Re: Multiple Audio Streams

[James Courtier-Dutton <James@superbug.demon.co.uk>]

AthlonRob wrote:

>On Sat, 2002-10-05 at 12:29, Sagi Bashari wrote:
>  
>
>>No answer on the users list, forwarding to devel.
>>    
>>
>
>Yes... let me go ahead and re-hash this for those who don't want to read
>through the earlier email.
>
>Sagi and I have two different soundcards with somewhat similar, yet
>different, problems.  (Ambigious enough?)
>
>His soundcard theoretically supports hardware mixing both in actual
>hardware and in the ALSA drivers, yet when he tries to open a second
>audio stream, the application attempting to do so simply hangs until the
>resource is free.  I think he said his card was a GTXP... I am
>unfamiliar with it.
>
>My soundcard also supports hardware mixing, but only in the hardware..
>not in the ALSA drivers.  Perhaps two threads would be ideal.  Oh well. 
>I'm running on an nForce board using its integrated audio.  The drivers
>nVidia provided (for OSS) simply consisted of an Intel i810 audio
>patch.  I guess y'all on the ALSA team were able to utilize the
>nVidia-released patch and do the same thing to the ALSA i810 drivers.
>
>Anyway... Sagi needs to know how to get the multiple streams working on
>his card, globally.
>
>I need to know if it is possible to get the nForce (using the patched
>i810 driver) to support hardware mixing so I can send many audio streams
>to it at once.  I have basically no programming experience, but may have
>a few friends who could help me if I had some clue of the how or the why
>of it.  Alternatively, since I cannot afford to send anybody hardware...
>if somebody was really interested in working on this, I could give you
>ssh access and work with me, here, physically... but I don't know how
>useful or feasable such a thing would be.
>
>Anyway... input on either or both topics by you guys who really know
>what you're doing would be much apperciated!  :-)
>
>Rob
>
>  
>
mypc: /proc/asound/card0/pcm0p# cat info
card: 0
device: 0
subdevice: 0
stream: PLAYBACK
id: CS4231
name: Yamaha OPL3-SA23
subname: subdevice #0
class: 0
subclass: 0
subdevices_count: 1
subdevices_avail: 1   <- This tells you how many streams the sound card 
can handle in hardware at the same time.
E.g. Only one application at a time can use the card.

As you can see, my old sound card can only handle one stream at once in 
hardware. Alsa does not do any software mixing.
I also have a SB Live in another machine, the subdevices_avail is then 
32 because the SB Live can handle 32 streams at once in hardware.

There are other applications/tools you can use, one of which is "JACK" 
that allows for multiple audio streams mixed in software and lots of 
other cool stuff.

Does this help you at all ?

Cheers
James





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