February 22, 2023, 11:10am
I am trying to capture RAW PAL video input and stream it over USB.
It’s sort of an intelligent USB camera project.
Capturing PAL video works without problems.
I was wondering if you can guide me regarding streaming raw video over USB.
If possible it would be great to act as a camera that supports usb video class.
My platform is apalis imx6 and ixora
Could you please share the output (as text) of
tdx-info on your module (
Getting Device Information with Tdx-Info | Toradex Developer Center)?
Could you please share a block diagram of what you are trying to accomplish? It will help us to understand your use case.
February 25, 2023, 2:10pm
You can find the block diagram above.
Ixora gets raw data from PAL camera. This works fine.
I plan to stream this
“raw” video data from Ixora to USB with gst-launch. I would be happy if you can guide me regarding this.
ps: I will post tdx-info output later on when I have access to the hardware again.
February 26, 2023, 6:19pm
To act as UVC camera, you need UVC USB gadget. If you have functioning /dev/video? of your capture device, then it should be quite easy to feed it to UVC gadget device. Hope this thread will help
Solved: UVC webcam gadget on i.MX8 HW - NXP Community
March 1, 2023, 11:44am
Thanks a lot.
I understand that UVC webcam gadget sends mjpeg encoded video stream.
I will check whether I can use mjpeg encoding in a lossless way.
March 1, 2023, 1:40pm
Unfortunately I did only bare metal UVC camera project in the past and didn’t try myself the same on Linux. UVC supports not only compressed stream- and frame based payloads, but as well uncompressed frame based payload (either packed 4:2:2 YUV format (YUY2) or 4:2:0 YUV format (NV12)).
uvc-gadget -f switch:
-f <format> Select frame format
0 = V4L2_PIX_FMT_YUYV
1 = V4L2_PIX_FMT_MJPEG
Googling reveals that “
V4L2_PIX_FMT_YUYV is known in the Windows environment as YUY2”. So this seems to be what you need for uncompressed video.
March 1, 2023, 2:11pm
Thanks a lot Edward,
I think this will be fine with my case