Control calls
All control calls are called with a pointer to the required data. The driver should dereference this pointer to get at the structure or field. Pointers are used in all calls to maintain consistency in the calling conventions. The driver should not return any value in the pointer.
VideoEnable (csCode = 2)This call is used to enable or disable the Zoomed Video data stream.
OSErr err = Control ( driverRefNum, cscZVVideoEnable, &theZVFlagRecord )
--> csFlag
Disable (false) or Enable (true) video
SetCurrentAnalogValue (csCode = 3)This call is used to set different analog values. One of the fields in the structure will specify which parameter is being set and another one will specify the value.
OSErr err = Control ( driverRefNum, cscZVSetCurrentAnalogValue, &theZVAnalogControlRecord )
--> whichControl
Which analog setting will be changed
--> value
Value to assign to that control
The range for the value field depends on which analog control is being set. These are detailed in the ZoomedVideo.h header file.
SetInput (csCode = 9)This call is used to select the input video source for the Zoomed Video Card.
OSErr err = Control ( driverRefNum, cscZVSetInput, &theUInt16 )
--> theUInt16
Specifies the video source
The Zoomed Video driver should number video sources sequentially, starting at 0. So, to select the first video source, the client will set the parameter to 0. (Most Zoomed Video cards only have one input).
SetInputStandard (csCode = 11)This call is used to specify the input signaling standard to digitize. The only three input signaling standards that are supported are NTSC, PAL, and SECAM.
OSErr err = Control ( driverRefNum, cscZVSetInputStandard, &theUInt16 )
--> theUInt16
Specifies the signaling standard to use. Valid values for this parameter are: ntscIn, palIn, secamIn