[FFmpeg-trac] #5071(avformat:reopened): FFmpeg doesn't use the correct palette when playing Apple Graphics (SMC) in Matroska

FFmpeg trac at avcodec.org
Mon Dec 7 05:23:07 CET 2015


#5071: FFmpeg doesn't use the correct palette when playing Apple Graphics (SMC) in
Matroska
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             Reporter:  matsp888    |                    Owner:
                 Type:  defect      |                   Status:  reopened
             Priority:  normal      |                Component:  avformat
              Version:  git-master  |               Resolution:
             Keywords:  mkv         |               Blocked By:
             Blocking:              |  Reproduced by developer:  1
Analyzed by developer:  0           |
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Comment (by matsp888):

 For the record, the original QuickTime file (and other files with Apple
 Graphics encoded video that I have here) has 0x0008 rather than 0xffff
 (-1) as its "color table ID" in the video sample description. From the
 QuickTime File Format specification, page 93:

 "Color table ID: A 16-bit integer that identifies which color table to
 use. If this field is set to –1, the default color table should be used
 for the specified depth. For all depths below 16 bits per pixel, this
 indicates a standard Macintosh color table for the specified depth. Depths
 of 16, 24, and 32 have no color table. If the color table ID is set to 0,
 a color table is contained within the sample description itself. The color
 table immediately follows the color table ID field in the sample
 description."

 So, the proper value to use here would be 0xffff, but it seems that FFmpeg
 accepts 0x0008 just as well, when processing Apple Graphics without a
 palette *in QuickTime* files. In any case it uses the default Macintosh
 palette.

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Ticket URL: <https://trac.ffmpeg.org/ticket/5071#comment:40>
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