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Re: File type for .m4a files

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Am Wed, 25 Feb 2026 10:07:36 +0000 schrub Meister Bob Latham:

> In article <834261b05c.jmb@jmc.bruck.orange.fr>,
>    Jean-Michel <jmc.bruck@orange.fr> wrote:
>> In message <5cb05d68febob@sick-of-spam.invalid>
>>           Bob Latham <bob@sick-of-spam.invalid> wrote:
> 
>> > In article <51a44bb05c.jmb@jmc.bruck.orange.fr>,
>> >    Jean-Michel <jmc.bruck@orange.fr> wrote:
>> >> In message <5cb0268addbob@sick-of-spam.invalid>
>> >>           Bob Latham <bob@sick-of-spam.invalid> wrote:
> 
> 
>> >> I have an mp4 audio file, which is played automatically by Mplayer,
>> >> but you can use it with KinoAmp
> 
>> >> from !boot file for Mplayer.
>> >> if "<File$Type_FB2>" = "" then Set File$Type_FB2 "AVI"
>> >> Set Alias$@RunType_FB2 Run <MPlayer$Dir>.!Run %%*0 Set File$Type_A63
>> >> "MKV"
>> >> Set Alias$@RunType_A63 Run <MPlayer$Dir>.!Run %%*0 Set File$Type_A64
>> >> "MP4"
>> >> Set Alias$@RunType_A64 Run <MPlayer$Dir>.!Run %%*0
> 
>> >> In my mimefile there is:
>> >> # Media type 'Video'
>> >> video/x-msvideo  AVI  fb2 .avi video/mp4               MP4          
>> >>   a64     .mp4 video/x-matroska        MKV             a63     .mkv
> 
> 
> 
>> from https://fileinfo.com/extension/m4a
> 
>> MPEG-4 files that store video bear the .mp4 file extension (.MP4
>> files). However, if the MPEG-4 file only stores audio, it is saved with
>> the .m4a extension, which stands for "MPEG-4 Audio." This name change
>> helped distinguish between MPEG-4 video files and MPEG-4 audio-only
>> files.
> 
>> Ihave tested m4a from here
>> https://getsamplefiles.com/sample-audio-files/m4a
> 
>> just changed the type to mp4 an Mplayer plays it, not AMplayer.
> 
> Thank you for your help it has moved me forward.
> 
> .mp4 files on my NAS were showing up as text files.
> This is 2026 and RO has no idea what an .m4a iTunes file is?
> 
> I now have an entry in my mimefile I have added...
> 
> audio/x-m4a		mp4		a64		.m4a
> 
> Sure enough, m4a files now show up in RISCOS as a64 mp4 files. Which
> from the icon, it is clear RO thinks this is a movie.
> 
> Am I correct in thinking that if I do this, RISCOS cannot tell if a file
> is a movie or compressed audio file from the file type.
> 
> I don't need to play the file in RISCOS I just need a means to test for
> its file type. Could I map it to another RO file type that doesn't clash
> with a movie file. Are there any user file types I could pinch one from
> that on my machines would be unique to .m4a?

There exists a list, with filetypes that aren't officially connected to 
any means and that are free to use for the normal user. Other filetypes 
are reserved for Acorn and special types and firms, e.g. Computer 
Concepts and other. It should be possible to use a free number from the 
user list and set the .m4a to this number.

Then the entries in the player applications startfile have to be changed 
in way, that the player also starts the now "new" filenumber. There a 
godd chances that the player will play the file then.

This list should be available on ROOL . Eventually therein exists an mp4 
audio file - then it should be enough to map the .m4a extensions to this. 

Eventually its enough to map the .m4a to an mp3 filetype.


> .mp4 files on my NAS were showing up as text files.
> This is 2026 and RO has no idea what an .m4a iTunes file is?

RISCOS never thinks about files and never did - in a way the rest of the 
computeruniverse did it. It has filetypes and You should clearly separate 
them from "file extensions" in Your thinking about such stuff.

Eventually there is an Filetype for MP4 Audio File in the list (mentioned 
above). Then You should use this for Your mapping.
An audioplayer, nevertheless, can start them directly only if its RunType 
is set in a correct way.
If so the player will load the file - and play it, if there a audio data 
in a known format in it. Otherwise the app will eventually crash. There is 
(normally) no checking, other than the filetype, if a file is a correct 
one. The unix magic number, wich a itunes Files should have, will not be 
read and evaluated by an RISC OS application.

You can see this as an "misbehave" on the RISC OS side - but one can also 
argue the other direction: Why can't the other filesystems handle 
correctly the well established filetypes in 2026 ?

-
kork der ork kümmert sich um den traminer

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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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