[FFmpeg-user] Order for Filters

Nicholas Robbins nickrobbins at yahoo.com
Fri Apr 15 01:07:12 CEST 2016

> On Thursday, April 14, 2016 1:15 PM, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:

> > Nicholas Robbins writes:
>>  > But if the input is letterboxed, you should definitely crop 
>>  > first.
>>  The input definitely appears to be letterboxed. Is there some 
>>  difference between "appearing" to be letterboxed and actually 
>>  being letterboxed that I should check for?
> Please remember that I live in PAL country and my mother tongue 
> is not English: Does "letterboxed" mean black bars either left 
> and right or above and below the actual image?
> If yes, what is the difference between "apparent black bars" 
> and "actual black bars"?

> I think we can agree that the black bars do not help fieldmatch 
> but take time to process and should therefore be removed as 
> early in the process as possible.
> Carl Eugen

"letterboxed" means black bars top and bottom. I didn't know if there might be a difference or not. Maybe there is a way to encode the black bars in the mpeg video stream besides just black pixels. I didn't know. Seems like its just black pixels.

I thought before would be better, but wanted to make sure that the crop wouldn't mess us the fieldmatch, like a scale would for instance.

Thanks for your advice.


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