[FFmpeg-trac] #7498(undetermined:closed): webm rotation metadata results in deformed output.

FFmpeg trac at avcodec.org
Mon Oct 22 07:54:16 EEST 2018

#7498: webm rotation metadata results in deformed output.
             Reporter:  carl         |                    Owner:
                 Type:  defect       |                   Status:  closed
             Priority:  normal       |                Component:
              Version:  unspecified  |  undetermined
             Keywords:               |               Resolution:  invalid
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0
Changes (by Gyan):

 * status:  reopened => closed
 * resolution:   => invalid


 I don't see any orientation metadata in the webm sample. ffmpeg reports a
 1920x1080 raster with sample aspect ratio of 19:60 which should result in
 a display raster of 608x1080 at 1x size.

 FFmpeg will not automatically convert frames to square-pixel. It will
 convey the SAR to the output format if it supports storing that attribute.
 It's then up to the reading app to read and apply that value. For apps (or
 formats) which don't do that, the workaround is to use Carl's suggested
 filter syntax. I would add one thing, though: `-vf
 scale=iw*sar:ih,setsar=1`. The setsar is added for safety, since the
 computed value by scale may not be perfect unity.

Ticket URL: <https://trac.ffmpeg.org/ticket/7498#comment:3>
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