[FFmpeg-user] ffmpeg-2.1 + setsar + setdar question

[Carl Eugen Hoyos]

David Favor <david <at> davidfavor.com> writes:

> Question about how to do video stream copy (maybe via filter)
> when the only operation is to strip/change SAR + DAR.

Use the command line option -aspect with -vcodec copy

> David-Favor-iMac# ffmpeg -y -i broken.mp4 -c:a copy 
> -c:v libx264 -crf 20 -preset:v veryfast 
> -vf setsar=sar=0 -vf setdar=dar=0 -t 10 test.mp4 

> David-Favor-iMac# ffmpeg -y -i broken.mp4 -c:a copy 
> -c:v libx264 -crf 20 -preset:v veryfast 
> -vf setdar=dar=0 -vf setsar=sar=0 -t 10 test.mp4 

These are equally broken in two ways:
Don't use -vf setdar -vf setsar, either use one or the 
other, in your case either:
-vf setsar=sar=x/y (sorry, too lazy to calculate)
or:
-vf setdar=dar=4/3
To set a display aspect ratio of 4/3 (assuming this is 
what you want).
Don't set a ratio of 0, this seems not correct to me 
unless you know a specific reason why.

Note that I suspect the original ratio is simply correct 
and the result of cropping.

What is avinfo?

Carl Eugen