Description It's limited that WebRTC only supports VP8 video codec at the moment. While there are widespread video communication usage, i.e, WebEx, Tandberg, etc, that are based upon H264[1]. Meanwhile, there are Crosswalk customer requirements hoping to add H264 support for WebRTC.
Affected component: Chromium Crosswalk / WebRTC Related feature: XWALK-2310 Target release: Crosswalk v10 Target Platform - Android P1, Tizen P2. Implementation details: Basically there would be three parts of changes, 1. Codec negotiation to use H264. Plan to support H264 negotiation under command option guard. H264 will be the communication codec only if command line enables H264, AND both WebRTC ends support H264 encoding/decoding. Otherwise, go through the normal Vp8 codec path. Changes will mainly be in Libjingle. 2. Add encoding/decoding support for H264. There are two ways to enable this change, internal way and external way. For internal way, we can add implementation inside WebRTC project by leveraging OpenH264 APIs, there is long discussion over this option[2], disadvantage is it has to include H264 implementation binaries internally, this may raise potential license issues. The external way would configure encoder/decoder outside WebRTC, Chromium Android/ChromeOS has the VDA/EDA implementation of the WebRTC codec interfaces, then the handle of implementation is passed to WebRTC inside Libjingle. It doesn't have the license issues. Consider Crosswalk is open source project, I prefer the latter option. Changes will happen in Chromium Crosswalk. 3. RTP packetization/depacketization support for H264. Upstream has added support for this. Ideally we can use it for the network transmission of H264 encoded data. If changes are required, it would be inside WebRTC. References: [1] H.264 as Mandatory to Implement Video Codec for WebRTC. http://tools.ietf.org/html/draft-burman-rtcweb-h264-proposal-04#section-8 [2] H.264 patch for Google Chrome webrtc video call. https://groups.google.com/forum/#!topic/discuss-webrtc/U-y3or-dBOU Thanks, Changbin
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