Skipped frames when displaying RTP / H.264 stream

[Nicolas Dufresne]

On jeu, 2020-02-06 at 07:45 -0600, jean-philippe wrote:
> Me again... I thought I'd post my latest findings in case it rings a bell
> with anyone on the mailing list.
> 
> To recap, I detect one lost frame every 128 with the following pipeline:
> videotestsrc is-live=true !
> video/x-raw,width=640,height=480,format=I420,framerate=30/1 ! queue !
> vpuenc_h264 ! queue ! rtph264pay ! queue ! rtph264depay ! fpsdisplaysink
> text-overlay=false video-sink=fakesink sync=false
> 
> This is with the i.MX8MMini. So a 30Hz video stream comes out at 29.77Hz.
> 
> I've now found out that the H.264 stream contains one Filler NALU every 128
> NALUs. 
> The NALUs surrounding the Filler look fine, no different from the other VCL
> NALUs in the stream.
> 
> So I think rtph264pay and/or rtph264depay may be dropping a frame when it
> encounters a Filler NALU.

Can you capture a GOP with such filler and share ? Seems like something we can
capture in a unit test if this is the case.

> 
> I'm now reading the RTP spec + looking at the code, but any suggestion
> appreciated...
> 
> 
> 
> --
> Sent from: http://gstreamer-devel.966125.n4.nabble.com/
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