[Sugar-devel] Fw: [Csnd] Re: Re: Re: Getting around a (sound) device assignment problem in SoaS
abhunkin at uncg.edu
Tue Sep 29 10:25:20 EDT 2009
I neglected to mention perhaps the most important fact of all: with SoaS,
any MIDI controller(s) must be plugged in AFTER boot and BEFORE compiling a
.csnd. Users must be given explicit instruction to this effect.
Note that this limitation does not apply to the XO.
My thoughts are:
1) Getting around this limitation is far more trouble that it's worth;
2) In the world of XO and Sugar-on-a-Stick a potential misunderstanding
would arise rarely in any case.
----- Original Message -----
From: "Art Hunkins" <abhunkin at uncg.edu>
To: <csound at lists.bath.ac.uk>
Cc: <pbrobinson at gmail.com>
Sent: Monday, September 28, 2009 4:35 PM
Subject: Re: [Csnd] Re: Re: Re: Getting around a (sound) device assignment
problem in SoaS
> Hi, Andres,
> With further experimentation, I've found that the following <CsOptions>
> will work fine for my purposes in the XO-1/Sugar-on-a-Stick context:
> -odac -+rtaudio=alsa -+rtmidi=alsa -M hw:1,0
> Alsa is low-latency as is supported (to this date) on all XO and SoaS
> -odac refers indeed to the default plughw and makes the conversions you
> mention, at no apparent cost - whereas -odac:hw:0,0 does not. -odac will
> thus work as long as there is a single (usually the builtin) hardware
> device. This is something I can count on.
> -M hw:1,0 will work as long as only one controller is attached (which I
> can count on for my single-controller .csd's), and as long as any built-in
> MIDI interface (rare these days, as Peter pointed out) is not being used.
> I think I can count on MIDI being via USB. (If someone on the outside
> chance *did* want to use a builtin MIDI interface, he can change hw:1,0 to
> So, the above will work in all usual configurations, as long as:
> built-in audio is used;
> one USB MIDI controller is used
> For my multiple MIDI controller versions, these will
> use: -+rtmidi=alsa -Ma
> as soon as Peter finds the time to incorporate your multi-controller
> Once this is achieved, all my issues are settled, and I'll be a "happy
> camper" (= find my joy).
> Art Hunkins
> ----- Original Message -----
> From: "Andres Cabrera" <mantaraya36 at gmail.com>
> To: <csound at lists.bath.ac.uk>
> Sent: Monday, September 28, 2009 3:27 PM
> Subject: [Csnd] Re: Re: Re: Getting around a (sound) device assignment
> problem in SoaS
> Since there's been no reply, I'll take a stab, but I may be compeltely
> I think alsa names hw: real hardware devices. Hardware devices can be
> constrained as to the number of channels or sample rates supported.
> There might be software interfaces to these devices (like the alsa
> "default" interface), which are plughw: devices, which can take care
> of sample rate conversion and different number of channels. To
> override the default settings, you would need to mess with the
> .asounrc file, which I wouldn't recommend since it might take you a
> while, as it is not very documented.
> On Wed, Sep 23, 2009 at 9:41 PM, Art Hunkins <abhunkin at uncg.edu> wrote:
>> In starting down the road Victor suggests (and to solve the problem
>> addressed in the subject), I immediately ran into an anomaly. I've no
>> whether the issue is Csound's or Sugar/Linux.
>> In working with the XO-1, I settled on a stereo SR=32000. (This is the
>> maximum SR I can use with my .csd's and get glitch-free sound on the
>> I developed all my work using the <CsOption> -odac
>> Faced with the fact of different device assignments with Sugar on a Stick
>> (Soas) when MIDI controller(s) are inserted prior to boot, I need to
>> for other assignments for -odac, such as hw:1,0.
>> Bottom line: -odac executed fine with SR=32000; -odac:hw:0,0 (its
>> equivalent) does not, *though it does fine with SR=44100!* The error
>> is: Unable to set sample rate on soundcard. Failed to initialize real
>> audio output.
>> Apparently there is a difference between 'plughw' (as -odac is referred
>> in my error log) and -odac:hw:0,0 (referred to as hw:0,0 in log).
>> Linux folk: what is going on here? I need both to: 1) use SR=32000, and
>> test for different hardware device assignments - including -odac:hw:1,0
>> too doesn't like SR=32000).
>> Art Hunkins
>> ----- Original Message ----- From: "victor" <Victor.Lazzarini at nuim.ie>
>> To: <csound at lists.bath.ac.uk>
>> Sent: Tuesday, September 22, 2009 3:52 AM
>> Subject: [Csnd] Re: Getting around a (sound) device assignment problem in
>>> The compile() function in the API (and in the csndsugui module) returns
>>> 0 if successful and non-zero if not. You can check for this and
>>> with different options (etc) until it works.
>>> ----- Original Message ----- From: "Art Hunkins" <abhunkin at uncg.edu>
>>> To: <sugar-devel at lists.sugarlabs.org>
>>> Cc: <csound at lists.bath.ac.uk>
>>> Sent: Tuesday, September 22, 2009 4:03 AM
>>> Subject: [Csnd] Getting around a (sound) device assignment problem in
>>>> For SoaS (Fedora Linux), there remains a problem of device assignment
>>>> involving audio out and MIDI in.
>>>> Basically, if you boot SoaS *then* plug in a MIDI controller, audio is
>>>> assigned C0D0; and MIDI, C1D0 (this is as expected). If you plug in a
>>>> controller and then boot SoaS, MIDI gets C0D0 and audio C1D0 (this is
>>>> as expected!)
>>>> The latter arrangement generates the following error message (in its
>>>> a script is run:
>>>> Can't open device 'plughw' for audio output.
>>>> It will be necessary to either do something either in Sugar, its Csound
>>>> module, or in the python script that runs Csound to work with this
>>>> So far, I've tried making manual changes to the file names (reflecting
>>>> the "proper"
>>>> device numbers, but the error remains.
>>>> Suggestions? Especially from the Sugar side?
>>>> It would seem that Sugar needs to
>>>> look for and assign *audio* device numbers before *MIDI* device
>>>> note that this issue does *not* exist for the native XO-1. Perhaps
>>>> snooping around
>>>> in that code would be enlightening.) I'd appreciate the help; I'm
>>>> absolutely lost here.
>>>> Art Hunkins
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