[FFmpeg-trac] #5178(avformat:new): isom cannot be a MAJOR BRAND in MP4 created from ffmpeg

[FFmpeg]

#5178: isom cannot be a MAJOR BRAND in MP4 created from ffmpeg
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             Reporter:               |                    Owner:
  richardbushell                     |                   Status:  new
                 Type:  defect       |                Component:  avformat
             Priority:  normal       |               Resolution:
              Version:  unspecified  |               Blocked By:
             Keywords:  mov          |  Reproduced by developer:  0
             Blocking:               |
Analyzed by developer:  0            |
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Comment (by richardbushell):

 512 is written currently (which I believe is the Minor Version for ISOM).
 Obviously your -brand option doesn't change this.

 Can you confirm whether whether ffmpeg definitely writes mp41 (or mp42)
 files. And if so, I'd also need to re-check what the Minor Brand value
 should be.

 Yes, MP4Box -brand mp42:0 does overwrite these values anyway so need need
 to use a binary editor. Without changing the Minor Version MPEG-DASH
 conformance tool throws an error reporting it as invalid value.

 We've been changing this value for some time using MP4Box, which solves
 the problem. But I thought I'd best flag it with yourselves as it would be
 great to fix it. ISOM can be listed as a Compatible brand, but not a Major
 brand as per the specs. If corrected, we could omit the MP4Box step.

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Ticket URL: <https://trac.ffmpeg.org/ticket/5178#comment:7>
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