blob: a69bd19690edda83da8cb147776dd6de15a77cca [file] [log] [blame]
* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
#include "absl/types/optional.h"
#include "rtc_base/bitstream_reader.h"
#include "rtc_base/system/rtc_export.h"
namespace webrtc {
// A class for parsing out sequence parameter set (SPS) data from an H264 NALU.
class RTC_EXPORT SpsParser {
// The parsed state of the SPS. Only some select values are stored.
// Add more as they are actually needed.
struct RTC_EXPORT SpsState {
SpsState(const SpsState&);
uint32_t width = 0;
uint32_t height = 0;
uint32_t delta_pic_order_always_zero_flag = 0;
uint32_t separate_colour_plane_flag = 0;
uint32_t frame_mbs_only_flag = 0;
uint32_t log2_max_frame_num = 4; // Smallest valid value.
uint32_t log2_max_pic_order_cnt_lsb = 4; // Smallest valid value.
uint32_t pic_order_cnt_type = 0;
uint32_t max_num_ref_frames = 0;
uint32_t vui_params_present = 0;
uint32_t id = 0;
// Unpack RBSP and parse SPS state from the supplied buffer.
static absl::optional<SpsState> ParseSps(const uint8_t* data, size_t length);
// Parse the SPS state, up till the VUI part, for a buffer where RBSP
// decoding has already been performed.
static absl::optional<SpsState> ParseSpsUpToVui(BitstreamReader& reader);
} // namespace webrtc