Notifies a video callback function or window that the video capture driver returned the specified buffer to the application.
dwParam1
Address of a VIDEOHDR structure identifying the buffer.
dwParam2
Not used.
For VIDEO_IN channels, buffers are returned when they have been filled. For VIDEO_OUT channels, buffers are returned after they are displayed. All buffers are returned for the DVM_STREAM_RESET message.
This message is used by video capture drivers, installable compressors, and other types of installable drivers to signal an application that new data is available.