[FFmpeg-user] Extract all keyframes

[Simon Thelen]

On 27/06/14 at 11:37, Matthew Bondy wrote:
> My question: When I do not specify the frame rate I assume ffmpeg uses some
> default (20, 25?). The number of frames generated is in excess of the known
> number of keyframes by the ratio of 20/17 (or is it 25?, I cannot recall).
> When I use the option -r 17 (should I be more precise? '-r 17.1'?) I obtain
> a suitable number of frames but on the command line ffmpeg indicates the
> frame rate as it extracts the frames. This number fluctuates. Is the
> effective frame rate for keyframes a variable or is this a source of error
> in my analysis (I bring the images into software for material deformation
> analysis).
That's just the encoding fps. ie how many frames are being encoded every
second and has absolutely nothing to do with the fps of either the input
or the output file.

-- 
Simon Thelen