Adding "adapter" ORTC objects on top of ChannelManager/BaseChannel/etc.

webrtc/ortc/rtptransportcontrolleradapter.cc

+/*
+ *  Copyright 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 "webrtc/ortc/rtptransportcontrolleradapter.h"
+
+#include <algorithm>  // For "remove", "find".
+#include <sstream>
+#include <set>
+#include <unordered_map>
+#include <utility>  // For std::move.
+
+#include "webrtc/api/proxy.h"
+#include "webrtc/base/checks.h"
+#include "webrtc/media/base/mediaconstants.h"
+#include "webrtc/ortc/ortcrtpreceiveradapter.h"
+#include "webrtc/ortc/ortcrtpsenderadapter.h"
+#include "webrtc/ortc/rtpparametersconversion.h"
+#include "webrtc/ortc/rtptransportadapter.h"
+
+namespace webrtc {
+
+// Note: It's assumed that each individual list doesn't have conflicts, since
+// they should have been detected already by rtpparametersconversion.cc. This
+// only needs to detect conflicts *between* A and B.
+template <typename C1, typename C2>
+static RTCError CheckForIdConflicts(
+    const std::vector<C1>& codecs_a,
+    const cricket::RtpHeaderExtensions& extensions_a,
+    const cricket::StreamParamsVec& streams_a,
+    const std::vector<C2>& codecs_b,
+    const cricket::RtpHeaderExtensions& extensions_b,
+    const cricket::StreamParamsVec& streams_b) {
+  std::ostringstream oss;
+  // Since it's assumed that C1 and C2 are different types, codecs_a and
+  // codecs_b should never contain the same payload type, and thus we can just
+  // use a set.
+  std::set<int> seen_payload_types;
+  for (const C1& codec : codecs_a) {
+    seen_payload_types.insert(codec.id);
+  }
+  for (const C2& codec : codecs_b) {
+    if (!seen_payload_types.insert(codec.id).second) {
+      oss << "Same payload type used for audio and video codecs: " << codec.id;
+      LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, oss.str());
+    }
+  }
+  // Audio and video *may* use the same header extensions, so use a map.
+  std::unordered_map<int, std::string> seen_extensions;
+  for (const webrtc::RtpExtension& extension : extensions_a) {
+    seen_extensions[extension.id] = extension.uri;
+  }
+  for (const webrtc::RtpExtension& extension : extensions_b) {
+    if (seen_extensions.find(extension.id) != seen_extensions.end() &&
+        seen_extensions.at(extension.id) != extension.uri) {
+      oss << "Same ID used for different RTP header extensions: "
+          << extension.id;
+      LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, oss.str());
+    }
+  }
+  std::set<uint32_t> seen_ssrcs;
+  for (const cricket::StreamParams& stream : streams_a) {
+    seen_ssrcs.insert(stream.ssrcs.begin(), stream.ssrcs.end());
+  }
+  for (const cricket::StreamParams& stream : streams_b) {
+    for (uint32_t ssrc : stream.ssrcs) {
+      if (!seen_ssrcs.insert(ssrc).second) {
+        oss << "Same SSRC used for audio and video senders: " << ssrc;
+        LOG_AND_RETURN_ERROR(RTCErrorType::INVALID_PARAMETER, oss.str());
+      }
+    }
+  }
+  return RTCError::OK();
+}
+
+BEGIN_OWNED_PROXY_MAP(RtpTransportController)
+PROXY_SIGNALING_THREAD_DESTRUCTOR()
+PROXY_CONSTMETHOD0(std::vector<RtpTransportInterface*>, GetTransports)
+protected:
+RtpTransportControllerAdapter* GetInternal() override {
+  return internal();
+}
+END_PROXY_MAP()
+
+// static
+std::unique_ptr<RtpTransportControllerInterface>
+RtpTransportControllerAdapter::CreateProxied(
+    const cricket::MediaConfig& config,
+    cricket::ChannelManager* channel_manager,
+    webrtc::RtcEventLog* event_log,
+    rtc::Thread* signaling_thread,
+    rtc::Thread* worker_thread) {
+  RtpTransportControllerAdapter* wrapped = new RtpTransportControllerAdapter(
+      config, channel_manager, event_log, signaling_thread, worker_thread);
+  return RtpTransportControllerProxyWithInternal<
+      RtpTransportControllerAdapter>::Create(signaling_thread, worker_thread,
+                                             wrapped);
+}
+
+RtpTransportControllerAdapter::~RtpTransportControllerAdapter() {
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  if (!transport_proxies_.empty()) {
+    LOG(LS_ERROR)
+        << "Destroying RtpTransportControllerAdapter while RtpTransports "
+           "are still using it; this is unsafe.";
+  }
+  if (voice_channel_) {
+    // This would mean audio RTP senders/receivers that are using us haven't
+    // been destroyed. This isn't safe (see error log above).
+    DestroyVoiceChannel();
+  }
+  if (voice_channel_) {
+    // This would mean video RTP senders/receivers that are using us haven't
+    // been destroyed. This isn't safe (see error log above).
+    DestroyVideoChannel();
+  }
+}
+
+RTCErrorOr<std::unique_ptr<OrtcRtpSenderInterface>>
+RtpTransportControllerAdapter::CreateProxiedRtpSender(
+    cricket::MediaType kind,
+    RtpTransportInterface* transport_proxy) {
+  RTC_DCHECK(transport_proxy);
+  RTC_DCHECK(std::find(transport_proxies_.begin(), transport_proxies_.end(),
+                       transport_proxy) != transport_proxies_.end());
+  std::unique_ptr<OrtcRtpSenderAdapter> new_sender(
+      new OrtcRtpSenderAdapter(kind, transport_proxy, this));
+  RTCError err;
+  switch (kind) {
+    case cricket::MEDIA_TYPE_AUDIO:
+      err = AttachAudioSender(new_sender.get(), transport_proxy->GetInternal());
+      break;
+    case cricket::MEDIA_TYPE_VIDEO:
+      err = AttachVideoSender(new_sender.get(), transport_proxy->GetInternal());
+      break;
+    case cricket::MEDIA_TYPE_DATA:
+      RTC_NOTREACHED();
+  }
+  if (!err.ok()) {
+    return err;
+  }
+
+  return OrtcRtpSenderAdapter::CreateProxy(std::move(new_sender));
+}
+
+RTCErrorOr<std::unique_ptr<OrtcRtpReceiverInterface>>
+RtpTransportControllerAdapter::CreateProxiedRtpReceiver(
+    cricket::MediaType kind,
+    RtpTransportInterface* transport_proxy) {
+  RTC_DCHECK(transport_proxy);
+  RTC_DCHECK(std::find(transport_proxies_.begin(), transport_proxies_.end(),
+                       transport_proxy) != transport_proxies_.end());
+  std::unique_ptr<OrtcRtpReceiverAdapter> new_receiver(
+      new OrtcRtpReceiverAdapter(kind, transport_proxy, this));
+  RTCError err;
+  switch (kind) {
+    case cricket::MEDIA_TYPE_AUDIO:
+      err = AttachAudioReceiver(new_receiver.get(),
+                                transport_proxy->GetInternal());
+      break;
+    case cricket::MEDIA_TYPE_VIDEO:
+      err = AttachVideoReceiver(new_receiver.get(),
+                                transport_proxy->GetInternal());
+      break;
+    case cricket::MEDIA_TYPE_DATA:
+      RTC_NOTREACHED();
+  }
+  if (!err.ok()) {
+    return err;
+  }
+
+  return OrtcRtpReceiverAdapter::CreateProxy(std::move(new_receiver));
+}
+
+std::vector<RtpTransportInterface*>
+RtpTransportControllerAdapter::GetTransports() const {
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  return transport_proxies_;
+}
+
+void RtpTransportControllerAdapter::AddTransport(
+    RtpTransportInterface* transport_proxy) {
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  transport_proxies_.push_back(transport_proxy);
+}
+
+void RtpTransportControllerAdapter::RemoveTransport(
+    RtpTransportAdapter* inner_transport) {
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  auto it = std::find_if(transport_proxies_.begin(), transport_proxies_.end(),
+                         [inner_transport](RtpTransportInterface* proxy) {
+                           return proxy->GetInternal() == inner_transport;
+                         });
+  if (it == transport_proxies_.end()) {
+    RTC_NOTREACHED();
+    return;
+  }
+  transport_proxies_.erase(it);
+}
+
+RTCError RtpTransportControllerAdapter::SetRtcpParameters(
+    const RtcpParameters& parameters,
+    RtpTransportInterface* inner_transport) {
+  do {
+    if (inner_transport == inner_audio_transport_) {
+      CopyRtcpParametersToDescriptions(parameters, &local_audio_description_,
+                                       &remote_audio_description_);
+      if (!voice_channel_->SetLocalContent(&local_audio_description_,
+                                           cricket::CA_OFFER, nullptr)) {
+        break;
+      }
+      if (!voice_channel_->SetRemoteContent(&remote_audio_description_,
+                                            cricket::CA_ANSWER, nullptr)) {
+        break;
+      }
+    } else if (inner_transport == inner_video_transport_) {
+      CopyRtcpParametersToDescriptions(parameters, &local_video_description_,
+                                       &remote_video_description_);
+      if (!video_channel_->SetLocalContent(&local_video_description_,
+                                           cricket::CA_OFFER, nullptr)) {
+        break;
+      }
+      if (!video_channel_->SetRemoteContent(&remote_video_description_,
+                                            cricket::CA_ANSWER, nullptr)) {
+        break;
+      }
+    }
+    return RTCError::OK();
+  } while (false);
+  LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
+                       "Failed to apply new RTCP parameters.");
+}
+
+RTCError RtpTransportControllerAdapter::ValidateAndApplyAudioSenderParameters(
+    const RtpParameters& parameters,
+    uint32_t* primary_ssrc) {
+  RTC_DCHECK(voice_channel_);
+  RTC_DCHECK(have_audio_sender_);
+
+  auto codecs_result = ToCricketCodecs<cricket::AudioCodec>(parameters.codecs);
+  if (!codecs_result.ok()) {
+    return codecs_result.MoveError();
+  }
+
+  auto extensions_result = ToRtpHeaderExtensions(parameters.header_extensions);
+  if (!extensions_result.ok()) {
+    return extensions_result.MoveError();
+  }
+
+  auto stream_params_result = MakeSendStreamParamsVec(
+      parameters.encodings, inner_audio_transport_->GetRtcpParameters().cname,
+      local_audio_description_);
+  if (!stream_params_result.ok()) {
+    return stream_params_result.MoveError();
+  }
+
+  // Check that audio/video sender aren't using the same IDs to refer to
+  // different things, if they share the same transport.
+  if (inner_audio_transport_ == inner_video_transport_) {
+    RTCError err = CheckForIdConflicts(
+        codecs_result.value(), extensions_result.value(),
+        stream_params_result.value(), remote_video_description_.codecs(),
+        remote_video_description_.rtp_header_extensions(),
+        local_video_description_.streams());
+    if (!err.ok()) {
+      return err;
+    }
+  }
+
+  cricket::RtpTransceiverDirection local_direction =
+      cricket::RtpTransceiverDirection::FromMediaContentDirection(
+          local_audio_description_.direction());
+  int bandwidth = cricket::kAutoBandwidth;
+  if (parameters.encodings.size() == 1u) {
+    if (parameters.encodings[0].max_bitrate_bps) {
+      bandwidth = *parameters.encodings[0].max_bitrate_bps;
+    }
+    local_direction.send = parameters.encodings[0].active;
+  } else {
+    local_direction.send = false;
+  }
+  if (primary_ssrc && !stream_params_result.value().empty()) {
+    *primary_ssrc = stream_params_result.value()[0].first_ssrc();
+  }
+
+  // Validation is done, so we can attempt applying the descriptions. Sent
+  // codecs and header extensions go in remote description, streams go in
+  // local.
+  //
+  // If there are no codecs or encodings, just leave the previous set of
+  // codecs. The media engine doesn't like an empty set of codecs.
+  if (local_audio_description_.streams().empty() &&
+      remote_audio_description_.codecs().empty()) {
+  } else {
+    remote_audio_description_.set_codecs(codecs_result.MoveValue());
+  }
+  remote_audio_description_.set_rtp_header_extensions(
+      extensions_result.MoveValue());
+  remote_audio_description_.set_bandwidth(bandwidth);
+  local_audio_description_.mutable_streams() = stream_params_result.MoveValue();
+  // Direction set based on encoding "active" flag.
+  local_audio_description_.set_direction(
+      local_direction.ToMediaContentDirection());
+  remote_audio_description_.set_direction(
+      local_direction.Reversed().ToMediaContentDirection());
+
+  // Set remote content first, to ensure the stream is created with the correct
+  // codec.
+  if (!voice_channel_->SetRemoteContent(&remote_audio_description_,
+                                        cricket::CA_OFFER, nullptr)) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
+                         "Failed to apply remote parameters to media channel.");
+  }
+  if (!voice_channel_->SetLocalContent(&local_audio_description_,
+                                       cricket::CA_ANSWER, nullptr)) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
+                         "Failed to apply local parameters to media channel.");
+  }
+  return RTCError::OK();
+}
+
+RTCError RtpTransportControllerAdapter::ValidateAndApplyVideoSenderParameters(
+    const RtpParameters& parameters,
+    uint32_t* primary_ssrc) {
+  RTC_DCHECK(video_channel_);
+  RTC_DCHECK(have_video_sender_);
+
+  auto codecs_result = ToCricketCodecs<cricket::VideoCodec>(parameters.codecs);
+  if (!codecs_result.ok()) {
+    return codecs_result.MoveError();
+  }
+
+  auto extensions_result = ToRtpHeaderExtensions(parameters.header_extensions);
+  if (!extensions_result.ok()) {
+    return extensions_result.MoveError();
+  }
+
+  auto stream_params_result = MakeSendStreamParamsVec(
+      parameters.encodings, inner_video_transport_->GetRtcpParameters().cname,
+      local_video_description_);
+  if (!stream_params_result.ok()) {
+    return stream_params_result.MoveError();
+  }
+
+  // Check that audio/video sender aren't using the same IDs to refer to
+  // different things, if they share the same transport.
+  if (inner_audio_transport_ == inner_video_transport_) {
+    RTCError err = CheckForIdConflicts(
+        codecs_result.value(), extensions_result.value(),
+        stream_params_result.value(), remote_audio_description_.codecs(),
+        remote_audio_description_.rtp_header_extensions(),
+        local_audio_description_.streams());
+    if (!err.ok()) {
+      return err;
+    }
+  }
+
+  cricket::RtpTransceiverDirection local_direction =
+      cricket::RtpTransceiverDirection::FromMediaContentDirection(
+          local_video_description_.direction());
+  int bandwidth = cricket::kAutoBandwidth;
+  if (parameters.encodings.size() == 1u) {
+    if (parameters.encodings[0].max_bitrate_bps) {
+      bandwidth = *parameters.encodings[0].max_bitrate_bps;
+    }
+    local_direction.send = parameters.encodings[0].active;
+  } else {
+    local_direction.send = false;
+  }
+  if (primary_ssrc && !stream_params_result.value().empty()) {
+    *primary_ssrc = stream_params_result.value()[0].first_ssrc();
+  }
+
+  // Validation is done, so we can attempt applying the descriptions. Sent
+  // codecs and header extensions go in remote description, streams go in
+  // local.
+  //
+  // If there are no codecs or encodings, just leave the previous set of
+  // codecs. The media engine doesn't like an empty set of codecs.
+  if (local_video_description_.streams().empty() &&
+      remote_video_description_.codecs().empty()) {
+  } else {
+    remote_video_description_.set_codecs(codecs_result.MoveValue());
+  }
+  remote_video_description_.set_rtp_header_extensions(
+      extensions_result.MoveValue());
+  remote_video_description_.set_bandwidth(bandwidth);
+  local_video_description_.mutable_streams() = stream_params_result.MoveValue();
+  // Direction set based on encoding "active" flag.
+  local_video_description_.set_direction(
+      local_direction.ToMediaContentDirection());
+  remote_video_description_.set_direction(
+      local_direction.Reversed().ToMediaContentDirection());
+
+  // Set remote content first, to ensure the stream is created with the correct
+  // codec.
+  if (!video_channel_->SetRemoteContent(&remote_video_description_,
+                                        cricket::CA_OFFER, nullptr)) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
+                         "Failed to apply remote parameters to media channel.");
+  }
+  if (!video_channel_->SetLocalContent(&local_video_description_,
+                                       cricket::CA_ANSWER, nullptr)) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
+                         "Failed to apply local parameters to media channel.");
+  }
+  return RTCError::OK();
+}
+
+RTCError RtpTransportControllerAdapter::ValidateAndApplyAudioReceiverParameters(
+    const RtpParameters& parameters) {
+  RTC_DCHECK(voice_channel_);
+  RTC_DCHECK(have_audio_receiver_);
+
+  auto codecs_result = ToCricketCodecs<cricket::AudioCodec>(parameters.codecs);
+  if (!codecs_result.ok()) {
+    return codecs_result.MoveError();
+  }
+
+  auto extensions_result = ToRtpHeaderExtensions(parameters.header_extensions);
+  if (!extensions_result.ok()) {
+    return extensions_result.MoveError();
+  }
+
+  cricket::RtpTransceiverDirection local_direction =
+      cricket::RtpTransceiverDirection::FromMediaContentDirection(
+          local_audio_description_.direction());
+  auto stream_params_result = ToStreamParamsVec(parameters.encodings);
+  if (!stream_params_result.ok()) {
+    return stream_params_result.MoveError();
+  }
+
+  // Check that audio/video receive aren't using the same IDs to refer to
+  // different things, if they share the same transport.
+  if (inner_audio_transport_ == inner_video_transport_) {
+    RTCError err = CheckForIdConflicts(
+        codecs_result.value(), extensions_result.value(),
+        stream_params_result.value(), local_video_description_.codecs(),
+        local_video_description_.rtp_header_extensions(),
+        remote_video_description_.streams());
+    if (!err.ok()) {
+      return err;
+    }
+  }
+
+  local_direction.recv =
+      !parameters.encodings.empty() && parameters.encodings[0].active;
+
+  // Validation is done, so we can attempt applying the descriptions. Received
+  // codecs and header extensions go in local description, streams go in
+  // remote.
+  //
+  // If there are no codecs or encodings, just leave the previous set of
+  // codecs. The media engine doesn't like an empty set of codecs.
+  if (remote_audio_description_.streams().empty() &&
+      local_audio_description_.codecs().empty()) {
+  } else {
+    local_audio_description_.set_codecs(codecs_result.MoveValue());
+  }
+  local_audio_description_.set_rtp_header_extensions(
+      extensions_result.MoveValue());
+  remote_audio_description_.mutable_streams() =
+      stream_params_result.MoveValue();
+  // Direction set based on encoding "active" flag.
+  local_audio_description_.set_direction(
+      local_direction.ToMediaContentDirection());
+  remote_audio_description_.set_direction(
+      local_direction.Reversed().ToMediaContentDirection());
+
+  if (!voice_channel_->SetLocalContent(&local_audio_description_,
+                                       cricket::CA_OFFER, nullptr)) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
+                         "Failed to apply local parameters to media channel.");
+  }
+  if (!voice_channel_->SetRemoteContent(&remote_audio_description_,
+                                        cricket::CA_ANSWER, nullptr)) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
+                         "Failed to apply remote parameters to media channel.");
+  }
+  return RTCError::OK();
+}
+
+RTCError RtpTransportControllerAdapter::ValidateAndApplyVideoReceiverParameters(
+    const RtpParameters& parameters) {
+  RTC_DCHECK(video_channel_);
+  RTC_DCHECK(have_video_receiver_);
+
+  auto codecs_result = ToCricketCodecs<cricket::VideoCodec>(parameters.codecs);
+  if (!codecs_result.ok()) {
+    return codecs_result.MoveError();
+  }
+
+  auto extensions_result = ToRtpHeaderExtensions(parameters.header_extensions);
+  if (!extensions_result.ok()) {
+    return extensions_result.MoveError();
+  }
+
+  cricket::RtpTransceiverDirection local_direction =
+      cricket::RtpTransceiverDirection::FromMediaContentDirection(
+          local_video_description_.direction());
+  int bandwidth = cricket::kAutoBandwidth;
+  auto stream_params_result = ToStreamParamsVec(parameters.encodings);
+  if (!stream_params_result.ok()) {
+    return stream_params_result.MoveError();
+  }
+
+  // Check that audio/video receiver aren't using the same IDs to refer to
+  // different things, if they share the same transport.
+  if (inner_audio_transport_ == inner_video_transport_) {
+    RTCError err = CheckForIdConflicts(
+        codecs_result.value(), extensions_result.value(),
+        stream_params_result.value(), local_audio_description_.codecs(),
+        local_audio_description_.rtp_header_extensions(),
+        remote_audio_description_.streams());
+    if (!err.ok()) {
+      return err;
+    }
+  }
+
+  local_direction.recv =
+      !parameters.encodings.empty() && parameters.encodings[0].active;
+
+  // Validation is done, so we can attempt applying the descriptions. Received
+  // codecs and header extensions go in local description, streams go in
+  // remote.
+  //
+  // If there are no codecs or encodings, just leave the previous set of
+  // codecs. The media engine doesn't like an empty set of codecs.
+  if (remote_video_description_.streams().empty() &&
+      local_video_description_.codecs().empty()) {
+  } else {
+    local_video_description_.set_codecs(codecs_result.MoveValue());
+  }
+  local_video_description_.set_rtp_header_extensions(
+      extensions_result.MoveValue());
+  local_video_description_.set_bandwidth(bandwidth);
+  remote_video_description_.mutable_streams() =
+      stream_params_result.MoveValue();
+  // Direction set based on encoding "active" flag.
+  local_video_description_.set_direction(
+      local_direction.ToMediaContentDirection());
+  remote_video_description_.set_direction(
+      local_direction.Reversed().ToMediaContentDirection());
+
+  if (!video_channel_->SetLocalContent(&local_video_description_,
+                                       cricket::CA_OFFER, nullptr)) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
+                         "Failed to apply local parameters to media channel.");
+  }
+  if (!video_channel_->SetRemoteContent(&remote_video_description_,
+                                        cricket::CA_ANSWER, nullptr)) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
+                         "Failed to apply remote parameters to media channel.");
+  }
+  return RTCError::OK();
+}
+
+RtpTransportControllerAdapter::RtpTransportControllerAdapter(
+    const cricket::MediaConfig& config,
+    cricket::ChannelManager* channel_manager,
+    webrtc::RtcEventLog* event_log,
+    rtc::Thread* signaling_thread,
+    rtc::Thread* worker_thread)
+    : signaling_thread_(signaling_thread),
+      worker_thread_(worker_thread),
+      media_controller_(MediaControllerInterface::Create(config,
+                                                         worker_thread,
+                                                         channel_manager,
+                                                         event_log)) {
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  RTC_DCHECK(channel_manager);
+  // MediaControllerInterface::Create should never fail.
+  RTC_DCHECK(media_controller_);
+  // Add "dummy" codecs to the descriptions, because the media engines
+  // currently reject empty lists of codecs. Note that these codecs will never
+  // actually be used, because when parameters are set, the dummy codecs will
+  // be replaced by actual codecs before any send/receive streams are created.
+  static const cricket::AudioCodec dummy_audio(0, cricket::kPcmuCodecName, 8000,
+                                               0, 1);
+  static const cricket::VideoCodec dummy_video(96, cricket::kVp8CodecName);
+  local_audio_description_.AddCodec(dummy_audio);
+  remote_audio_description_.AddCodec(dummy_audio);
+  local_video_description_.AddCodec(dummy_video);
+  remote_video_description_.AddCodec(dummy_video);
+}
+
+RTCError RtpTransportControllerAdapter::AttachAudioSender(
+    OrtcRtpSenderAdapter* sender,
+    RtpTransportInterface* inner_transport) {
+  if (have_audio_sender_) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::UNSUPPORTED_OPERATION,
+                         "Using two audio RtpSenders with the same "
+                         "RtpTransportControllerAdapter is not currently "
+                         "supported.");
+  }
+  if (inner_audio_transport_ && inner_audio_transport_ != inner_transport) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::UNSUPPORTED_OPERATION,
+                         "Using different transports for the audio "
+                         "RtpSender and RtpReceiver is not currently "
+                         "supported.");
+  }
+  // If setting new transport, extract its RTCP parameters and create voice
+  // channel.
+  if (!inner_audio_transport_) {
+    CopyRtcpParametersToDescriptions(inner_transport->GetRtcpParameters(),
+                                     &local_audio_description_,
+                                     &remote_audio_description_);
+    inner_audio_transport_ = inner_transport;
+    CreateVoiceChannel();
+  }
+  have_audio_sender_ = true;
+  sender->SignalDestroyed.connect(
+      this, &RtpTransportControllerAdapter::OnAudioSenderDestroyed);
+  return RTCError::OK();
+}
+
+RTCError RtpTransportControllerAdapter::AttachVideoSender(
+    OrtcRtpSenderAdapter* sender,
+    RtpTransportInterface* inner_transport) {
+  if (have_video_sender_) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::UNSUPPORTED_OPERATION,
+                         "Using two video RtpSenders with the same "
+                         "RtpTransportControllerAdapter is not currently "
+                         "supported.");
+  }
+  if (inner_video_transport_ && inner_video_transport_ != inner_transport) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::UNSUPPORTED_OPERATION,
+                         "Using different transports for the video "
+                         "RtpSender and RtpReceiver is not currently "
+                         "supported.");
+  }
+  // If setting new transport, extract its RTCP parameters and create video
+  // channel.
+  if (!inner_video_transport_) {
+    CopyRtcpParametersToDescriptions(inner_transport->GetRtcpParameters(),
+                                     &local_video_description_,
+                                     &remote_video_description_);
+    inner_video_transport_ = inner_transport;
+    CreateVideoChannel();
+  }
+  have_video_sender_ = true;
+  sender->SignalDestroyed.connect(
+      this, &RtpTransportControllerAdapter::OnVideoSenderDestroyed);
+  return RTCError::OK();
+}
+
+RTCError RtpTransportControllerAdapter::AttachAudioReceiver(
+    OrtcRtpReceiverAdapter* receiver,
+    RtpTransportInterface* inner_transport) {
+  if (have_audio_receiver_) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::UNSUPPORTED_OPERATION,
+                         "Using two audio RtpReceivers with the same "
+                         "RtpTransportControllerAdapter is not currently "
+                         "supported.");
+  }
+  if (inner_audio_transport_ && inner_audio_transport_ != inner_transport) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::UNSUPPORTED_OPERATION,
+                         "Using different transports for the audio "
+                         "RtpReceiver and RtpReceiver is not currently "
+                         "supported.");
+  }
+  // If setting new transport, extract its RTCP parameters and create voice
+  // channel.
+  if (!inner_audio_transport_) {
+    CopyRtcpParametersToDescriptions(inner_transport->GetRtcpParameters(),
+                                     &local_audio_description_,
+                                     &remote_audio_description_);
+    inner_audio_transport_ = inner_transport;
+    CreateVoiceChannel();
+  }
+  have_audio_receiver_ = true;
+  receiver->SignalDestroyed.connect(
+      this, &RtpTransportControllerAdapter::OnAudioReceiverDestroyed);
+  return RTCError::OK();
+}
+
+RTCError RtpTransportControllerAdapter::AttachVideoReceiver(
+    OrtcRtpReceiverAdapter* receiver,
+    RtpTransportInterface* inner_transport) {
+  if (have_video_receiver_) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::UNSUPPORTED_OPERATION,
+                         "Using two video RtpReceivers with the same "
+                         "RtpTransportControllerAdapter is not currently "
+                         "supported.");
+  }
+  if (inner_video_transport_ && inner_video_transport_ != inner_transport) {
+    LOG_AND_RETURN_ERROR(RTCErrorType::UNSUPPORTED_OPERATION,
+                         "Using different transports for the video "
+                         "RtpReceiver and RtpReceiver is not currently "
+                         "supported.");
+  }
+  // If setting new transport, extract its RTCP parameters and create video
+  // channel.
+  if (!inner_video_transport_) {
+    CopyRtcpParametersToDescriptions(inner_transport->GetRtcpParameters(),
+                                     &local_video_description_,
+                                     &remote_video_description_);
+    inner_video_transport_ = inner_transport;
+    CreateVideoChannel();
+  }
+  have_video_receiver_ = true;
+  receiver->SignalDestroyed.connect(
+      this, &RtpTransportControllerAdapter::OnVideoReceiverDestroyed);
+  return RTCError::OK();
+}
+
+void RtpTransportControllerAdapter::OnAudioSenderDestroyed() {
+  if (!have_audio_sender_) {
+    RTC_NOTREACHED();
+    return;
+  }
+  // Empty parameters should result in sending being stopped.
+  RTCError err =
+      ValidateAndApplyAudioSenderParameters(RtpParameters(), nullptr);
+  RTC_DCHECK(err.ok());
+  have_audio_sender_ = false;
+  if (!have_audio_receiver_) {
+    DestroyVoiceChannel();
+  }
+}
+
+void RtpTransportControllerAdapter::OnVideoSenderDestroyed() {
+  if (!have_video_sender_) {
+    RTC_NOTREACHED();
+    return;
+  }
+  // Empty parameters should result in sending being stopped.
+  RTCError err =
+      ValidateAndApplyVideoSenderParameters(RtpParameters(), nullptr);
+  RTC_DCHECK(err.ok());
+  have_video_sender_ = false;
+  if (!have_video_receiver_) {
+    DestroyVideoChannel();
+  }
+}
+
+void RtpTransportControllerAdapter::OnAudioReceiverDestroyed() {
+  if (!have_audio_receiver_) {
+    RTC_NOTREACHED();
+    return;
+  }
+  // Empty parameters should result in receiving being stopped.
+  RTCError err = ValidateAndApplyAudioReceiverParameters(RtpParameters());
+  RTC_DCHECK(err.ok());
+  have_audio_receiver_ = false;
+  if (!have_audio_sender_) {
+    DestroyVoiceChannel();
+  }
+}
+
+void RtpTransportControllerAdapter::OnVideoReceiverDestroyed() {
+  if (!have_video_receiver_) {
+    RTC_NOTREACHED();
+    return;
+  }
+  // Empty parameters should result in receiving being stopped.
+  RTCError err = ValidateAndApplyVideoReceiverParameters(RtpParameters());
+  RTC_DCHECK(err.ok());
+  have_video_receiver_ = false;
+  if (!have_video_sender_) {
+    DestroyVideoChannel();
+  }
+}
+
+void RtpTransportControllerAdapter::CreateVoiceChannel() {
+  voice_channel_ = media_controller_->channel_manager()->CreateVoiceChannel(
+      media_controller_.get(),
+      inner_audio_transport_->GetRtpPacketTransport()->GetInternal(),
+      inner_audio_transport_->GetRtcpPacketTransport()
+          ? inner_audio_transport_->GetRtcpPacketTransport()->GetInternal()
+          : nullptr,
+      signaling_thread_, "audio", false, cricket::AudioOptions());
+  RTC_DCHECK(voice_channel_);
+  voice_channel_->Enable(true);
+}
+
+void RtpTransportControllerAdapter::CreateVideoChannel() {
+  video_channel_ = media_controller_->channel_manager()->CreateVideoChannel(
+      media_controller_.get(),
+      inner_video_transport_->GetRtpPacketTransport()->GetInternal(),
+      inner_video_transport_->GetRtcpPacketTransport()
+          ? inner_video_transport_->GetRtcpPacketTransport()->GetInternal()
+          : nullptr,
+      signaling_thread_, "video", false, cricket::VideoOptions());
+  RTC_DCHECK(video_channel_);
+  video_channel_->Enable(true);
+}
+
+void RtpTransportControllerAdapter::DestroyVoiceChannel() {
+  RTC_DCHECK(voice_channel_);
+  media_controller_->channel_manager()->DestroyVoiceChannel(voice_channel_);
+  voice_channel_ = nullptr;
+  inner_audio_transport_ = nullptr;
+}
+
+void RtpTransportControllerAdapter::DestroyVideoChannel() {
+  RTC_DCHECK(video_channel_);
+  media_controller_->channel_manager()->DestroyVideoChannel(video_channel_);
+  video_channel_ = nullptr;
+  inner_video_transport_ = nullptr;
+}
+
+void RtpTransportControllerAdapter::CopyRtcpParametersToDescriptions(
+    const RtcpParameters& params,
+    cricket::MediaContentDescription* local,
+    cricket::MediaContentDescription* remote) {
+  local->set_rtcp_mux(params.mux);
+  remote->set_rtcp_mux(params.mux);
+  local->set_rtcp_reduced_size(params.reduced_size);
+  remote->set_rtcp_reduced_size(params.reduced_size);
+  for (cricket::StreamParams& stream_params : local->mutable_streams()) {
+    stream_params.cname = params.cname;
+  }
+}
+
+uint32_t RtpTransportControllerAdapter::GenerateUnusedSsrc(
+    std::set<uint32_t>* new_ssrcs) const {
+  uint32_t ssrc;
+  do {
+    ssrc = rtc::CreateRandomNonZeroId();
+  } while (
+      cricket::GetStreamBySsrc(local_audio_description_.streams(), ssrc) ||
+      cricket::GetStreamBySsrc(remote_audio_description_.streams(), ssrc) ||
+      cricket::GetStreamBySsrc(local_video_description_.streams(), ssrc) ||
+      cricket::GetStreamBySsrc(remote_video_description_.streams(), ssrc) ||
+      !new_ssrcs->insert(ssrc).second);
+  return ssrc;
+}
+
+RTCErrorOr<cricket::StreamParamsVec>
+RtpTransportControllerAdapter::MakeSendStreamParamsVec(
+    std::vector<RtpEncodingParameters> encodings,
+    const std::string& cname,
+    const cricket::MediaContentDescription& description) const {
+  if (encodings.size() > 1u) {
+    LOG_AND_RETURN_ERROR(webrtc::RTCErrorType::UNSUPPORTED_PARAMETER,
+                         "ORTC API implementation doesn't currently "
+                         "support simulcast or layered encodings.");
+  } else if (encodings.empty()) {
+    return cricket::StreamParamsVec();
+  }
+  RtpEncodingParameters& encoding = encodings[0];
+  std::set<uint32_t> new_ssrcs;
+  if (encoding.ssrc) {
+    new_ssrcs.insert(*encoding.ssrc);
+  }
+  if (encoding.rtx && encoding.rtx->ssrc) {
+    new_ssrcs.insert(*encoding.rtx->ssrc);
+  }
+  // May need to fill missing SSRCs with generated ones.
+  if (!encoding.ssrc) {
+    if (!description.streams().empty()) {
+      encoding.ssrc.emplace(description.streams()[0].first_ssrc());
+    } else {
+      encoding.ssrc.emplace(GenerateUnusedSsrc(&new_ssrcs));
+    }
+  }
+  if (encoding.rtx && !encoding.rtx->ssrc) {
+    uint32_t existing_rtx_ssrc;
+    if (!description.streams().empty() &&
+        description.streams()[0].GetFidSsrc(
+            description.streams()[0].first_ssrc(), &existing_rtx_ssrc)) {
+      encoding.rtx->ssrc.emplace(existing_rtx_ssrc);
+    } else {
+      encoding.rtx->ssrc.emplace(GenerateUnusedSsrc(&new_ssrcs));
+    }
+  }
+
+  auto result = ToStreamParamsVec(encodings);
+  if (!result.ok()) {
+    return result.MoveError();
+  }
+  // If conversion was successful, there should be one StreamParams.
+  RTC_DCHECK_EQ(1u, result.value().size());
+  result.value()[0].cname = cname;
+  return result;
+}
+
+}  // namespace webrtc