Sushma wrote: >> Pre-Vista, it is possible to insert an audio class upper filter to >> intercept the kernel streaming ioctls. It is surprisingly difficult in >> that situation to figure out what format the audio is in every case, so >> plan some frustrating test time. >> >> > > If the implement a audio class upper filter, what IRPs i need to look > out for capturing the data. > All kernel streaming transactions take place in internal ioctls, IRP_MJ_INTERNAL_DEVICE_CONTROL. Data gets transferred with IOCTL_KS_READ_STREAM and IOCTL_KS_WRITE_STREAM. You'll also need to monitor the property exchanges through IOCTL_KS_PROPERTY. There are a lot of properties being exchanged. If you don't have kernel streaming experience, you have a LOT of reading to do. -- Tim Roberts, timr@xxxxxxxxx Providenza & Boekelheide, Inc.