Hello Raph, Upon reviewing the spec I apologize profusely that I have to reneg on my previous response. I had forgotten that the ADPCM format is not an officially supported format in the USB Audio specifications and therefore is not supported by the USBAudio.sys driver. Again, my apologies, DJ ________________________________ From: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Raphael Lamy Sent: Tuesday, April 13, 2004 4:51 AM To: wdmaudiodev@xxxxxxxxxxxxx Subject: [wdmaudiodev] ADPCM Hi, In the Audio USB specification, I don't find the way to inform windows to use the ADPCM format ? Which WFormatTag have I to use ? I only see the MPEG, AC3, muLaw, Alaw, PCM ... but not ADPCM ? Could you help me ? Thanks in advance Raph