Hi everybody! I am developing an upper class audio filter, in order to add some effects on the audio stream, but some problems confused me. 1. If there are more than one soundcards installed in the system, in the process of IOCTL_KS_WRITE_STREAM or IOCTL_KS_PROPERTY, how can I detect which soundcard the data is being sent to? 2. I have tracked the KSPROPERTY_CONNECTION_DATAFORMAT, but found something strange. A. The wBitsPerSample will always be 16, no matter what I have set in the player. B. I can't receive the message when the nSamplesPerSec have been set to 44100. And if I use directx as the output in player, I can receive the message, but nSamplesPerSec=100. Is there anyone can help me solve these problems? --------------------------------- Do You Yahoo!? 注册世界一流品质的雅虎免费电邮