[FFmpeg-user] Overwriting JPEG at output

[Jose Luis Rivas]

Hi,

I'm trying to get an AVI trough RTSP (or any input, really, be it a
static video, by e.g.) to output a still JPEG, and this been
overwritten. This is a line of what I'm trying and what I've already tried:

snip:start 8< ------
ffmpeg -i test.webm -r 1 -f image2 -s qvga what.jpg
ffmpeg -loop_output 1 -i test.webm -r 1 -f image2 -s qvga what.jpg
ffmpeg -loop_output 1 -i test.webm -r 1 -f image2 -s qvga -vframes 1
what.jpg
------ >8 snip:end

None of them work for what I want, not even using '-y' flag. I also
tried using the '%d', and I was suggested on IRC to make it rewrite if
it were working on a limit of digits, but it doesn't, it just goes to
infinite.

Someone could help me out here? I need it to write a single JPEG file,
and not an mjpeg. I want to pass it on base64 and need only a JPEG each
time.

Regards,