Using compositor with shmsrc

[Guru Govindan]

Hi Nirbheek,
Thanks a lot for your response.
I'm building a video wall of security cameras where the compositor runs in
a different process and the camera ingest in a different process.

I want to use the compositor from a different process so that I will be
able set multiple layouts.
I saw your blog post on gstproxy, but it works only inside one process.

http://blog.nirbheek.in/2018/02/decoupling-gstreamer-pipelines.html?m=1
I was trying to use ipcpipelinesink but was having issues running it
without ipcpipelineslave. Shmsrc seemed best for my usecase but doesn't
seem to work with the compositor.

I appreciate your help with this.
Best regards.
Guru


On Sun, Dec 25, 2022, 4:41 AM Nirbheek Chauhan <nirbheek.chauhan at gmail.com>
wrote:

> Hi Guru,
>
> The easiest way to do this is to use appsrc / appsink instead of
> shmsrc / shmsink and set the format=time property on appsrc.
>
> You will have to write code to manually push samples from appsink to
> appsrc, though. So it won't work using gst-launch.
>
> Cheers,
> Nirbheek
>
> On Sun, Dec 25, 2022 at 2:45 PM Guru Govindan via gstreamer-devel
> <gstreamer-devel at lists.freedesktop.org> wrote:
> >
> > Hi,
> > I have the a few pipelines that send raw video shmsink like below
> >
> > ```
> > gst-launch-1.0 videotestsrc !
> video/x-raw,format=I420,width=640,height=360,framerate=15/1 ! timeoverlay !
> queue ! shmsink socket-path=/tmp/test1 shm-size=20000000 sync=true
> >
> > gst-launch-1.0 videotestsrc !
> video/x-raw,format=I420,width=640,height=360,framerate=15/1 ! timeoverlay !
> queue ! shmsink socket-path=/tmp/test2 shm-size=20000000 sync=true
> >
> > ```
> >
> > I am trying to mux the videos using the compositor plugin in another
> process like this
> >
> > ```
> > gst-launch-1.0 shmsrc socket-path=/tmp/test1 is-live=true ! queue !
> video/x-raw,format=I420,width=640,height=360 ! compositor name=comp
> sink_1::xpos=860 ! videoconvert ! autovideosink \
> > shmsrc socket-path=/tmp/test2 is-live=true ! queue !
> video/x-raw,format=I420,width=640,height=360 ! comp.
> > ```
> >
> > However I get an assertion error that GST_FORMAT_TIME is not available
> like below.
> >
> > ```
> >
> ERROR:../subprojects/gst-plugins-base/gst-libs/gst/video/gstvideoaggregator.c:2322:gst_video_aggregator_sink_event:
> assertion failed: (seg.format == GST_FORMAT_TIME)
> > Bail out!
> ERROR:../subprojects/gst-plugins-base/gst-libs/gst/video/gstvideoaggregator.c:2322:gst_video_aggregator_sink_event:
> assertion failed: (seg.format == GST_FORMAT_TIME)
> > [1]    268025 abort (core dumped)  GST_DEBUG=4 gst-launch-1.0 shmsrc
> socket-path=/tmp/test1 is-live=true !
> > ```
> >
> > Is there a way to manually add GST_FORMAT_TIME?
> >
> > I tried the videomixer element and have the same issue there. I tried
> inserting identity sync=true but that doesnt seem to do the trick.
> >
> > I appreciate any help in this!
> > Thanks a lot!
> > Guru
> >
> >
> > ~
> >
>
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