flexfec_sender.cc | Explore in Territory

/*
 *  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 "modules/rtp_rtcp/include/flexfec_sender.h"

#include <string.h>

#include <list>
#include <utility>

#include "absl/strings/string_view.h"
#include "api/environment/environment.h"
#include "api/units/time_delta.h"
#include "api/units/timestamp.h"
#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
#include "modules/rtp_rtcp/source/forward_error_correction.h"
#include "modules/rtp_rtcp/source/rtp_header_extensions.h"
#include "modules/rtp_rtcp/source/rtp_packet_to_send.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"

namespace webrtc {

namespace {

// Let first sequence number be in the first half of the interval.
constexpr uint16_t kMaxInitRtpSeqNumber = …;

// See breakdown in flexfec_header_reader_writer.cc.
constexpr size_t kFlexfecMaxHeaderSize = …;

// Since we will mainly use FlexFEC to protect video streams, we use a 90 kHz
// clock for the RTP timestamps. (This is according to the RFC, which states
// that it is RECOMMENDED to use the same clock frequency for FlexFEC as for
// the protected media stream.)
// The constant converts from clock millisecond timestamps to the 90 kHz
// RTP timestamp.
const int kMsToRtpTimestamp = …;

// How often to log the generated FEC packets to the text log.
constexpr TimeDelta kPacketLogInterval = …;

RtpHeaderExtensionMap RegisterSupportedExtensions(
    const std::vector<RtpExtension>& rtp_header_extensions) { … }

}  // namespace

FlexfecSender::FlexfecSender(
    const Environment& env,
    int payload_type,
    uint32_t ssrc,
    uint32_t protected_media_ssrc,
    absl::string_view mid,
    const std::vector<RtpExtension>& rtp_header_extensions,
    rtc::ArrayView<const RtpExtensionSize> extension_sizes,
    const RtpState* rtp_state)
    : … { … }

FlexfecSender::~FlexfecSender() = default;

// We are reusing the implementation from UlpfecGenerator for SetFecParameters,
// AddRtpPacketAndGenerateFec, and FecAvailable.
void FlexfecSender::SetProtectionParameters(
    const FecProtectionParams& delta_params,
    const FecProtectionParams& key_params) { … }

void FlexfecSender::AddPacketAndGenerateFec(const RtpPacketToSend& packet) { … }

std::vector<std::unique_ptr<RtpPacketToSend>> FlexfecSender::GetFecPackets() { … }

// The overhead is BWE RTP header extensions and FlexFEC header.
size_t FlexfecSender::MaxPacketOverhead() const { … }

DataRate FlexfecSender::CurrentFecRate() const { … }

absl::optional<RtpState> FlexfecSender::GetRtpState() { … }

}  // namespace webrtc
chromium/third_party/webrtc/modules/rtp_rtcp/source/flexfec_sender.cc
