video decoding on imx8mq vpu via v4l2

[Martin Kepplinger <martin.kepplinger@puri.sm>]

Hi,

I'd like to test decoding an mpeg2 or h264 video file on imx8mq, using
its vpu:

I use Philipp's changes for imx8m from
https://git.pengutronix.de/cgit/pza/linux/log/?h=hantro/imx8m-wip in my
tree:

https://source.puri.sm/martin.kepplinger/linux-next/commits/5.6-rc1/librem5__integration

and play around with gstreamer, taking notes at
https://source.puri.sm/Librem5/linux-next/issues/74

The driver probes fine and v4l2 appearently sees the MEM2MEM decoder:

$ v4l2-ctl --list-devices
nxp,imx8mq-vpu-dec (platform: hantro-vpu):
	/dev/video0


AFAIK gstreamer should provide a "v4l2videodec" element which it doesn't:

$ gst-inspect-1.0|grep -i v4l
video4linux2:  v4l2deviceprovider (GstDeviceProviderFactory)
video4linux2:  v4l2radio: Radio (video4linux2) Tuner
video4linux2:  v4l2sink: Video (video4linux2) Sink
video4linux2:  v4l2src: Video (video4linux2) Source


First: Philipp, do you plan to continue working on supporting hantro for
imx8m upstream?

Then: What codec would be appropriate to test decoding now? It seems
like h264 is supposed to be implemented. How do you test?

And finally: What could be missing here? I use debian's gstreamer
package, but in this case it can't really be a config/build issue in
gstreamer, right?

thanks,

                                martin