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      1 /*
      2  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #include "webrtc/video_engine/vie_sync_module.h"
     12 
     13 #include "webrtc/modules/rtp_rtcp/interface/rtp_receiver.h"
     14 #include "webrtc/modules/rtp_rtcp/interface/rtp_rtcp.h"
     15 #include "webrtc/modules/video_coding/main/interface/video_coding.h"
     16 #include "webrtc/system_wrappers/interface/critical_section_wrapper.h"
     17 #include "webrtc/system_wrappers/interface/logging.h"
     18 #include "webrtc/system_wrappers/interface/trace_event.h"
     19 #include "webrtc/video_engine/stream_synchronization.h"
     20 #include "webrtc/video_engine/vie_channel.h"
     21 #include "webrtc/voice_engine/include/voe_video_sync.h"
     22 
     23 namespace webrtc {
     24 
     25 enum { kSyncInterval = 1000};
     26 
     27 int UpdateMeasurements(StreamSynchronization::Measurements* stream,
     28                        const RtpRtcp& rtp_rtcp, const RtpReceiver& receiver) {
     29   if (!receiver.Timestamp(&stream->latest_timestamp))
     30     return -1;
     31   if (!receiver.LastReceivedTimeMs(&stream->latest_receive_time_ms))
     32     return -1;
     33 
     34   uint32_t ntp_secs = 0;
     35   uint32_t ntp_frac = 0;
     36   uint32_t rtp_timestamp = 0;
     37   if (0 != rtp_rtcp.RemoteNTP(&ntp_secs,
     38                               &ntp_frac,
     39                               NULL,
     40                               NULL,
     41                               &rtp_timestamp)) {
     42     return -1;
     43   }
     44 
     45   bool new_rtcp_sr = false;
     46   if (!UpdateRtcpList(
     47       ntp_secs, ntp_frac, rtp_timestamp, &stream->rtcp, &new_rtcp_sr)) {
     48     return -1;
     49   }
     50 
     51   return 0;
     52 }
     53 
     54 ViESyncModule::ViESyncModule(VideoCodingModule* vcm,
     55                              ViEChannel* vie_channel)
     56     : data_cs_(CriticalSectionWrapper::CreateCriticalSection()),
     57       vcm_(vcm),
     58       vie_channel_(vie_channel),
     59       video_receiver_(NULL),
     60       video_rtp_rtcp_(NULL),
     61       voe_channel_id_(-1),
     62       voe_sync_interface_(NULL),
     63       last_sync_time_(TickTime::Now()),
     64       sync_() {
     65 }
     66 
     67 ViESyncModule::~ViESyncModule() {
     68 }
     69 
     70 int ViESyncModule::ConfigureSync(int voe_channel_id,
     71                                  VoEVideoSync* voe_sync_interface,
     72                                  RtpRtcp* video_rtcp_module,
     73                                  RtpReceiver* video_receiver) {
     74   CriticalSectionScoped cs(data_cs_.get());
     75   voe_channel_id_ = voe_channel_id;
     76   voe_sync_interface_ = voe_sync_interface;
     77   video_receiver_ = video_receiver;
     78   video_rtp_rtcp_ = video_rtcp_module;
     79   sync_.reset(new StreamSynchronization(voe_channel_id, vie_channel_->Id()));
     80 
     81   if (!voe_sync_interface) {
     82     voe_channel_id_ = -1;
     83     if (voe_channel_id >= 0) {
     84       // Trying to set a voice channel but no interface exist.
     85       return -1;
     86     }
     87     return 0;
     88   }
     89   return 0;
     90 }
     91 
     92 int ViESyncModule::VoiceChannel() {
     93   return voe_channel_id_;
     94 }
     95 
     96 int32_t ViESyncModule::TimeUntilNextProcess() {
     97   return static_cast<int32_t>(kSyncInterval -
     98       (TickTime::Now() - last_sync_time_).Milliseconds());
     99 }
    100 
    101 int32_t ViESyncModule::Process() {
    102   CriticalSectionScoped cs(data_cs_.get());
    103   last_sync_time_ = TickTime::Now();
    104 
    105   const int current_video_delay_ms = vcm_->Delay();
    106 
    107   if (voe_channel_id_ == -1) {
    108     return 0;
    109   }
    110   assert(video_rtp_rtcp_ && voe_sync_interface_);
    111   assert(sync_.get());
    112 
    113   int audio_jitter_buffer_delay_ms = 0;
    114   int playout_buffer_delay_ms = 0;
    115   if (voe_sync_interface_->GetDelayEstimate(voe_channel_id_,
    116                                             &audio_jitter_buffer_delay_ms,
    117                                             &playout_buffer_delay_ms) != 0) {
    118     return 0;
    119   }
    120   const int current_audio_delay_ms = audio_jitter_buffer_delay_ms +
    121       playout_buffer_delay_ms;
    122 
    123   RtpRtcp* voice_rtp_rtcp = NULL;
    124   RtpReceiver* voice_receiver = NULL;
    125   if (0 != voe_sync_interface_->GetRtpRtcp(voe_channel_id_, &voice_rtp_rtcp,
    126                                            &voice_receiver)) {
    127     return 0;
    128   }
    129   assert(voice_rtp_rtcp);
    130   assert(voice_receiver);
    131 
    132   if (UpdateMeasurements(&video_measurement_, *video_rtp_rtcp_,
    133                          *video_receiver_) != 0) {
    134     return 0;
    135   }
    136 
    137   if (UpdateMeasurements(&audio_measurement_, *voice_rtp_rtcp,
    138                          *voice_receiver) != 0) {
    139     return 0;
    140   }
    141 
    142   int relative_delay_ms;
    143   // Calculate how much later or earlier the audio stream is compared to video.
    144   if (!sync_->ComputeRelativeDelay(audio_measurement_, video_measurement_,
    145                                    &relative_delay_ms)) {
    146     return 0;
    147   }
    148 
    149   TRACE_COUNTER1("webrtc", "SyncCurrentVideoDelay", current_video_delay_ms);
    150   TRACE_COUNTER1("webrtc", "SyncCurrentAudioDelay", current_audio_delay_ms);
    151   TRACE_COUNTER1("webrtc", "SyncRelativeDelay", relative_delay_ms);
    152   int target_audio_delay_ms = 0;
    153   int target_video_delay_ms = current_video_delay_ms;
    154   // Calculate the necessary extra audio delay and desired total video
    155   // delay to get the streams in sync.
    156   if (!sync_->ComputeDelays(relative_delay_ms,
    157                             current_audio_delay_ms,
    158                             &target_audio_delay_ms,
    159                             &target_video_delay_ms)) {
    160     return 0;
    161   }
    162 
    163   if (voe_sync_interface_->SetMinimumPlayoutDelay(
    164       voe_channel_id_, target_audio_delay_ms) == -1) {
    165     LOG(LS_ERROR) << "Error setting voice delay.";
    166   }
    167   vcm_->SetMinimumPlayoutDelay(target_video_delay_ms);
    168   return 0;
    169 }
    170 
    171 int ViESyncModule::SetTargetBufferingDelay(int target_delay_ms) {
    172   CriticalSectionScoped cs(data_cs_.get());
    173   if (!voe_sync_interface_) {
    174     LOG(LS_ERROR) << "voe_sync_interface_ NULL, can't set playout delay.";
    175     return -1;
    176   }
    177   sync_->SetTargetBufferingDelay(target_delay_ms);
    178   // Setting initial playout delay to voice engine (video engine is updated via
    179   // the VCM interface).
    180   voe_sync_interface_->SetInitialPlayoutDelay(voe_channel_id_,
    181                                               target_delay_ms);
    182   return 0;
    183 }
    184 
    185 }  // namespace webrtc
    186