clGetDeviceIDsFromDX9MediaAdapterKHR

Query a media adapter for any associated OpenCL devices.

cl_int clGetDeviceIDsFromDX9MediaAdapterKHR ( cl_platform_id platform,
  cl_uint num_media_adapters,
  cl_dx9_media_adapter_type_khr *media_adapters_type,
  void *media_adapters,
  cl_dx9_media_adapter_set_khr media_adapter_set,
  cl_uint num_entries,
  cl_device_id *devices,
  cl_int *num_devices)

Parameters

platform

Refers to the platform ID returned by clGetPlatformIDs.

num_media_adapters

The number of media adapters.

media_adapters_type

An array of num_media_adapters entries. Each entry specifies the type of media adapter and must be one of the values described in the table below.

cl_dx9_media_adapter_type_khr Type of media adapters
CL_ADAPTER_D3D9_KHR IDirect3DDevice9 *
CL_ADAPTER_D3D9EX_KHR IDirect3DDevice9Ex *
CL_ADAPTER_DXVA_KHR IDXVAHD_Device *
media_adapters

An array of num_media_adapters entries. Each entry specifies the actual adapter whose type is specified by media_adapter_type. The media_adapters must be one of the types describes in the table above.

media_adapter_set

Specifies the set of adapters to return and must be one of the values described in the table below.

cl_dx9_media_adapter_set_khr Description
CL_PREFERRED_DEVICES_FOR_MEDIA_ADAPTER_KHR The preferred OpenCL devices associated with the media adapter.
CL_ALL_DEVICES_FOR_MEDIA_ADAPTER_KHR All OpenCL devices that may interoperate with the media adapter.
num_entries

The number of cl_device_id entries that can be added to devices. If devices is not NULL, the num_entries must be greater than zero.

devices

Returns a list of OpenCL devices found that support the list of media adapters specified. The cl_device_id values returned in devices can be used to identify a specific OpenCL device. If devices argument is NULL, this argument is ignored. The number of OpenCL devices returned is the minimum of the value specified by num_entries or the number of OpenCL devices whose type matches device_type.

num_devices

Returns the number of OpenCL devices. If num_devices is NULL, this argument is ignored.

Description

Queries a media adapter for any associated OpenCL devices. Adapters with associated OpenCL devices can enable media surface sharing between the two.

Notes

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.

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)
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_MEDIA_ADAPTER_TYPE_KHR, CL_MEM_MEDIA_SURFACE_INFO_KHR and CL_IMAGE_MEDIA_SURFACE_PLANE_KHR as described for clGetImageInfo and in the information below about accessing mapped regions of a memory object.

Accessing mapped regions of a memory object

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 or clEnqueueMapImage) 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) 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 or clEnqueueMapImage.

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 or clEnqueueMapImage can be used as ptr argument value to clEnqueueReadBuffer, clEnqueueWriteBuffer, clEnqueueReadBufferRect, clEnqueueWriteBufferRect, clEnqueueReadImage, and clEnqueueWriteImage, provided the rules described above are adhered to.

Errors

Returns CL_SUCCESS if the function is executed successfully. Otherwise, it returns one of the following errors:

  • CL_INVALID_PLATFORM if platform is not a valid platform.
  • CL_INVALID_VALUE if num_media_adapters is zero or if media_adapters_type is NULL or if media_adapters is NULL.
  • CL_INVALID_VALUE if any of the entries in media_adapters_type or media_adapters is not a valid value.
  • CL_INVALID_VALUE if media_adapter_set is not a valid value.
  • CL_INVALID_VALUE if num_entries is equal to zero and devices is not NULL or if both num_devices and devices are NULL.
  • CL_DEVICE_NOT_FOUND if no OpenCL devices that correspond to adapters specified in media_adapters and media_adapters_type were found.
  • CL_OUT_OF_RESOURCES if there is a failure to allocate resources required by the OpenCL implementation on the device.
  • CL_OUT_OF_HOST_MEMORY if there is a failure to allocate resources required by the OpenCL implementation on the host.

Specification

OpenCL Specification

Also see

cl_khr_dx9_media_sharing, clGetDeviceIDsFromDX9MediaAdapterKHR, clCreateFromDX9MediaSurfaceKHR, clEnqueueAcquireDX9MediaSurfacesKHR, clEnqueueReleaseDX9MediaSurfacesKHR,

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