Make WebRTC compatible with OpenH264 v1.6.

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.
  *
  */
 
 #include "webrtc/modules/video_coding/codecs/h264/h264_encoder_impl.h"
 
 #include <limits>
 
 #include "third_party/openh264/src/codec/api/svc/codec_api.h"
 #include "third_party/openh264/src/codec/api/svc/codec_app_def.h"
 #include "third_party/openh264/src/codec/api/svc/codec_def.h"
+#include "third_party/openh264/src/codec/api/svc/codec_ver.h"
 
 #include "webrtc/base/checks.h"
 #include "webrtc/base/logging.h"
 #include "webrtc/common_video/libyuv/include/webrtc_libyuv.h"
 #include "webrtc/system_wrappers/include/metrics.h"
 
 namespace webrtc {
 
 namespace {
 
@@ skipping 113 matching lines @@
     // Copy the entire layer's data (including start codes).
     memcpy(encoded_image->_buffer + encoded_image->_length,
            layerInfo.pBsBuf,
            layer_len);
     encoded_image->_length += layer_len;
   }
 }
 
 H264EncoderImpl::H264EncoderImpl()
     : openh264_encoder_(nullptr),
+      number_of_cores_(0),
       encoded_image_callback_(nullptr),
       has_reported_init_(false),
       has_reported_error_(false) {
 }
 
 H264EncoderImpl::~H264EncoderImpl() {
   Release();
 }
 
 int32_t H264EncoderImpl::InitEncode(const VideoCodec* codec_settings,
@@ skipping 270 matching lines @@
       encoder_params.iPicWidth, encoder_params.iPicHeight, number_of_cores_);
   // The base spatial layer 0 is the only one we use.
   encoder_params.sSpatialLayers[0].iVideoWidth = encoder_params.iPicWidth;
   encoder_params.sSpatialLayers[0].iVideoHeight = encoder_params.iPicHeight;
   encoder_params.sSpatialLayers[0].fFrameRate = encoder_params.fMaxFrameRate;
   encoder_params.sSpatialLayers[0].iSpatialBitrate =
       encoder_params.iTargetBitrate;
   encoder_params.sSpatialLayers[0].iMaxSpatialBitrate =
       encoder_params.iMaxBitrate;
   // Slice num according to number of threads.
+#if (OPENH264_MAJOR == 1) && (OPENH264_MINOR <= 5)
   encoder_params.sSpatialLayers[0].sSliceCfg.uiSliceMode = SM_AUTO_SLICE;
+#else
+  encoder_params.sSpatialLayers[0].sSliceArgument.uiSliceMode =
+      SM_FIXEDSLCNUM_SLICE;

[stefan-webrtc, 2016/10/24 10:42:02]

Maybe comment on what this means? Reading the header file it seems to mean that
it will use the appropriate number of slices to achieve good multi-threading.
The slices are not optimized for bitstream robustness.

https://github.com/cisco/openh264/blob/997f0ed69b811697611fceb2d12ca8cfe42352...

[sprang_webrtc, 2016/10/24 11:28:19]

Comment above still says "// Slice num according to number of threads."? :)

[hbos_chromium, 2016/10/24 14:10:37]

According to the link, SM_FIXEDSLCNUM_SLICE sets it in accordance with SliceNum
(SSliceArgument::uiSliceNum). Since we don't set
sSpatialLayers[0].sSliceArgument it would use its default value, which I believe
is 0,
https://github.com/cisco/openh264/blob/997f0ed69b811697611fceb2d12ca8cfe42352....
"uiSliceNum=0 means auto design it with cpu core number".

So this should be auto. Up to you if you want to explicitly set it to 0 and add
a comment saying it is based on the number of cores.

+#endif
 
   return encoder_params;
 }
 
 void H264EncoderImpl::ReportInit() {
   if (has_reported_init_)
     return;
   RTC_HISTOGRAM_ENUMERATION("WebRTC.Video.H264EncoderImpl.Event",
                             kH264EncoderEventInit,
                             kH264EncoderEventMax);
@@ skipping 16 matching lines @@
 
 int32_t H264EncoderImpl::SetPeriodicKeyFrames(bool enable) {
   return WEBRTC_VIDEO_CODEC_OK;
 }
 
 void H264EncoderImpl::OnDroppedFrame() {
   quality_scaler_.ReportDroppedFrame();
 }
 
 }  // namespace webrtc