[FFmpeg-devel] [PATCH]Reset rotation information when using the transpose filter

Carl Eugen Hoyos cehoyos at ag.or.at
Thu Nov 15 11:05:04 CET 2012

Clément Bœsch <ubitux <at> gmail.com> writes:

> > >  - transpose is a filter to physically change the 
> > >    video: the correct way is likely to kept the 
> > >    metadata after the transcode (isn't it the case?)
> > 
> > I believe that this is the bug:
> > The metadata should not be kept if the transcode 
> > filter is used (it should be reset).
> > 
> Why?

Sample from ticket #505:
$ ffmpeg -i sample-in-issue-505.mov out.mov
Plays correctly with QuickTime, this was implemented 
by Stefan Gehrer.
Cannot play correctly with other software that does not 
implement mov rotation (MPlayer).
$ ffmpeg -i sample-in-issue-505.mov -vf transpose=1 out.mov
Plays fine with every player except those that implement 
mov rotation (QuickTime).

The bug is that the transpose filter does not reset 
"rotate" metadata.
I do not understand why the "rotate" metadata cannot be 
overwritten from the command line...

And if a player correctly implements mov rotation by 
reading FFmpeg's "rotate" metadata and inserting the 
transpose filter, I don't see any problem if the filter
resets "rotate": It simply makes no difference in that 
case imo.

Carl Eugen

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