chromium/third_party/webrtc/modules/rtp_rtcp/source/rtp_packetizer_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/rtp_packetizer_av1.h"

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

#include <algorithm>

#include "api/array_view.h"
#include "api/video/video_frame_type.h"
#include "modules/rtp_rtcp/source/leb128.h"
#include "modules/rtp_rtcp/source/rtp_packet_to_send.h"
#include "rtc_base/byte_buffer.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"

namespace webrtc {
namespace {
constexpr int kAggregationHeaderSize = …;
// when there are 3 or less OBU (fragments) in a packet, size of the last one
// can be omited.
constexpr int kMaxNumObusToOmitSize = …;
constexpr uint8_t kObuSizePresentBit = …;
constexpr int kObuTypeSequenceHeader = …;
constexpr int kObuTypeTemporalDelimiter = …;
constexpr int kObuTypeTileList = …;
constexpr int kObuTypePadding = …;

// Overhead introduced by "even distribution" of packet sizes.
constexpr size_t kBytesOverheadEvenDistribution = …;
// Experimentally determined minimum amount of potential savings per packet to
// make "even distribution" of packet sizes worthwhile.
constexpr size_t kMinBytesSavedPerPacketWithEvenDistribution = …;

bool ObuHasExtension(uint8_t obu_header) { … }

bool ObuHasSize(uint8_t obu_header) { … }

int ObuType(uint8_t obu_header) { … }

// Given `remaining_bytes` free bytes left in a packet, returns max size of an
// OBU fragment that can fit into the packet.
// i.e. MaxFragmentSize + Leb128Size(MaxFragmentSize) <= remaining_bytes.
int MaxFragmentSize(int remaining_bytes) { … }

}  // namespace

RtpPacketizerAv1::RtpPacketizerAv1(rtc::ArrayView<const uint8_t> payload,
                                   RtpPacketizer::PayloadSizeLimits limits,
                                   VideoFrameType frame_type,
                                   bool is_last_frame_in_picture,
                                   bool even_distribution)
    : … { … }

std::vector<RtpPacketizerAv1::Obu> RtpPacketizerAv1::ParseObus(
    rtc::ArrayView<const uint8_t> payload) { … }

int RtpPacketizerAv1::AdditionalBytesForPreviousObuElement(
    const Packet& packet) { … }

std::vector<RtpPacketizerAv1::Packet> RtpPacketizerAv1::Packetize(
    rtc::ArrayView<const Obu> obus,
    PayloadSizeLimits limits) { … }

std::vector<RtpPacketizerAv1::Packet> RtpPacketizerAv1::PacketizeAboutEqually(
    rtc::ArrayView<const Obu> obus,
    PayloadSizeLimits limits) { … }

uint8_t RtpPacketizerAv1::AggregationHeader() const { … }

bool RtpPacketizerAv1::NextPacket(RtpPacketToSend* packet) { … }

}  // namespace webrtc