looking for help creating a mime type

kendell clark coffeekingms at gmail.com
Wed Apr 13 03:55:56 UTC 2016

I've filed the bug already. I seem to be stuck though. I've found the
magic number that uniquely identifies an audible audio file in the
ffmpeg source code at libavformat/aadec.c. The problem is, I can't
locate that number in the file anywhere to put it in mime editor. I
think I might need a little help. I want to generate a test.aa file,
which I thought about doing by copying a valid audio book and just
deleting the audio out of it, but I'm not sure how to do that either.
Please bear with me, I'm still new at all of this. I've already cloned
the shared mime info github repository, and I've read the hacking file,
but the last step, giving a unique string or integer is the part I'm
having trouble with. I did find a hex editor I can use, hexdump.I've run
the following command: hexdump --C test.aa > temp, but I'm not sure what
I'm looking for in that file. I've looked at all of the test cases in
tests, but how were those generated?
Kendell Clark

kendell clark wrote:
> hi
> Ok, the bug has been filed at:
> https://bugs.freedesktop.org/show_bug.cgi?id=94889. This provides
> support for the audible audio format, but purely based on the file
> extension. Next is to get support for this put into gstreamer. Where
> should I start for that? I'm no programmer, but since the audible file
> is a container with other audio inside of it it shouldn't be too hard.
> Usually mp3, but occasionally the acelp or sony's HAC ((hearing aid
> compatible) codecs are used, although I don't have any idea what those
> last two are.
> Thanks
> Kendell Clark
> Jerome Leclanche wrote:
>> You can use the command line hex editor you probably already have
>> installed. hexdump -C file.aa | less. There's plenty of gui ones too.
>> A magic number isn't required (nor even necessarily available), the
>> .aa extension isn't used by anything else I believe so you could just
>> use that.
>> J. Leclanche
>> On Mon, Apr 11, 2016 at 9:09 AM, kendell clark <coffeekingms at gmail.com> wrote:
>>> hi
>>> Thank you very much for that link. I now have some of the bits I need to
>>> create a fully functioning mime type. The one thing I'm missing is a way
>>> of uniquely identifying audible audio files without relying on the file
>>> extension. If I can't find this, creating a mime type will be pretty
>>> easy, but I'd prefer to  be able to uniquely identify the file type if
>>> possible. It's amusing. The audible website swears that you can't
>>> convert their files into other formats, and yet I did so via ffmpeg.
>>> What else should I do? I can't seem to find an accessible hex editor, so
>>> if anyone is willing to help me out there by getting some form of magic
>>> info, integer, string, etc that I can use to single out the audible
>>> format I'd really appreciate it. Don't worry, I'm not asking anyone to
>>> do all the work for me, I'm still going to file the bug and make sure
>>> everything complies with the mime spec.
>>> Thanks
>>> Kendell Clark
>>> Jerome Leclanche wrote:
>>>> Your first step will be figuring out if there is any existing media
>>>> type for this type of file.
>>>> Looking at http://www.digitalpreservation.gov/formats/fdd/fdd000103.shtml#sign
>>>> I see audio/audible
>>>> audio/x-pn-audibleaudio, the latter which looks like it could be used in xdg.
>>>> After that you'll want to file a bug on the freedesktop bugzilla
>>>> (https://bugs.freedesktop.org/), and provide a patch if possible.
>>>> There's other mime type requests on that bugzilla you can take example
>>>> on.
>>>> J. Leclanche
>>>> On Mon, Apr 11, 2016 at 8:33 AM, kendell clark <coffeekingms at gmail.com> wrote:
>>>>> hi all
>>>>> After a lot of digging through my cd collection, I came across an
>>>>> audible audio file I had backed up who knows how long ago. I've been
>>>>> wanting to create fully functioning mime types for this and it's
>>>>> enhanced audio counterpart for a while now. I'm a complete novice at
>>>>> this, so I'm looking for any willing helpers. I can upload the files
>>>>> somewhere so if anyone decides to help me they can have access to them.
>>>>> Note that these are legal files, legally obtained from audible with an
>>>>> active account, mine. Well, not active anymore, but it was when these
>>>>> files were obtained. These seem to be mp3 files with some strange stuff
>>>>> at the beginning, because simply renaming the file extension doesn't
>>>>> allow them to be played, but I can easily convert them with ffmpeg. Any
>>>>> help would be greatly appreciated.
>>>>> Thanks
>>>>> Kendell Clark
>>>>> _______________________________________________
>>>>> xdg mailing list
>>>>> xdg at lists.freedesktop.org
>>>>> https://lists.freedesktop.org/mailman/listinfo/xdg
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