diff options
Diffstat (limited to 'media/libstagefright/avc_utils.cpp')
-rw-r--r-- | media/libstagefright/avc_utils.cpp | 47 |
1 files changed, 40 insertions, 7 deletions
diff --git a/media/libstagefright/avc_utils.cpp b/media/libstagefright/avc_utils.cpp index b822868..38a1f6b 100644 --- a/media/libstagefright/avc_utils.cpp +++ b/media/libstagefright/avc_utils.cpp @@ -40,6 +40,25 @@ unsigned parseUE(ABitReader *br) { return x + (1u << numZeroes) - 1; } +signed parseSE(ABitReader *br) { + unsigned codeNum = parseUE(br); + + return (codeNum & 1) ? (codeNum + 1) / 2 : -(codeNum / 2); +} + +static void skipScalingList(ABitReader *br, size_t sizeOfScalingList) { + size_t lastScale = 8; + size_t nextScale = 8; + for (size_t j = 0; j < sizeOfScalingList; ++j) { + if (nextScale != 0) { + signed delta_scale = parseSE(br); + nextScale = (lastScale + delta_scale + 256) % 256; + } + + lastScale = (nextScale == 0) ? lastScale : nextScale; + } +} + // Determine video dimensions from the sequence parameterset. void FindAVCDimensions( const sp<ABuffer> &seqParamSet, @@ -63,7 +82,24 @@ void FindAVCDimensions( parseUE(&br); // bit_depth_luma_minus8 parseUE(&br); // bit_depth_chroma_minus8 br.skipBits(1); // qpprime_y_zero_transform_bypass_flag - CHECK_EQ(br.getBits(1), 0u); // seq_scaling_matrix_present_flag + + if (br.getBits(1)) { // seq_scaling_matrix_present_flag + for (size_t i = 0; i < 8; ++i) { + if (br.getBits(1)) { // seq_scaling_list_present_flag[i] + + // WARNING: the code below has not ever been exercised... + // need a real-world example. + + if (i < 6) { + // ScalingList4x4[i],16,... + skipScalingList(&br, 16); + } else { + // ScalingList8x8[i-6],64,... + skipScalingList(&br, 64); + } + } + } + } } parseUE(&br); // log2_max_frame_num_minus4 @@ -251,9 +287,7 @@ status_t getNextNALUnit( return OK; } -static sp<ABuffer> FindNAL( - const uint8_t *data, size_t size, unsigned nalType, - size_t *stopOffset) { +static sp<ABuffer> FindNAL(const uint8_t *data, size_t size, unsigned nalType) { const uint8_t *nalStart; size_t nalSize; while (getNextNALUnit(&data, &size, &nalStart, &nalSize, true) == OK) { @@ -293,7 +327,7 @@ sp<MetaData> MakeAVCCodecSpecificData(const sp<ABuffer> &accessUnit) { const uint8_t *data = accessUnit->data(); size_t size = accessUnit->size(); - sp<ABuffer> seqParamSet = FindNAL(data, size, 7, NULL); + sp<ABuffer> seqParamSet = FindNAL(data, size, 7); if (seqParamSet == NULL) { return NULL; } @@ -303,8 +337,7 @@ sp<MetaData> MakeAVCCodecSpecificData(const sp<ABuffer> &accessUnit) { FindAVCDimensions( seqParamSet, &width, &height, &sarWidth, &sarHeight); - size_t stopOffset; - sp<ABuffer> picParamSet = FindNAL(data, size, 8, &stopOffset); + sp<ABuffer> picParamSet = FindNAL(data, size, 8); CHECK(picParamSet != NULL); size_t csdSize = |