= pkaudio =

pkaudio is a multi-puropose audio library written in '' '''python''' ''. Benchmarks will prove that python is perfectly capable of low-latency and reliable audio work. Sceptics need only install the pksampler and watch the cpu usage! ([milestone:pksampler-0.4 pkaudio progress])

''NEWS''

I've written a pkaudio prototype, and it has made pksampler-0.4 possible. All of it is re-usable and easily readable with plenty of unit tests, so go for it!

== The ideal audio library ==

 * synchronous/asynchronous api
 * transparent multi-card I/O
 * reliable real-time performance
 * low-latency communication
 * cross-platform
 * standard/clean dependency list
 * audio graphs
 * event output (like peak levels)
 * music sequencing
 * disk buffering
 * decent media support
 * easy extension model

== Status ==

Look at this unit test, just look at it!
{{{
#!python
class SchedulerTest(unittest.TestCase):

    def setUp(self):
        self.sound = buffering.Sound(1000, 44100)
        buffering.Filler(NoZeros(1000), self.sound).run()
        self.periodsize = 75
        self.clock = engine.Clock()
        self.sched = scheduler.Scheduler(self.sound, self.clock)

    def test_play(self):
        frame = 400
        self.sched.play(frame)
        stream_out = []
        target = numarray.array([0] * self.periodsize, numarray.Int16)
        for i in range(10):
            self.clock.set(self.periodsize * i, self.periodsize)
            self.sched.render(target)
            stream_out.extend(target)
        self.assertFalse(numarray.any(target[:frame]))
        self.assertTrue(numarray.all(target[frame:]))
}}}


== the python equivalent ==

''simple design, expect to throw out quite a few''


''Threads''
 * each sample, io
 * buffer, io
 * proc migration?
   * profile w/ in-proc audio first
   * consider migrating later

''Model''
 * graphs
   * mixer
   * effects
 * dsp buffer-routines
  * volume(block)
  * resample
  * copy?

''Communication''
 * in events are easy
 * out events
   * peaks

'''HOWTO'''
 * ''pyogg: ld: multiple definitions of symbol _Py_OggError''
   * PyObject *Py_OggError; should be "extern"
   * PyObject *Py_OggError; should go in _oggmodule.c

'''hurdles'''
 * [SOLVED] realtime and the GIL (audio/buffering)
   * How can we buffer from the disk if the real-time thread cannot block?
   * C extensions unlock the GIL whild loading. Run a print test.
   * Remember, the lock can be held if it is only accessing small amounts of memory.
   * Querying memory can generally happen without locking the GIL.
   * '''all (good) C extensions release the GIL, including python I/O.'''
 * buffer ops
   * [SOLVED] written to device?
   * [SOLVED] read from disk? 
   * [SOLVED] audioop?