MJPEG USB camera to H264 Encoding Pipeline

[Marianna Smidth Buschle]

Try running with '-v' and/or '--gst-debug=*:3,GST_CAPS:5' in order to 
inspect the CAPS and try to see where it is failing.

Alternatively try reducing the pipeline to see if you can pinpoint which 
part is failing and why:

gst-launch-1.0 v4l2src device=/dev/video2 ! jpegparse ! fakesink -v --gst-debug=*:3,GST_CAPS:5
gst-launch-1.0 v4l2src device=/dev/video2 ! jpegparse ! v4l2jpegdec ! fakesink -v --gst-debug=*:3,GST_CAPS:5
gst-launch-1.0 v4l2src device=/dev/video2 ! jpegparse ! v4l2jpegdec ! videoconvert ! v4l2h264enc ! fakesink -v --gst-debug=*:3,GST_CAPS:5

...

Best Regards
Marianna

On 05.07.2022 14.03, gstreamer-devel-request at lists.freedesktop.org wrote:
> Hi,
>
> I'm running gstreamer on an i.MX8QM with H264 and JPEG HW
> encoding/decoding. My end goal is to process two MJPEG streams from two
> different USB cameras, do some light processing in OpenCV and then encode
> it in H264. My first step was to simply create a gstreamer pipeline to
> transcode the frames coming from the camera into H264 and write them to a
> file. Small proof-of-concept. However, I'm running into issues linking
> the v4l2jpegdec v4l2h264enc elements.  This is the pipeline I'm using (it's
> taken from NXP's official user guide on using i.MX8 with GStreamer [1]).
> Have tried a lot of variations, but the results (even with detailed
> logging) have looked very similar:
>
> gst-launch-1.0 v4l2src device=/dev/video2 ! jpegparse ! v4l2jpegdec ! queue
> ! videoconvert ! v4l2h264enc ! h264parse ! matroskamux ! filesink
> location=out.mkv
>
> And this is the output I'm getting:
> Setting pipeline to PAUSED ...
> Pipeline is live and does not need PREROLL ...
> Setting pipeline to PLAYING ...
> New clock: GstSystemClock
> ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0: Internal
> data stream error.
> Additional debug info:
> ../git/libs/gst/base/gstbasesrc.c(3072): gst_base_src_loop ():
> /GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
> streaming stopped, reason not-negotiated (-4)
>
> I have a 7MB log file obtained by running GST_DEBUG_LEVEL=6, but I'm not
> sure if the correct etiquette is to attach it to this email. I've also
> tried using caps filtering and used gst-inspect to make sure the src of the
> jpegdecoder matches the sink of the h264 encoder. Not looking for a
> straight response, but a few hints on where I can look next, as I'm feeling
> a bit lost.
>
> Also, since my goal is to have the OpenCV app between the MJPEG decoder and
> the H264 encoder, should I just abandon the goal of having a manual
> pipeline working first and simply start testing straight with the
> application?
>
> Thirdly, is it feasible to expect the i.MX8QM to be able to decode the
> streams from two MJPEG cameras (1080p at 60FPS), combine them and then encode
> the result using H264? Or do I need a different processor?
>
> Thank you!
>
> [1]
> https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/i-MX-8-GStreamer-User-Guide/ta-p/1098942

-- 
Best regards / Med venlig hilsen
“Marianna Smidth Buschle”