コード例 #1
0
ファイル: avc_utils.cpp プロジェクト: whr4935/Media
signed parseSEWithFallback(ABitReader *br, signed fallback) {
    // NOTE: parseUE cannot normally return ~0 as the max supported value is 0xFFFE
    unsigned codeNum = parseUEWithFallback(br, ~0U);
    if (codeNum == ~0U) {
        return fallback;
    }
    return (codeNum & 1) ? (codeNum + 1) / 2 : -signed(codeNum / 2);
}
コード例 #2
0
status_t HevcParameterSets::parseSps(const uint8_t* data, size_t size) {
    // See Rec. ITU-T H.265 v3 (04/2015) Chapter 7.3.2.2 for reference
    NALBitReader reader(data, size);
    // Skip sps_video_parameter_set_id
    reader.skipBits(4);
    uint8_t maxSubLayersMinus1 = reader.getBitsWithFallback(3, 0);
    // Skip sps_temporal_id_nesting_flag;
    reader.skipBits(1);
    // Skip general profile
    reader.skipBits(96);
    if (maxSubLayersMinus1 > 0) {
        bool subLayerProfilePresentFlag[8];
        bool subLayerLevelPresentFlag[8];
        for (int i = 0; i < maxSubLayersMinus1; ++i) {
            subLayerProfilePresentFlag[i] = reader.getBitsWithFallback(1, 0);
            subLayerLevelPresentFlag[i] = reader.getBitsWithFallback(1, 0);
        }
        // Skip reserved
        reader.skipBits(2 * (8 - maxSubLayersMinus1));
        for (int i = 0; i < maxSubLayersMinus1; ++i) {
            if (subLayerProfilePresentFlag[i]) {
                // Skip profile
                reader.skipBits(88);
            }
            if (subLayerLevelPresentFlag[i]) {
                // Skip sub_layer_level_idc[i]
                reader.skipBits(8);
            }
        }
    }
    // Skip sps_seq_parameter_set_id
    skipUE(&reader);
    uint8_t chromaFormatIdc = parseUEWithFallback(&reader, 0);
    mParams.add(kChromaFormatIdc, chromaFormatIdc);
    if (chromaFormatIdc == 3) {
        // Skip separate_colour_plane_flag
        reader.skipBits(1);
    }
    // Skip pic_width_in_luma_samples
    skipUE(&reader);
    // Skip pic_height_in_luma_samples
    skipUE(&reader);
    if (reader.getBitsWithFallback(1, 0) /* i.e. conformance_window_flag */) {
        // Skip conf_win_left_offset
        skipUE(&reader);
        // Skip conf_win_right_offset
        skipUE(&reader);
        // Skip conf_win_top_offset
        skipUE(&reader);
        // Skip conf_win_bottom_offset
        skipUE(&reader);
    }
    mParams.add(kBitDepthLumaMinus8, parseUEWithFallback(&reader, 0));
    mParams.add(kBitDepthChromaMinus8, parseUEWithFallback(&reader, 0));

    // log2_max_pic_order_cnt_lsb_minus4
    size_t log2MaxPicOrderCntLsb = parseUEWithFallback(&reader, 0) + (size_t)4;
    bool spsSubLayerOrderingInfoPresentFlag = reader.getBitsWithFallback(1, 0);
    for (uint32_t i = spsSubLayerOrderingInfoPresentFlag ? 0 : maxSubLayersMinus1;
            i <= maxSubLayersMinus1; ++i) {
        skipUE(&reader); // sps_max_dec_pic_buffering_minus1[i]
        skipUE(&reader); // sps_max_num_reorder_pics[i]
        skipUE(&reader); // sps_max_latency_increase_plus1[i]
    }

    skipUE(&reader); // log2_min_luma_coding_block_size_minus3
    skipUE(&reader); // log2_diff_max_min_luma_coding_block_size
    skipUE(&reader); // log2_min_luma_transform_block_size_minus2
    skipUE(&reader); // log2_diff_max_min_luma_transform_block_size
    skipUE(&reader); // max_transform_hierarchy_depth_inter
    skipUE(&reader); // max_transform_hierarchy_depth_intra
    if (reader.getBitsWithFallback(1, 0)) { // scaling_list_enabled_flag u(1)
        // scaling_list_data
        if (reader.getBitsWithFallback(1, 0)) { // sps_scaling_list_data_present_flag
            for (uint32_t sizeId = 0; sizeId < 4; ++sizeId) {
                for (uint32_t matrixId = 0; matrixId < 6; matrixId += (sizeId == 3) ? 3 : 1) {
                    if (!reader.getBitsWithFallback(1, 1)) {
                        // scaling_list_pred_mode_flag[sizeId][matrixId]
                        skipUE(&reader); // scaling_list_pred_matrix_id_delta[sizeId][matrixId]
                    } else {
                        uint32_t coefNum = std::min(64, (1 << (4 + (sizeId << 1))));
                        if (sizeId > 1) {
                            skipSE(&reader); // scaling_list_dc_coef_minus8[sizeId − 2][matrixId]
                        }
                        for (uint32_t i = 0; i < coefNum; ++i) {
                            skipSE(&reader); // scaling_list_delta_coef
                        }
                    }
                }
            }
        }
    }
    reader.skipBits(1); // amp_enabled_flag
    reader.skipBits(1); // sample_adaptive_offset_enabled_flag u(1)
    if (reader.getBitsWithFallback(1, 0)) { // pcm_enabled_flag
        reader.skipBits(4); // pcm_sample_bit_depth_luma_minus1
        reader.skipBits(4); // pcm_sample_bit_depth_chroma_minus1 u(4)
        skipUE(&reader); // log2_min_pcm_luma_coding_block_size_minus3
        skipUE(&reader); // log2_diff_max_min_pcm_luma_coding_block_size
        reader.skipBits(1); // pcm_loop_filter_disabled_flag
    }
    uint32_t numShortTermRefPicSets = parseUEWithFallback(&reader, 0);
    uint32_t numPics = 0;
    for (uint32_t i = 0; i < numShortTermRefPicSets; ++i) {
        // st_ref_pic_set(i)
        if (i != 0 && reader.getBitsWithFallback(1, 0)) { // inter_ref_pic_set_prediction_flag
            reader.skipBits(1); // delta_rps_sign
            skipUE(&reader); // abs_delta_rps_minus1
            uint32_t nextNumPics = 0;
            for (uint32_t j = 0; j <= numPics; ++j) {
                if (reader.getBitsWithFallback(1, 0) // used_by_curr_pic_flag[j]
                        || reader.getBitsWithFallback(1, 0)) { // use_delta_flag[j]
                    ++nextNumPics;
                }
            }
            numPics = nextNumPics;
        } else {
            uint32_t numNegativePics = parseUEWithFallback(&reader, 0);
            uint32_t numPositivePics = parseUEWithFallback(&reader, 0);
            if (numNegativePics > UINT32_MAX - numPositivePics) {
                return ERROR_MALFORMED;
            }
            numPics = numNegativePics + numPositivePics;
            for (uint32_t j = 0; j < numPics; ++j) {
                skipUE(&reader); // delta_poc_s0|1_minus1[i]
                reader.skipBits(1); // used_by_curr_pic_s0|1_flag[i]
            }
        }
    }
    if (reader.getBitsWithFallback(1, 0)) { // long_term_ref_pics_present_flag
        uint32_t numLongTermRefPicSps = parseUEWithFallback(&reader, 0);
        for (uint32_t i = 0; i < numLongTermRefPicSps; ++i) {
            reader.skipBits(log2MaxPicOrderCntLsb); // lt_ref_pic_poc_lsb_sps[i]
            reader.skipBits(1); // used_by_curr_pic_lt_sps_flag[i]
        }
    }
    reader.skipBits(1); // sps_temporal_mvp_enabled_flag
    reader.skipBits(1); // strong_intra_smoothing_enabled_flag
    if (reader.getBitsWithFallback(1, 0)) { // vui_parameters_present_flag
        if (reader.getBitsWithFallback(1, 0)) { // aspect_ratio_info_present_flag
            uint32_t aspectRatioIdc = reader.getBitsWithFallback(8, 0);
            if (aspectRatioIdc == 0xFF /* EXTENDED_SAR */) {
                reader.skipBits(16); // sar_width
                reader.skipBits(16); // sar_height
            }
        }
        if (reader.getBitsWithFallback(1, 0)) { // overscan_info_present_flag
            reader.skipBits(1); // overscan_appropriate_flag
        }
        if (reader.getBitsWithFallback(1, 0)) { // video_signal_type_present_flag
            reader.skipBits(3); // video_format
            uint32_t videoFullRangeFlag;
            if (reader.getBitsGraceful(1, &videoFullRangeFlag)) {
                mParams.add(kVideoFullRangeFlag, videoFullRangeFlag);
            }
            if (reader.getBitsWithFallback(1, 0)) { // colour_description_present_flag
                mInfo = (Info)(mInfo | kInfoHasColorDescription);
                uint32_t colourPrimaries, transferCharacteristics, matrixCoeffs;
                if (reader.getBitsGraceful(8, &colourPrimaries)) {
                    mParams.add(kColourPrimaries, colourPrimaries);
                }
                if (reader.getBitsGraceful(8, &transferCharacteristics)) {
                    mParams.add(kTransferCharacteristics, transferCharacteristics);
                    if (transferCharacteristics == 16 /* ST 2084 */
                            || transferCharacteristics == 18 /* ARIB STD-B67 HLG */) {
                        mInfo = (Info)(mInfo | kInfoIsHdr);
                    }
                }
                if (reader.getBitsGraceful(8, &matrixCoeffs)) {
                    mParams.add(kMatrixCoeffs, matrixCoeffs);
                }
            }
            // skip rest of VUI
        }
    }

    return reader.overRead() ? ERROR_MALFORMED : OK;
}