[FFmpeg-user] Order for Filters

[Nicholas Robbins]

> On Thursday, April 14, 2016 9:22 AM, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:

> > Nicholas Robbins <nickrobbins-at-yahoo.com <at> ffmpeg.org> writes:
> 
>>  I have some MKV's from a DVD that are telecined and 
>>  letterboxed. I would normally use
>> 
>>  "-vf fieldmatch,decimate"
>> 
>>  however, I want to add a crop filter. Which order would be 
>>  better? Crop before fieldmatch or fieldmatch before crop?
> 
> While it generally doesn't matter and it would speed up the 
> process to first crop, I wanted to suggest to do the cropping 
> later so fieldmatch has more data to decide if a frame is 
> interlaced.
> 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?

-Nick