Cannot get Still Image in Wia Snapshot

[parkerlived]

Hello sir:

I am Programming UVC avstream driver for months, but I met one

problem,that is : in XP system, I used the WIA to snapshot the

still image,the Wia will pop a message "the camera is processing

your request",in the same time I could see the debug message of

my driver's Snapshot routine appeared in DebugView window, the

message seemed it was normal (because in the same condition,

that I used the Graphedit and AMCap can get the Still Image),but

the Wia couldn't get the Still Image,by the way,the preview

function is normal. On the other hand, I tested my driver

in Vista using Graphedit and AMCap to get still image were normal

as in XP.So, Where am I missing the key point?

Wish you can help me, please.

parkerlived