Acquire OpenCL memory objects that have been created from a media surface.
command_queue
A valid command-queue.
num_objects
The number of memory objects to be acquired in mem_objects
.
mem_objects
A pointer to a list of OpenCL memory objects that were created from media surfaces.
num_events_in_wait_list
, event_wait_list
Specify events that need to complete before this particular
command can be executed. If event_wait_list
is NULL, then this particular command does not wait on any
event to complete. If event_wait_list
is
NULL, num_events_in_wait_list
must be 0. If
event_wait_list
is not NULL, the list of events
pointed to by event_wait_list
must be valid and
num_events_in_wait_list
must be greater than 0. The events
specified in event_wait_list
act as synchronization points.
event
Returns n
event object that identifies this particular
command and can be used to query or queue a wait for this particular command
to complete. event
can be NULL in which case it will not
be possible for the application to query the status of this command or queue
a wait for this command to complete.
If the event_wait_list
and the
event
arguments are not NULL, the
event
argument should not refer to an element of the
event_wait_list
array.
Used to acquire OpenCL memory objects that have been created from a media
surface. The media surfaces are acquired by the OpenCL context associated with
command_queue
and can therefore be used by all command-queues
associated with the OpenCL context.
OpenCL memory objects created from media surfaces must be acquired before they can be used by any OpenCL commands queued to a command-queue. If an OpenCL memory object created from a media surface is used while it is not currently acquired by OpenCL, the call attempting to use that OpenCL memory object will return CL_DX9_MEDIA_SURFACE_NOT_ACQUIRED_KHR.
If CL_CONTEXT_INTEROP_USER_SYNC
is not
specified as CL_TRUE
during context creation,
clEnqueueAcquireDX9MediaSurfacesKHR
provides the synchronization
guarantee that any media adapter API calls involving the interop device(s) used in the
OpenCL context made before clEnqueueAcquireDX9MediaSurfacesKHR
is called will complete executing before event
reports
completion and before the execution of any subsequent OpenCL work issued
in command_queue
begins. If the context was created with
properties specifying CL_CONTEXT_INTEROP_USER_SYNC
as
CL_TRUE
, the user is responsible for guaranteeing that any
media adapter API calls involving the interop device(s) used in the OpenCL context
made before clEnqueueAcquireDX9MediaSurfacesKHR
is called have
completed before calling clEnqueueAcquireDX9MediaSurfacesKHR
.
The goal of this extension is to allow applications to use media surfaces as OpenCL memory objects. This allows efficient sharing of data between OpenCL and selected adapter APIs (only DX9 for now). If this extension is supported, an OpenCL image object can be created from a media surface and the OpenCL API can be used to execute kernels that read and/or write memory objects that are media surfaces. Note that OpenCL memory objects may be created from the adapter media surface if and only if the OpenCL context has been created from that adapter.
If this extension is supported by an implementation,
the string "cl_khr_dx9_media_sharing" will be present in the
CL_PLATFORM_EXTENSIONS
(see clGetPlatformInfo)
or CL_DEVICE_EXTENSIONS
(see clGetDeviceInfo).
As currently proposed the interfaces for this
extension would be provided in cl_dx9_media_sharing.h
.
This section includes the D3D surface formats that are supported when the adapter type is one of the Direct 3D lineage. Using a D3D surface format not listed here is an error. To extend the use of this extension to support media adapters beyond DirectX9 tables similar to the ones in this section will need to be defined for the surface formats supported by the new media adapter. All implementations that support this extension are required to support the NV12 surface format, the other surface formats supported are the same surface formats that the adapter you are sharing with supports as long as they are listed in the two tables below (Tables 9.10.3 and 9.10.4).
FOUR CC code | CL image format (channel order, channel data type) |
---|---|
FOURCC('N', 'V', '1', '2'), Plane 0 |
CL_R, CL_UNORM_INT8
|
FOURCC('N', 'V', '1', '2'), Plane 1 |
CL_RG, CL_UNORM_INT8
|
FOURCC('Y', 'V', '1', '2'), Plane 0 |
CL_R, CL_UNORM_INT8
|
FOURCC('Y', 'V', '1', '2'), Plane 1 |
CL_R, CL_UNORM_INT8
|
FOURCC('Y', 'V', '1', '2'), Plane 2 |
CL_R, CL_UNORM_INT8
|
In the table above, NV12 Plane 0 corresponds to the luminance (Y) channel and Plane 1
corresponds to the UV channels. The YV12 Plane 0 corresponds to the Y channel, Plane
1 to the U channel and Plane 2 to the V channel. Note that the YUV formats map to
CL_R
and CL_RG
but do not perform any YUV to
RGB conversion and vice-versa.
D3D format | CL image format (channel order, channel data type) |
---|---|
D3DFMT_R32F |
CL_R, CL_FLOAT
|
D3DFMT_R16F |
CL_R, CL_HALF_FLOAT
|
D3DFMT_L16 |
CL_R, CL_UNORM_INT16
|
D3DFMT_A8 |
CL_A, CL_UNORM_INT8
|
D3DFMT_L8 |
CL_R, CL_UNORM_INT8
|
D3DFMT_G32R32F |
CL_RG, CL_FLOAT
|
D3DFMT_G16R16F |
CL_RG, CL_HALF_FLOAT
|
D3DFMT_G16R16 |
CL_RG, CL_UNORM_INT16
|
D3DFMT_A8L8 |
CL_RG, CL_UNORM_INT8
|
D3DFMT_A32B32G32R32F |
CL_RGBA, CL_FLOAT
|
D3DFMT_A16B16G16R16F |
CL_RGBA, CL_HALF_FLOAT
|
D3DFMT_A16B16G16R16 |
CL_RGBA, CL_UNORM_INT16
|
D3DFMT_A8B8G8R8 |
CL_RGBA, CL_UNORM_INT8
|
D3DFMT_X8B8G8R8 |
CL_RGBA, CL_UNORM_INT8
|
D3DFMT_A8R8G8B8 |
CL_BGRA, CL_UNORM_INT8
|
D3DFMT_X8R8G8B8 |
CL_BGRA, CL_UNORM_INT8
|
Note that D3D9 format names seem to imply that the order of the color channels are switched
relative to OpenCL but this is not the case. For example, layout of channels for each pixel
for D3DFMT_A32FB32FG32FR32F
is the same as
CL_RGBA
, CL_FLOAT
.
Properties of media surface objects may be queried using
clGetMemObjectInfo
and clGetImageInfo with
param_name
CL_MEM_DX9_MEDIA_ADAPTER_TYPE_KHR
,
CL_MEM_DX9_MEDIA_SURFACE_INFO_KHR
and
CL_IMAGE_DX9_MEDIA_SURFACE_PLANE_KHR
.
Returns CL_SUCCESS returns CL_SUCCESS
if the function is executed successfully. If num_objects
is 0 and
mem_objects
is NULL then the function does nothing and returns
CL_SUCCESS. Otherwise it returns one of the following errors:
num_objects
is zero and mem_objects
is not a NULL value or if
num_objects
> 0 and mem_objects
is NULL.
mem_objects
are not valid OpenCL memory objects or if memory
objects in mem_objects
have not been created from media surfaces.
command_queue
is not a valid command-queue.
command_queue
was not created from a device that can share
the media surface referenced by mem_objects
.
mem_objects
have previously been acquired
using clEnqueueAcquireDX9MediaSurfacesKHR
but have not been released using
clEnqueueReleaseDX9MediaSurfacesKHR.
event_wait_list
is NULL and
num_event_in_wait_list
> 0,
or event_wait_list
is not NULL and
num_event_in_wait_list
is 0, or if event objects in
event_wait_list
are not valid events.