[MPlayer-users] play specified frame range?

[Kichigai Mentat]

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On Mar 20, 2006, at 20.59, Nick Rout wrote:

>
> On Mon, 20 Mar 2006 20:39:53 -0600
> Kichigai Mentat wrote:
>
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>> On Mar 20, 2006, at 20.21, Nick Rout wrote:
>>
>>> How can i get mplayer to play a specified frame range, eg from
>>> frame 500
>>> to frame 2500?
>>>
>>> I can see -ss (seek to time) and -sb (seek to byte) but no seek to
>>> frame. Also can't see anywhere to specify how long to play for.
>> Well, the "how long to play for" IS in the documentation, it's just
>> not listed as duration in frame. I believe what you were looking for
>> is -endpos
>>
>> As far as figuring out frames, just do the math. If your footage is
>> 29.97 frames per second, then one frame is 0.033 seconds long. If
>> it's 23.97 frames, then it's 0.042 seconds. Otherwise, no, the
>> feature you want doesn't exist.
>>
>
> Thank you.  As most of my stuff is PAL, the framerate is 25, and the
> calulation is a lot easier :-)

You mean people exist outside of the US have computers?! ;)

>
> Oh and -endpos seems to only relate to mencoder. I have an  
> acquaintance
> who wishes to play specific bits of a file, frame or time accurate (he
> prefers frame but he can use a calculator!). For teaching purposes he
> wants to be able to set up a system where he can play a specified  
> chunk,
> then discuss with the class, then play some more, etc.

Well, not that hard.

mencoder -ss (start point) -endpos (end point) -ovc copy -oac copy -o  
(output filename).avi (input filename).(input extension)

They'll be ready to go for class! He could even play them in  
something like XMMS with video support, or VLC, and scroll through  
the parts in a playlist. I'm pretty sure XMMS and VLC have an option  
somewhere to not automatically proceed to the next item in a playlist.

>
> -- 
> Nick Rout <nick at rout.co.nz>
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