VL_EXT_EVENT_RECV(3dm)					VL_EXT_EVENT_RECV(3dm)

NAME    [Toc]    [Back]

     VL_EXT_EVENT_RECV - VL Event Receive library extension for	O2
     workstations (now obsolete)

SYNOPSIS    [Toc]    [Back]

     #include <dmedia/vl.h>

DESCRIPTION    [Toc]    [Back]

     This API has been supplanted by a cross-platform API for video and
     DMbuffers.	 It is supported for backwards compatibility only.  Please see
     vlintro(3dm).

     The VL Event Receive extension provides a mechanism for video
     applications to send and receive DMbuffers	on the O2 system.  These
     buffers can be used to move images	between	software subsystems, such as
     dmIC and OpenGL (see glIntro(3G)),	without	copying	any data.

     The VL Event Receive extension consists of	the following function calls:

     vlPathGetFD(3dm) -	Get the	event file descriptor associated with a	VL
     path

     vlEventRecv(3dm) -	Receive	a VL event from	a VL path

     vlEventToDMBuffer(3dm) - Get a pointer to the DMBuffer referenced by a VL
     event

     vlDMBufferSend(3dm) - Send	a VL buffer to a VL path

     vlDMPoolGetParams(3dm) - Determine	the memory pool	requirements for this
     VL	memory node

     The following standard VL function	calls may be particularly useful with
     the above named function calls:

     vlDMPoolRegister(3dm) - Register a	DMPool with a VL node for memory
     transfers

     vlDMPoolDeregister(3dm) - Deregister a DMPool with	a VL node

     vlGetFilledByNode(3dm) - Determine	the depth of a VL event	queue


DIGITAL	MEDIA BUFFERS
     The Video Library supports	digital	media buffers, dmbuffer(3dm), for some
     devices. DMbuffers	replace	the fixed ring buffer of DMRB with a more
     flexible mechanism	based on a FIFO. DMbuffers provide the ability to
     retain individual buffers without stopping	video transfers.  They can be
     used to pass data efficiently, by reference instead of copying, between
     different video paths and between libraries. (e.g., digital media Image
     Converter,	dmIC(3dm).)



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VL_EXT_EVENT_RECV(3dm)					VL_EXT_EVENT_RECV(3dm)



     The routines in the VL Event Receive extension are	incompatible with some
     of	the existing vl	interfaces.  Using them	in combination may result in
     the error VLAPIConflict.

     The following routines are	specific to DMbuffers:

	  vlPathGetFD(3dm)
	  vlEventRecv(3dm)
	  vlEventToDMBuffer(3dm)
	  vlDMBufferSend(3dm)
	  vlDMPoolGetParams(3dm)
	  vlDMPoolR
     The following routines cannot be used with	DMbuffers:

	  Event	Oriented:
	      vlPending
	      vlNextEvent
	      vlCheckEvent
	      vlPeekEvent

	  Callbacks and	Handlers:
	      vlMainLoop
	      vlRegisterHandler
	      vlRemoveHandler
	      vlAddCallback
	      vlRemoveCallback
	      vlRemoveAllCallbacks
	      vlCallCallbacks

	  Buffer Oriented:
	      vlCreateBuffer
	      vlRegisterBuffer
	      vlDeregisterBuffer
	      vlBufferAdvise
	      vlBufferGetFD
	      vlBufferDone
	      vlBufferReset
	      vlDestroyBuffer
	      vlGetNextFree
	      vlPutFree
	      vlPutValid
	      vlGetNextValid
	      vlGetLatestValid
	      vlGetActiveRegion
	      vlGetDMediaInfo
	      vlGetImageInfo






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VL_EXT_EVENT_RECV(3dm)					VL_EXT_EVENT_RECV(3dm)

EXAMPLE    [Toc]    [Back]

     The following example demonstrates	the creation of	a DMbufferpool and its
     registration for use with a VL path and node.

	       DMbufferpool pool;
	       DMParams	plist;
	       int xfersize;

	       /* Create a parameter list */
	       dmParamsCreate(&plist);

	       xfersize	= vlGetTransferSize(svr, path);

	       /* set our requirements for the pool */
	       dmBufferSetPoolDefaults(plist, num_frames, xfersize, DM_TRUE, DM_TRUE);

	       /* request the vl's requirements	for the	pool */
	       vlDMPoolGetParams(svr, path, drn, plist);

	       /* create the pool */
	       dmBufferCreatePool(plist, &pool);

	       /* register it with the path and	node */
	       vlDMPoolRegister(svr, path, drn,	pool);

NOTES    [Toc]    [Back]

     The vlinfo(1) command reports which video library extensions are
     available on a system.

     Extensions	may be queried programmatically	using the vlGetString(3dm)
     function of the video library.

SEE ALSO    [Toc]    [Back]

     vlEventRecv(3dm), vlDMBufferSend(3dm), vlGetString(3dm),
     vlDMPoolGetParams(3dm), dmbuffer(3dm), dmIC(3dm)


									PPPPaaaaggggeeee 3333