playing multiple sound streams with single channel card?

playing multiple sound streams with single channel card?

[David Bruzos]

Hi again:
One of the problems with software speech is that most laptop sound hardware can not play multiple sounds at the same 
time.  This can be a big problem, if you like to listen to music or play any other sounds while using your computer.  I 
have this problem on my laptop and I would like to fix it...

I know that looking for better drivers is out of the question and that some cards do not support multiple channels any 
way.  So, here is what I have come up with:
I can use the "esd" or the "arts" sound servers to play multiple audio files on a single channel sound card.  I don't 
know how many people have tried this, but it actually works very well.  However, this has the disadvantage that the 
application you are trying to use must support the sound server output method.  For example, I use mplayer to play 
mp3's, ogg', etc.
Well, as far as I know, there is no way to have flite send its audio to a sound server.  I understand that it must use 
the /dev/dsp device directly.  Is this correct?

If flite can't speak through a sound server, then, the only solution would be to use a virtual /dev/dsp device that can 
perform software mixing.  This 
solution is very elegant, because all of the applications on your system would be able to play audio without any 
modifications or special switches...
I know this sounds kind of "out there", but there is such virtual sound system available.  The problem is that is not 
free.  The company that makes the comertial version of OSS also makes a product called "virtual mixer" that does just 
what I discribed above.  I have looked all over the Internet for a free alternative and did not find anything...  If 
anyone knows of a free alternative project, please let me know!!!

This is something that I am very interested in incorporating in a future software synth howto...


Thanx again!



David Bruzos

Re: playing multiple sound streams with single channel card?

[Luke Yelavich]

On Thu, Nov 04, 2004 at 04:43:11PM EST, David Bruzos wrote:
> Hi again:
> One of the problems with software speech is that most laptop sound hardware can not play multiple sounds at the same 
> time.  This can be a big problem, if you like to listen to music or play any other sounds while using your computer.  I 
> have this problem on my laptop and I would like to fix it...

If you use ALSA, there is in fact a plugin to do just this called dmix. 
the downside is you have to write a somewhat complex configuration file 
to make it work properly, and then it requires a lot of tweaking to get 
right, and even then you can't get best results.

I suggest going to http://www.alsa-project.org and looking through their 
documentation section about this.

Luke

Re: playing multiple sound streams with single channel card?

[Kirk Reiser]

I understand that alsa is suppose to support soft mixing but I've not
been able to get it to work.  You might want to ask on the alsa-users
mailing list or something like that.

  Kirk

-- 

Kirk Reiser				The Computer Braille Facility
e-mail: kirk@braille.uwo.ca		University of Western Ontario
phone: (519) 661-3061