_bits[i], 1, 1,
                     vc9_subblkpat_codes[i], 1, 1, 1);
        }
        for(i=0; i<4; i++)
        {
            INIT_VLC(&vc9_4mv_block_pattern_vlc[i], VC9_4MV_BLOCK_PATTERN_VLC_BITS, 16,
                     vc9_4mv_block_pattern_bits[i], 1, 1,
                     vc9_4mv_block_pattern_codes[i], 1, 1, 1);
            INIT_VLC(&vc9_cbpcy_p_vlc[i], VC9_CBPCY_P_VLC_BITS, 64,
                     vc9_cbpcy_p_bits[i], 1, 1,
                     vc9_cbpcy_p_codes[i], 2, 2, 1);
            INIT_VLC(&vc9_mv_diff_vlc[i], VC9_MV_DIFF_VLC_BITS, 73,
                     vc9_mv_diff_bits[i], 1, 1,
                     vc9_mv_diff_codes[i], 2, 2, 1);
        }
    }

    /* Other defaults */
    v->pq = -1;
    v->mvrange = 0; /* 7.1.1.18, p80 */

    return 0;
}

#if HAS_ADVANCED_PROFILE
/**
 * Decode sequence header's Hypothetic Reference Decoder data
 * @see 6.2.1, p32
 * @param v The VC9Context to initialize
 * @param gb A GetBitContext initialized from AVCodecContext extra_data
 * @return Status
 */
static int decode_hrd(VC9Context *v, GetBitContext *gb)
{
    int i, num;

    num = 1 + get_bits(gb, 5);

    /*hrd rate*/
    if (v->hrd_rate || num != v->hrd_num_leaky_buckets)
    {
        av_freep(&v->hrd_rate);
    }
    if (!v->hrd_rate) v->hrd_rate = av_malloc(num*sizeof(uint16_t));
    if (!v->hrd_rate) return -1;

    /*hrd buffer*/
    if (v->hrd_buffer || num != v->hrd_num_leaky_buckets)
    {
        av_freep(&v->hrd_buffer);
    }
    if (!v->hrd_buffer) v->hrd_buffer = av_malloc(num*sizeof(uint16_t));
    if (!v->hrd_buffer)
    {
        av_freep(&v->hrd_rate);
        return -1;
    }

    /*hrd fullness*/
    if (v->hrd_fullness || num != v->hrd_num_leaky_buckets)
    {
        av_freep(&v->hrd_buffer);
    }
    if (!v->hrd_fullness) v->hrd_fullness = av_malloc(num*sizeof(uint8_t));
    if (!v->hrd_fullness)
    {
        av_freep(&v->hrd_rate);
        av_freep(&v->hrd_buffer);
        return -1;
    }
    v->hrd_num_leaky_buckets = num;

    //exponent in base-2 for rate
    v->bit_rate_exponent = 6 + get_bits(gb, 4);
    //exponent in base-2 for buffer_size
    v->buffer_size_exponent = 4 + get_bits(gb, 4);

    for (i=0; i<num; i++)
    {
        //mantissae, ordered (if not, use a function ?
        v->hrd_rate[i] = 1 + get_bits(gb, 16);
        if (i && v->hrd_rate[i-1]>=v->hrd_rate[i])
        {
            av_log(v->s.avctx, AV_LOG_ERROR, "HDR Rates aren't strictly increasing:"
                   "%i vs %i\n", v->hrd_rate[i-1], v->hrd_rate[i]);
            return -1;
        }
        v->hrd_buffer[i] = 1 + get_bits(gb, 16);
        if (i && v->hrd_buffer[i-1]<v->hrd_buffer[i])
        {
            av_log(v->s.avctx, AV_LOG_ERROR, "HDR Buffers aren't decreasing:"
                   "%i vs %i\n", v->hrd_buffer[i-1], v->hrd_buffer[i]);
            return -1;
        }
    }
    return 0;
}

/**
 * Decode sequence header for Advanced Profile
 * @see Table 2, p18
 * @see 6.1.7, pp21-27
 * @param v The VC9Context to initialize
 * @param gb A GetBitContext initialized from AVCodecContext extra_data
 * @return Status
 */
static int decode_advanced_sequence_header(AVCodecContext *avctx, GetBitContext *gb)
{
    VC9Context *v = avctx->priv_data;
    int nr, dr, aspect_ratio;

    v->postprocflag = get_bits(gb, 1);
    v->broadcast = get_bits(gb, 1);
    v->interlace = get_bits(gb, 1);

    v->tfcntrflag = get_bits(gb, 1);
    v->finterpflag = get_bits(gb, 1); //common
    v->panscanflag = get_bits(gb, 1);
    v->reserved = get_bits(gb, 1);
    if (v->reserved)
    {
        av_log(avctx, AV_LOG_ERROR, "RESERVED should be 0 (is %i)\n",
               v->reserved);
        return -1;
    }
    if (v->extended_mv)
        v->extended_dmv = get_bits(gb, 1);

    /* 6.1.7, p21 */
    if (get_bits(gb, 1) /* pic_size_flag */)
    {
        avctx->coded_width = get_bits(gb, 12) << 1;
        avctx->coded_height = get_bits(gb, 12) << 1;
        if ( get_bits(gb, 1) /* disp_size_flag */)
        {
            avctx->width = get_bits(gb, 14);
            avctx->height = get_bits(gb, 14);
        }

        /* 6.1.7.4, p23 */
        if ( get_bits(gb, 1) /* aspect_ratio_flag */)
        {
            aspect_ratio = get_bits(gb, 4); //SAR
            if (aspect_ratio == 0x0F) //FF_ASPECT_EXTENDED
            {
                avctx->sample_aspect_ratio.num = 1 + get_bits(gb, 8);
                avctx->sample_aspect_ratio.den = 1 + get_bits(gb, 8);
            }
            else if (aspect_ratio == 0x0E)
            {
                av_log(avctx, AV_LOG_DEBUG, "Reserved AR found\n");
            }
            else
            {
              avctx->sample_aspect_ratio = vc9_pixel_aspect[aspect_ratio];
            }
        }
    }
    else
    {
        avctx->coded_width = avctx->width;
        avctx->coded_height = avctx->height;
    }

    /* 6.1.8, p23 */
    if ( get_bits(gb, 1) /* framerateflag */)
    {
        if ( !get_bits(gb, 1) /* framerateind */)
        {
            nr = get_bits(gb, 8);
            dr = get_bits(gb, 4);
            if (nr<1)
            {
                av_log(avctx, AV_LOG_ERROR, "0 is forbidden for FRAMERATENR\n");
                return -1;
            }
            if (nr>5)
            {
                av_log(avctx, AV_LOG_ERROR,
                       "Reserved FRAMERATENR %i not handled\n", nr);
                nr = 5; /* overflow protection */
            }
            if (dr<1)
            {
                av_log(avctx, AV_LOG_ERROR, "0 is forbidden for FRAMERATEDR\n");
                return -1;
            }
            if (dr>2)
            {
                av_log(avctx, AV_LOG_ERROR,
                       "Reserved FRAMERATEDR %i not handled\n", dr);
                dr = 2; /* overflow protection */
            }
            avctx->time_base.num = fps_nr[dr - 1];
            avctx->time_base.den = fps_nr[nr - 1];
        }
        else
        {
            nr = get_bits(gb, 16);
            // 0.03125->2048Hz / 0.03125Hz
            avctx->time_base.den = 1000000;
            avctx->time_base.num = 31250*(1+nr);
        }
    }

    /* 6.1.9, p25 */
    if ( get_bits(gb, 1) /* color_format_flag */)
    {
        //Chromacity coordinates of color primaries
        //like ITU-R BT.709-2, BT.470-2, ...
        v->color_prim = get_bits(gb, 8);
        if (v->color_prim<1)
        {
            av_log(avctx, AV_LOG_ERROR, "0 for COLOR_PRIM is forbidden\n");
            return -1;
        }
        if (v->color_prim == 3 || v->color_prim>6)
        {
            av_log(avctx, AV_LOG_DEBUG, "Reserved COLOR_PRIM %i found\n",
                   v->color_prim);
            return -1;
        }

        //Opto-electronic transfer characteristics
        v->transfer_char = get_bits(gb, 8);
        if (v->transfer_char < 1)
        {
            av_log(avctx, AV_LOG_ERROR, "0 for TRAMSFER_CHAR is forbidden\n");
            return -1;
        }
        if (v->transfer_char == 3 || v->transfer_char>8)
        {
            av_log(avctx, AV_LOG_DEBUG, "Reserved TRANSFERT_CHAR %i found\n",
                   v->color_prim);
            return -1;
        }

        //Matrix coefficient for primariev->YCbCr
        v->matrix_coef = get_bits(gb, 8);
        if (v->matrix_coef < 1)
        {
            av_log(avctx, AV_LOG_ERROR, "0 for MATRIX_COEF is forbidden\n");
            return -1;
        }
        if ((v->matrix_coef > 2 && v->matrix_coef < 6) || v->matrix_coef > 7)
        {
            av_log(avctx, AV_LOG_DEBUG, "Reserved MATRIX_COEF %i found\n",
                   v->color_prim);
            return -1;
        }
    }

    //Hypothetical reference decoder indicator flag
    v->hrd_param_flag = get_bits(gb, 1);
    if (v->hrd_param_flag)
    {
      if (decode_hrd(v, gb) < 0) return -1;
    }

    /*reset scaling ranges, 6.2.2 & 6.2.3, p33*/
    v->range_mapy_flag = 0;
    v->range_mapuv_flag = 0;

    av_log(avctx, AV_LOG_DEBUG, "Advanced profile not supported yet\n");
    return -1;
}
#endif

/**
 * 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)
{
    VC9Context *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 == 2)
    {
        av_log(avctx, AV_LOG_ERROR, "Profile value 2 is forbidden\n");
        return -1;
    }

#if HAS_ADVANCED_PROFILE
    if (v->profile == PROFILE_ADVANCED)
    {
        v->level = get_bits(gb, 3);
        if(v->level >= 5)
        {
            av_log(avctx, AV_LOG_ERROR, "Reserved LEVEL %i\n",v->level);
        }
        v->chromaformat = get_bits(gb, 2);
        if (v->chromaformat != 1)
        {
            av_log(avctx, AV_LOG_ERROR,
                   "Only 4:2:0 chroma format supported\n");
            return -1;
        }
    }
    else
#endif
    {
        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_bits(gb, 1); //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");
    }

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

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

#if HAS_ADVANCED_PROFILE
    if (v->profile < PROFILE_ADVANCED)
#endif
    {
        v->res_transtab = get_bits(gb, 1);
        if (v->res_transtab)
        {
            av_log(avctx, AV_LOG_ERROR,
                   "1 for reserved RES_TRANSTAB is forbidden\n");
            return -1;
        }
    }

    v->overlap = get_bits(gb, 1); //common

#if HAS_ADVANCED_PROFILE
    if (v->profile < PROFILE_ADVANCED)
#endif
    {
        v->s.resync_marker = get_bits(gb, 1);
        v->rangered = get_bits(gb, 1);
        if (v->rangered && v->profile == PROFILE_SIMPLE)
        {
            av_log(avctx, AV_LOG_DEBUG,
                   "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

#if HAS_ADVANCED_PROFILE