[MPlayer-users] play or encode only range of frames

[Corey Hickey]

Adam Nielsen wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> 
>>You can use -ss to specify time from where to begin encoding. So I
>>guess if you know original movie framerate, you can calculate the
>>right value using formula:
>>desired_start_frame / fps = desired_start_time
> 
> 
> -ss will take decimal values (10.5) so you should be able to get it fairly 
> accurate.  I'm still not sure how well it works though, because mplayer 
> doesn't seek nicely with it (although mencoder seems ok.)  So far I prefer to 
> allow a little extra on the front of the encoding, and trim it off afterwards 
> with avidemux2 (which can be automated - you could even use avidemux2 in a 
> script solely for cutting an AVI, assuming the AVI is using a supported 
> codec.)
> 
> 

The trouble is that mplayer will never seek to a non-keyframe. So, if
you use -ss, it will actually start at the nearest keyframe rather than
exactly where you specify.

-Corey