DVM_STREAM_STOP

The DVM_STREAM_STOP message requests a user-mode video capture driver to stop a video stream.

Parameters

dwDriverID

Video channel identifier. For this message, the driver should only accept VIDEO_IN. (For details, see Opening Video Channels.)

hDriver

Driver handle.

uMsg

DVM_STREAM_STOP

lParam1

Not used.

lParam2

Not used.

Return Value

The driver should return DV_ERR_OK if the operation succeeds. Otherwise, it should return one of the DV_ERR error codes defined in msvideo.h. Custom error codes are also allowed (see DVM_GETERRORTEXT).

Comments

A client sends the DVM_STREAM_STOP message by calling the driver’s DriverProc entry point, passing the specified parameter values. Applications can send this message by calling the videoStreamStop function, which is described in the Video for Windows Development Kit.

When a driver receives this message it stops the input stream, typically by requesting the kernel-mode driver to disable capture interrupts. The driver retains its queue of empty buffers. If a buffer has been partially filled, the driver marks it as done and places the actual length of the data in the dwBytesUsed member of the buffer’s VIDEOHDR structure.

If the client has not previously sent a DVM_STREAM_START message, the DVM_STREAM_STOP message has no effect and the driver should return DV_ERR_OK.

For more information about video capture streams, see Transferring Streams of Captured Data.

User-mode video capture drivers using VCUser.lib can call VC_StreamStop when processing the DVM_STREAM_STOP message.