[FFmpeg-user] how to equal ratio scale the video

[Werner Robitza]

On Thu, Jan 2, 2014 at 11:19 AM, Werner Robitza
<werner.robitza at gmail.com> wrote:
> On Thu, Jan 2, 2014 at 9:59 AM, （忍）不轻云 <449127727 at qq.com> wrote:
>> if(gt(a,16/9),1280,trunc(oh*a*2)/2)':'if(gt(a,16/9),trunc(ow/a/2)*2,720)
>
> I could be mistaken since you haven't described what you want to
> accomplish, but 1280 is the width, so you need:
>
> 1280,trunc(ow*a*2)/2
>
> Likewise, for the second part:
>
> trunc(oh/a/2)*2,720)

Actually, you may want to use (ow*a/2)*2 since that way you'll end up
with an even number.