[MPlayer-users] Re: one frame forward/backward

[D Richard Felker III]

On Wed, Jul 16, 2003 at 10:53:58AM -0700, Dean S. Messing wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> 
> Alex Dunaevsky wrote:
>  :: AFAIK you will be able to seek to next/previous keyframe. Keyframes 
>  :: are set while encoding. So you can reencode the file with some codec 
>  :: that allows setting keyframe interval (e.g. libavcodec) and be as 
>  :: precise as you wish.
>  :: 
>  :: -- 
>  :: Best regards,
>  :: Alex Dunaevsky  <alexcrow at ua.fm>
> 
> Are such keyframes set when encoding uncompressed
> video?  I use mplayer for my research.  I encode
> .avi files from sequences of .png source material.
> I would very much like to get mplayer to single
> step on frames but, so far, have failed to be able
> to do it.  Even when I set fps to 1, rapidly
> hitting the space bar twice moves me ahead 3 or
> more frames.
> 
> Is there any way to get single step action via the
> encoding process?

If you're doing research watching uncompressed frames, and need to see
them one at a time, mplayer is not the right tool for the job. You'd
be much better off with a simple image viewer like xli that waits to
show the next image until you press a key. MPlayer's core is designed
around maintaining A/V sync and preventing gaps in the audio through
deep buffering and buffer measurement, so it's not made to facilitate
things like single-step seek.

Rich