[FFmpeg-trac] #3366(avformat:new): Support muxing pcm_s16be to mp4

[FFmpeg]

#3366: Support muxing pcm_s16be to mp4
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             Reporter:  cehoyos     |                    Owner:
                 Type:  defect      |                   Status:  new
             Priority:  normal      |                Component:  avformat
              Version:  git-master  |               Resolution:
             Keywords:  mov         |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
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Comment (by muken):

 Replying to [comment:3 cehoyos]:
 > Replying to [comment:2 muken]:
 > > MP4 file format itself has no support of 'raw ' and 'twos'.
 >
 > So what does "Sample Entry Codes Registered to ISO" means then?
 >
 Registered identifiers of CODEC for derived file formats of ISO Base Media
 file format (14496-12).
 Vendors can avoid defining the same identifier by consulting this list.

 > > These identifiers are defined in Motion JPEG 2000 file format
 (15444-3).
 > > You need add the JP2 Signature Box at the start of file and add 'mjp2'
 brand into the  File Type Box if muxing them.
 >
 > But we don't do that currently for other codecs that we allow in isom or
 do I misunderstand?

 What CODECs?
 Some CODECs are defined under ISO Base Media file format (ISOBMFF), such
 as AC-3, Enhanced AC-3, DTS Audio, etc..., and not specific derived file
 formats.
 ISOBMFF is designed to be used by derived file formats.
 Branding 'isom' or later versions ('iso2', 'iso3', ... ) only is not
 preferred.
 The specification of any derived file format shall define and document
 what CODECs are usable and how they are restricted in this file format.
 You can see these definitions in all derived file formats (MP4 file
 formats , 3GPP, UltraViolet DECE Common File Format and so on).

 For example.
 DTS defines encapsulation of DTS Audio into ISOBMFF in #9302J81100.
 Therefore, under all versions of ISOBMFF, you can mux DTS Audio without
 any restriction except for what #9302J81100 documents.
 DECE Common File Format is derived from ISOBMFF and defines the
 encapsulation and the additional restrictions of DTS Audio according to
 #9302J81100.
 Thus, you shall follow the restrictions of DECE Common File Format to
 encapsulate DTS Audio into DECE Common File Format.
 If not, then it means there are incompatibilities inside the file i.e.
 out-of-spec.
 You can't mux DTS Audio beyond the additional restrictions into DECE
 Common File Format.

 About 'raw ' and 'twos', these identifiers are not defined in ISOBMFF but
 defined in Motion JPEG 2000.
 Therefore, you can mux them as long as the destination file has
 compatibility of Motion JPEG 2000.
 Note that you can make chimera of derived file formats as long as keeping
 all compatibility of them.

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Ticket URL: <https://trac.ffmpeg.org/ticket/3366#comment:4>
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