Added EncodedImage::GetBufferPaddingBytes.

webrtc/modules/video_coding/codecs/h264/h264.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/include/h264.h"
 
 #if defined(WEBRTC_IOS)
 #include "webrtc/modules/video_coding/codecs/h264/h264_video_toolbox_decoder.h"
 #include "webrtc/modules/video_coding/codecs/h264/h264_video_toolbox_encoder.h"
 #endif
 
 #include "webrtc/base/checks.h"
 
 namespace webrtc {
 
+// TODO(hbos): The FFmpeg video decoder will require up to 8 bytes, update this
+// when the FFmpeg decoder is added.

[stefan-webrtc, 2016/01/19 15:06:20]

Should we also file a bug to the ffmpeg project? Seems like something they
should be able to fix.

[hbos, 2016/01/19 16:50:34]

It is documented in their source code
(https://code.google.com/p/chromium/codesearch#chromium/src/third_party/ffmpeg...)
so they already know about it. Think I should create a bug anyway?

[stefan-webrtc, 2016/01/21 10:34:47]

I think we should at least ask whether they would consider fixing it. I don't
see any reason why it should behave in this way, as they can read the whole
frame except the end as chunks of 64 bits. I'd be surprised if that would end up
being a performance issue.

[hbos, 2016/01/21 11:17:26]

Agreed, I created a ticket (https://trac.ffmpeg.org/ticket/5176).

Got a reply: "[...] if we wouldn't have padding we would have to check every
time if we're at the end of the buffer [...] Don't expect any changes, this is a
clear design decision."

+const size_t kEncodedImagePaddingH264 = 0;
+
 // We need this file to be C++ only so it will compile properly for all
 // platforms. In order to write ObjC specific implementations we use private
 // externs. This function is defined in h264.mm.
 #if defined(WEBRTC_IOS)
 extern bool IsH264CodecSupportedObjC();
 #endif
 
 bool IsH264CodecSupported() {
 #if defined(WEBRTC_IOS)
   return IsH264CodecSupportedObjC();
@@ skipping 24 matching lines @@
   RTC_NOTREACHED();
   return nullptr;
 #endif
 }
 
 bool H264Decoder::IsSupported() {
   return IsH264CodecSupported();
 }
 
 }  // namespace webrtc