chromium/third_party/webrtc/modules/rtp_rtcp/source/video_rtp_depacketizer_av1.cc

/*
 *  Copyright (c) 2019 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 "modules/rtp_rtcp/source/video_rtp_depacketizer_av1.h"

#include <stddef.h>
#include <stdint.h>

#include <utility>

#include "modules/rtp_rtcp/source/leb128.h"
#include "modules/rtp_rtcp/source/rtp_video_header.h"
#include "rtc_base/byte_buffer.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
#include "rtc_base/numerics/safe_conversions.h"

namespace webrtc {
namespace {
// AV1 format:
//
// RTP payload syntax:
//     0 1 2 3 4 5 6 7
//    +-+-+-+-+-+-+-+-+
//    |Z|Y| W |N|-|-|-| (REQUIRED)
//    +=+=+=+=+=+=+=+=+ (REPEATED W-1 times, or any times if W = 0)
//    |1|             |
//    +-+ OBU fragment|
//    |1|             | (REQUIRED, leb128 encoded)
//    +-+    size     |
//    |0|             |
//    +-+-+-+-+-+-+-+-+
//    |  OBU fragment |
//    |     ...       |
//    +=+=+=+=+=+=+=+=+
//    |     ...       |
//    +=+=+=+=+=+=+=+=+ if W > 0, last fragment MUST NOT have size field
//    |  OBU fragment |
//    |     ...       |
//    +=+=+=+=+=+=+=+=+
//
//
// OBU syntax:
//     0 1 2 3 4 5 6 7
//    +-+-+-+-+-+-+-+-+
//    |0| type  |X|S|-| (REQUIRED)
//    +-+-+-+-+-+-+-+-+
// X: | TID |SID|-|-|-| (OPTIONAL)
//    +-+-+-+-+-+-+-+-+
//    |1|             |
//    +-+ OBU payload |
// S: |1|             | (OPTIONAL, variable length leb128 encoded)
//    +-+    size     |
//    |0|             |
//    +-+-+-+-+-+-+-+-+
//    |  OBU payload  |
//    |     ...       |
class ArrayOfArrayViews { … };

class ArrayOfArrayViews::const_iterator { … };

ArrayOfArrayViews::const_iterator ArrayOfArrayViews::begin() const { … }

ArrayOfArrayViews::const_iterator ArrayOfArrayViews::end() const { … }

void ArrayOfArrayViews::CopyTo(uint8_t* destination,
                               const_iterator first) const { … }

struct ObuInfo { … };
// Expect that majority of the frame won't use more than 4 obus.
// In a simple stream delta frame consist of single Frame OBU, while key frame
// also has Sequence Header OBU.
VectorObuInfo;

constexpr uint8_t kObuSizePresentBit = …;

bool ObuHasExtension(uint8_t obu_header) { … }

bool ObuHasSize(uint8_t obu_header) { … }

bool RtpStartsWithFragment(uint8_t aggregation_header) { … }
bool RtpEndsWithFragment(uint8_t aggregation_header) { … }
int RtpNumObus(uint8_t aggregation_header) { … }
int RtpStartsNewCodedVideoSequence(uint8_t aggregation_header) { … }

// Reorgonizes array of rtp payloads into array of obus:
// fills ObuInfo::data field.
// Returns empty vector on error.
VectorObuInfo ParseObus(
    rtc::ArrayView<const rtc::ArrayView<const uint8_t>> rtp_payloads) { … }

// Calculates sizes for the Obu, i.e. base on ObuInfo::data field calculates
// all other fields in the ObuInfo structure.
// Returns false if obu found to be misformed.
bool CalculateObuSizes(ObuInfo* obu_info) { … }

}  // namespace

rtc::scoped_refptr<EncodedImageBuffer> VideoRtpDepacketizerAv1::AssembleFrame(
    rtc::ArrayView<const rtc::ArrayView<const uint8_t>> rtp_payloads) { … }

absl::optional<VideoRtpDepacketizer::ParsedRtpPayload>
VideoRtpDepacketizerAv1::Parse(rtc::CopyOnWriteBuffer rtp_payload) { … }

}  // namespace webrtc