webrtc/call/rtx_receive_stream.cc

/*
 *  Copyright (c) 2017 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 <utility>

#include "webrtc/call/rtx_receive_stream.h"
#include "webrtc/modules/rtp_rtcp/source/rtp_packet_received.h"

namespace webrtc {

RtxReceiveStream::RtxReceiveStream(
    RtpPacketSinkInterface* media_sink,
    std::map<int, int> rtx_payload_type_map,
    uint32_t media_ssrc)
    : media_sink_(media_sink),
      rtx_payload_type_map_(std::move(rtx_payload_type_map)),
      media_ssrc_(media_ssrc) {}

void RtxReceiveStream::OnRtpPacket(const RtpPacketReceived& rtx_packet) {
  rtc::ArrayView<const uint8_t> payload = rtx_packet.payload();

  if (payload.size() < kRtxHeaderSize) {
    return;
  }

  auto it = rtx_payload_type_map_.find(rtx_packet.PayloadType());
  if (it == rtx_payload_type_map_.end()) {
    return;
  }
  RtpPacketReceived media_packet;
  media_packet.CopyHeaderFrom(rtx_packet);

  media_packet.SetSsrc(media_ssrc_);
  media_packet.SetSequenceNumber((payload[0] << 8) + payload[1]);
  media_packet.SetPayloadType(it->second);

  // Skip the RTX header.
  rtc::ArrayView<const uint8_t> rtx_payload =
      payload.subview(kRtxHeaderSize);

  uint8_t* media_payload = media_packet.AllocatePayload(rtx_payload.size());
  RTC_DCHECK(media_payload != nullptr);

  memcpy(media_payload, rtx_payload.data(), rtx_payload.size());

  media_sink_->OnRtpPacket(media_packet);
}

}  // namespace webrtc