[FFmpeg-user] scale video filter and force_original_aspect_ratio option

Lou lou at lrcd.com
Thu Nov 28 21:06:13 CET 2013

On Wed, Nov 27, 2013, at 01:05 PM, James Darnley wrote:
> Does the force_original_aspect_ratio option of the scale filter work as
> described in the online docs?
> > One useful instance of this option is that when you know a specific
> > device’s maximum allowed resolution, you can use this to limit the
> > output video to that, while retaining the aspect ratio. For example,
> > device A allows 1280x720 playback, and your video is 1920x800. Using
> > this option (set it to decrease) and specifying 1280x720 to the
> > command line makes the output 1280x533.
> I read that to be "If and only if the video is larger than the size you
> set it will be scaled to fit within the size you set."  Is that reading
> wrong?  I've been trying to get it to work when encoding a random set of
> files, some smaller and some larger, than what I want but all are
> resized to fit.


   Enable decreasing or increasing output video width or height if
   necessary to keep the original aspect ratio.

Keywords "if necessary" seem to imply that smaller sized inputs will not
be increased when decrease is used, but the docs do not indicate what
occurs in this case.

I haven't looked at the code and I may be missing something (which
occurs more than I prefer), but it seems bug reportable to me.

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