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

Michael Niedermayer michael at niedermayer.cc
Wed Mar 22 20:32:11 EET 2017


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
> 
> See references to trac #4560. fate-filter-meta-4560-rotate0 tests this.
> It's easier to adjust the hack for supporting it than arguing for its
> removal, so ffmpeg CLI now explicitly catches this case, and essentially
> replaces the "rotate" value with a display matrix side data. (It would
> be easier for both user and implementation to create an explicit option
> for rotation.)
> 
> When the code under FF_API_OLD_ROTATE_API is disabled, one FATE
> reference file has to be updated (because "rotate" is not exported
> anymore).
> ---
>  cmdutils.c            |  4 ++++
>  ffmpeg.c              | 11 ++++++++---
>  ffmpeg.h              |  1 +
>  ffmpeg_opt.c          | 12 ++++++++----
>  libavformat/mov.c     |  2 ++
>  libavformat/movenc.c  |  4 ++++
>  libavformat/version.h |  3 +++
>  7 files changed, 30 insertions(+), 7 deletions(-)

this breaks rotate handling

for example:
./ffmpeg -i ~/tickets/4012/IMG_4596.MOV  -t 0.5  test.mov
./ffplay test.mov
is upside down

https://s.natalian.org/2014-10-07/IMG_4596.MOV

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The misfortune of the wise is better than the prosperity of the fool.
-- Epicurus
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