Share v4l2src between seceral processes

[almog1]

I want to share a camera stream (v4l2src) between several processes.

Those pipelines work on my PC but don’t work on Xavier NX

gst-launch-1.0 -v videotestsrc ! "video/x-raw, format=YUY2, color-matrix=sdtv, chroma-site=mpeg2, width=(int)320, height=(int)240, framerate=(fraction)30/1" ! shmsink socket-path=/tmp/blah shm-size=20000000

gst-launch-1.0 shmsrc socket-path=/tmp/blah ! "video/x-raw, format=YUY2, color-matrix=sdtv, chroma-site=mpeg2, width=(int)320, height=(int)240,framerate=(fraction)30/1" ! queue ! videoconvert ! autovideosink

on NX:

demo@tegra-ubuntu:~/workspace/v4l2loopback$ gst-launch-1.0 -v videotestsrc ! "video/x-raw, format=YUY2, color-matrix=sdtv, chroma-site=mpeg2, width=(int)320, height=(int)240, framerate=(fraction)30/1" ! shmsink socket-path=/tmp/blah shm-size=20000000
Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
/GstPipeline:pipeline0/GstVideoTestSrc:videotestsrc0.GstPad:src: caps = video/x-raw, format=(string)YUY2, width=(int)320, height=(int)240, framerate=(fraction)30/1, multiview-mode=(string)mono, color-matrix=(string)sdtv, chroma-site=(string)mpeg2, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive
/GstPipeline:pipeline0/GstCapsFilter:capsfilter0.GstPad:src: caps = video/x-raw, format=(string)YUY2, width=(int)320, height=(int)240, framerate=(fraction)30/1, multiview-mode=(string)mono, color-matrix=(string)sdtv, chroma-site=(string)mpeg2, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive
/GstPipeline:pipeline0/GstShmSink:shmsink0.GstPad:sink: caps = video/x-raw, format=(string)YUY2, width=(int)320, height=(int)240, framerate=(fraction)30/1, multiview-mode=(string)mono, color-matrix=(string)sdtv, chroma-site=(string)mpeg2, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive
/GstPipeline:pipeline0/GstCapsFilter:capsfilter0.GstPad:sink: caps = video/x-raw, format=(string)YUY2, width=(int)320, height=(int)240, framerate=(fraction)30/1, multiview-mode=(string)mono, color-matrix=(string)sdtv, chroma-site=(string)mpeg2, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock

demo@tegra-ubuntu:~/workspace/v4l2loopback$ gst-launch-1.0 -v videotestsrc ! "video/x-raw, format=YUY2, color-matrix=sdtv, chroma-site=mpeg2, width=(int)320, height=(int)240, framerate=(fraction)30/1" ! shmsink socket-path=/tmp/blah shm-size=20000000
Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
/GstPipeline:pipeline0/GstVideoTestSrc:videotestsrc0.GstPad:src: caps = video/x-raw, format=(string)YUY2, width=(int)320, height=(int)240, framerate=(fraction)30/1, multiview-mode=(string)mono, color-matrix=(string)sdtv, chroma-site=(string)mpeg2, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive
/GstPipeline:pipeline0/GstCapsFilter:capsfilter0.GstPad:src: caps = video/x-raw, format=(string)YUY2, width=(int)320, height=(int)240, framerate=(fraction)30/1, multiview-mode=(string)mono, color-matrix=(string)sdtv, chroma-site=(string)mpeg2, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive
/GstPipeline:pipeline0/GstShmSink:shmsink0.GstPad:sink: caps = video/x-raw, format=(string)YUY2, width=(int)320, height=(int)240, framerate=(fraction)30/1, multiview-mode=(string)mono, color-matrix=(string)sdtv, chroma-site=(string)mpeg2, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive
/GstPipeline:pipeline0/GstCapsFilter:capsfilter0.GstPad:sink: caps = video/x-raw, format=(string)YUY2, width=(int)320, height=(int)240, framerate=(fraction)30/1, multiview-mode=(string)mono, color-matrix=(string)sdtv, chroma-site=(string)mpeg2, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock

Is it the right way to get a stream to several processes?

[DaneLLL]

Hi,
We don’t have experience of using shmsink and shmsrc. Would need other users to share suggestion.

A possible solution is to run UDP streaming. Please refer to this topic and can give it a try:
Gstreamer TCPserversink 2-3 seconds latency - #5 by DaneLLL