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

[Michael Niedermayer]

On Fri, Mar 24, 2017 at 01:49:16PM +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.
> 
> ffmpeg CLI has to be updated to use the new API. In particular, we must
> not allow to leak the "rotate" tag into the muxer. Some muxers will
> catch this properly (like mov), but others (like mkv) can add it as
> generic tag. Note applications, which use libavformat and assume the
> old rotate API, will interpret such "rotate" user tags as rotate
> metadata (which it is not), and incorrectly rotate the video.
> 
> The ffmpeg/ffplay tools drop the use of the old API for muxing and
> demuxing, as all muxers/demuxers support the new API. This will mean
> that the tools will not mistakenly interpret per-track "rotate" user
> tags as rotate metadata. It will _not_ be treated as regression.
> 
> 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            | 10 +---------
>  ffmpeg.c              | 41 ++++++++++++++++++++++++++++++++++++-----
>  ffmpeg.h              |  1 +
>  ffmpeg_opt.c          | 12 ++++++++----
>  libavformat/mov.c     |  2 ++
>  libavformat/movenc.c  |  4 ++++
>  libavformat/version.h |  3 +++
>  7 files changed, 55 insertions(+), 18 deletions(-)

Is this intended to fix (relative to last patch)

./ffmpeg -i ~/tickets/4012/IMG_4596.MOV  -t 0.5  test.mov
./ffplay test.mov

?

it seems to still be upside down with this applied

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Those who are best at talking, realize last or never when they are wrong.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 181 bytes
Desc: Digital signature
URL: <http://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20170325/98acaed1/attachment.sig>