webrtcbin: 4K h264 problems
rob at engineeredarts.co.uk
Mon Oct 11 07:55:34 UTC 2021
We're also struggling to get h264 video to work reliably via webrtc, but
here on Ubuntu (18.04 & 20.04), even at lower resolutions & bit rate.
It does sound like a similar situation though - when it occasionally
works, the video is stuttery with packet loss reported in
On 11/10/2021 06:09, David Ely via gstreamer-devel wrote:
> We are having issues sending a 4K, H264 stream through WebRTC on
> Windows (3840x2160, 30hz, 8Mbs). Playback of the video stream stutters
> or may get stuck. Our application captures the desktop, encodes it to
> H264 and streams it to Chrome or another of our applications, both of
> which exhibit the problem. This issue only happens on Windows, CentOS7
> and Ubuntu20.04 work (using the same hardware). Lower resolutions
> (1080P) work across all 3 operations systems. Chrome's
> webrtc-internals shows the packetsLost or freezeCount increase when
> the stutter occurs.
> Points of note:
> * Our GStreamer version is 1.19.1.
> * This was reproduced with two PCs on a local network. The problem
> won't occur if the sender and receiver are on the same computer.
> * We did some Wireshark captures on the sending PC and it showed
> some packets aren't making it to the NIC. It appears occasionally
> a NAL is being truncated.
> * In attempt reduced the scope of the problem, I reproduced the
> issue in one of the gst-examples
> (webrtc\sendonly\webrtc-unidirectional-h264.c) by modifying the
> pipeline to stream from a file (I only tested this on Windows).
> The file is 30hz, 4K H264 video with a birate of 8 Mbs. The
> pipeline looks like this
> o /filesrc location=C:\tmp\test.mkv ! queue ! matroskademux !
> queue ! h264parse !
> video/x-h264,alignment=au,stream-format=byte-stream !
> rtph264pay config-interval=1 aggregate-mode !
> ! webrtcbin/
> * Reducing the bitrate alleviates the problem.
> * For reference this is our application's pipeline on Windows
> o /dxgiscreencapsrc cursor=true !
> video/x-raw,format=BGRA,framerate=30/1 ! videoconvert ! queue
> ! video/x-raw,format=I420 ! nvh264enc preset=low-latency-hp
> bitrate=8192 rc-mode=cbr gop-size=90 zerolatency=true !
> ! rtph264pay !
> application/x-rtp,media=video,encoding-name=H264,payload=96 !
> As I was able to reproduce the issue in the modified example it points
> to webrtcbin as the problem.
> Any help/suggestions to resolve the problem would be greatly appreciated.
> *David Ely*
> Software Architect
> +61 7 3123 7133
> david.ely at immersaview.com <mailto:david.ely at immersaview.com>
> www.immersaview.com <http://www.immersaview.com/>
> 13/67 Depot St, Banyo, QLD 4014
> This electronic mail transmission is confidential and is intended only
> for the review of the party to whom it is addressed.
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