The DVM_GET_CHANNEL_CAPS message requests a user-mode video capture driver to return the capabilities of a video channel.
Parameters
dwDriverID
Video channel identifier. One of VIDEO_EXTERNALIN, VIDEO_IN, VIDEO_OUT, VIDEO_EXTERNALOUT. (For details, see Opening Video Channels.)
hDriver
Driver handle.
uMsg
DVM_GET_CHANNEL_CAPS
lParam1
Pointer to a CHANNEL_CAPS structure.
lParam2
Size of the CHANNEL_CAPS 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_GET_CHANNEL_CAPS message by calling the driver's DriverProc entry point, passing the specified parameter values. Applications can send this message by calling the videoGetChannelCaps function, which is described in the Video for Windows Development Kit.
The driver fills in the client-supplied CHANNEL_CAPS structure with channel information for the specified channel.