2011/11/1 yvan volochine
<yvan.pd@gmail.com>
On 11/01/2011 04:23 AM, Jean-Michel Dumas wrote:
It's great to see pyo make an appearance in this discussion. For
completion's sake, here's the "128 sine waves with random freq mixed down
to stereo" example written in pyo. I find it much more readable than either
SC or cSound, but that's only a matter of taste i guess.
Sine([random.uniform(20,20000) for i in range(128)]).mix(2)
A Csound example would use 128 lines or some simili-loop opcode. The best way should be to script Csound from python or lua...!
indeed, pyo looks really cool, kudos ;)
a couple of remarks with your example though.
my sc example description was not 100% accurate:
the random freqs have exponential distribution (ExpRand) and Splay does
the stereo mix down but with a level compensation (equal power) so you
don't blow up your ears/pa like in the above pyo example :p
That's the cool thing with a pure python
module, you can use any function in the random module... To be more like
you SC example, the line should be:
a = Sine([100 * random.expovariate(0.5) for i in range(128)], mul=1./128).mix(2).out()
also, running this pyo line uses 25% of my Core Duo 1.83 while sc
example uses 15% (and I'm not running excellent Tim Blechmann's
multicore-aware sound server supernova, just default scsynth)
No doubt, SC is the best audio engine regarding CPU
usage... With pyo, there is an overhead to deal with the Python Global
Interpreter Lock (GIL). It makes python very safe but take some times to
acquire and release before and after the audio callback. In the case of
playing a bunch of oscillators, I would probably use OscBank which can
compute hundreds of oscillators in a single loop, very efficient!
BTW, (getting a bit OT here) I have some questions about pyo.
is there a way to use double precision ?
from pyo64 import *
$ >>> from pyo import *
$ pyo version 0.5.0 (uses single precision)
for the Server to boot properly, I have to start jackd, then
Server().boot() gives me an Error with PortAudio incorrect channels
number (???), stop jackd, and then Server boots fine..
it seems also that it segfaults easily.. no time right now but I'll make more tests some time...
jack
and portaudio don't really like each other! Portaudio won't initialize
if jack is started. You can use pyo with jack by setting the Server's
host:
s = Server(host="jack").boot()
Cheers,
Olivier