[FFmpeg-trac] #8735(avcodec:new): videotoolbox causes chroma artifacts in comparison to sw decoding

[FFmpeg]

#8735: videotoolbox causes chroma artifacts in comparison to sw decoding
--------------------------------------+-----------------------------------
             Reporter:  der_richter   |                    Owner:
                 Type:  defect        |                   Status:  new
             Priority:  normal        |                Component:  avcodec
              Version:  git-master    |               Resolution:
             Keywords:  videotoolbox  |               Blocked By:
             Blocking:                |  Reproduced by developer:  0
Analyzed by developer:  0             |
--------------------------------------+-----------------------------------

Comment (by der_richter):

 this is again a question only someone can answer that knows the internals
 of ffmpeg and the limitations of the videotoolbox API. since i don't know
 what the videotoolbox API exactly returns i can only guess. though it
 looks like wrongly sampled chroma planes.

 as a test i reencoded the file to a format that the quicktime player can
 decode and playback. https://0x0.st/iW-I.mp4
 this file also has the same problem as mentioned above, though with
 quicktime player the artifacts are a lot less pronounced. see screenshot
 below. i also verified that it used hwdec/videotoolbox for decoding. so if
 Apple doesn't use a private API it should be possible to fix or lessen the
 problem considerably.

 [[Image(https://0x0.st/iW-l.png)]]

--
Ticket URL: <https://trac.ffmpeg.org/ticket/8735#comment:3>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker