FFmpeg command with -ss option fails on .flv files

Question

I am using FFmpeg to extract screenshot from a video with the following command

/usr/bin/ffmpeg -ss 15 -y -i test.flv -vcodec mjpeg -vframes 1 -an -f rawvideo test.png

But the command fails. Last 3 lines of the response are

frame=    0 fps=  0 q=0.0 Lsize=       0kB time=00:00:00.00 bitrate=   0.0kbits/s
video:0kB audio:0kB global headers:0kB muxing overhead -nan%
Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)

Note that command runs successfully for other video types (3gp, mp4).

Also, when I replace "-ss 15" option with "itsoffset 15" it runs successfully with flv files as well.

Does anybody know why -ss option doesn't work for .flv files?

Answer 1

In newer versions of ffmpeg the -ss and -t options must go after -i [filename].

Answer 2

It might be a syntax issue. The following should work just fine:

/usr/bin/ffmpeg -ss 15 -y -i test.flv -frames:v 1 -an test.png

Notice i removed the codec and the format parameters. I don't think it's wise to force mjpeg on a png continuer & flv is not a rawvideo format