Hello Daniel! > Actually, I think you want to support WAVE_FORMAT_EXTENSIBLE in your driver. I have a support for these formats. I asked why SysAudio sometimes gives me an *incorrect* descriptor, specifying wFormatTag=WAVE_FORMAT_EXTENSIBLE and cbSize=0, and how to process such descriptor. There are another cases when a driver can receive an incorrect format descriptor from Windows audio subsystem. For example, you may got a descriptor with wValidBitsPerSample=0. Regards, Eugene ****************** 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.com/