How to grab an uncompressed image from the UVC camera, e.g. with ffmpeg?

[ventilator]

I configured the camera to deliver uncompressed images, that seems to work, according to ffmpeg

ffmpeg -list_options true -f dshow -i video="UVC Camera"

[dshow @ 00000193bd719840]   vcodec=mjpeg  min s=1280x720 fps=15 max s=1280x720 fps=30
[dshow @ 00000193bd719840]   vcodec=mjpeg  min s=1280x720 fps=15 max s=1280x720 fps=30
...
[dshow @ 00000193bd719840]   pixel_format=yuyv422  min s=1920x1080 fps=15 max s=1920x1080 fps=30
[dshow @ 00000193bd719840]   pixel_format=yuyv422  min s=1920x1080 fps=15 max s=1920x1080 fps=30

Then I can record a compressed mpeg stream with
ffmpeg -f dshow -video_size 1280x720 -framerate 15 -i video="UVC Camera" -vcodec mjpeg out.avi

That works fine, I get a video.

But once I ask the camera for an uncompressed stream, nothing happens:

ffmpeg -f dshow -video_size 1920x1080 -framerate 15 -i video="UVC Camera" -pixel_format yuyv422 uncompressed.avi

• Has anyone grabbed uncompressed images? Can you share your method? Ultimately I would like to grab the images with OpenCV, but also there I only get black images