When you say "serious delay" do you mean that the audio is out of sync with the video? One of the filters use KxProxy which uses very small buffers. That is probably the one that works well. The other filter uses the WaveAPI and uses big buffers. So what happens is that the video starts playing immediately while it takes a short time for audio buffer to fill up. If you are capturing audio/video to a file, it should not be a problem as both streams are time stamped. But if you are previewing audio/video, then it can be a problem to use the WaveAPI filter since the WaveAPI buffers are so large. And, you cannot time stamp the audio/video preview stream because then the video renderer will cause the video to start and stop. If you are using GraphEdit to build the graph, there is no solution (that I know of). But, if you write a program using direct show (basically doing the same thing as GraphEdit), you can use the WaveAPI filter and you change the buffer size that it uses in the program. I have done this before and it works great.but, right now I cannot remember the exact details. If you need to know, let me know and I will post the information. From what I remember, there is no sample in the DDK that shows this. But the functions are documented somewhere.I just cannot remember the com interface name right now. I may have posted an answer similar to this in this forum, but I am not sure. _____ From: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of ??? Sent: Saturday, January 29, 2005 7:01 AM To: wdmaudiodev@xxxxxxxxxxxxx Subject: [wdmaudiodev] One Audio Driver Problem Dear All: I am developing an audio driver which is based on Streaming Minidriver framework. When I use the filter within "WDM Streaming Capture Devices" category, the audio stream (44100MHz) is listened well. However, when I use the filter of "Audio Capture Sources" folder, there is a serious delay (1 ~ 2 secs) which is happened. I don't know what's happened in this delay. The filter within "Audio Capture Sources" folder is a virtual filter, right? Why can't the MasterClock be offered from DirectShow manager for this filter? Can you help me to solve this problem? Best Regards, H.P.