hwcontext_opencl.c

/*
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#define CL_USE_DEPRECATED_OPENCL_1_2_APIS

#include <string.h>

#include "config.h"

#include "avassert.h"
#include "avstring.h"
#include "common.h"
#include "hwcontext.h"
#include "hwcontext_internal.h"
#include "hwcontext_opencl.h"
#include "mem.h"
#include "pixdesc.h"

#if HAVE_OPENCL_VAAPI_BEIGNET
#include <unistd.h>
#include <va/va.h>
#include <va/va_drmcommon.h>
#include <CL/cl_intel.h>
#include "hwcontext_vaapi.h"
#endif

#if HAVE_OPENCL_DRM_BEIGNET
#include <unistd.h>
#include <CL/cl_intel.h>
#include "hwcontext_drm.h"
#endif

#if HAVE_OPENCL_VAAPI_INTEL_MEDIA
#if CONFIG_LIBMFX
#include <mfx/mfxstructures.h>
#endif
#include <va/va.h>
#include <CL/va_ext.h>
#include "hwcontext_vaapi.h"
#endif

#if HAVE_OPENCL_DXVA2
#define COBJMACROS
#include <CL/cl_dx9_media_sharing.h>
#include <dxva2api.h>
#include "hwcontext_dxva2.h"
#endif

#if HAVE_OPENCL_D3D11
#include <CL/cl_d3d11.h>
#include "hwcontext_d3d11va.h"
#endif

#if HAVE_OPENCL_DRM_ARM
#include <CL/cl_ext.h>
#include <drm_fourcc.h>
#include "hwcontext_drm.h"
#endif


typedef struct OpenCLDeviceContext {
    // Default command queue to use for transfer/mapping operations on
    // the device.  If the user supplies one, this is a reference to it.
    // Otherwise, it is newly-created.
    cl_command_queue command_queue;

    // The platform the context exists on.  This is needed to query and
    // retrieve extension functions.
    cl_platform_id platform_id;

    // Platform/device-specific functions.
#if HAVE_OPENCL_DRM_BEIGNET
    int beignet_drm_mapping_usable;
    clCreateImageFromFdINTEL_fn clCreateImageFromFdINTEL;
#endif

#if HAVE_OPENCL_VAAPI_INTEL_MEDIA
    int qsv_mapping_usable;
    clCreateFromVA_APIMediaSurfaceINTEL_fn
        clCreateFromVA_APIMediaSurfaceINTEL;
    clEnqueueAcquireVA_APIMediaSurfacesINTEL_fn
        clEnqueueAcquireVA_APIMediaSurfacesINTEL;
    clEnqueueReleaseVA_APIMediaSurfacesINTEL_fn
        clEnqueueReleaseVA_APIMediaSurfacesINTEL;
#endif

#if HAVE_OPENCL_DXVA2
    int dxva2_mapping_usable;
    cl_dx9_media_adapter_type_khr dx9_media_adapter_type;

    clCreateFromDX9MediaSurfaceKHR_fn
        clCreateFromDX9MediaSurfaceKHR;
    clEnqueueAcquireDX9MediaSurfacesKHR_fn
        clEnqueueAcquireDX9MediaSurfacesKHR;
    clEnqueueReleaseDX9MediaSurfacesKHR_fn
        clEnqueueReleaseDX9MediaSurfacesKHR;
#endif

#if HAVE_OPENCL_D3D11
    int d3d11_mapping_usable;
    clCreateFromD3D11Texture2DKHR_fn
        clCreateFromD3D11Texture2DKHR;
    clEnqueueAcquireD3D11ObjectsKHR_fn
        clEnqueueAcquireD3D11ObjectsKHR;
    clEnqueueReleaseD3D11ObjectsKHR_fn
        clEnqueueReleaseD3D11ObjectsKHR;
#endif

#if HAVE_OPENCL_DRM_ARM
    int drm_arm_mapping_usable;
#endif
} OpenCLDeviceContext;

typedef struct OpenCLFramesContext {
    // Command queue used for transfer/mapping operations on this frames
    // context.  If the user supplies one, this is a reference to it.
    // Otherwise, it is a reference to the default command queue for the
    // device.
    cl_command_queue command_queue;

#if HAVE_OPENCL_DXVA2 || HAVE_OPENCL_D3D11
    // For mapping APIs which have separate creation and acquire/release
    // steps, this stores the OpenCL memory objects corresponding to each
    // frame.
    int                   nb_mapped_frames;
    AVOpenCLFrameDescriptor *mapped_frames;
#endif
} OpenCLFramesContext;


static void CL_CALLBACK opencl_error_callback(const char *errinfo,
                                              const void *private_info,
                                              size_t cb,
                                              void *user_data)
{
    AVHWDeviceContext *ctx = user_data;
    av_log(ctx, AV_LOG_ERROR, "OpenCL error: %s\n", errinfo);
}

static void opencl_device_free(AVHWDeviceContext *hwdev)
{
    AVOpenCLDeviceContext *hwctx = hwdev->hwctx;
    cl_int cle;

    cle = clReleaseContext(hwctx->context);
    if (cle != CL_SUCCESS) {
        av_log(hwdev, AV_LOG_ERROR, "Failed to release OpenCL "
               "context: %d.\n", cle);
    }
}

static struct {
    const char *key;
    cl_platform_info name;
} opencl_platform_params[] = {
    { "platform_profile",    CL_PLATFORM_PROFILE    },
    { "platform_version",    CL_PLATFORM_VERSION    },
    { "platform_name",       CL_PLATFORM_NAME       },
    { "platform_vendor",     CL_PLATFORM_VENDOR     },
    { "platform_extensions", CL_PLATFORM_EXTENSIONS },
};

static struct {
    const char *key;
    cl_device_info name;
} opencl_device_params[] = {
    { "device_name",         CL_DEVICE_NAME         },
    { "device_vendor",       CL_DEVICE_VENDOR       },
    { "driver_version",      CL_DRIVER_VERSION      },
    { "device_version",      CL_DEVICE_VERSION      },
    { "device_profile",      CL_DEVICE_PROFILE      },
    { "device_extensions",   CL_DEVICE_EXTENSIONS   },
};

static struct {
    const char *key;
    cl_device_type type;
} opencl_device_types[] = {
    { "cpu",         CL_DEVICE_TYPE_CPU         },
    { "gpu",         CL_DEVICE_TYPE_GPU         },
    { "accelerator", CL_DEVICE_TYPE_ACCELERATOR },
    { "custom",      CL_DEVICE_TYPE_CUSTOM      },
    { "default",     CL_DEVICE_TYPE_DEFAULT     },
    { "all",         CL_DEVICE_TYPE_ALL         },
};

static char *opencl_get_platform_string(cl_platform_id platform_id,
                                        cl_platform_info key)
{
    char *str;
    size_t size;
    cl_int cle;
    cle = clGetPlatformInfo(platform_id, key, 0, NULL, &size);
    if (cle != CL_SUCCESS)
        return NULL;
    str = av_malloc(size);
    if (!str)
        return NULL;
    cle = clGetPlatformInfo(platform_id, key, size, str, &size);
    if (cle != CL_SUCCESS) {
        av_free(str);
        return NULL;
    }
    av_assert0(strlen(str) + 1 == size);
    return str;
}

static char *opencl_get_device_string(cl_device_id device_id,
                                      cl_device_info key)
{
    char *str;
    size_t size;
    cl_int cle;
    cle = clGetDeviceInfo(device_id, key, 0, NULL, &size);
    if (cle != CL_SUCCESS)
        return NULL;
    str = av_malloc(size);
    if (!str)
        return NULL;
    cle = clGetDeviceInfo(device_id, key, size, str, &size);
    if (cle != CL_SUCCESS) {
        av_free(str);
        return NULL;
    }
    av_assert0(strlen(str) + 1== size);
    return str;
}

static int opencl_check_platform_extension(cl_platform_id platform_id,
                                           const char *name)
{
    char *str;
    int found = 0;
    str = opencl_get_platform_string(platform_id,
                                     CL_PLATFORM_EXTENSIONS);
    if (str && strstr(str, name))
        found = 1;
    av_free(str);
    return found;
}

static int opencl_check_device_extension(cl_device_id device_id,
                                         const char *name)
{
    char *str;
    int found = 0;
    str = opencl_get_device_string(device_id,
                                   CL_DEVICE_EXTENSIONS);
    if (str && strstr(str, name))
        found = 1;
    av_free(str);
    return found;
}

static av_unused int opencl_check_extension(AVHWDeviceContext *hwdev,
                                            const char *name)
{
    AVOpenCLDeviceContext *hwctx = hwdev->hwctx;
    OpenCLDeviceContext    *priv = hwdev->internal->priv;

    if (opencl_check_platform_extension(priv->platform_id, name)) {
        av_log(hwdev, AV_LOG_DEBUG,
               "%s found as platform extension.\n", name);
        return 1;
    }

    if (opencl_check_device_extension(hwctx->device_id, name)) {
        av_log(hwdev, AV_LOG_DEBUG,
               "%s found as device extension.\n", name);
        return 1;
    }

    return 0;
}

static int opencl_enumerate_platforms(AVHWDeviceContext *hwdev,
                                      cl_uint *nb_platforms,
                                      cl_platform_id **platforms,
                                      void *context)
{
    cl_int cle;

    cle = clGetPlatformIDs(0, NULL, nb_platforms);
    if (cle != CL_SUCCESS) {
        av_log(hwdev, AV_LOG_ERROR, "Failed to get number of "
               "OpenCL platforms: %d.\n", cle);
        return AVERROR(ENODEV);
    }
    av_log(hwdev, AV_LOG_DEBUG, "%u OpenCL platforms found.\n",
           *nb_platforms);

    *platforms = av_malloc_array(*nb_platforms, sizeof(**platforms));
    if (!*platforms)
        return AVERROR(ENOMEM);

    cle = clGetPlatformIDs(*nb_platforms, *platforms, NULL);
    if (cle != CL_SUCCESS) {
        av_log(hwdev, AV_LOG_ERROR, "Failed to get list of OpenCL "
               "platforms: %d.\n", cle);
        av_freep(platforms);
        return AVERROR(ENODEV);
    }

    return 0;
}

static int opencl_filter_platform(AVHWDeviceContext *hwdev,
                                  cl_platform_id platform_id,
                                  const char *platform_name,
                                  void *context)
{
    AVDictionary *opts = context;
    const AVDictionaryEntry *param;
    char *str;
    int i, ret = 0;

    for (i = 0; i < FF_ARRAY_ELEMS(opencl_platform_params); i++) {
        param = av_dict_get(opts, opencl_platform_params[i].key,
                            NULL, 0);
        if (!param)
            continue;

        str = opencl_get_platform_string(platform_id,
                                         opencl_platform_params[i].name);
        if (!str) {
            av_log(hwdev, AV_LOG_ERROR, "Failed to query %s "
                   "of platform \"%s\".\n",
                   opencl_platform_params[i].key, platform_name);
            return AVERROR_UNKNOWN;
        }
        if (!av_stristr(str, param->value)) {
            av_log(hwdev, AV_LOG_DEBUG, "%s does not match (\"%s\").\n",
                   param->key, str);
            ret = 1;
        }
        av_free(str);
    }

    return ret;
}

static int opencl_enumerate_devices(AVHWDeviceContext *hwdev,
                                    cl_platform_id platform_id,
                                    const char *platform_name,
                                    cl_uint *nb_devices,
                                    cl_device_id **devices,
                                    void *context)
{
    cl_int cle;

    cle = clGetDeviceIDs(platform_id, CL_DEVICE_TYPE_ALL,
                         0, NULL, nb_devices);
    if (cle == CL_DEVICE_NOT_FOUND) {
        av_log(hwdev, AV_LOG_DEBUG, "No devices found "
               "on platform \"%s\".\n", platform_name);
        *nb_devices = 0;
        return 0;
    } else if (cle != CL_SUCCESS) {
        av_log(hwdev, AV_LOG_ERROR, "Failed to get number of devices "
               "on platform \"%s\": %d.\n", platform_name, cle);
        return AVERROR(ENODEV);
    }
    av_log(hwdev, AV_LOG_DEBUG, "%u OpenCL devices found on "
           "platform \"%s\".\n", *nb_devices, platform_name);

    *devices = av_malloc_array(*nb_devices, sizeof(**devices));
    if (!*devices)
        return AVERROR(ENOMEM);

    cle = clGetDeviceIDs(platform_id, CL_DEVICE_TYPE_ALL,
                         *nb_devices, *devices, NULL);
    if (cle != CL_SUCCESS) {
        av_log(hwdev, AV_LOG_ERROR, "Failed to get list of devices "
               "on platform \"%s\": %d.\n", platform_name, cle);
        av_freep(devices);
        return AVERROR(ENODEV);
    }

    return 0;
}

static int opencl_filter_device(AVHWDeviceContext *hwdev,
                                cl_device_id device_id,
                                const char *device_name,
                                void *context)
{
    AVDictionary *opts = context;
    const AVDictionaryEntry *param;
    char *str;
    int i, ret = 0;

    param = av_dict_get(opts, "device_type", NULL, 0);
    if (param) {
        cl_device_type match_type = 0, device_type;
        cl_int cle;

        for (i = 0; i < FF_ARRAY_ELEMS(opencl_device_types); i++) {
            if (!strcmp(opencl_device_types[i].key, param->value)) {
                match_type = opencl_device_types[i].type;
                break;
            }
        }
        if (!match_type) {
            av_log(hwdev, AV_LOG_ERROR, "Unknown device type %s.\n",
                   param->value);
            return AVERROR(EINVAL);
        }

        cle = clGetDeviceInfo(device_id, CL_DEVICE_TYPE,
                              sizeof(device_type), &device_type, NULL);
        if (cle != CL_SUCCESS) {
            av_log(hwdev, AV_LOG_ERROR, "Failed to query device type "
                   "of device \"%s\".\n", device_name);
            return AVERROR_UNKNOWN;
        }

        if (!(device_type & match_type)) {
            av_log(hwdev, AV_LOG_DEBUG, "device_type does not match.\n");
            return 1;
        }
    }

    for (i = 0; i < FF_ARRAY_ELEMS(opencl_device_params); i++) {
        param = av_dict_get(opts, opencl_device_params[i].key,
                            NULL, 0);
        if (!param)
            continue;

        str = opencl_get_device_string(device_id,
                                       opencl_device_params[i].name);
        if (!str) {
            av_log(hwdev, AV_LOG_ERROR, "Failed to query %s "
                   "of device \"%s\".\n",
                   opencl_device_params[i].key, device_name);
            return AVERROR_UNKNOWN;
        }
        if (!av_stristr(str, param->value)) {
            av_log(hwdev, AV_LOG_DEBUG, "%s does not match (\"%s\").\n",
                   param->key, str);
            ret = 1;
        }
        av_free(str);
    }

    return ret;
}

typedef struct OpenCLDeviceSelector {
    int platform_index;
    int device_index;
    void *context;
    int (*enumerate_platforms)(AVHWDeviceContext *hwdev,
                               cl_uint *nb_platforms,
                               cl_platform_id **platforms,
                               void *context);
    int (*filter_platform)    (AVHWDeviceContext *hwdev,
                               cl_platform_id platform_id,
                               const char *platform_name,
                               void *context);
    int (*enumerate_devices)  (AVHWDeviceContext *hwdev,
                               cl_platform_id platform_id,
                               const char *platform_name,
                               cl_uint *nb_devices,
                               cl_device_id **devices,
                               void *context);
    int (*filter_device)      (AVHWDeviceContext *hwdev,
                               cl_device_id device_id,
                               const char *device_name,
                               void *context);
} OpenCLDeviceSelector;

static int opencl_device_create_internal(AVHWDeviceContext *hwdev,
                                         const OpenCLDeviceSelector *selector,
                                         cl_context_properties *props)
{
    cl_uint      nb_platforms;
    cl_platform_id *platforms = NULL;
    cl_platform_id  platform_id;
    cl_uint      nb_devices;
    cl_device_id   *devices = NULL;
    AVOpenCLDeviceContext *hwctx = hwdev->hwctx;
    cl_int cle;
    cl_context_properties default_props[3];
    char *platform_name_src = NULL,
         *device_name_src   = NULL;
    int err, found, p, d;

    err = selector->enumerate_platforms(hwdev, &nb_platforms, &platforms,
                                        selector->context);
    if (err)
        return err;

    found = 0;
    for (p = 0; p < nb_platforms; p++) {
        const char *platform_name;

        if (selector->platform_index >= 0 &&
            selector->platform_index != p)
            continue;

        av_freep(&platform_name_src);
        platform_name_src = opencl_get_platform_string(platforms[p],
                                                           CL_PLATFORM_NAME);
        if (platform_name_src)
            platform_name = platform_name_src;
        else
            platform_name = "Unknown Platform";

        if (selector->filter_platform) {
            err = selector->filter_platform(hwdev, platforms[p],
                                            platform_name,
                                            selector->context);
            if (err < 0)
                goto fail;
            if (err > 0)
                continue;
        }

        err = opencl_enumerate_devices(hwdev, platforms[p], platform_name,
                                       &nb_devices, &devices,
                                       selector->context);
        if (err < 0)
            continue;

        for (d = 0; d < nb_devices; d++) {
            const char *device_name;

            if (selector->device_index >= 0 &&
                selector->device_index != d)
                continue;

            av_freep(&device_name_src);
            device_name_src = opencl_get_device_string(devices[d],
                                                           CL_DEVICE_NAME);
            if (device_name_src)
                device_name = device_name_src;
            else
                device_name = "Unknown Device";

            if (selector->filter_device) {
                err = selector->filter_device(hwdev, devices[d],
                                              device_name,
                                              selector->context);
                if (err < 0)
                    goto fail;
                if (err > 0)
                    continue;
            }

            av_log(hwdev, AV_LOG_VERBOSE, "%d.%d: %s / %s\n", p, d,
                   platform_name, device_name);

            ++found;
            platform_id      = platforms[p];
            hwctx->device_id = devices[d];
        }

        av_freep(&devices);
    }

    if (found == 0) {
        av_log(hwdev, AV_LOG_ERROR, "No matching devices found.\n");
        err = AVERROR(ENODEV);
        goto fail;
    }
    if (found > 1) {
        av_log(hwdev, AV_LOG_ERROR, "More than one matching device found.\n");
        err = AVERROR(ENODEV);
        goto fail;
    }

    if (!props) {
        props = default_props;
        default_props[0] = CL_CONTEXT_PLATFORM;
        default_props[1] = (intptr_t)platform_id;
        default_props[2] = 0;
    } else {
        if (props[0] == CL_CONTEXT_PLATFORM && props[1] == 0)
            props[1] = (intptr_t)platform_id;
    }

    hwctx->context = clCreateContext(props, 1, &hwctx->device_id,
                                     &opencl_error_callback, hwdev, &cle);
    if (!hwctx->context) {
        av_log(hwdev, AV_LOG_ERROR, "Failed to create OpenCL context: "
               "%d.\n", cle);
        err = AVERROR(ENODEV);
        goto fail;
    }

    hwdev->free = &opencl_device_free;

    err = 0;
fail:
    av_freep(&platform_name_src);
    av_freep(&device_name_src);
    av_freep(&platforms);
    av_freep(&devices);
    return err;
}

static int opencl_device_create(AVHWDeviceContext *hwdev, const char *device,
                                AVDictionary *opts, int flags)
{
    OpenCLDeviceSelector selector = {
        .context = opts,
        .enumerate_platforms = &opencl_enumerate_platforms,
        .filter_platform     = &opencl_filter_platform,
        .enumerate_devices   = &opencl_enumerate_devices,
        .filter_device       = &opencl_filter_device,
    };

    if (device && device[0]) {
        // Match one or both indices for platform and device.
        int d = -1, p = -1, ret;
        if (device[0] == '.')
            ret = sscanf(device, ".%d", &d);
        else
            ret = sscanf(device, "%d.%d", &p, &d);
        if (ret < 1) {
            av_log(hwdev, AV_LOG_ERROR, "Invalid OpenCL platform/device "
                   "index specification \"%s\".\n", device);
            return AVERROR(EINVAL);
        }
        selector.platform_index = p;
        selector.device_index   = d;
    } else {
        selector.platform_index = -1;
        selector.device_index   = -1;
    }

    return opencl_device_create_internal(hwdev, &selector, NULL);
}

static int opencl_device_init(AVHWDeviceContext *hwdev)
{
    AVOpenCLDeviceContext *hwctx = hwdev->hwctx;
    OpenCLDeviceContext    *priv = hwdev->internal->priv;
    cl_int cle;

    if (hwctx->command_queue) {
        cle = clRetainCommandQueue(hwctx->command_queue);
        if (cle != CL_SUCCESS) {
            av_log(hwdev, AV_LOG_ERROR, "Failed to retain external "
                   "command queue: %d.\n", cle);
            return AVERROR(EIO);
        }
        priv->command_queue = hwctx->command_queue;
    } else {
        priv->command_queue = clCreateCommandQueue(hwctx->context,
                                                   hwctx->device_id,
                                                   0, &cle);
        if (!priv->command_queue) {
            av_log(hwdev, AV_LOG_ERROR, "Failed to create internal "
                   "command queue: %d.\n", cle);
            return AVERROR(EIO);
        }
    }

    cle = clGetDeviceInfo(hwctx->device_id, CL_DEVICE_PLATFORM,
                          sizeof(priv->platform_id), &priv->platform_id,
                          NULL);
    if (cle != CL_SUCCESS) {
        av_log(hwdev, AV_LOG_ERROR, "Failed to determine the OpenCL "
               "platform containing the device.\n");
        return AVERROR(EIO);
    }

#define CL_FUNC(name, desc) do {                                \
        if (fail)                                               \
            break;                                              \
        priv->name = clGetExtensionFunctionAddressForPlatform(  \
            priv->platform_id, #name);                          \
        if (!priv->name) {                                      \
            av_log(hwdev, AV_LOG_VERBOSE,                       \
                   desc " function not found (%s).\n", #name);  \
            fail = 1;                                           \
        } else {                                                \
            av_log(hwdev, AV_LOG_VERBOSE,                       \
                   desc " function found (%s).\n", #name);      \
        }                                                       \
    } while (0)

#if HAVE_OPENCL_DRM_BEIGNET
    {
        int fail = 0;

        CL_FUNC(clCreateImageFromFdINTEL,
                "Beignet DRM to OpenCL image mapping");

        if (fail) {
            av_log(hwdev, AV_LOG_WARNING, "Beignet DRM to OpenCL "
                   "mapping not usable.\n");
            priv->beignet_drm_mapping_usable = 0;
        } else {
            priv->beignet_drm_mapping_usable = 1;
        }
    }
#endif

#if HAVE_OPENCL_VAAPI_INTEL_MEDIA
    {
        size_t props_size;
        cl_context_properties *props = NULL;
        VADisplay va_display;
        const char *va_ext = "cl_intel_va_api_media_sharing";
        int i, fail = 0;

        if (!opencl_check_extension(hwdev, va_ext)) {
            av_log(hwdev, AV_LOG_VERBOSE, "The %s extension is "
                   "required for QSV to OpenCL mapping.\n", va_ext);
            goto no_qsv;
        }

        cle = clGetContextInfo(hwctx->context, CL_CONTEXT_PROPERTIES,
                               0, NULL, &props_size);
        if (cle != CL_SUCCESS) {
            av_log(hwdev, AV_LOG_VERBOSE, "Failed to get context "
                   "properties: %d.\n", cle);
            goto no_qsv;
        }
        if (props_size == 0) {
            av_log(hwdev, AV_LOG_VERBOSE, "Media sharing must be "
                   "enabled on context creation to use QSV to "
                   "OpenCL mapping.\n");
            goto no_qsv;
        }

        props = av_malloc(props_size);
        if (!props)
            return AVERROR(ENOMEM);

        cle = clGetContextInfo(hwctx->context, CL_CONTEXT_PROPERTIES,
                               props_size, props, NULL);
        if (cle != CL_SUCCESS) {
            av_log(hwdev, AV_LOG_VERBOSE, "Failed to get context "
                   "properties: %d.\n", cle);
            goto no_qsv;
        }

        va_display = NULL;
        for (i = 0; i < (props_size / sizeof(*props) - 1); i++) {
            if (props[i] == CL_CONTEXT_VA_API_DISPLAY_INTEL) {
                va_display = (VADisplay)(intptr_t)props[i+1];
                break;
            }
        }
        if (!va_display) {
            av_log(hwdev, AV_LOG_VERBOSE, "Media sharing must be "
                   "enabled on context creation to use QSV to "
                   "OpenCL mapping.\n");
            goto no_qsv;
        }
        if (!vaDisplayIsValid(va_display)) {
            av_log(hwdev, AV_LOG_VERBOSE, "A valid VADisplay is "
                   "required on context creation to use QSV to "
                   "OpenCL mapping.\n");
            goto no_qsv;
        }

        CL_FUNC(clCreateFromVA_APIMediaSurfaceINTEL,
                "Intel QSV to OpenCL mapping");
        CL_FUNC(clEnqueueAcquireVA_APIMediaSurfacesINTEL,
                "Intel QSV in OpenCL acquire");
        CL_FUNC(clEnqueueReleaseVA_APIMediaSurfacesINTEL,
                "Intel QSV in OpenCL release");

        if (fail) {
        no_qsv:
            av_log(hwdev, AV_LOG_WARNING, "QSV to OpenCL mapping "
                   "not usable.\n");
            priv->qsv_mapping_usable = 0;
        } else {
            priv->qsv_mapping_usable = 1;
        }
        av_free(props);
    }
#endif

#if HAVE_OPENCL_DXVA2
    {
        int fail = 0;

        CL_FUNC(clCreateFromDX9MediaSurfaceKHR,
                "DXVA2 to OpenCL mapping");
        CL_FUNC(clEnqueueAcquireDX9MediaSurfacesKHR,
                "DXVA2 in OpenCL acquire");
        CL_FUNC(clEnqueueReleaseDX9MediaSurfacesKHR,
                "DXVA2 in OpenCL release");

        if (fail) {
            av_log(hwdev, AV_LOG_WARNING, "DXVA2 to OpenCL mapping "
                   "not usable.\n");
            priv->dxva2_mapping_usable = 0;
        } else {
            priv->dx9_media_adapter_type = CL_ADAPTER_D3D9EX_KHR;
            priv->dxva2_mapping_usable = 1;
        }
    }
#endif

#if HAVE_OPENCL_D3D11
    {
        const char *d3d11_ext = "cl_khr_d3d11_sharing";
        const char *nv12_ext  = "cl_intel_d3d11_nv12_media_sharing";
        int fail = 0;

        if (!opencl_check_extension(hwdev, d3d11_ext)) {
            av_log(hwdev, AV_LOG_VERBOSE, "The %s extension is "
                   "required for D3D11 to OpenCL mapping.\n", d3d11_ext);
            fail = 1;
        } else if (!opencl_check_extension(hwdev, nv12_ext)) {
            av_log(hwdev, AV_LOG_VERBOSE, "The %s extension may be "
                   "required for D3D11 to OpenCL mapping.\n", nv12_ext);
            // Not fatal.
        }

        CL_FUNC(clCreateFromD3D11Texture2DKHR,
                "D3D11 to OpenCL mapping");
        CL_FUNC(clEnqueueAcquireD3D11ObjectsKHR,
                "D3D11 in OpenCL acquire");
        CL_FUNC(clEnqueueReleaseD3D11ObjectsKHR,
                "D3D11 in OpenCL release");

        if (fail) {
            av_log(hwdev, AV_LOG_WARNING, "D3D11 to OpenCL mapping "
                   "not usable.\n");
            priv->d3d11_mapping_usable = 0;
        } else {
            priv->d3d11_mapping_usable = 1;
        }
    }
#endif

#if HAVE_OPENCL_DRM_ARM
    {
        const char *drm_arm_ext = "cl_arm_import_memory";
        const char *image_ext   = "cl_khr_image2d_from_buffer";
        int fail = 0;

        if (!opencl_check_extension(hwdev, drm_arm_ext)) {
            av_log(hwdev, AV_LOG_VERBOSE, "The %s extension is "
                   "required for DRM to OpenCL mapping on ARM.\n",
                   drm_arm_ext);
            fail = 1;
        }
        if (!opencl_check_extension(hwdev, image_ext)) {
            av_log(hwdev, AV_LOG_VERBOSE, "The %s extension is "
                   "required for DRM to OpenCL mapping on ARM.\n",
                   image_ext);
            fail = 1;
        }

        // clImportMemoryARM() is linked statically.

        if (fail) {
            av_log(hwdev, AV_LOG_WARNING, "DRM to OpenCL mapping on ARM "
                   "not usable.\n");
            priv->drm_arm_mapping_usable = 0;
        } else {
            priv->drm_arm_mapping_usable = 1;
        }
    }
#endif

#undef CL_FUNC

    return 0;
}

static void opencl_device_uninit(AVHWDeviceContext *hwdev)
{
    OpenCLDeviceContext *priv = hwdev->internal->priv;
    cl_int cle;

    if (priv->command_queue) {
        cle = clReleaseCommandQueue(priv->command_queue);
        if (cle != CL_SUCCESS) {
            av_log(hwdev, AV_LOG_ERROR, "Failed to release internal "
                   "command queue reference: %d.\n", cle);
        }
        priv->command_queue = NULL;
    }
}

#if HAVE_OPENCL_VAAPI_INTEL_MEDIA
static int opencl_filter_intel_media_vaapi_platform(AVHWDeviceContext *hwdev,
                                                    cl_platform_id platform_id,
                                                    const char *platform_name,
                                                    void *context)
{
    // This doesn't exist as a platform extension, so just test whether
    // the function we will use for device enumeration exists.

    if (!clGetExtensionFunctionAddressForPlatform(platform_id,
            "clGetDeviceIDsFromVA_APIMediaAdapterINTEL")) {
        av_log(hwdev, AV_LOG_DEBUG, "Platform %s does not export the "
               "VAAPI device enumeration function.\n", platform_name);
        return 1;
    } else {
        return 0;
    }
}

static int opencl_enumerate_intel_media_vaapi_devices(AVHWDeviceContext *hwdev,
                                                      cl_platform_id platform_id,
                                                      const char *platform_name,
                                                      cl_uint *nb_devices,
                                                      cl_device_id **devices,
                                                      void *context)
{
    VADisplay va_display = context;
    clGetDeviceIDsFromVA_APIMediaAdapterINTEL_fn
        clGetDeviceIDsFromVA_APIMediaAdapterINTEL;
    cl_int cle;
    int err;

    clGetDeviceIDsFromVA_APIMediaAdapterINTEL =
        clGetExtensionFunctionAddressForPlatform(platform_id,
            "clGetDeviceIDsFromVA_APIMediaAdapterINTEL");
    if (!clGetDeviceIDsFromVA_APIMediaAdapterINTEL) {
        av_log(hwdev, AV_LOG_ERROR, "Failed to get address of "
               "clGetDeviceIDsFromVA_APIMediaAdapterINTEL().\n");
        return AVERROR_UNKNOWN;
    }

    cle = clGetDeviceIDsFromVA_APIMediaAdapterINTEL(
        platform_id, CL_VA_API_DISPLAY_INTEL, va_display,
        CL_PREFERRED_DEVICES_FOR_VA_API_INTEL, 0, NULL, nb_devices);
    if (cle == CL_DEVICE_NOT_FOUND) {
        av_log(hwdev, AV_LOG_DEBUG, "No VAAPI-supporting devices found "
               "on platform \"%s\".\n", platform_name);
        *nb_devices = 0;
        return 0;
    } else if (cle != CL_SUCCESS) {
        av_log(hwdev, AV_LOG_ERROR, "Failed to get number of devices "
               "on platform \"%s\": %d.\n", platform_name, cle);
        return AVERROR_UNKNOWN;
    }

    *devices = av_malloc_array(*nb_devices, sizeof(**devices));
    if (!*devices)
        return AVERROR(ENOMEM);

    cle = clGetDeviceIDsFromVA_APIMediaAdapterINTEL(
        platform_id, CL_VA_API_DISPLAY_INTEL, va_display,
        CL_PREFERRED_DEVICES_FOR_VA_API_INTEL, *nb_devices, *devices, NULL);
    if (cle != CL_SUCCESS) {
        av_log(hwdev, AV_LOG_ERROR, "Failed to get list of VAAPI-supporting "
               "devices on platform \"%s\": %d.\n", platform_name, cle);
        av_freep(devices);
        return AVERROR_UNKNOWN;
    }

    return 0;
}

static int opencl_filter_intel_media_vaapi_device(AVHWDeviceContext *hwdev,
                                                  cl_device_id device_id,
                                                  const char *device_name,
                                                  void *context)
{
    const char *va_ext = "cl_intel_va_api_media_sharing";

    if (opencl_check_device_extension(device_id, va_ext)) {
        return 0;
    } else {
        av_log(hwdev, AV_LOG_DEBUG, "Device %s does not support the "
               "%s extension.\n", device_name, va_ext);
        return 1;
    }
}
#endif

#if HAVE_OPENCL_DXVA2
static int opencl_filter_dxva2_platform(AVHWDeviceContext *hwdev,
                                        cl_platform_id platform_id,
                                        const char *platform_name,
                                        void *context)
{
    const char *dx9_ext = "cl_khr_dx9_media_sharing";

    if (opencl_check_platform_extension(platform_id, dx9_ext)) {
        return 0;
    } else {