DVM_STREAM_GETPOSITION

The DVM_STREAM_GETPOSITION message requests a user-mode video capture driver to return the current stream position.

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_GETPOSITION

lParam1

Pointer to an MMTIME structure. (The MMTIME structure is defined in mmsystem.h and described in the Win32 SDK.)

lParam2

Size, in bytes, of the MMTIME structure.

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

The client specifies a requested time format in the MMTIME structure’s wType member. If the driver cannot support the requested format, it uses a format it can support, and places the format type in wType. Video-capture drivers generally use the millisecond time format.

The driver should initialize the stream position when it receives a DVM_STREAM_START or a DVM_STREAM_RESET message.

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

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