Got a job where the customer is supplying a computer with three separate MP3 outputs that he wants to hook up to his home audio system so he and his family can listen to whatever they individually want wherever they are. The last part is easy. I’m just having trouble imagining a Windows XP system playing three different MP3s at once without the three different sound cards barfing all over each other’s interupts. I’m also too familiar with the poor excuse for multitasking in every version of Windows I’ve tried. But can it be done in linux?
There are many different DMA and IRQ channels that the cards can run on. I would think it would be ok. Say you have 5 pci slots, you can put 5 NIC cards in, 5 VGA cards, or 5 sound cards, you may encounter some problems initially, but should be able to overcome those problems by manually setting the IRQ’s and such through the BIOS and device properties in Windows.
Linux is no sweat from the operating system side. It can support multiple sound cards and any application can select which one it wants to use. That’s the easy part.
The application could be a little trickier. XMMS can be started multiple times for any user, and for each instance you can select a different sound card for output. The thing is, it won’t remember all of the settings for the different instances. You might start each instance under a different user name, and then the preferences would be stored properly.
There are other players, and there’s probably one out there that will take a command line parameter to select the sound card for output. That would be the easiest way.
It could be done in Linux very simply (three simultaneous logins), however, chances are your client will not be familiar enough with the OS to be able to use it.
Installing three sound cards in XP is easy. Getting them to all play the same thing is also easy. Having three instances of Winamp or WMP mapped to the different outputs and keeping track of everything, not so easy.
Setting up a thin client network would be much simpler, but more expensive. Do any of the kids have their own computers?
It should be possible to do this in Windows as well. Setup and configure the 3 different sound cards. Manually set IRQs and Addresses if you’re getting conflicts.
Then load Winamp. Set it to open multiple instances. Set each instance of Winamp to output to a specific sound card from Options/Preferences/Audio/Direct Sound/Output Device.
Perhaps a better option than having three instances of one program would be to have three different MP3 players. WMP, Winamp, and whatever other freebie you can find, all mapped to different devices.
Then, all you have to do is train them to associate each program with the speakers it is driving.
(Chuckling)
Yeah, they probably do, considering their daddy. Also considering him, cost is not an issue. I have no idea why we aren’t using three networked PCs, and that’s probably subject to change. In fact, the way these projects go all of my work yesterday was for naught because of changes last night. I won’t have to do the real work, anyway–I just do pictures captioned with “And then a miracle occurs!” and the hardware and software guys take it from there. I just remember earlier Windows- and Intel-based hardware/software incompatibilities and figure that Jesus himself would screw around with this setup for a few hours then smite the guy who suggested it.
Just in case anyone cares, PCI devices can share IRQ’s. Sometimes that leads to annoying problems but generally it works fine.
SoundBlaster live! and Audigy use a DSP (digital signal processor) that actually has 4 full stereo outputs (and 6 full stereo inputs!!)built in. Unfortunately, the SoundBlaster drivers do not allow access to these independently. Along comes kxproject (www.kxproject.com) and viola! you now have full independent access to all 4 sets of stereo outputs, and 14 (mono, 6 stereo) inputs! Don’t know how you would route the sound from the programs to the individual outputs, it does come with a pretty sophisticated routing program. Try it, it might just work!
I asked around here about it and my boss says it’s really cool how they do it and rather high maintenence, but the customer has the people for it. I suggested it would be easier to network three PCs with the MP3s on the server but the blank look he gave suggests that its main value is its cool, “ain’t NOBODY has this!” value. And the customer wants to do it with DVDs next. :rolleyes:
Sorry for the bump, but I saw this Slashdot article and remembered this thread. It may be of some assistance…