Piping h264 video stream to stdout

[sl13]

Hi,
First of all, thank you for the great project. I am currently working with a Raspberry Pi 2 and a Logitech C925e.
The local streaming with your project works on the first try, but unfortunately this is not what I want to achieve.
I would like to transfer the h264 stream of the camera via rtmp to Youtube.
I already got this working successfully with ffmpeg and the raspberry pi camera and I think the easiest way would be to use the ffmpeg software for the Logitech camera as well.
For this project I would have to write the h264 camera data to stdout and forward it to ffmpeg.
Currently I am not sure how to implement this. Where can I find the h264 video data and how can I write it to stdout?

I would be grateful for any help.
Best regards,
Sven

[soyersoyer]

I used to think about this as well.

GStreamer also has an mjpegh264 demuxer, maybe that is more suitable for you.

https://gstreamer.freedesktop.org/documentation/uvch264/uvch264mjpgdemux.html

But with this code:

Initalize the camera and such like in fmp4streamer.py, create an MP4Writer instead of Streamingserver,
use sys.stdout instead of self.wfile

                mp4_writer = MP4Writer(self.wfile, config.width(), config.height(), config.rotation(), config.timescale(), h264parser.sps, h264parser.pps)
                while True:
                    nalus, frame_secs, frame_usecs = h264parser.read_frame()
                    mp4_writer.add_frame(nalus, frame_secs, frame_usecs)

[sl13]

Thank you very much for your help. Unfortunately, I can't get either of the two variants to work. I have carried out some tests for the gstreamer variant. The following two pieplines work without problems.

gst-launch-1.0 -v v4l2src device=/dev/video0 ! "video/x-raw, width=640,height=480,framerate=30/1" ! videoconvert ! autovideosink
gst-launch-1.0 -v v4l2src device=/dev/video0 ! "image/jpeg,parsed=true,width=640,height=480" ! jpegdec ! videoconvert ! autovideosink

But when I add the demuxer "uvch264mjpgdemux" to the piepline it doesn't work.

gst-launch-1.0 -v v4l2src device=/dev/video0 ! "image/jpeg,parsed=true,width=640,height=480" ! uvch264mjpgdemux ! "video/x-h264,width=640,height=480,framerate=30/1" ! avdec_h264 ! videoconvert ! autovideosink

The following error report is displayed:

Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Got context from element 'autovideosink0': gst.gl.GLDisplay=context, gst.gl.GLDisplay=(GstGLDisplay)"\(GstGLDisplayX11\)\ gldisplayx11-0";
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
/GstPipeline:pipeline0/GstV4l2Src:v4l2src0.GstPad:src: caps = image/jpeg, parsed=(boolean)true, width=(int)640, height=(int)480, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1, colorimetry=(string)2:4:5:1
/GstPipeline:pipeline0/GstCapsFilter:capsfilter0.GstPad:src: caps = image/jpeg, parsed=(boolean)true, width=(int)640, height=(int)480, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1, colorimetry=(string)2:4:5:1
/GstPipeline:pipeline0/GstUvcH264MjpgDemux:uvch264mjpgdemux0.GstPad:jpeg: caps = image/jpeg, parsed=(boolean)true, width=(int)640, height=(int)480, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1, colorimetry=(string)2:4:5:1
/GstPipeline:pipeline0/GstUvcH264MjpgDemux:uvch264mjpgdemux0.GstPad:sink: caps = image/jpeg, parsed=(boolean)true, width=(int)640, height=(int)480, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1, colorimetry=(string)2:4:5:1
/GstPipeline:pipeline0/GstCapsFilter:capsfilter0.GstPad:sink: caps = image/jpeg, parsed=(boolean)true, width=(int)640, height=(int)480, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1, colorimetry=(string)2:4:5:1
ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0: Internal data stream error.
Additional debug info:
../libs/gst/base/gstbasesrc.c(3127): gst_base_src_loop (): /GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
streaming stopped, reason not-linked (-1)
Execution ended after 0:00:00.315406966
Setting pipeline to NULL ...
Freeing pipeline ...

I know the problem has nothing to do with your software, but do you have any idea what the error could be?

[soyersoyer]

Maybe these can help:

https://kakaroto.homelinux.net/2012/09/uvc-h264-encoding-cameras-support-in-gstreamer/
https://www.oz9aec.net/software/gstreamer/using-the-logitech-c920-webcam-with-gstreamer-12