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312 lines
11 KiB
312 lines
11 KiB
// Copyright 2019 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "cast/streaming/receiver_session.h"
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#include <algorithm>
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#include <chrono>
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#include <string>
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#include <utility>
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#include "absl/strings/match.h"
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#include "absl/strings/numbers.h"
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#include "cast/common/channel/message_util.h"
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#include "cast/common/public/message_port.h"
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#include "cast/streaming/environment.h"
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#include "cast/streaming/message_fields.h"
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#include "cast/streaming/offer_messages.h"
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#include "cast/streaming/receiver.h"
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#include "cast/streaming/sender_message.h"
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#include "util/json/json_helpers.h"
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#include "util/osp_logging.h"
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namespace openscreen {
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namespace cast {
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// Using statements for constructor readability.
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using Preferences = ReceiverSession::Preferences;
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using ConfiguredReceivers = ReceiverSession::ConfiguredReceivers;
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namespace {
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template <typename Stream, typename Codec>
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std::unique_ptr<Stream> SelectStream(
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const std::vector<Codec>& preferred_codecs,
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const std::vector<Stream>& offered_streams) {
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for (auto codec : preferred_codecs) {
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for (const Stream& offered_stream : offered_streams) {
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if (offered_stream.codec == codec) {
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OSP_DVLOG << "Selected " << CodecToString(codec)
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<< " as codec for streaming";
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return std::make_unique<Stream>(offered_stream);
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}
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}
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}
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return nullptr;
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}
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DisplayResolution ToDisplayResolution(const Resolution& resolution) {
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return DisplayResolution{resolution.width, resolution.height};
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}
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} // namespace
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ReceiverSession::Client::~Client() = default;
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Preferences::Preferences() = default;
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Preferences::Preferences(std::vector<VideoCodec> video_codecs,
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std::vector<AudioCodec> audio_codecs)
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: Preferences(video_codecs, audio_codecs, nullptr, nullptr) {}
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Preferences::Preferences(std::vector<VideoCodec> video_codecs,
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std::vector<AudioCodec> audio_codecs,
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std::unique_ptr<Constraints> constraints,
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std::unique_ptr<DisplayDescription> description)
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: video_codecs(std::move(video_codecs)),
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audio_codecs(std::move(audio_codecs)),
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constraints(std::move(constraints)),
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display_description(std::move(description)) {}
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Preferences::Preferences(Preferences&&) noexcept = default;
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Preferences& Preferences::operator=(Preferences&&) noexcept = default;
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ReceiverSession::ReceiverSession(Client* const client,
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Environment* environment,
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MessagePort* message_port,
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Preferences preferences)
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: client_(client),
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environment_(environment),
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preferences_(std::move(preferences)),
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session_id_(MakeUniqueSessionId("streaming_receiver")),
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messager_(message_port,
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session_id_,
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[this](Error error) {
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OSP_DLOG_WARN << "Got a session messager error: " << error;
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client_->OnError(this, error);
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}),
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packet_router_(environment_) {
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OSP_DCHECK(client_);
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OSP_DCHECK(environment_);
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messager_.SetHandler(
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SenderMessage::Type::kOffer,
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[this](SenderMessage message) { OnOffer(std::move(message)); });
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environment_->SetSocketSubscriber(this);
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}
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ReceiverSession::~ReceiverSession() {
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ResetReceivers(Client::kEndOfSession);
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}
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void ReceiverSession::OnSocketReady() {
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if (pending_session_) {
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InitializeSession(*pending_session_);
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pending_session_.reset();
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}
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}
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void ReceiverSession::OnSocketInvalid(Error error) {
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if (pending_session_) {
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SendErrorAnswerReply(pending_session_->sequence_number,
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"Failed to bind UDP socket");
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pending_session_.reset();
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}
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client_->OnError(this,
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Error(Error::Code::kSocketFailure,
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"The environment is invalid and should be replaced."));
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}
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bool ReceiverSession::SessionProperties::IsValid() const {
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return (selected_audio || selected_video) && sequence_number >= 0;
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}
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void ReceiverSession::OnOffer(SenderMessage message) {
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// We just drop offers we can't respond to. Note that libcast senders will
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// always send a strictly positive sequence numbers, but zero is permitted
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// by the spec.
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if (message.sequence_number < 0) {
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OSP_DLOG_WARN
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<< "Dropping offer with missing sequence number, can't respond";
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return;
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}
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if (!message.valid) {
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SendErrorAnswerReply(message.sequence_number,
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"Failed to parse malformed OFFER");
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client_->OnError(this, Error(Error::Code::kParameterInvalid,
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"Received invalid OFFER message"));
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return;
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}
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auto properties = std::make_unique<SessionProperties>();
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properties->sequence_number = message.sequence_number;
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const Offer& offer = absl::get<Offer>(message.body);
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if (!offer.audio_streams.empty() && !preferences_.audio_codecs.empty()) {
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properties->selected_audio =
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SelectStream(preferences_.audio_codecs, offer.audio_streams);
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}
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if (!offer.video_streams.empty() && !preferences_.video_codecs.empty()) {
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properties->selected_video =
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SelectStream(preferences_.video_codecs, offer.video_streams);
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}
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if (!properties->IsValid()) {
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SendErrorAnswerReply(message.sequence_number,
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"Failed to select any streams from OFFER");
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return;
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}
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switch (environment_->socket_state()) {
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// If the environment is ready or in a bad state, we can respond
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// immediately.
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case Environment::SocketState::kInvalid:
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SendErrorAnswerReply(message.sequence_number,
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"UDP socket is closed, likely due to a bind error.");
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break;
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case Environment::SocketState::kReady:
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InitializeSession(*properties);
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break;
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// Else we need to store the properties we just created until we get a
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// ready or error event.
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case Environment::SocketState::kStarting:
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pending_session_ = std::move(properties);
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break;
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}
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}
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void ReceiverSession::InitializeSession(const SessionProperties& properties) {
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Answer answer = ConstructAnswer(properties);
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if (!answer.IsValid()) {
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// If the answer message is invalid, there is no point in setting up a
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// negotiation because the sender won't be able to connect to it.
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SendErrorAnswerReply(properties.sequence_number,
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"Failed to construct an ANSWER message");
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return;
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}
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// Only spawn receivers if we know we have a valid answer message.
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ConfiguredReceivers receivers = SpawnReceivers(properties);
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client_->OnMirroringNegotiated(this, std::move(receivers));
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const Error result = messager_.SendMessage(ReceiverMessage{
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ReceiverMessage::Type::kAnswer, properties.sequence_number,
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true /* valid */, std::move(answer)});
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if (!result.ok()) {
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client_->OnError(this, std::move(result));
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}
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}
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std::unique_ptr<Receiver> ReceiverSession::ConstructReceiver(
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const Stream& stream) {
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// Session config is currently only for mirroring.
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SessionConfig config = {stream.ssrc, stream.ssrc + 1,
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stream.rtp_timebase, stream.channels,
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stream.target_delay, stream.aes_key,
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stream.aes_iv_mask, /* is_pli_enabled */ true};
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return std::make_unique<Receiver>(environment_, &packet_router_,
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std::move(config));
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}
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ConfiguredReceivers ReceiverSession::SpawnReceivers(
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const SessionProperties& properties) {
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OSP_DCHECK(properties.IsValid());
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ResetReceivers(Client::kRenegotiated);
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AudioCaptureConfig audio_config;
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if (properties.selected_audio) {
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current_audio_receiver_ =
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ConstructReceiver(properties.selected_audio->stream);
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audio_config =
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AudioCaptureConfig{properties.selected_audio->codec,
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properties.selected_audio->stream.channels,
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properties.selected_audio->bit_rate,
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properties.selected_audio->stream.rtp_timebase,
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properties.selected_audio->stream.target_delay};
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}
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VideoCaptureConfig video_config;
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if (properties.selected_video) {
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current_video_receiver_ =
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ConstructReceiver(properties.selected_video->stream);
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std::vector<DisplayResolution> display_resolutions;
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std::transform(properties.selected_video->resolutions.begin(),
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properties.selected_video->resolutions.end(),
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std::back_inserter(display_resolutions),
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ToDisplayResolution);
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video_config = VideoCaptureConfig{
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properties.selected_video->codec,
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FrameRate{properties.selected_video->max_frame_rate.numerator,
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properties.selected_video->max_frame_rate.denominator},
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properties.selected_video->max_bit_rate, std::move(display_resolutions),
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properties.selected_video->stream.target_delay};
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}
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return ConfiguredReceivers{
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current_audio_receiver_.get(), std::move(audio_config),
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current_video_receiver_.get(), std::move(video_config)};
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}
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void ReceiverSession::ResetReceivers(Client::ReceiversDestroyingReason reason) {
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if (current_video_receiver_ || current_audio_receiver_) {
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client_->OnReceiversDestroying(this, reason);
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current_audio_receiver_.reset();
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current_video_receiver_.reset();
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}
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}
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Answer ReceiverSession::ConstructAnswer(const SessionProperties& properties) {
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OSP_DCHECK(properties.IsValid());
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std::vector<int> stream_indexes;
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std::vector<Ssrc> stream_ssrcs;
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if (properties.selected_audio) {
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stream_indexes.push_back(properties.selected_audio->stream.index);
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stream_ssrcs.push_back(properties.selected_audio->stream.ssrc + 1);
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}
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if (properties.selected_video) {
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stream_indexes.push_back(properties.selected_video->stream.index);
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stream_ssrcs.push_back(properties.selected_video->stream.ssrc + 1);
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}
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absl::optional<Constraints> constraints;
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if (preferences_.constraints) {
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constraints = absl::optional<Constraints>(*preferences_.constraints);
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}
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absl::optional<DisplayDescription> display;
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if (preferences_.display_description) {
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display =
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absl::optional<DisplayDescription>(*preferences_.display_description);
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}
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return Answer{environment_->GetBoundLocalEndpoint().port,
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std::move(stream_indexes),
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std::move(stream_ssrcs),
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std::move(constraints),
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std::move(display),
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std::vector<int>{}, // receiver_rtcp_event_log
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std::vector<int>{}, // receiver_rtcp_dscp
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supports_wifi_status_reporting_};
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}
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void ReceiverSession::SendErrorAnswerReply(int sequence_number,
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const char* message) {
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const Error error(Error::Code::kParseError, message);
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OSP_DLOG_WARN << message;
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const Error result = messager_.SendMessage(ReceiverMessage{
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ReceiverMessage::Type::kAnswer, sequence_number, false /* valid */,
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ReceiverError{static_cast<int>(Error::Code::kParseError), message}});
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if (!result.ok()) {
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client_->OnError(this, std::move(result));
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}
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}
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} // namespace cast
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} // namespace openscreen
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