Topic: Windows API sound card functions

[James]

I think it's always best to generisize as much as possible.

I also do not believe that C-Media will always be the best choice of super cheap 7.1 sound devices.

James.  

[drlava]

I just get frustrated because I see it a lot in open source projects, lots of people re-creating the wheel when their energies could be spent toward revolutionary improvements. I don't have the desire or time to do the direct interface on my own, but feel that we could accomplish it together and learn a lot in the process.

[Fanny Pack]

I just realized that by going to USB as you suggest for the cmedia card you would eliminate all of the windows config nightmare that I hate.  But, you are still stuck with a single driver for a single chip so I don't think it would be worth it... unless you could buy a couple hundred of them and sell them as laser DACs with your driver.  That isn't a bad idea actually.

[drlava]

exactly! AND it could be set up to support multiple units of the same kind at once!
No it's not a bad idea, and did you know that the cm6206 drivers also work with cm106?  there are only so many ways to slice and dice 8 channel streaming data to USB.  Their future chips I expect would only require minor changes for compatibility.  Sure it would need software buffering like what I do now but that's no big deal, it's a given. 

[Fanny Pack]

Well, you kind of have me interested in doing it just to see if it can be done now.  I have no idea how to write to a USB port without using something like a FTDI driver or virtual com port, though.  Also, when the device is detected by Windows it will want to install a driver.  I guess you would have to make it install your fake one instead and communicate through it.  I am not sure how that works but everyone is doing it so it can't be too hard to figure out.

[drlava]

Looks like a DDK must be downloaded.  It includes the compiler and samples.
http://www.osronline.com/article.cfm?article=20

[Fanny Pack]

Yea, that part is pretty well documented.  It's the part about writing to the USB port that puzzles me.  I don't recall the data sheets for those devices saying anything about it but I haven't looked at one in a long time.

[Fanny Pack]

Well, looks like there is some sort of standard USB audio device spec for all audio USB devices.  I found this pdf http://www.usb.org/developers/devclass_docs/audio10.pdf that talks about it.  Over 100 pages of mumbo jumbo.  I think I will go back to doing what i was doing now. LOL.

[drlava]

The good thing is that most of that doesn't apply, for this an audio streaming endpoint and HID endpoint are what is needed.  It does look complex, there must be an audio driver example code out there that would help