sps_parser.h (1898B)
1 /* 2 * Copyright (c) 2016 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef COMMON_VIDEO_H264_SPS_PARSER_H_ 12 #define COMMON_VIDEO_H264_SPS_PARSER_H_ 13 14 #include <cstdint> 15 #include <optional> 16 17 #include "api/array_view.h" 18 #include "rtc_base/bitstream_reader.h" 19 #include "rtc_base/system/rtc_export.h" 20 21 namespace webrtc { 22 23 // A class for parsing out sequence parameter set (SPS) data from an H264 NALU. 24 class RTC_EXPORT SpsParser { 25 public: 26 // The parsed state of the SPS. Only some select values are stored. 27 // Add more as they are actually needed. 28 struct RTC_EXPORT SpsState { 29 SpsState(); 30 SpsState(const SpsState&); 31 ~SpsState(); 32 33 uint32_t width = 0; 34 uint32_t height = 0; 35 uint32_t delta_pic_order_always_zero_flag = 0; 36 uint32_t chroma_format_idc = 1; 37 uint32_t separate_colour_plane_flag = 0; 38 uint32_t frame_mbs_only_flag = 0; 39 uint32_t log2_max_frame_num = 4; // Smallest valid value. 40 uint32_t log2_max_pic_order_cnt_lsb = 4; // Smallest valid value. 41 uint32_t pic_order_cnt_type = 0; 42 uint32_t max_num_ref_frames = 0; 43 uint32_t vui_params_present = 0; 44 uint32_t id = 0; 45 }; 46 47 // Unpack RBSP and parse SPS state from the supplied buffer. 48 static std::optional<SpsState> ParseSps(ArrayView<const uint8_t> data); 49 50 protected: 51 // Parse the SPS state, up till the VUI part, for a buffer where RBSP 52 // decoding has already been performed. 53 static std::optional<SpsState> ParseSpsUpToVui(BitstreamReader& reader); 54 }; 55 56 } // namespace webrtc 57 #endif // COMMON_VIDEO_H264_SPS_PARSER_H_