"-r 1 " is just going to use the input file sampling rate, no? I don't
think this is a sampling rate problem unless there's signs of "rolling
shutters" or total disconnect in the expected output playback.
"You need to check with V4L utilities or ffmpeg, which formats /
resolutions your v4l2
I can't say for certain as its been some time since I used ffmpeg, but
there are only a fixed number of resolutions to pass to ffmpeg using the -s
size parameter and the behavior isn't what you're probably looking for.
What you probably need to look at is the scaling filter:
