Re: [sc-users] HardwareBufferSize & Aggregate Device

[Alberto de Campo <adc@xxxxxxxx>]

hi josh,

I reported that a while ago with tests:
when one relies on system default input and output to be joined into a device,
the audio input always stays on I believe 512 samples, and of these,
the first e.g. 128 or so are looped.

It does work properly when using an aggregate device, but then you lose
hardware volume control which is quite handy sometimes.

best, adc

> Date: Sun, 1 Mar 2009 01:06:20 +0200
> To: sc-dev@xxxxxxxxxxxxxxxx
> From: Alberto de Campo <adc@xxxxxxxx>
> Subject: SoundIn bug at lower blocksizes
> X-Attachments: :AdC_C2D:2135571:HWBufSize256_osx.png:
>
> Hi,
>
> testing different hardware buffer sizes, a strange bug turned up:
>
> On Intel MBP 2.4 GHz, OS 10.5.6, built-in hardware (microphone),
> at 256 samples, the audio-input gets mangled -
> it seems that blocks of 256 sampes are repeated twice,
> rather than getting the next block of audio input.
>
> at 128 samples, the same 128 samples get looped 4 times before the
> audio changes.
>
> test:
>
> s.quit;
> s.options.hardwareBufferSize_(512);
> s.boot;
> { SoundIn.ar(0) }.play; // sounds OK
> // record and open in soundfile editor
>
> s.quit;
> s.options.hardwareBufferSize_(256);
> s.boot;
> { SoundIn.ar(0) }.play; // buzzy, distorted
> // record and open in soundfile editor to check: loops blocks 256 twice
>
>
> s.quit;
> s.options.hardwareBufferSize_(128);
> s.boot;
> { SoundIn.ar(0) }.play; // also broken, loops 128 samples 4x
>
>
> Is this just my machine?


> Your hardware probably doesn't support that buffer size.
>
> Josh
>
> On Jul 23, 2009, at 2:28 AM, Jorn van Dijk wrote:
>
> > Hello list,
> >
> > The following is annoying me for a while now:
> >
> > When I change the hardwarebuffersize to something like this:
> > Server.local.options.hardwareBufferSize_(64);
> > Server.internal.options.hardwareBufferSize_(64);
> >
> > And listen to the input:
> > s.boot;
> > {SoundIn.ar}.play
> >
> > The signal is distorted.
> >
> >
> > When I make an aggregate device with the built-in input and output and do:
> > Server.local.options.device_("SC");
> > Server.internal.options.device_("SC");
> >
> > Server.local.options.hardwareBufferSize_(64);
> > Server.internal.options.hardwareBufferSize_(64);
> >
> > There is no problem.
> >
> > I read that you don't need an aggregate device anymore on intel 
> > computers. But I have this problem on all the intel osx computers I 
> > try it on. PowerPC is fine.
> > I'm using the latest svn version.
> >
> > Do you guys have this problem too?
> >
> > Jorn
>
> ******************************************
>
> /* Joshua D. Parmenter
>
> <http://www.realizedsound.net/josh/>http://www.realizedsound.net/josh/
>
>
> "Every composer - at all times and in all cases - gives his own 
> interpretation of how modern society is structured: whether actively 
> or passively, consciously or unconsciously, he makes choices in this 
> regard. He may be conservative or he may subject himself to 
> continual renewal; or he may strive for a revolutionary, historical 
> or social palingenesis." - Luigi Nono
>
> */


--
--
Prof Dr Alberto de Campo
Bergstrasse 59/33
A-8020 Graz, Austria
e-mail : adc@xxxxxxxx
--

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