Re: File type for .m4a files

From	Harriet Bazley <harriet@bazleyfamily.co.uk>
Newsgroups	comp.sys.acorn.apps
Subject	Re: File type for .m4a files
Date	2026-02-25 16:42 +0000
Organization	A noiseless patient Spider
Message-ID	<086ac4b05c.harriet@bazleyfamily.co.uk> (permalink)
References	(2 earlier) <5cb05d68febob@sick-of-spam.invalid> <834261b05c.jmb@jmc.bruck.orange.fr> <5cb0a048fabob@sick-of-spam.invalid> <10nmnso$p7r3$1@solani.org> <5cb0b3d857bob@sick-of-spam.invalid>

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On 25 Feb 2026 as I do recall,
          Bob Latham  wrote:

> So as no official mapping to m4a exists (very disappointing)

As I understand it, 'M4A' is a subset of the MP4 standard - MP4 files
can contain both audio and video streams, and an M4A file is simply an
MP4 file where the normal video content is missing.  Since any MP4
player can play an M4A file and RISC OS doesn't have any concept of a
player that can *only* play the audio content without being able to
handle the video content as well, it doesn't distinguish (or need
to) between MP4 files with and without video streams in them.   Simply
mapping M4A files to the &A64 filetype ought to be sufficient for
desktop purposes;  what the icon *looks* like is completely irrelevant,
provided that the correct player is launched when you double-click on
them....

In the same way, a Drawfile can contain both sprite and vector (and
text area!) data, but RISC OS doesn't have special filetypes for
Drawfiles that are just being used as wrappers for sprites with no
actual shapes or lines defined in them.   Any application that can
display vector graphics in a Drawfile can equally well display a
Drawfile with sprite data in it.

(Many applications *can't*  correctly handle Drawfiles with text areas
in them, given that this facility is basically a deprecated form of DTP
that has been superseded by actual dedicated DTP software, so arguably
the OS ought to have a special filetype that distinguishes text area
data from other more generic Drawfile content - but it doesn't!)

> I looked for an obscure value in the user's section. I chose 0B7 which
> seems free. I've given it an icon and mapped it to .m4a and it even
> plays in a couple of players. So hopefully, provided 0B7 does get used
> by something official I should be okay.
> 
All the filetypes with values less than &100 are unavailable to
'official' software, so nothing will ever be allocated to any of them.
They are reserved for local use (and use by 'unofficial' software that
you might write and want to distribute, with the drawback that there is
absolutely no guarantee that someone else's unofficial software might
choose to use the same filetype and some unlucky random user just might
attempt to run both applications on the same computer....)

-- 
Harriet Bazley                     ==  Loyaulte me lie ==

A statement of fact cannot be insolent

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Thread

File type for .m4a files Bob Latham <bob@sick-of-spam.invalid> - 2026-02-24 11:57 +0000
  Re: File type for .m4a files Jean-Michel <jmc.bruck@orange.fr> - 2026-02-24 19:43 +0100
    Re: File type for .m4a files Bob Latham <bob@sick-of-spam.invalid> - 2026-02-24 21:57 +0000
      Re: File type for .m4a files Jean-Michel <jmc.bruck@orange.fr> - 2026-02-24 23:39 +0100
        Re: File type for .m4a files Bob Latham <bob@sick-of-spam.invalid> - 2026-02-25 10:07 +0000
          Re: File type for .m4a files Sebastian Barthel <naitsabes@freenet.de> - 2026-02-25 11:54 +0000
            Re: File type for .m4a files Bob Latham <bob@sick-of-spam.invalid> - 2026-02-25 13:41 +0000
              Re: File type for .m4a files Harriet Bazley <harriet@bazleyfamily.co.uk> - 2026-02-25 16:42 +0000
                Re: File type for .m4a files Bob Latham <bob@sick-of-spam.invalid> - 2026-02-25 18:30 +0000
                Re: File type for .m4a files Harriet Bazley <harriet@bazleyfamily.co.uk> - 2026-02-25 22:08 +0000
                Re: File type for .m4a files Bob Latham <bob@sick-of-spam.invalid> - 2026-02-26 09:03 +0000
                Re: File type for .m4a files Sebastian Barthel <naitsabes@freenet.de> - 2026-02-26 13:53 +0000
                Re: File type for .m4a files David Higton <dave@davehigton.me.uk> - 2026-02-26 17:09 +0000
                Re: File type for .m4a files Steve Fryatt <news@stevefryatt.org.uk> - 2026-02-26 23:27 +0000
                Re: File type for .m4a files Jean-Michel <jmc.bruck@orange.fr> - 2026-02-27 08:38 +0100
                Re: File type for .m4a files Bob Latham <bob@sick-of-spam.invalid> - 2026-03-04 11:14 +0000
                Re: File type for .m4a files Chris Newman <mec@npost.uk> - 2026-03-04 13:08 +0000
                Re: File type for .m4a files Bob Latham <bob@sick-of-spam.invalid> - 2026-03-04 17:52 +0000
  Re: File type for .m4a files David Higton <dave@davehigton.me.uk> - 2026-02-25 20:09 +0000
    Re: File type for .m4a files Bob Latham <bob@sick-of-spam.invalid> - 2026-02-25 22:09 +0000
    Re: File type for .m4a files Harriet Bazley <harriet@bazleyfamily.co.uk> - 2026-02-25 22:09 +0000

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