Decoding video when there is packet loss is not an easy task. Recent Chrome versions have been plagued by video corruption issues related to a new video jitter buffer introduced in Chrome 58. These issues are hard to debug since they occur only when certain packets are lost. To combat these issues, webrtc.org has a pretty powerful tool to reproduce and analyze them called video_replay. When I saw another video corruption issue filed by Stian Selnes I told him about that tool. With an easy reproduction of the stream, the WebRTC video team at Google made short work of the bug. Unfortunately this process is not too well documented, so we asked Stian to walk us through the process of capturing the necessary data and using the video_replay tool. Stian, who works at Pexip, has been dealing with real-time communication for more than 10 years. He has experience in large parts of the media stack with a special interest in video codecs and other types of signal processing, network protocols and error resilience.
debug
All posts tagged debug
webrtcH4cKS: ~ WebRTC Externals – the cross-browser WebRTC debug extension
I am a big fan of Chrome’s webrtc-internals tool. It is one of the most useful debugging tools for WebRTC and when it was added to Chrome back in 2012 it made my life a lot easier. I even wrote a lengthy series of blog post together with Tsahi Levent-Levi describing how to use it to debug issues recently.
Firefox has a similar about:webrtc page which shows the local and remote SDP for each page as well as a very useful grid of ICE candidates. But unlike Chrome it does not show the exact order of API calls or nice graphs obtained from the getStats API. I miss both features dearly. Edge and Safari don’t support similar debugging helpers currently either.
webrtcH4cKS: ~ Debugging VP8 is more fun than it used to be
Editor Note: Fippo uses a lot of advanced WebRTC terms below – if you are a regular reader of this blog then don’t let that scare you. Wireshark is a great tool for diagnosing media issues and inspecting signaling packets even if you’re not building a media server. {“editor”, “chad hart“}
Stuff breaks all the time and then you need to debug it. My favorite tool for this remains Wireshark as we have seen previously. Its fairly useful for debugging all the ICE and DTLS stuff but recently I’ve had to debug the media traffic itself.
