DVM_STREAM_UNPREPAREHEADER

Notifies a video capture driver to clean up the preparation performed by DVM_STREAM_PREPAREHEADER.

Returns DV_ERR_OK if successful or an error code otherwise. The following errors are defined:

DV_ERR_STILLPLAYING	Indicates the data buffer is still in the device driver's available queue.
DV_ERR_NOTSUPPORTED	Unable to handle data block preparation. (This return lets MSVIDEO unprepare the data block.)

dwParam1: Address of a VIDEOHDR structure identifying the buffer.
dwParam2: Size, in bytes, of the VIDEOHDR structure.

This message is the complementary message to DVM_STREAM_PREPAREHEADER. This message unlocks the data buffer. Unpreparing a buffer not previously prepared has no effect, and the device driver returns DRV_ERR_OK.