[FFmpeg-user] ffplay at half size by means of a math function

[Dave P]

On Jun 30, 2015 11:32 AM, "Jim Shupert, Jr." <jshupert at theppsgroup.com>
wrote:
>
>
>
> Friends,
>
> I wish to be able to play a file with ffplay but have it play at 1/2 the
> real size
>
> with -x NUM  -y NUM
> I can control play size with
> ffplay -x 640 -y 360 -i dog.avi
> this works as hoped
>
> but what I would really like to do is do some math on the file and scale
> it down
>
>
> with something like
> ffplay -vf=scale=iw/2:ih/2 -i /media/data/zzz-s/NASA_logo.mov

You need a blank space after -vf

-vf scale=