There is a problem when v4l2src + compositor

Nicolas Dufresne nicolas at ndufresne.ca
Wed Apr 14 19:28:18 UTC 2021


Le mardi 13 avril 2021 à 22:14 -0500, inaho330 a écrit :
> Hi
> 
> I make a program which pipeline like this:
> 
> gst-launch-1.0 v4l2src  ! video/x-raw,format=YV12,width=1280,height=720 !
> timeoverlay  ! queue  ! videomixer ! vaapih264enc rate-control=vbr
> bitrate=1000 ! video/x-h264 ! h264parse config-interval=1  ! mpegtsmux !
> udpsink host=172.16.6.109 port=23333
> 
> It work fine. But If I use compositor instead of videomixer like this:
> 
> gst-launch-1.0 v4l2src  ! video/x-raw,format=YV12,width=1280,height=720 !
> timeoverlay  ! queue  ! compositor ! vaapih264enc rate-control=vbr
> bitrate=1000 ! video/x-h264 ! h264parse config-interval=1  ! mpegtsmux !
> udpsink host=172.16.6.109 port=23333
> 
> The compositor just only output the first frame it get .

Works here on 1.18.2, but the start is bursty, which I can fix adding start-
time-selection=first to the compositor. That's because v4l2src is live and the
very first timestamp isn't going to be zero. My camera is pretty fast to start,
but I've seen UVC camera taking up to 10s to start.

> 
> But if i use videotestsrc or appsrc , it work fine.
> 
> Does anyone know where the problem is? 
> Is there any way to debug it?
> 
> THanks!
> 
> 
> 
> --
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