diff options
Diffstat (limited to 'common/NalParser.cpp')
| -rw-r--r-- | common/NalParser.cpp | 217 |
1 files changed, 0 insertions, 217 deletions
diff --git a/common/NalParser.cpp b/common/NalParser.cpp deleted file mode 100644 index 3216574..0000000 --- a/common/NalParser.cpp +++ /dev/null @@ -1,217 +0,0 @@ -// Copyright 2021 The Chromium Authors. All rights reserved. -// Use of this source code is governed by a BSD-style license that can be -// found in the LICENSE file. - -//#define LOG_NDEBUG 0 -#define LOG_TAG "NalParser" - -#include <v4l2_codec2/common/NalParser.h> - -#include <algorithm> - -#include <media/stagefright/foundation/ABitReader.h> -#include <utils/Log.h> - -namespace android { - -namespace { - -enum H264ProfileIDC { - kProfileIDCAVLC444 = 44, - kProfileIDScalableBaseline = 83, - kProfileIDScalableHigh = 86, - kProfileIDCHigh = 100, - kProfileIDHigh10 = 110, - kProfileIDSMultiviewHigh = 118, - kProfileIDHigh422 = 122, - kProfileIDStereoHigh = 128, - kProfileIDHigh444Predictive = 244, -}; - -constexpr uint32_t kYUV444Idc = 3; - -// Read unsigned int encoded with exponential-golomb. -uint32_t parseUE(ABitReader* br) { - uint32_t numZeroes = 0; - while (br->getBits(1) == 0) { - ++numZeroes; - } - uint32_t val = br->getBits(numZeroes); - return val + (1u << numZeroes) - 1; -} - -// Read signed int encoded with exponential-golomb. -int32_t parseSE(ABitReader* br) { - uint32_t codeNum = parseUE(br); - return (codeNum & 1) ? (codeNum + 1) >> 1 : -static_cast<int32_t>(codeNum >> 1); -} - -// Skip a H.264 sequence scaling list in the specified bitstream. -void skipScalingList(ABitReader* br, size_t scalingListSize) { - size_t nextScale = 8; - size_t lastScale = 8; - for (size_t j = 0; j < scalingListSize; ++j) { - if (nextScale != 0) { - int32_t deltaScale = parseSE(br); // delta_sl - if (deltaScale < -128) { - ALOGW("delta scale (%d) is below range, capping to -128", deltaScale); - deltaScale = -128; - } else if (deltaScale > 127) { - ALOGW("delta scale (%d) is above range, capping to 127", deltaScale); - deltaScale = 127; - } - nextScale = (lastScale + (deltaScale + 256)) % 256; - } - lastScale = (nextScale == 0) ? lastScale : nextScale; - } -} - -// Skip the H.264 sequence scaling matrix in the specified bitstream. -void skipScalingMatrix(ABitReader* br, size_t numScalingLists) { - for (size_t i = 0; i < numScalingLists; ++i) { - if (br->getBits(1)) { // seq_scaling_list_present_flag - if (i < 6) { - skipScalingList(br, 16); - } else { - skipScalingList(br, 64); - } - } - } -} - -} // namespace - -NalParser::NalParser(const uint8_t* data, size_t length) - : mCurrNalDataPos(data), mDataEnd(data + length) { - mNextNalStartCodePos = findNextStartCodePos(); -} - -bool NalParser::locateNextNal() { - if (mNextNalStartCodePos == mDataEnd) return false; - mCurrNalDataPos = mNextNalStartCodePos + kNalStartCodeLength; // skip start code. - mNextNalStartCodePos = findNextStartCodePos(); - return true; -} - -bool NalParser::locateSPS() { - while (locateNextNal()) { - if (length() == 0) continue; - if (type() != kSPSType) continue; - return true; - } - - return false; -} - -const uint8_t* NalParser::data() const { - return mCurrNalDataPos; -} - -size_t NalParser::length() const { - if (mNextNalStartCodePos == mDataEnd) return mDataEnd - mCurrNalDataPos; - size_t length = mNextNalStartCodePos - mCurrNalDataPos; - // The start code could be 3 or 4 bytes, i.e., 0x000001 or 0x00000001. - return *(mNextNalStartCodePos - 1) == 0x00 ? length - 1 : length; -} - -uint8_t NalParser::type() const { - // First byte is forbidden_zero_bit (1) + nal_ref_idc (2) + nal_unit_type (5) - constexpr uint8_t kNALTypeMask = 0x1f; - return *mCurrNalDataPos & kNALTypeMask; -} - -const uint8_t* NalParser::findNextStartCodePos() const { - return std::search(mCurrNalDataPos, mDataEnd, kNalStartCode, - kNalStartCode + kNalStartCodeLength); -} - -bool NalParser::findCodedColorAspects(ColorAspects* colorAspects) { - ALOG_ASSERT(colorAspects); - ALOG_ASSERT(type() == kSPSType); - - // Unfortunately we can't directly jump to the Video Usability Information (VUI) parameters that - // contain the color aspects. We need to parse the entire SPS header up until the values we - // need. - - // Skip first byte containing type. - ABitReader br(mCurrNalDataPos + 1, length() - 1); - - uint32_t profileIDC = br.getBits(8); // profile_idc - br.skipBits(16); // constraint flags + reserved bits + level_idc - parseUE(&br); // seq_parameter_set_id - - if (profileIDC == kProfileIDCHigh || profileIDC == kProfileIDHigh10 || - profileIDC == kProfileIDHigh422 || profileIDC == kProfileIDHigh444Predictive || - profileIDC == kProfileIDCAVLC444 || profileIDC == kProfileIDScalableBaseline || - profileIDC == kProfileIDScalableHigh || profileIDC == kProfileIDSMultiviewHigh || - profileIDC == kProfileIDStereoHigh) { - uint32_t chromaFormatIDC = parseUE(&br); - if (chromaFormatIDC == kYUV444Idc) { // chroma_format_idc - br.skipBits(1); // separate_colour_plane_flag - } - parseUE(&br); // bit_depth_luma_minus8 - parseUE(&br); // bit_depth_chroma_minus8 - br.skipBits(1); // lossless_qpprime_y_zero_flag - - if (br.getBits(1)) { // seq_scaling_matrix_present_flag - const size_t numScalingLists = (chromaFormatIDC != kYUV444Idc) ? 8 : 12; - skipScalingMatrix(&br, numScalingLists); - } - } - - parseUE(&br); // log2_max_frame_num_minus4 - uint32_t pictureOrderCountType = parseUE(&br); // pic_order_cnt_type - if (pictureOrderCountType == 0) { - parseUE(&br); // log2_max_pic_order_cnt_lsb_minus4 - } else if (pictureOrderCountType == 1) { - br.skipBits(1); // delta_pic_order_always_zero_flag - parseSE(&br); // offset_for_non_ref_pic - parseSE(&br); // offset_for_top_to_bottom_field - uint32_t numReferenceFrames = parseUE(&br); // num_ref_frames_in_pic_order_cnt_cycle - for (uint32_t i = 0; i < numReferenceFrames; ++i) { - parseUE(&br); // offset_for_ref_frame - } - } - - parseUE(&br); // num_ref_frames - br.skipBits(1); // gaps_in_frame_num_value_allowed_flag - parseUE(&br); // pic_width_in_mbs_minus1 - parseUE(&br); // pic_height_in_map_units_minus1 - if (!br.getBits(1)) { // frame_mbs_only_flag - br.skipBits(1); // mb_adaptive_frame_field_flag - } - br.skipBits(1); // direct_8x8_inference_flag - - if (br.getBits(1)) { // frame_cropping_flag - parseUE(&br); // frame_cropping_rect_left_offset - parseUE(&br); // frame_cropping_rect_right_offset - parseUE(&br); // frame_cropping_rect_top_offset - parseUE(&br); // frame_cropping_rect_bottom_offset - } - - if (br.getBits(1)) { // vui_parameters_present_flag - if (br.getBits(1)) { // VUI aspect_ratio_info_present_flag - if (br.getBits(8) == 255) { // VUI aspect_ratio_idc == extended sample aspect ratio - br.skipBits(32); // VUI sar_width + sar_height - } - } - - if (br.getBits(1)) { // VUI overscan_info_present_flag - br.skipBits(1); // VUI overscan_appropriate_flag - } - if (br.getBits(1)) { // VUI video_signal_type_present_flag - br.skipBits(3); // VUI video_format - colorAspects->fullRange = br.getBits(1); // VUI video_full_range_flag - if (br.getBits(1)) { // VUI color_description_present_flag - colorAspects->primaries = br.getBits(8); // VUI colour_primaries - colorAspects->transfer = br.getBits(8); // VUI transfer_characteristics - colorAspects->coeffs = br.getBits(8); // VUI matrix_coefficients - return !br.overRead(); - } - } - } - - return false; -} - -} // namespace android |