Revert of Use RC_TIMESTAMP_MODE for OpenH264.

webrtc/modules/video_coding/codecs/h264/h264_encoder_impl.cc

 /*
  *  Copyright (c) 2015 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 206 matching lines @@
   } else {
     ReportError();
     return WEBRTC_VIDEO_CODEC_ERR_PARAMETER;
   }
   init_params.iPicWidth = codec_settings_.width;
   init_params.iPicHeight = codec_settings_.height;
   // |init_params| uses bit/s, |codec_settings_| uses kbit/s.
   init_params.iTargetBitrate = codec_settings_.targetBitrate * 1000;
   init_params.iMaxBitrate = codec_settings_.maxBitrate * 1000;
   // Rate Control mode
-  init_params.iRCMode = RC_TIMESTAMP_MODE;
+  init_params.iRCMode = RC_BITRATE_MODE;
   init_params.fMaxFrameRate = static_cast<float>(codec_settings_.maxFramerate);
 
   // The following parameters are extension parameters (they're in SEncParamExt,
   // not in SEncParamBase).
   init_params.bEnableFrameSkip =
       codec_settings_.codecSpecific.H264.frameDroppingOn;
   // |uiIntraPeriod|    - multiple of GOP size
   // |keyFrameInterval| - number of frames
   init_params.uiIntraPeriod =
       codec_settings_.codecSpecific.H264.keyFrameInterval;
@@ skipping 98 matching lines @@
   }
   if (frame.width()  != codec_settings_.width ||
       frame.height() != codec_settings_.height) {
     LOG(LS_WARNING) << "Encoder initialized for " << codec_settings_.width
                     << "x" << codec_settings_.height << " but trying to encode "
                     << frame.width() << "x" << frame.height() << " frame.";
     ReportError();
     return WEBRTC_VIDEO_CODEC_ERR_SIZE;
   }
 
-  RTC_DCHECK(frame_types != nullptr);
-  // We only support a single stream.
-  RTC_DCHECK_EQ(1u, frame_types->size());
-  // Force key frame?
-  if ((*frame_types)[0] == kVideoFrameKey) {
+  bool force_key_frame = false;
+  if (frame_types != nullptr) {
+    // We only support a single stream.
+    RTC_DCHECK_EQ(frame_types->size(), static_cast<size_t>(1));
+    // Skip frame?
+    if ((*frame_types)[0] == kEmptyFrame) {
+      return WEBRTC_VIDEO_CODEC_OK;
+    }
+    // Force key frame?
+    force_key_frame = (*frame_types)[0] == kVideoFrameKey;
+  }
+  if (force_key_frame) {
     // API doc says ForceIntraFrame(false) does nothing, but calling this
     // function forces a key frame regardless of the |bIDR| argument's value.
+    // (If every frame is a key frame we get lag/delays.)
     openh264_encoder_->ForceIntraFrame(true);
   }
 
   // EncodeFrame input.
   SSourcePicture picture;
   memset(&picture, 0, sizeof(SSourcePicture));
   picture.iPicWidth = frame.width();
   picture.iPicHeight = frame.height();
   picture.iColorFormat = EVideoFormatType::videoFormatI420;
   picture.uiTimeStamp = frame.ntp_time_ms();
@@ skipping 71 matching lines @@
 }
 
 int32_t H264EncoderImpl::SetPeriodicKeyFrames(bool enable) {
   return WEBRTC_VIDEO_CODEC_OK;
 }
 
 void H264EncoderImpl::OnDroppedFrame() {
 }
 
 }  // namespace webrtc