When muxing, the AVStreams' side-data is typically set
by the caller before avformat_write_header();
it is not documented to be else. Yet the Matroska muxer
added an AVStereo3D side data if certain metadata
was present:
Since commit 4d686fb721b485ebbc4c7779d927d876c1e630f7
(adding support for AVStereo3D stream side-data),
the Matroska muxer checked certain stream tags that
contain Matroska's StereoMode and (if they are present)
converted this value into an AVStereo3D struct that
gets attached to the AVStream (reusing a function from
the demuxer). Afterwards the AVStereo3D side data struct
(whether it has just been added by the muxer or not) gets
parsed and converted back into a Matroska StereoMode.
Besides being an API violation this change broke
StereoMode values without a corresponding AVStereo3D
(namely the anaglyph ones).
This commit fixes this: A StereoMode given via tags
is now used-as-is; if no such tag exists and an AVStereo3D
side data exists, it is converted into the corresponding
StereoMode (if possible). This approach also fixes
handling of the anaglyph ones; the changes to the
matroska-stereo_mode are due to this.
The new STEREOMODE_STEREO3D_MAPPING has been put to
good use for this.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
884653ee5b