Reconfigure video encoders even when not sending.

webrtc/media/engine/webrtcvideoengine2.cc

 /*
  *  Copyright (c) 2014 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.
  */
 
@@ skipping 1532 matching lines @@
     const VideoFrame& frame) {
   TRACE_EVENT0("webrtc", "WebRtcVideoSendStream::OnFrame");
   webrtc::VideoFrame video_frame(frame.GetVideoFrameBuffer(), 0, 0,
                                  frame.GetVideoRotation());
   rtc::CritScope cs(&lock_);
   if (stream_ == NULL) {
     // Frame input before send codecs are configured, dropping frame.
     return;
   }
 
-  // Not sending, abort early to prevent expensive reconfigurations while
-  // setting up codecs etc.
-  if (!sending_)
-    return;
-
   if (muted_) {
     // Create a black frame to transmit instead.
     CreateBlackFrame(&video_frame,
                      static_cast<int>(frame.GetWidth()),
                      static_cast<int>(frame.GetHeight()),
                      video_frame.rotation());
   }
 
   int64_t frame_delta_ms = frame.GetTimeStamp() / rtc::kNumNanosecsPerMillisec;
   // frame->GetTimeStamp() is essentially a delta, align to webrtc time
   if (first_frame_timestamp_ms_ == 0) {
     first_frame_timestamp_ms_ = rtc::Time() - frame_delta_ms;
   }
 
   last_frame_timestamp_ms_ = first_frame_timestamp_ms_ + frame_delta_ms;
   video_frame.set_render_time_ms(last_frame_timestamp_ms_);
   // Reconfigure codec if necessary.
   SetDimensions(video_frame.width(), video_frame.height());
   last_rotation_ = video_frame.rotation();
 
+  // Not sending, abort after reconfiguration. Reconfiguration should still
+  // occur to permit sending this input as quickly as possible once we start
+  // sending (without having to reconfigure then).
+  if (!sending_) {
+    return;
+  }
+
   stream_->Input()->IncomingCapturedFrame(video_frame);
 }
 
 bool WebRtcVideoChannel2::WebRtcVideoSendStream::SetCapturer(
     VideoCapturer* capturer) {
   TRACE_EVENT0("webrtc", "WebRtcVideoSendStream::SetCapturer");
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
   if (!DisconnectCapturer() && capturer == NULL) {
     return false;
   }
@@ skipping 941 matching lines @@
         rtx_mapping[video_codecs[i].codec.id] !=
             fec_settings.red_payload_type) {
       video_codecs[i].rtx_payload_type = rtx_mapping[video_codecs[i].codec.id];
     }
   }
 
   return video_codecs;
 }
 
 }  // namespace cricket