I'm trying to extract thumbnails using mplayer with this command:
mplayer -nosound -ss 1 -vf screenshot -frames 1 -vo png:z=9 jump.mpg
The problem is that it results in an almost grey image.
If I now try and execute the command:
mplayer -ss 1 jump.mpg
Then the video plays back skipping the first second (as expected), but the first second of the playback is mostly grey. Technically, I think it displays the diff to the previous frame, until it gets to a key frame, where the whole frame is encoded in the video.
Now the question is: How do I force mplayer to seek to a key frame, so I avoid this grey image when extracting?
I found the option -hr-seek off, which sounds like it should do the right thing, but it doesn't.
Just use mplayer2, the seek problem is solved. I tested myself:
http://www.mplayer2.org/differences/
on debian/ubuntu just install via apt-get install mplayer2