modules/rtp_rtcp/source/rtp_receiver_impl.cc - src/webrtc - Git at Google

 /*
  *  Copyright (c) 2012 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/modules/rtp_rtcp/source/rtp_receiver_impl.h"

 #include <assert.h>
 #include <math.h>
 #include <stdlib.h>
 #include <string.h>

 #include <set>
 #include <vector>

 #include "webrtc/common_types.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_payload_registry.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
 #include "webrtc/modules/rtp_rtcp/source/rtp_receiver_strategy.h"
 #include "webrtc/rtc_base/logging.h"

 namespace webrtc {

 using RtpUtility::Payload;

 // Only return the sources in the last 10 seconds.
 const int64_t kGetSourcesTimeoutMs = 10000;

 RtpReceiver* RtpReceiver::CreateVideoReceiver(
     Clock* clock,
     RtpData* incoming_payload_callback,
     RtpFeedback* incoming_messages_callback,
     RTPPayloadRegistry* rtp_payload_registry) {
   RTC_DCHECK(incoming_payload_callback != nullptr);
   if (!incoming_messages_callback)
     incoming_messages_callback = NullObjectRtpFeedback();
   return new RtpReceiverImpl(
       clock, incoming_messages_callback, rtp_payload_registry,
       RTPReceiverStrategy::CreateVideoStrategy(incoming_payload_callback));
 }

 RtpReceiver* RtpReceiver::CreateAudioReceiver(
     Clock* clock,
     RtpData* incoming_payload_callback,
     RtpFeedback* incoming_messages_callback,
     RTPPayloadRegistry* rtp_payload_registry) {
   RTC_DCHECK(incoming_payload_callback != nullptr);
   if (!incoming_messages_callback)
     incoming_messages_callback = NullObjectRtpFeedback();
   return new RtpReceiverImpl(
       clock, incoming_messages_callback, rtp_payload_registry,
       RTPReceiverStrategy::CreateAudioStrategy(incoming_payload_callback));
 }

 RtpReceiverImpl::RtpReceiverImpl(Clock* clock,
                                  RtpFeedback* incoming_messages_callback,
                                  RTPPayloadRegistry* rtp_payload_registry,
                                  RTPReceiverStrategy* rtp_media_receiver)
     : clock_(clock),
       rtp_payload_registry_(rtp_payload_registry),
       rtp_media_receiver_(rtp_media_receiver),
       cb_rtp_feedback_(incoming_messages_callback),
       last_receive_time_(0),
       last_received_payload_length_(0),
       ssrc_(0),
       num_csrcs_(0),
       current_remote_csrc_(),
       last_received_timestamp_(0),
       last_received_frame_time_ms_(-1),
       last_received_sequence_number_(0) {
   assert(incoming_messages_callback);

   memset(current_remote_csrc_, 0, sizeof(current_remote_csrc_));
 }

 RtpReceiverImpl::~RtpReceiverImpl() {
   for (int i = 0; i < num_csrcs_; ++i) {
     cb_rtp_feedback_->OnIncomingCSRCChanged(current_remote_csrc_[i], false);
   }
 }

 int32_t RtpReceiverImpl::RegisterReceivePayload(const CodecInst& audio_codec) {
   rtc::CritScope lock(&critical_section_rtp_receiver_);

   // TODO(phoglund): Try to streamline handling of the RED codec and some other
   // cases which makes it necessary to keep track of whether we created a
   // payload or not.
   bool created_new_payload = false;
   int32_t result = rtp_payload_registry_->RegisterReceivePayload(
       audio_codec, &created_new_payload);
   if (created_new_payload) {
     if (rtp_media_receiver_->OnNewPayloadTypeCreated(audio_codec) != 0) {
       LOG(LS_ERROR) << "Failed to register payload: " << audio_codec.plname
                     << "/" << static_cast<int>(audio_codec.pltype);
       return -1;
     }
   }
   return result;
 }

 int32_t RtpReceiverImpl::RegisterReceivePayload(const VideoCodec& video_codec) {
   rtc::CritScope lock(&critical_section_rtp_receiver_);
   return rtp_payload_registry_->RegisterReceivePayload(video_codec);
 }

 int32_t RtpReceiverImpl::DeRegisterReceivePayload(
     const int8_t payload_type) {
   rtc::CritScope lock(&critical_section_rtp_receiver_);
   return rtp_payload_registry_->DeRegisterReceivePayload(payload_type);
 }

 uint32_t RtpReceiverImpl::SSRC() const {
   rtc::CritScope lock(&critical_section_rtp_receiver_);
   return ssrc_;
 }

 // Get remote CSRC.
 int32_t RtpReceiverImpl::CSRCs(uint32_t array_of_csrcs[kRtpCsrcSize]) const {
   rtc::CritScope lock(&critical_section_rtp_receiver_);

   assert(num_csrcs_ <= kRtpCsrcSize);

   if (num_csrcs_ > 0) {
     memcpy(array_of_csrcs, current_remote_csrc_, sizeof(uint32_t)*num_csrcs_);
   }
   return num_csrcs_;
 }

 int32_t RtpReceiverImpl::Energy(
     uint8_t array_of_energy[kRtpCsrcSize]) const {
   return rtp_media_receiver_->Energy(array_of_energy);
 }

 bool RtpReceiverImpl::IncomingRtpPacket(
   const RTPHeader& rtp_header,
   const uint8_t* payload,
   size_t payload_length,
   PayloadUnion payload_specific,
   bool in_order) {
   // Trigger our callbacks.
   CheckSSRCChanged(rtp_header);

   int8_t first_payload_byte = payload_length > 0 ? payload[0] : 0;
   bool is_red = false;

   if (CheckPayloadChanged(rtp_header, first_payload_byte, &is_red,
                           &payload_specific) == -1) {
     if (payload_length == 0) {
       // OK, keep-alive packet.
       return true;
     }
     LOG(LS_WARNING) << "Receiving invalid payload type.";
     return false;
   }

   WebRtcRTPHeader webrtc_rtp_header;
   memset(&webrtc_rtp_header, 0, sizeof(webrtc_rtp_header));
   webrtc_rtp_header.header = rtp_header;
   CheckCSRC(webrtc_rtp_header);

   auto audio_level =
       rtp_header.extension.hasAudioLevel
           ? rtc::Optional<uint8_t>(rtp_header.extension.audioLevel)
           : rtc::Optional<uint8_t>();
   UpdateSources(audio_level);

   size_t payload_data_length = payload_length - rtp_header.paddingLength;

   bool is_first_packet_in_frame = false;
   {
     rtc::CritScope lock(&critical_section_rtp_receiver_);
     if (HaveReceivedFrame()) {
       is_first_packet_in_frame =
           last_received_sequence_number_ + 1 == rtp_header.sequenceNumber &&
           last_received_timestamp_ != rtp_header.timestamp;
     } else {
       is_first_packet_in_frame = true;
     }
   }

   int32_t ret_val = rtp_media_receiver_->ParseRtpPacket(
       &webrtc_rtp_header, payload_specific, is_red, payload, payload_length,
       clock_->TimeInMilliseconds(), is_first_packet_in_frame);

   if (ret_val < 0) {
     return false;
   }

   {
     rtc::CritScope lock(&critical_section_rtp_receiver_);

     last_receive_time_ = clock_->TimeInMilliseconds();
     last_received_payload_length_ = payload_data_length;

     if (in_order) {
       if (last_received_timestamp_ != rtp_header.timestamp) {
         last_received_timestamp_ = rtp_header.timestamp;
         last_received_frame_time_ms_ = clock_->TimeInMilliseconds();
       }
       last_received_sequence_number_ = rtp_header.sequenceNumber;
     }
   }
   return true;
 }

 TelephoneEventHandler* RtpReceiverImpl::GetTelephoneEventHandler() {
   return rtp_media_receiver_->GetTelephoneEventHandler();
 }

 std::vector<RtpSource> RtpReceiverImpl::GetSources() const {
   rtc::CritScope lock(&critical_section_rtp_receiver_);

   int64_t now_ms = clock_->TimeInMilliseconds();
   std::vector<RtpSource> sources;

   RTC_DCHECK(std::is_sorted(ssrc_sources_.begin(), ssrc_sources_.end(),
                             [](const RtpSource& lhs, const RtpSource& rhs) {
                               return lhs.timestamp_ms() < rhs.timestamp_ms();
                             }));
   RTC_DCHECK(std::is_sorted(csrc_sources_.begin(), csrc_sources_.end(),
                             [](const RtpSource& lhs, const RtpSource& rhs) {
                               return lhs.timestamp_ms() < rhs.timestamp_ms();
                             }));

   std::set<uint32_t> selected_ssrcs;
   for (auto rit = ssrc_sources_.rbegin(); rit != ssrc_sources_.rend(); ++rit) {
     if ((now_ms - rit->timestamp_ms()) > kGetSourcesTimeoutMs) {
       break;
     }
     if (selected_ssrcs.insert(rit->source_id()).second) {
       sources.push_back(*rit);
     }
   }

   for (auto rit = csrc_sources_.rbegin(); rit != csrc_sources_.rend(); ++rit) {
     if ((now_ms - rit->timestamp_ms()) > kGetSourcesTimeoutMs) {
       break;
     }
     sources.push_back(*rit);
   }
   return sources;
 }

 bool RtpReceiverImpl::Timestamp(uint32_t* timestamp) const {
   rtc::CritScope lock(&critical_section_rtp_receiver_);
   if (!HaveReceivedFrame())
     return false;
   *timestamp = last_received_timestamp_;
   return true;
 }

 bool RtpReceiverImpl::LastReceivedTimeMs(int64_t* receive_time_ms) const {
   rtc::CritScope lock(&critical_section_rtp_receiver_);
   if (!HaveReceivedFrame())
     return false;
   *receive_time_ms = last_received_frame_time_ms_;
   return true;
 }

 bool RtpReceiverImpl::HaveReceivedFrame() const {
   return last_received_frame_time_ms_ >= 0;
 }

 // Implementation note: must not hold critsect when called.
 void RtpReceiverImpl::CheckSSRCChanged(const RTPHeader& rtp_header) {
   bool new_ssrc = false;
   bool re_initialize_decoder = false;
   char payload_name[RTP_PAYLOAD_NAME_SIZE];
   size_t channels = 1;
   uint32_t rate = 0;

   {
     rtc::CritScope lock(&critical_section_rtp_receiver_);

     int8_t last_received_payload_type =
         rtp_payload_registry_->last_received_payload_type();
     if (ssrc_ != rtp_header.ssrc ||
         (last_received_payload_type == -1 && ssrc_ == 0)) {
       // We need the payload_type_ to make the call if the remote SSRC is 0.
       new_ssrc = true;

       last_received_timestamp_ = 0;
       last_received_sequence_number_ = 0;
       last_received_frame_time_ms_ = -1;

       // Do we have a SSRC? Then the stream is restarted.
       if (ssrc_ != 0) {
         // Do we have the same codec? Then re-initialize coder.
         if (rtp_header.payloadType == last_received_payload_type) {
           re_initialize_decoder = true;

           const Payload* payload = rtp_payload_registry_->PayloadTypeToPayload(
               rtp_header.payloadType);
           if (!payload) {
             return;
           }
           payload_name[RTP_PAYLOAD_NAME_SIZE - 1] = 0;
           strncpy(payload_name, payload->name, RTP_PAYLOAD_NAME_SIZE - 1);
           if (payload->audio) {
             channels = payload->typeSpecific.Audio.channels;
             rate = payload->typeSpecific.Audio.rate;
           }
         }
       }
       ssrc_ = rtp_header.ssrc;
     }
   }

   if (new_ssrc) {
     // We need to get this to our RTCP sender and receiver.
     // We need to do this outside critical section.
     cb_rtp_feedback_->OnIncomingSSRCChanged(rtp_header.ssrc);
   }

   if (re_initialize_decoder) {
     if (-1 ==
         cb_rtp_feedback_->OnInitializeDecoder(
             rtp_header.payloadType, payload_name,
             rtp_header.payload_type_frequency, channels, rate)) {
       // New stream, same codec.
       LOG(LS_ERROR) << "Failed to create decoder for payload type: "
                     << static_cast<int>(rtp_header.payloadType);
     }
   }
 }

 // Implementation note: must not hold critsect when called.
 // TODO(phoglund): Move as much as possible of this code path into the media
 // specific receivers. Basically this method goes through a lot of trouble to
 // compute something which is only used by the media specific parts later. If
 // this code path moves we can get rid of some of the rtp_receiver ->
 // media_specific interface (such as CheckPayloadChange, possibly get/set
 // last known payload).
 int32_t RtpReceiverImpl::CheckPayloadChanged(const RTPHeader& rtp_header,
                                              const int8_t first_payload_byte,
                                              bool* is_red,
                                              PayloadUnion* specific_payload) {
   bool re_initialize_decoder = false;

   char payload_name[RTP_PAYLOAD_NAME_SIZE];
   int8_t payload_type = rtp_header.payloadType;

   {
     rtc::CritScope lock(&critical_section_rtp_receiver_);

     int8_t last_received_payload_type =
         rtp_payload_registry_->last_received_payload_type();
     // TODO(holmer): Remove this code when RED parsing has been broken out from
     // RtpReceiverAudio.
     if (payload_type != last_received_payload_type) {
       if (rtp_payload_registry_->red_payload_type() == payload_type) {
         // Get the real codec payload type.
         payload_type = first_payload_byte & 0x7f;
         *is_red = true;

         if (rtp_payload_registry_->red_payload_type() == payload_type) {
           // Invalid payload type, traced by caller. If we proceeded here,
           // this would be set as |_last_received_payload_type|, and we would no
           // longer catch corrupt packets at this level.
           return -1;
         }

         // When we receive RED we need to check the real payload type.
         if (payload_type == last_received_payload_type) {
           rtp_media_receiver_->GetLastMediaSpecificPayload(specific_payload);
           return 0;
         }
       }
       bool should_discard_changes = false;

       rtp_media_receiver_->CheckPayloadChanged(
         payload_type, specific_payload,
         &should_discard_changes);

       if (should_discard_changes) {
         *is_red = false;
         return 0;
       }

       const Payload* payload =
           rtp_payload_registry_->PayloadTypeToPayload(payload_type);
       if (!payload) {
         // Not a registered payload type.
         return -1;
       }
       payload_name[RTP_PAYLOAD_NAME_SIZE - 1] = 0;
       strncpy(payload_name, payload->name, RTP_PAYLOAD_NAME_SIZE - 1);

       rtp_payload_registry_->set_last_received_payload_type(payload_type);

       re_initialize_decoder = true;

       rtp_media_receiver_->SetLastMediaSpecificPayload(payload->typeSpecific);
       rtp_media_receiver_->GetLastMediaSpecificPayload(specific_payload);

       if (!payload->audio) {
         bool media_type_unchanged =
             rtp_payload_registry_->ReportMediaPayloadType(payload_type);
         if (media_type_unchanged) {
           // Only reset the decoder if the media codec type has changed.
           re_initialize_decoder = false;
         }
       }
     } else {
       rtp_media_receiver_->GetLastMediaSpecificPayload(specific_payload);
       *is_red = false;
     }
   }  // End critsect.

   if (re_initialize_decoder) {
     if (-1 ==
         rtp_media_receiver_->InvokeOnInitializeDecoder(
             cb_rtp_feedback_, payload_type, payload_name, *specific_payload)) {
       return -1;  // Wrong payload type.
     }
   }
   return 0;
 }

 // Implementation note: must not hold critsect when called.
 void RtpReceiverImpl::CheckCSRC(const WebRtcRTPHeader& rtp_header) {
   int32_t num_csrcs_diff = 0;
   uint32_t old_remote_csrc[kRtpCsrcSize];
   uint8_t old_num_csrcs = 0;

   {
     rtc::CritScope lock(&critical_section_rtp_receiver_);

     if (!rtp_media_receiver_->ShouldReportCsrcChanges(
         rtp_header.header.payloadType)) {
       return;
     }
     old_num_csrcs  = num_csrcs_;
     if (old_num_csrcs > 0) {
       // Make a copy of old.
       memcpy(old_remote_csrc, current_remote_csrc_,
              num_csrcs_ * sizeof(uint32_t));
     }
     const uint8_t num_csrcs = rtp_header.header.numCSRCs;
     if ((num_csrcs > 0) && (num_csrcs <= kRtpCsrcSize)) {
       // Copy new.
       memcpy(current_remote_csrc_,
              rtp_header.header.arrOfCSRCs,
              num_csrcs * sizeof(uint32_t));
     }
     if (num_csrcs > 0 || old_num_csrcs > 0) {
       num_csrcs_diff = num_csrcs - old_num_csrcs;
       num_csrcs_ = num_csrcs;  // Update stored CSRCs.
     } else {
       // No change.
       return;
     }
   }  // End critsect.

   bool have_called_callback = false;
   // Search for new CSRC in old array.
   for (uint8_t i = 0; i < rtp_header.header.numCSRCs; ++i) {
     const uint32_t csrc = rtp_header.header.arrOfCSRCs[i];

     bool found_match = false;
     for (uint8_t j = 0; j < old_num_csrcs; ++j) {
       if (csrc == old_remote_csrc[j]) {  // old list
         found_match = true;
         break;
       }
     }
     if (!found_match && csrc) {
       // Didn't find it, report it as new.
       have_called_callback = true;
       cb_rtp_feedback_->OnIncomingCSRCChanged(csrc, true);
     }
   }
   // Search for old CSRC in new array.
   for (uint8_t i = 0; i < old_num_csrcs; ++i) {
     const uint32_t csrc = old_remote_csrc[i];

     bool found_match = false;
     for (uint8_t j = 0; j < rtp_header.header.numCSRCs; ++j) {
       if (csrc == rtp_header.header.arrOfCSRCs[j]) {
         found_match = true;
         break;
       }
     }
     if (!found_match && csrc) {
       // Did not find it, report as removed.
       have_called_callback = true;
       cb_rtp_feedback_->OnIncomingCSRCChanged(csrc, false);
     }
   }
   if (!have_called_callback) {
     // If the CSRC list contain non-unique entries we will end up here.
     // Using CSRC 0 to signal this event, not interop safe, other
     // implementations might have CSRC 0 as a valid value.
     if (num_csrcs_diff > 0) {
       cb_rtp_feedback_->OnIncomingCSRCChanged(0, true);
     } else if (num_csrcs_diff < 0) {
       cb_rtp_feedback_->OnIncomingCSRCChanged(0, false);
     }
   }
 }

 void RtpReceiverImpl::UpdateSources(
     const rtc::Optional<uint8_t>& ssrc_audio_level) {
   rtc::CritScope lock(&critical_section_rtp_receiver_);
   int64_t now_ms = clock_->TimeInMilliseconds();

   for (size_t i = 0; i < num_csrcs_; ++i) {
     auto map_it = iterator_by_csrc_.find(current_remote_csrc_[i]);
     if (map_it == iterator_by_csrc_.end()) {
       // If it is a new CSRC, append a new object to the end of the list.
       csrc_sources_.emplace_back(now_ms, current_remote_csrc_[i],
                                  RtpSourceType::CSRC);
     } else {
       // If it is an existing CSRC, move the object to the end of the list.
       map_it->second->update_timestamp_ms(now_ms);
       csrc_sources_.splice(csrc_sources_.end(), csrc_sources_, map_it->second);
     }
     // Update the unordered_map.
     iterator_by_csrc_[current_remote_csrc_[i]] = std::prev(csrc_sources_.end());
   }

   // If this is the first packet or the SSRC is changed, insert a new
   // contributing source that uses the SSRC.
   if (ssrc_sources_.empty() || ssrc_sources_.rbegin()->source_id() != ssrc_) {
     ssrc_sources_.emplace_back(now_ms, ssrc_, RtpSourceType::SSRC);
   } else {
     ssrc_sources_.rbegin()->update_timestamp_ms(now_ms);
   }

   ssrc_sources_.back().set_audio_level(ssrc_audio_level);

   RemoveOutdatedSources(now_ms);
 }

 void RtpReceiverImpl::RemoveOutdatedSources(int64_t now_ms) {
   std::list<RtpSource>::iterator it;
   for (it = csrc_sources_.begin(); it != csrc_sources_.end(); ++it) {
     if ((now_ms - it->timestamp_ms()) <= kGetSourcesTimeoutMs) {
       break;
     }
     iterator_by_csrc_.erase(it->source_id());
   }
   csrc_sources_.erase(csrc_sources_.begin(), it);

   std::vector<RtpSource>::iterator vec_it;
   for (vec_it = ssrc_sources_.begin(); vec_it != ssrc_sources_.end();
        ++vec_it) {
     if ((now_ms - vec_it->timestamp_ms()) <= kGetSourcesTimeoutMs) {
       break;
     }
   }
   ssrc_sources_.erase(ssrc_sources_.begin(), vec_it);
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 2012 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/modules/rtp_rtcp/source/rtp_receiver_impl.h"

	#include <assert.h>
	#include <math.h>
	#include <stdlib.h>
	#include <string.h>

	#include <set>
	#include <vector>

	#include "webrtc/common_types.h"
	#include "webrtc/modules/rtp_rtcp/include/rtp_payload_registry.h"
	#include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
	#include "webrtc/modules/rtp_rtcp/source/rtp_receiver_strategy.h"
	#include "webrtc/rtc_base/logging.h"

	namespace webrtc {

	using RtpUtility::Payload;

	// Only return the sources in the last 10 seconds.
	const int64_t kGetSourcesTimeoutMs = 10000;

	RtpReceiver* RtpReceiver::CreateVideoReceiver(
	Clock* clock,
	RtpData* incoming_payload_callback,
	RtpFeedback* incoming_messages_callback,
	RTPPayloadRegistry* rtp_payload_registry) {
	RTC_DCHECK(incoming_payload_callback != nullptr);
	if (!incoming_messages_callback)
	incoming_messages_callback = NullObjectRtpFeedback();
	return new RtpReceiverImpl(
	clock, incoming_messages_callback, rtp_payload_registry,
	RTPReceiverStrategy::CreateVideoStrategy(incoming_payload_callback));
	}

	RtpReceiver* RtpReceiver::CreateAudioReceiver(
	Clock* clock,
	RtpData* incoming_payload_callback,
	RtpFeedback* incoming_messages_callback,
	RTPPayloadRegistry* rtp_payload_registry) {
	RTC_DCHECK(incoming_payload_callback != nullptr);
	if (!incoming_messages_callback)
	incoming_messages_callback = NullObjectRtpFeedback();
	return new RtpReceiverImpl(
	clock, incoming_messages_callback, rtp_payload_registry,
	RTPReceiverStrategy::CreateAudioStrategy(incoming_payload_callback));
	}

	RtpReceiverImpl::RtpReceiverImpl(Clock* clock,
	RtpFeedback* incoming_messages_callback,
	RTPPayloadRegistry* rtp_payload_registry,
	RTPReceiverStrategy* rtp_media_receiver)
	: clock_(clock),
	rtp_payload_registry_(rtp_payload_registry),
	rtp_media_receiver_(rtp_media_receiver),
	cb_rtp_feedback_(incoming_messages_callback),
	last_receive_time_(0),
	last_received_payload_length_(0),
	ssrc_(0),
	num_csrcs_(0),
	current_remote_csrc_(),
	last_received_timestamp_(0),
	last_received_frame_time_ms_(-1),
	last_received_sequence_number_(0) {
	assert(incoming_messages_callback);

	memset(current_remote_csrc_, 0, sizeof(current_remote_csrc_));
	}

	RtpReceiverImpl::~RtpReceiverImpl() {
	for (int i = 0; i < num_csrcs_; ++i) {
	cb_rtp_feedback_->OnIncomingCSRCChanged(current_remote_csrc_[i], false);
	}
	}

	int32_t RtpReceiverImpl::RegisterReceivePayload(const CodecInst& audio_codec) {
	rtc::CritScope lock(&critical_section_rtp_receiver_);

	// TODO(phoglund): Try to streamline handling of the RED codec and some other
	// cases which makes it necessary to keep track of whether we created a
	// payload or not.
	bool created_new_payload = false;
	int32_t result = rtp_payload_registry_->RegisterReceivePayload(
	audio_codec, &created_new_payload);
	if (created_new_payload) {
	if (rtp_media_receiver_->OnNewPayloadTypeCreated(audio_codec) != 0) {
	LOG(LS_ERROR) << "Failed to register payload: " << audio_codec.plname
	<< "/" << static_cast<int>(audio_codec.pltype);
	return -1;
	}
	}
	return result;
	}

	int32_t RtpReceiverImpl::RegisterReceivePayload(const VideoCodec& video_codec) {
	rtc::CritScope lock(&critical_section_rtp_receiver_);
	return rtp_payload_registry_->RegisterReceivePayload(video_codec);
	}

	int32_t RtpReceiverImpl::DeRegisterReceivePayload(
	const int8_t payload_type) {
	rtc::CritScope lock(&critical_section_rtp_receiver_);
	return rtp_payload_registry_->DeRegisterReceivePayload(payload_type);
	}

	uint32_t RtpReceiverImpl::SSRC() const {
	rtc::CritScope lock(&critical_section_rtp_receiver_);
	return ssrc_;
	}

	// Get remote CSRC.
	int32_t RtpReceiverImpl::CSRCs(uint32_t array_of_csrcs[kRtpCsrcSize]) const {
	rtc::CritScope lock(&critical_section_rtp_receiver_);

	assert(num_csrcs_ <= kRtpCsrcSize);

	if (num_csrcs_ > 0) {
	memcpy(array_of_csrcs, current_remote_csrc_, sizeof(uint32_t)*num_csrcs_);
	}
	return num_csrcs_;
	}

	int32_t RtpReceiverImpl::Energy(
	uint8_t array_of_energy[kRtpCsrcSize]) const {
	return rtp_media_receiver_->Energy(array_of_energy);
	}

	bool RtpReceiverImpl::IncomingRtpPacket(
	const RTPHeader& rtp_header,
	const uint8_t* payload,
	size_t payload_length,
	PayloadUnion payload_specific,
	bool in_order) {
	// Trigger our callbacks.
	CheckSSRCChanged(rtp_header);

	int8_t first_payload_byte = payload_length > 0 ? payload[0] : 0;
	bool is_red = false;

	if (CheckPayloadChanged(rtp_header, first_payload_byte, &is_red,
	&payload_specific) == -1) {
	if (payload_length == 0) {
	// OK, keep-alive packet.
	return true;
	}
	LOG(LS_WARNING) << "Receiving invalid payload type.";
	return false;
	}

	WebRtcRTPHeader webrtc_rtp_header;
	memset(&webrtc_rtp_header, 0, sizeof(webrtc_rtp_header));
	webrtc_rtp_header.header = rtp_header;
	CheckCSRC(webrtc_rtp_header);

	auto audio_level =
	rtp_header.extension.hasAudioLevel
	? rtc::Optional<uint8_t>(rtp_header.extension.audioLevel)
	: rtc::Optional<uint8_t>();
	UpdateSources(audio_level);

	size_t payload_data_length = payload_length - rtp_header.paddingLength;

	bool is_first_packet_in_frame = false;
	{
	rtc::CritScope lock(&critical_section_rtp_receiver_);
	if (HaveReceivedFrame()) {
	is_first_packet_in_frame =
	last_received_sequence_number_ + 1 == rtp_header.sequenceNumber &&
	last_received_timestamp_ != rtp_header.timestamp;
	} else {
	is_first_packet_in_frame = true;
	}
	}

	int32_t ret_val = rtp_media_receiver_->ParseRtpPacket(
	&webrtc_rtp_header, payload_specific, is_red, payload, payload_length,
	clock_->TimeInMilliseconds(), is_first_packet_in_frame);

	if (ret_val < 0) {
	return false;
	}

	{
	rtc::CritScope lock(&critical_section_rtp_receiver_);

	last_receive_time_ = clock_->TimeInMilliseconds();
	last_received_payload_length_ = payload_data_length;

	if (in_order) {
	if (last_received_timestamp_ != rtp_header.timestamp) {
	last_received_timestamp_ = rtp_header.timestamp;
	last_received_frame_time_ms_ = clock_->TimeInMilliseconds();
	}
	last_received_sequence_number_ = rtp_header.sequenceNumber;
	}
	}
	return true;
	}

	TelephoneEventHandler* RtpReceiverImpl::GetTelephoneEventHandler() {
	return rtp_media_receiver_->GetTelephoneEventHandler();
	}

	std::vector<RtpSource> RtpReceiverImpl::GetSources() const {
	rtc::CritScope lock(&critical_section_rtp_receiver_);

	int64_t now_ms = clock_->TimeInMilliseconds();
	std::vector<RtpSource> sources;

	RTC_DCHECK(std::is_sorted(ssrc_sources_.begin(), ssrc_sources_.end(),
	[](const RtpSource& lhs, const RtpSource& rhs) {
	return lhs.timestamp_ms() < rhs.timestamp_ms();
	}));
	RTC_DCHECK(std::is_sorted(csrc_sources_.begin(), csrc_sources_.end(),
	[](const RtpSource& lhs, const RtpSource& rhs) {
	return lhs.timestamp_ms() < rhs.timestamp_ms();
	}));

	std::set<uint32_t> selected_ssrcs;
	for (auto rit = ssrc_sources_.rbegin(); rit != ssrc_sources_.rend(); ++rit) {
	if ((now_ms - rit->timestamp_ms()) > kGetSourcesTimeoutMs) {
	break;
	}
	if (selected_ssrcs.insert(rit->source_id()).second) {
	sources.push_back(*rit);
	}
	}

	for (auto rit = csrc_sources_.rbegin(); rit != csrc_sources_.rend(); ++rit) {
	if ((now_ms - rit->timestamp_ms()) > kGetSourcesTimeoutMs) {
	break;
	}
	sources.push_back(*rit);
	}
	return sources;
	}

	bool RtpReceiverImpl::Timestamp(uint32_t* timestamp) const {
	rtc::CritScope lock(&critical_section_rtp_receiver_);
	if (!HaveReceivedFrame())
	return false;
	*timestamp = last_received_timestamp_;
	return true;
	}

	bool RtpReceiverImpl::LastReceivedTimeMs(int64_t* receive_time_ms) const {
	rtc::CritScope lock(&critical_section_rtp_receiver_);
	if (!HaveReceivedFrame())
	return false;
	*receive_time_ms = last_received_frame_time_ms_;
	return true;
	}

	bool RtpReceiverImpl::HaveReceivedFrame() const {
	return last_received_frame_time_ms_ >= 0;
	}

	// Implementation note: must not hold critsect when called.
	void RtpReceiverImpl::CheckSSRCChanged(const RTPHeader& rtp_header) {
	bool new_ssrc = false;
	bool re_initialize_decoder = false;
	char payload_name[RTP_PAYLOAD_NAME_SIZE];
	size_t channels = 1;
	uint32_t rate = 0;

	{
	rtc::CritScope lock(&critical_section_rtp_receiver_);

	int8_t last_received_payload_type =
	rtp_payload_registry_->last_received_payload_type();
	if (ssrc_ != rtp_header.ssrc \|\|
	(last_received_payload_type == -1 && ssrc_ == 0)) {
	// We need the payload_type_ to make the call if the remote SSRC is 0.
	new_ssrc = true;

	last_received_timestamp_ = 0;
	last_received_sequence_number_ = 0;
	last_received_frame_time_ms_ = -1;

	// Do we have a SSRC? Then the stream is restarted.
	if (ssrc_ != 0) {
	// Do we have the same codec? Then re-initialize coder.
	if (rtp_header.payloadType == last_received_payload_type) {
	re_initialize_decoder = true;

	const Payload* payload = rtp_payload_registry_->PayloadTypeToPayload(
	rtp_header.payloadType);
	if (!payload) {
	return;
	}
	payload_name[RTP_PAYLOAD_NAME_SIZE - 1] = 0;
	strncpy(payload_name, payload->name, RTP_PAYLOAD_NAME_SIZE - 1);
	if (payload->audio) {
	channels = payload->typeSpecific.Audio.channels;
	rate = payload->typeSpecific.Audio.rate;
	}
	}
	}
	ssrc_ = rtp_header.ssrc;
	}
	}

	if (new_ssrc) {
	// We need to get this to our RTCP sender and receiver.
	// We need to do this outside critical section.
	cb_rtp_feedback_->OnIncomingSSRCChanged(rtp_header.ssrc);
	}

	if (re_initialize_decoder) {
	if (-1 ==
	cb_rtp_feedback_->OnInitializeDecoder(
	rtp_header.payloadType, payload_name,
	rtp_header.payload_type_frequency, channels, rate)) {
	// New stream, same codec.
	LOG(LS_ERROR) << "Failed to create decoder for payload type: "
	<< static_cast<int>(rtp_header.payloadType);
	}
	}
	}

	// Implementation note: must not hold critsect when called.
	// TODO(phoglund): Move as much as possible of this code path into the media
	// specific receivers. Basically this method goes through a lot of trouble to
	// compute something which is only used by the media specific parts later. If
	// this code path moves we can get rid of some of the rtp_receiver ->
	// media_specific interface (such as CheckPayloadChange, possibly get/set
	// last known payload).
	int32_t RtpReceiverImpl::CheckPayloadChanged(const RTPHeader& rtp_header,
	const int8_t first_payload_byte,
	bool* is_red,
	PayloadUnion* specific_payload) {
	bool re_initialize_decoder = false;

	char payload_name[RTP_PAYLOAD_NAME_SIZE];
	int8_t payload_type = rtp_header.payloadType;

	{
	rtc::CritScope lock(&critical_section_rtp_receiver_);

	int8_t last_received_payload_type =
	rtp_payload_registry_->last_received_payload_type();
	// TODO(holmer): Remove this code when RED parsing has been broken out from
	// RtpReceiverAudio.
	if (payload_type != last_received_payload_type) {
	if (rtp_payload_registry_->red_payload_type() == payload_type) {
	// Get the real codec payload type.
	payload_type = first_payload_byte & 0x7f;
	*is_red = true;

	if (rtp_payload_registry_->red_payload_type() == payload_type) {
	// Invalid payload type, traced by caller. If we proceeded here,
	// this would be set as \|_last_received_payload_type\|, and we would no
	// longer catch corrupt packets at this level.
	return -1;
	}

	// When we receive RED we need to check the real payload type.
	if (payload_type == last_received_payload_type) {
	rtp_media_receiver_->GetLastMediaSpecificPayload(specific_payload);
	return 0;
	}
	}
	bool should_discard_changes = false;

	rtp_media_receiver_->CheckPayloadChanged(
	payload_type, specific_payload,
	&should_discard_changes);

	if (should_discard_changes) {
	*is_red = false;
	return 0;
	}

	const Payload* payload =
	rtp_payload_registry_->PayloadTypeToPayload(payload_type);
	if (!payload) {
	// Not a registered payload type.
	return -1;
	}
	payload_name[RTP_PAYLOAD_NAME_SIZE - 1] = 0;
	strncpy(payload_name, payload->name, RTP_PAYLOAD_NAME_SIZE - 1);

	rtp_payload_registry_->set_last_received_payload_type(payload_type);

	re_initialize_decoder = true;

	rtp_media_receiver_->SetLastMediaSpecificPayload(payload->typeSpecific);
	rtp_media_receiver_->GetLastMediaSpecificPayload(specific_payload);

	if (!payload->audio) {
	bool media_type_unchanged =
	rtp_payload_registry_->ReportMediaPayloadType(payload_type);
	if (media_type_unchanged) {
	// Only reset the decoder if the media codec type has changed.
	re_initialize_decoder = false;
	}
	}
	} else {
	rtp_media_receiver_->GetLastMediaSpecificPayload(specific_payload);
	*is_red = false;
	}
	} // End critsect.

	if (re_initialize_decoder) {
	if (-1 ==
	rtp_media_receiver_->InvokeOnInitializeDecoder(
	cb_rtp_feedback_, payload_type, payload_name, *specific_payload)) {
	return -1; // Wrong payload type.
	}
	}
	return 0;
	}

	// Implementation note: must not hold critsect when called.
	void RtpReceiverImpl::CheckCSRC(const WebRtcRTPHeader& rtp_header) {
	int32_t num_csrcs_diff = 0;
	uint32_t old_remote_csrc[kRtpCsrcSize];
	uint8_t old_num_csrcs = 0;

	{
	rtc::CritScope lock(&critical_section_rtp_receiver_);

	if (!rtp_media_receiver_->ShouldReportCsrcChanges(
	rtp_header.header.payloadType)) {
	return;
	}
	old_num_csrcs = num_csrcs_;
	if (old_num_csrcs > 0) {
	// Make a copy of old.
	memcpy(old_remote_csrc, current_remote_csrc_,
	num_csrcs_ * sizeof(uint32_t));
	}
	const uint8_t num_csrcs = rtp_header.header.numCSRCs;
	if ((num_csrcs > 0) && (num_csrcs <= kRtpCsrcSize)) {
	// Copy new.
	memcpy(current_remote_csrc_,
	rtp_header.header.arrOfCSRCs,
	num_csrcs * sizeof(uint32_t));
	}
	if (num_csrcs > 0 \|\| old_num_csrcs > 0) {
	num_csrcs_diff = num_csrcs - old_num_csrcs;
	num_csrcs_ = num_csrcs; // Update stored CSRCs.
	} else {
	// No change.
	return;
	}
	} // End critsect.

	bool have_called_callback = false;
	// Search for new CSRC in old array.
	for (uint8_t i = 0; i < rtp_header.header.numCSRCs; ++i) {
	const uint32_t csrc = rtp_header.header.arrOfCSRCs[i];

	bool found_match = false;
	for (uint8_t j = 0; j < old_num_csrcs; ++j) {
	if (csrc == old_remote_csrc[j]) { // old list
	found_match = true;
	break;
	}
	}
	if (!found_match && csrc) {
	// Didn't find it, report it as new.
	have_called_callback = true;
	cb_rtp_feedback_->OnIncomingCSRCChanged(csrc, true);
	}
	}
	// Search for old CSRC in new array.
	for (uint8_t i = 0; i < old_num_csrcs; ++i) {
	const uint32_t csrc = old_remote_csrc[i];

	bool found_match = false;
	for (uint8_t j = 0; j < rtp_header.header.numCSRCs; ++j) {
	if (csrc == rtp_header.header.arrOfCSRCs[j]) {
	found_match = true;
	break;
	}
	}
	if (!found_match && csrc) {
	// Did not find it, report as removed.
	have_called_callback = true;
	cb_rtp_feedback_->OnIncomingCSRCChanged(csrc, false);
	}
	}
	if (!have_called_callback) {
	// If the CSRC list contain non-unique entries we will end up here.
	// Using CSRC 0 to signal this event, not interop safe, other
	// implementations might have CSRC 0 as a valid value.
	if (num_csrcs_diff > 0) {
	cb_rtp_feedback_->OnIncomingCSRCChanged(0, true);
	} else if (num_csrcs_diff < 0) {
	cb_rtp_feedback_->OnIncomingCSRCChanged(0, false);
	}
	}
	}

	void RtpReceiverImpl::UpdateSources(
	const rtc::Optional<uint8_t>& ssrc_audio_level) {
	rtc::CritScope lock(&critical_section_rtp_receiver_);
	int64_t now_ms = clock_->TimeInMilliseconds();

	for (size_t i = 0; i < num_csrcs_; ++i) {
	auto map_it = iterator_by_csrc_.find(current_remote_csrc_[i]);
	if (map_it == iterator_by_csrc_.end()) {
	// If it is a new CSRC, append a new object to the end of the list.
	csrc_sources_.emplace_back(now_ms, current_remote_csrc_[i],
	RtpSourceType::CSRC);
	} else {
	// If it is an existing CSRC, move the object to the end of the list.
	map_it->second->update_timestamp_ms(now_ms);
	csrc_sources_.splice(csrc_sources_.end(), csrc_sources_, map_it->second);
	}
	// Update the unordered_map.
	iterator_by_csrc_[current_remote_csrc_[i]] = std::prev(csrc_sources_.end());
	}

	// If this is the first packet or the SSRC is changed, insert a new
	// contributing source that uses the SSRC.
	if (ssrc_sources_.empty() \|\| ssrc_sources_.rbegin()->source_id() != ssrc_) {
	ssrc_sources_.emplace_back(now_ms, ssrc_, RtpSourceType::SSRC);
	} else {
	ssrc_sources_.rbegin()->update_timestamp_ms(now_ms);
	}

	ssrc_sources_.back().set_audio_level(ssrc_audio_level);

	RemoveOutdatedSources(now_ms);
	}

	void RtpReceiverImpl::RemoveOutdatedSources(int64_t now_ms) {
	std::list<RtpSource>::iterator it;
	for (it = csrc_sources_.begin(); it != csrc_sources_.end(); ++it) {
	if ((now_ms - it->timestamp_ms()) <= kGetSourcesTimeoutMs) {
	break;
	}
	iterator_by_csrc_.erase(it->source_id());
	}
	csrc_sources_.erase(csrc_sources_.begin(), it);

	std::vector<RtpSource>::iterator vec_it;
	for (vec_it = ssrc_sources_.begin(); vec_it != ssrc_sources_.end();
	++vec_it) {
	if ((now_ms - vec_it->timestamp_ms()) <= kGetSourcesTimeoutMs) {
	break;
	}
	}
	ssrc_sources_.erase(ssrc_sources_.begin(), vec_it);
	}

	} // namespace webrtc