Fix Channel::GetSendCodec when used together with SetEncoder.

webrtc/voice_engine/channel.cc

Index: webrtc/voice_engine/channel.cc
diff --git a/webrtc/voice_engine/channel.cc b/webrtc/voice_engine/channel.cc
index b0bae4e4ceb0e05cd1ca421efdbc5943cf640e19..35412ce41cec091b09f282e0ecf817cbe7d30d69 100644
--- a/webrtc/voice_engine/channel.cc
+++ b/webrtc/voice_engine/channel.cc
@@ -1288,10 +1288,16 @@ bool Channel::SetEncoder(int payload_type,
   // supposedly carries the sample rate, but only clock rate seems sensible to
   // send to the RTP/RTCP module.
   lies.plfreq = encoder->RtpTimestampRateHz();
-  lies.pacsize = 0;
+  lies.pacsize = rtc::CheckedDivExact(
+      static_cast<int>(encoder->Max10MsFramesInAPacket() * lies.plfreq), 100);
   lies.channels = encoder->NumChannels();
   lies.rate = 0;
 
+  // Store a similarily made-up CodecInst for GetSendCodec to return.

[henrika_webrtc, 2017/06/09 13:50:04]

Similar to what?

[ossu, 2017/06/09 13:54:00]

On line 1281 I explain that I'm making a CodecInst up. Down here I'm also making
one up. I'll update the comments to be clearer and add a TODO for me on this one
as well.

+  CodecInst send_codec = lies;
+  send_codec.plfreq = encoder->SampleRateHz();
+  cached_send_codec_.emplace(send_codec);
+
   if (_rtpRtcpModule->RegisterSendPayload(lies) != 0) {
     _rtpRtcpModule->DeRegisterSendPayload(payload_type);
     if (_rtpRtcpModule->RegisterSendPayload(lies) != 0) {
@@ -1343,18 +1349,16 @@ int32_t Channel::DeRegisterVoiceEngineObserver() {
 }
 
 int32_t Channel::GetSendCodec(CodecInst& codec) {
-  {
+  if (cached_send_codec_) {
+    codec = *cached_send_codec_;
+    return 0;
+  } else {
     const CodecInst* send_codec = codec_manager_.GetCodecInst();
     if (send_codec) {
       codec = *send_codec;
       return 0;
     }
   }
-  rtc::Optional<CodecInst> acm_send_codec = audio_coding_->SendCodec();
-  if (acm_send_codec) {
-    codec = *acm_send_codec;
-    return 0;
-  }
   return -1;
 }
 
@@ -1383,6 +1387,8 @@ int32_t Channel::SetSendCodec(const CodecInst& codec) {
     }
   }
 
+  cached_send_codec_.reset();
+
   return 0;
 }