VL_EXT_EVENT_RECV(3dm)VL_EXT_EVENT_RECV(3dm)NAMEVL_EXT_EVENT_RECV - VL Event Receive library extension for O2
workstations (now obsolete)
SYNOPSIS
#include <dmedia/vl.h>
DESCRIPTION
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).)
Page 1
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)vlDMPoolRegister(3dm)vlDMPoolDeregister(3dm)
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
Page 2
VL_EXT_EVENT_RECV(3dm)VL_EXT_EVENT_RECV(3dm)EXAMPLE
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
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 ALSOvlEventRecv(3dm), vlDMBufferSend(3dm), vlGetString(3dm),
vlDMPoolGetParams(3dm), dmbuffer(3dm), dmIC(3dm)
Page 3
