table of contents
clEnqueueReleaseDX9MediaSurfacesKHR - Release OpenCL memory objects that have been created from media surfaces.
cl_int clEnqueueReleaseDX9MediaSurfacesKHR(cl_command_queue command_queue, cl_uint num_objects, const cl_mem *mem_objects, cl_uint num_events_in_wait_list, const cl_event *event_wait_list, cl_event *event);
Used to release OpenCL memory objects that have been created from media surfaces. The media surfaces are released by the OpenCL context associated with command_queue.
OpenCL memory objects created from media surfaces which have been acquired by OpenCL must be released by OpenCL before they may be accessed by the media adapter API. Accessing a media surface while its corresponding OpenCL memory object is acquired is in error and will result in undefined behavior, including but not limited to possible OpenCL errors, data corruption, and program termination.
If CL_CONTEXT_INTEROP_USER_SYNC is not specified as CL_TRUE during context creation, clEnqueueReleaseDX9MediaSurfacesKHR provides the synchronization guarantee that any calls to media adapter APIs involving the interop device(s) used in the OpenCL context made after the call to clEnqueueReleaseDX9MediaSurfacesKHR will not start executing until after all events in event_wait_list are complete and all work already submitted to command_queue completes execution. 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 after clEnqueueReleaseDX9MediaSurfacesKHR will not start executing until after event returned by clEnqueueReleaseDX9MediaSurfacesKHR reports completion.
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_media_sharing" will be present in the CL_PLATFORM_EXTENSIONS or CL_DEVICE_EXTENSIONS string described in the table of allowed values for param_name for clGetDeviceInfo(3clc).
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.
|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)|
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(3clc) and clGetImageInfo(3clc) with param_name CL_MEM_MEDIA_ADAPTER_TYPE_KHR, CL_MEM_MEDIA_SURFACE_INFO_KHR and CL_IMAGE_MEDIA_SURFACE_PLANE_KHR as described for clGetImageInfo(3clc) and in the information below about accessing mapped regions of a memory object. Accessing mapped regions of a memory object.PP This section describes the behavior of OpenCL commands that access mapped regions of a memory object.
The contents of the region of a memory object and associated memory objects (sub-buffer objects or 1D image buffer objects that overlap this region) mapped for writing (i.e. CL_MAP_WRITE or CL_MAP_WRITE_INVALIDATE_REGION is set in map_flags argument to clEnqueueMapBuffer(3clc) or clEnqueueMapImage(3clc)) are considered to be undefined until this region is unmapped.
Multiple commands in command-queues can map a region or overlapping regions of a memory object and associated memory objects (sub-buffer objects or 1D image buffer objects that overlap this region) for reading (i.e. map_flags = CL_MAP_READ). The contents of the regions of a memory object mapped for reading can also be read by kernels and other OpenCL commands (such as clEnqueueCopyBuffer(3clc)) executing on a device(s).
Mapping (and unmapping) overlapped regions in a memory object and/or associated memory objects (sub-buffer objects or 1D image buffer objects that overlap this region) for writing is an error and will result in CL_INVALID_OPERATION error returned by clEnqueueMapBuffer(3clc) or clEnqueueMapImage(3clc).
If a memory object is currently mapped for writing, the application must ensure that the memory object is unmapped before any enqueued kernels or commands that read from or write to this memory object or any of its associated memory objects (sub-buffer or 1D image buffer objects) or its parent object (if the memory object is a sub-buffer or 1D image buffer object) begin execution; otherwise the behavior is undefined.
If a memory object is currently mapped for reading, the application must ensure that the memory object is unmapped before any enqueued kernels or commands that write to this memory object or any of its associated memory objects (sub-buffer or 1D image buffer objects) or its parent object (if the memory object is a sub-buffer or 1D image buffer object) begin execution; otherwise the behavior is undefined.
Accessing the contents of the memory region referred to by the mapped pointer that has been unmapped is undefined.
The mapped pointer returned by clEnqueueMapBuffer(3clc) or clEnqueueMapImage(3clc) can be used as ptr argument value to clEnqueueReadBuffer(3clc), clEnqueueWriteBuffer(3clc), clEnqueueReadBufferRect(3clc), clEnqueueWriteBufferRect(3clc), clEnqueueReadImage(3clc), and clEnqueueWriteImage(3clc), provided the rules described above are adhered to.
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:
cl_khr_dx9_media_sharing(3clc), clGetDeviceIDsFromDX9MediaAdapterKHR(3clc), clCreateFromDX9MediaSurfaceKHR(3clc), clEnqueueAcquireDX9MediaSurfacesKHR(3clc), clEnqueueReleaseDX9MediaSurfacesKHR(3clc)
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|01/14/2021||The Khronos Group|