[wdmaudiodev] USB audio multiple recording channels
- From: rgruner@xxxxxx
- To: wdmaudiodev@xxxxxxxxxxxxx
- Date: Thu, 17 Apr 2003 14:10:59 +0200 (MEST)
Hi!
I am developing a multichannel USB 2.0 audio device for recording 4 mono
audio channels, i.e. 2 stereo channels. It is intended to be managed by Windows
audio device class driver. For now I'm still experimenting with different
device topologies.
According to USB class definition for audio devices it should be possible to
manage two (or more) stereo channels by defining 2 stereo Input Terminals
(type microphone) and two Output Terminals (USB Streaming) which directly
connect to the two ITs. All terminals reside in the same Audio Control
Interface.
In the Audio Streaming Interface I define 2 Endpoints which connect to the
Output Terminals.
When connecting this device Windows detects it and loads the appropriate
drivers but I can only access the first stereo channel pair, the other one is
not visible. The utility grapher from the DDK however, shows the intended
topology.
I tried a second design which connects as two seperate devices to Windows,
each containing a pair of stereo channels. Doing it this way allows me to
access all channels correctly but it blows up my descriptors (which are
restricted in size by the USB I/F Chip I'm using) enormously.
Now my question: Is Windows in general only able to handle one stereo
channel for recording per device or is there a way to record more channels
without
enumerating as multiple devices?
Thanks for your help!
Robert
--
+++ GMX - Mail, Messaging & more http://www.gmx.net +++
Bitte lächeln! Fotogalerie online mit GMX ohne eigene Homepage!
******************
WDMAUDIODEV addresses:
Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx
Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe
Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe
Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx
URL to WDMAUDIODEV page:
http://www.wdmaudiodev.de/
Other related posts:
