[FFmpeg-user] Problem with DAR and SAR readout from AVCI-50 and DNxHD MXFs

Carl Eugen Hoyos cehoyos at ag.or.at
Thu May 8 19:09:29 CEST 2014

Christoph Gerstbauer <christophgerstbauer <at> gmx.at> writes:

> So you mean a SAR or DAR with "0:1" already means "undefined"?

First, there is not DAR:
There is a resolution and the sample aspect ratio (sometimes 
called pixel aspect ratio) and that allows to calculate the 
display aspect ratio and this is how it's shown on the 
If the stream does not define a SAR (or if it is invalid) 
then it will be set to 0:1 (or sometimes 0:0) which is 
invalid (as you already correctly stated).
Note that it is very important to signal an invalid SAR 
because files can define different SARs in the container 
and the video stream and you need to decide which one to 

The question is now if the dnxhd files you uploaded don't 
contain a definition for SAR or if FFmeg fails to read it.

Carl Eugen

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