[MPlayer-users] Re: Extracting image from a movie

[Stefan Sassenberg]

King wrote:
> Reimar Döffinger <Reimar.Doeffinger <at> stud.uni-karlsruhe.de> writes:
> 
> 
>>Hi,
>>
>>>Withe command
>>>
>>>mplayer levy.avi -ss 60 -vo png -nosound -frames 1
>>>
>>>I get two images one of the opening frame and one from the frame
>>> starting at 60 seconds. (etc. If a try to make images of 
>>>two frames with '-frames 2' I get three images. One of the
>>> first frame + the two frames starting from 60 sec.)
>>>
>>>I can't figure out why I get this first frame as a png image.
>>
>>Yes, I remeber that problem. It has to do with how -ss is implemented. 
>>It starts playback and then seeks, afaik, thus giving you always one 
>>frame from the beginning.
>>
>>Greetings,
>>Reimar Döffinger
>>
> 
> 
> If it first starts playing and then seeking can this then be considered a bug ?
> With some scripting I now can delete the first image I get (since this is always
> the opening frame) and use the second (in my web application), but it would
> still be nice to know how to grab a single frame with mplayer/mencoder and turn
> it into an image.
> 
I'd consider it a bug as long its behaviour differs from the description 
in the doc. The -ss option's behaviour is not clear to me anyway because 
it jumps to a frame _near_ the position requested but not necessarily 
exactly to it. I do not know enough about iframes to see the reason for 
this.

Stefan