[FFmpeg-user] How can I extract 8 linear thumbnails from videos with differnt length?

[Christian Ebert]

* Moritz Barsnick on Wednesday, April 06, 2016 at 23:13:25 +0200
> On Wed, Apr 06, 2016 at 21:02:17 +0200, Christoph Gerstbauer wrote:
>> I want to extract 8 thumbnails from every video I have which represents 
>> a linear "timeline" over the complete length (100percent) of the video.
> [...]
>> Is there a filter which can be used for that in combination with the 
>> -vframe command?
> 
> I don't think you'd need "-vframes" (that's what you meant?).
> 
>> I want to use ONE command line, where the video length is used as 100 
>> percent.
> 
> The select filter would be appropriate, *except* that the total length
> of the video is not available for its expression evaluation. So you
> would actually need two commands - one to determine the length, the
> other to extract the frames.

Depending on the calculation it may be easier/more intuitive to
use framerate:

ffmpeg -i input -filter:v framerate=1/10 out-%d.jpg

will create one image every ten secs.

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