[FFmpeg-user] Note to document maintainer

[Herve Flores]

Le 26 mars 2012 à 15:13, Donald McLachlan a écrit :

> 
> 
> On 24/03/2012 1:40 PM, Steve M. Fabac, Jr. wrote:
>> As a newbie I tried the following example:
>> 
>> The following example shows how to use ffmpeg for creating
>> a sequence of files ‘img-001.jpeg’, ‘img-002.jpeg’, ...,
>> taking one image every second from the input video:
>> 
>>  ffmpeg -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
>> 
>> So what's the change/addition to create an image every two seconds?
>> Every three seconds?  The needed switch may be buried in
>> the overall documentation. Having it in the "section 9.3 image 2"
>> would save newbie's a lot of searching.
>> 
>> Also, the single quotes above fail under Windows XP and the correct
>> command is: ffmpeg -i in.avi -vsync 1 -r 1 -f image2 img-%03d.jpeg
>> 
>> 
> 
> I have recently used -f image2 to extract a video to a series of pegs and it works just fine.
> 
> In the example you provided, "-r 1" sets the output frame rate to be 1 frame per second.  Did you try "-r 0.5" for one frame every 2 seconds?

…or "-r 1/2" ;-)

bye

Hervé