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Tag Archives: kivy

From my last post, I’m taking a little break from Chess as I turn my attention to a guitar I bought as a Christmas gift to myself. You see, I’m in the process of becoming a Guitar God, ala Jason Mraz, but that story is better reserved for my main blog no?

And well, since I can’t personally jam with Jason Mraz (or Chris Martin), I settle for MP3’s of his songs. The problem is, MP3s play abruptly without warning. There is no sufficient time between my hand pressing play and the song playing!

Jason Mraz Fanboy

And yes, I do have the CDs!

None of the MP3 players I know of is aspiring-musician-friendly as such. So, obviously, this makes it a nice candidate for a quick hack.

My requirements are simple:

  • Have a UI
  • Be able to play an MP3 file after a set countdown. And it has to be in MP3 format, hard requirement. If it is to be of any use with minimal hassles, it has to be MP3.


The first requirement makes it a good candidate for a web/JavaScript app. But then, as far as I know, JavaScript is not allowed access to the local filesystem for security purposes. So JavaScript (unfortunately) rules out the more-important requirement of the two I have.

The next obvious choice is Java since I’m quite used to utilizing Swing to develop desktop GUIs; in fact, I created the user interface of our thesis in Swing, from ground up. However, for a quick hack, I think Java might be overkill and there’s this Python library I’ve been wanting to play with for so long…


Kivy can handle my UI requirement, and rather beautifully so, if I may say. Now, searching around, there are multiple ways to play an MP3 file with Python. One of them is even a Kivy library! The other libraries I found are mp3play, musicplayer, and PyGame.

But one by one, problems emerged

  • PyGame’s mp3 support is limited.
  • The sample code in musicplayer’s PyPi page looks too complicated. (Yes, since this is just a quick project, I’m in lazy mode.)
  • mp3play only works for Windows XP.


And then the Kivy library. It would’ve been sweet to have a single library for all my project’s requirements. But alas…

Kivy has a SoundLoader class which automagically determines the best way to handle the given sound file’s format. I’m not good with design pattern terminology but, the way I see it, it looks like a combination of Factory and Strategy patterns. However, when I test code given in their documentation, I come across the following logs:

[INFO ] Kivy v1.8.0
[INFO ] [Logger ] Record log in /home/chad/.kivy/logs/kivy_15-01-04_6.txt
[DEBUG ] [Audio ] register SoundPygame
[INFO ] [Audio ] Providers: audio_pygame (audio_pygst, audio_sdl ignored)
[WARNING] [Audio ] Unable to find a loader for <test.mp3>


The only provider that loaded is PyGame’s. And, as I’ve noted above, PyGame’s mp3 support is shaky. In fact, Kivy’s code as of presstime only allows PyGame on MP3 files if it is running on Android. audio_pygst would’ve done the trick but then, as the logs indicate, it did not load.

So why did it not load? Looking at audio_pygst’s code, it imports the modules gi, pygst, and gst, in that order, respectively surrounded in try-catch statements should there be problems on the import.

I try to load them manually on Python’s shell and get the following result:

chad@galadriel:kivy$ python
Python 2.7.3 (default, Feb 27 2014, 19:58:35) 
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import gi
>>> import pygst
>>> import gst
/usr/lib/python2.7/dist-packages/gobject/ Warning: g_boxed_type_register_static: assertion `g_type_from_name (name) == 0' failed
  import gobject._gobject


Looking around, this seems to be an issue with gst 0.10.x. The obvious solution would be to upgrade. Unfortunately, gst updates for Ubuntu 12.04LTS seem to have stopped at 0.10.

So there. Much ado achieving nothing, for a quick hack. Maybe, I’ll look into using Java for this project, moving forward. Stay tuned!

Coldplay Fanboy