[FFmpeg-devel] [PATCH] avformat, ffmpeg: deprecate old rotation API

wm4 nfxjfg at googlemail.com
Tue Mar 21 15:14:33 EET 2017


On Tue, 21 Mar 2017 14:09:49 +0100
Clément Bœsch <u at pkh.me> wrote:

> On Tue, Mar 21, 2017 at 08:42:58AM +0100, wm4 wrote:
> > The old "API" that signaled rotation as a metadata value has been
> > replaced by DISPLAYMATRIX side data quite a while ago.
> > 
> > There is no reason to make muxers/demuxers/API users support both. In
> > addition, the metadata API is dangerous, as user tags could "leak" into
> > it, creating unintended features or bugs.
> > 
> > Unfortunately, hacks have been added, that allow the user to override
> > rotation by setting metadata explicitly, e.g. via
> > 
> >   -metadata:s:v:0 rotate=0
> >   
> 
> does remux and transcode properly keeps the property? And the other way
> around, can we still remove the rotate property?

Remuxing should keep the DISPLAY_MATRIX, there's nothing special about
it. Not sure what you mean by removing the rotate "property". The mp4
muxer, which is the only thing seems to support writing rotation,
always writes a display matrix. For removing metadata fields, no idea
how that works.


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