[L2Ork-dev] Purr Data and MP3 Objects

[Jonathan Wilkes]

On Wed, Sep 16, 2020 at 2:37 PM Linux ROUEN Normandie
<linux.rouen at free.fr> wrote:
>
> Hello Folks,
>
> I'm looking for some advises regarding Recording and Playing MP3 files -directly- inside Purr Data v2.13.0+ under GNU/Linux and Windows.
>
> In my MIDI/Audio projects under Purr Data I'm already using successfully:
> - [oggwrite~] / [oggread~] for .ogg (Vorbis) files (with lossy audio compression), and
> - [writesf~] / [readsf~] for  .wav, .aif, .au and .snd files (with uncompressed linear pulse-code modulation).
>
> But some users are requesting, among other demands, the possibility to handle also MP3 (with lossy data-compression) for extending the number of compatible Audio equipment (like TVs) able to read them.
>
> After analysis I found only 2 objects -not tested yet- from the 'unauthorized' library being able to deal with MP3:
> - [mp3write~] an MP3 file recorder v.0.4, and
> - [mp3cast~] an MP3 streamer v.0.5.
> But there is nothing about an MP3 file reader/player.
>
> Despite the many libraries installed by default, Purr Data could not create any of the following objects (see towards the end of the link - FR):
> - [mp3amp~],
> - [graphic-mp3amp~],
> - [mp3live~],
> - [mp3streamout~],
> - [mp3streamin~],
> - [mp3fileout~], and
> - [mp3play~] from 'iemlib library'.
>
> * [mp3play~] should be in the 'iemlib' library but it's not there when its help file is well present in '/opt/purr-data/lib/pd-l2ork/extra/iemlib/mp3play~-help.pd'.
> One strange thing is that the 'mp3play~.c' file is well present on the Git copy I made from Jonathan's repo for my French translations in:
> - '/home/joe/GitLab/purr-data/externals/build/src/mp3play~.c' (47 bytes), and
> - '/home/joe/GitLab/purr-data/externals/iemlib/iem_mp3/src/' (107 kB).

mp3play~ is not currently getting built (and wasn't in Pd-extended, either).

What a weirdo class structure! After compiling it, you must first create this:

[iem_mp3]

Which will then go in and trigger the setup routine for mp3play~, so
that you can then do this:

[mp3play~]

Both will create properly. I was able to play the test file and it
seemed to output something, though couldn't get my headphones to work
so I don't know if it sounded right.

It appears there are no dependencies for this object, so if we add it
then it will work in the web app, too!

I guess the first thing to do is look in Pd Vanilla and see if anyone
has done work on this object since 2003.

-Jonathan

>
> Any ideas - suggestions about an available and working [MP3 file reader/player] object?
> Thank you.
> - - - - - - - - - - - - - - - - - - - -
> Best,
> Joseph Gastelais
> LINUX ♥ ROUEN ♥ Normandie
> - - - - - - - - - - - - - - - - - - - -
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