libavutil/hwcontext_cuda.c - third_party/ffmpeg - Git at Google

 /*
  * 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
  */

 #include "buffer.h"
 #include "common.h"
 #include "hwcontext.h"
 #include "hwcontext_internal.h"
 #include "hwcontext_cuda_internal.h"
 #include "mem.h"
 #include "pixdesc.h"
 #include "pixfmt.h"
 #include "imgutils.h"

 #define CUDA_FRAME_ALIGNMENT 256

 typedef struct CUDAFramesContext {
     int shift_width, shift_height;
 } CUDAFramesContext;

 static const enum AVPixelFormat supported_formats[] = {
     AV_PIX_FMT_NV12,
     AV_PIX_FMT_YUV420P,
     AV_PIX_FMT_YUV444P,
     AV_PIX_FMT_P010,
     AV_PIX_FMT_P016,
     AV_PIX_FMT_YUV444P16,
     AV_PIX_FMT_0RGB32,
     AV_PIX_FMT_0BGR32,
 };

 static int cuda_frames_get_constraints(AVHWDeviceContext *ctx,
                                        const void *hwconfig,
                                        AVHWFramesConstraints *constraints)
 {
     int i;

     constraints->valid_sw_formats = av_malloc_array(FF_ARRAY_ELEMS(supported_formats) + 1,
                                                     sizeof(*constraints->valid_sw_formats));
     if (!constraints->valid_sw_formats)
         return AVERROR(ENOMEM);

     for (i = 0; i < FF_ARRAY_ELEMS(supported_formats); i++)
         constraints->valid_sw_formats[i] = supported_formats[i];
     constraints->valid_sw_formats[FF_ARRAY_ELEMS(supported_formats)] = AV_PIX_FMT_NONE;

     constraints->valid_hw_formats = av_malloc_array(2, sizeof(*constraints->valid_hw_formats));
     if (!constraints->valid_hw_formats)
         return AVERROR(ENOMEM);

     constraints->valid_hw_formats[0] = AV_PIX_FMT_CUDA;
     constraints->valid_hw_formats[1] = AV_PIX_FMT_NONE;

     return 0;
 }

 static void cuda_buffer_free(void *opaque, uint8_t *data)
 {
     AVHWFramesContext *ctx = opaque;
     AVCUDADeviceContext *hwctx = ctx->device_ctx->hwctx;
     CudaFunctions *cu = hwctx->internal->cuda_dl;

     CUcontext dummy;

     cu->cuCtxPushCurrent(hwctx->cuda_ctx);

     cu->cuMemFree((CUdeviceptr)data);

     cu->cuCtxPopCurrent(&dummy);
 }

 static AVBufferRef *cuda_pool_alloc(void *opaque, int size)
 {
     AVHWFramesContext     *ctx = opaque;
     AVCUDADeviceContext *hwctx = ctx->device_ctx->hwctx;
     CudaFunctions          *cu = hwctx->internal->cuda_dl;

     AVBufferRef *ret = NULL;
     CUcontext dummy = NULL;
     CUdeviceptr data;
     CUresult err;

     err = cu->cuCtxPushCurrent(hwctx->cuda_ctx);
     if (err != CUDA_SUCCESS) {
         av_log(ctx, AV_LOG_ERROR, "Error setting current CUDA context\n");
         return NULL;
     }

     err = cu->cuMemAlloc(&data, size);
     if (err != CUDA_SUCCESS)
         goto fail;

     ret = av_buffer_create((uint8_t*)data, size, cuda_buffer_free, ctx, 0);
     if (!ret) {
         cu->cuMemFree(data);
         goto fail;
     }

 fail:
     cu->cuCtxPopCurrent(&dummy);
     return ret;
 }

 static int cuda_frames_init(AVHWFramesContext *ctx)
 {
     CUDAFramesContext *priv = ctx->internal->priv;
     int i;

     for (i = 0; i < FF_ARRAY_ELEMS(supported_formats); i++) {
         if (ctx->sw_format == supported_formats[i])
             break;
     }
     if (i == FF_ARRAY_ELEMS(supported_formats)) {
         av_log(ctx, AV_LOG_ERROR, "Pixel format '%s' is not supported\n",
                av_get_pix_fmt_name(ctx->sw_format));
         return AVERROR(ENOSYS);
     }

     av_pix_fmt_get_chroma_sub_sample(ctx->sw_format, &priv->shift_width, &priv->shift_height);

     if (!ctx->pool) {
         int size = av_image_get_buffer_size(ctx->sw_format, ctx->width, ctx->height, CUDA_FRAME_ALIGNMENT);
         if (size < 0)
             return size;

         ctx->internal->pool_internal = av_buffer_pool_init2(size, ctx, cuda_pool_alloc, NULL);
         if (!ctx->internal->pool_internal)
             return AVERROR(ENOMEM);
     }

     return 0;
 }

 static int cuda_get_buffer(AVHWFramesContext *ctx, AVFrame *frame)
 {
     int res;

     frame->buf[0] = av_buffer_pool_get(ctx->pool);
     if (!frame->buf[0])
         return AVERROR(ENOMEM);

     res = av_image_fill_arrays(frame->data, frame->linesize, frame->buf[0]->data,
                                ctx->sw_format, ctx->width, ctx->height, CUDA_FRAME_ALIGNMENT);
     if (res < 0)
         return res;

     // YUV420P is a special case.
     // Nvenc expects the U/V planes in swapped order from how ffmpeg expects them, also chroma is half-aligned
     if (ctx->sw_format == AV_PIX_FMT_YUV420P) {
         frame->linesize[1] = frame->linesize[2] = frame->linesize[0] / 2;
         frame->data[2]     = frame->data[1];
         frame->data[1]     = frame->data[2] + frame->linesize[2] * ctx->height / 2;
     }

     frame->format = AV_PIX_FMT_CUDA;
     frame->width  = ctx->width;
     frame->height = ctx->height;

     return 0;
 }

 static int cuda_transfer_get_formats(AVHWFramesContext *ctx,
                                      enum AVHWFrameTransferDirection dir,
                                      enum AVPixelFormat **formats)
 {
     enum AVPixelFormat *fmts;

     fmts = av_malloc_array(2, sizeof(*fmts));
     if (!fmts)
         return AVERROR(ENOMEM);

     fmts[0] = ctx->sw_format;
     fmts[1] = AV_PIX_FMT_NONE;

     *formats = fmts;

     return 0;
 }

 static int cuda_transfer_data_from(AVHWFramesContext *ctx, AVFrame *dst,
                                    const AVFrame *src)
 {
     CUDAFramesContext           *priv = ctx->internal->priv;
     AVCUDADeviceContext *device_hwctx = ctx->device_ctx->hwctx;
     CudaFunctions                 *cu = device_hwctx->internal->cuda_dl;

     CUcontext dummy;
     CUresult err;
     int i;

     err = cu->cuCtxPushCurrent(device_hwctx->cuda_ctx);
     if (err != CUDA_SUCCESS)
         return AVERROR_UNKNOWN;

     for (i = 0; i < FF_ARRAY_ELEMS(src->data) && src->data[i]; i++) {
         CUDA_MEMCPY2D cpy = {
             .srcMemoryType = CU_MEMORYTYPE_DEVICE,
             .dstMemoryType = CU_MEMORYTYPE_HOST,
             .srcDevice     = (CUdeviceptr)src->data[i],
             .dstHost       = dst->data[i],
             .srcPitch      = src->linesize[i],
             .dstPitch      = dst->linesize[i],
             .WidthInBytes  = FFMIN(src->linesize[i], dst->linesize[i]),
             .Height        = src->height >> (i ? priv->shift_height : 0),
         };

         err = cu->cuMemcpy2DAsync(&cpy, device_hwctx->stream);
         if (err != CUDA_SUCCESS) {
             av_log(ctx, AV_LOG_ERROR, "Error transferring the data from the CUDA frame\n");
             return AVERROR_UNKNOWN;
         }
     }

     err = cu->cuStreamSynchronize(device_hwctx->stream);
     if (err != CUDA_SUCCESS) {
         av_log(ctx, AV_LOG_ERROR, "Error synchronizing CUDA stream\n");
         return AVERROR_UNKNOWN;
     }

     cu->cuCtxPopCurrent(&dummy);

     return 0;
 }

 static int cuda_transfer_data_to(AVHWFramesContext *ctx, AVFrame *dst,
                                  const AVFrame *src)
 {
     CUDAFramesContext           *priv = ctx->internal->priv;
     AVCUDADeviceContext *device_hwctx = ctx->device_ctx->hwctx;
     CudaFunctions                 *cu = device_hwctx->internal->cuda_dl;

     CUcontext dummy;
     CUresult err;
     int i;

     err = cu->cuCtxPushCurrent(device_hwctx->cuda_ctx);
     if (err != CUDA_SUCCESS)
         return AVERROR_UNKNOWN;

     for (i = 0; i < FF_ARRAY_ELEMS(src->data) && src->data[i]; i++) {
         CUDA_MEMCPY2D cpy = {
             .srcMemoryType = CU_MEMORYTYPE_HOST,
             .dstMemoryType = CU_MEMORYTYPE_DEVICE,
             .srcHost       = src->data[i],
             .dstDevice     = (CUdeviceptr)dst->data[i],
             .srcPitch      = src->linesize[i],
             .dstPitch      = dst->linesize[i],
             .WidthInBytes  = FFMIN(src->linesize[i], dst->linesize[i]),
             .Height        = src->height >> (i ? priv->shift_height : 0),
         };

         err = cu->cuMemcpy2DAsync(&cpy, device_hwctx->stream);
         if (err != CUDA_SUCCESS) {
             av_log(ctx, AV_LOG_ERROR, "Error transferring the data to the CUDA frame\n");
             return AVERROR_UNKNOWN;
         }
     }

     err = cu->cuStreamSynchronize(device_hwctx->stream);
     if (err != CUDA_SUCCESS) {
         av_log(ctx, AV_LOG_ERROR, "Error synchronizing CUDA stream\n");
         return AVERROR_UNKNOWN;
     }

     cu->cuCtxPopCurrent(&dummy);

     return 0;
 }

 static void cuda_device_uninit(AVHWDeviceContext *ctx)
 {
     AVCUDADeviceContext *hwctx = ctx->hwctx;

     if (hwctx->internal) {
         if (hwctx->internal->is_allocated && hwctx->cuda_ctx) {
             hwctx->internal->cuda_dl->cuCtxDestroy(hwctx->cuda_ctx);
             hwctx->cuda_ctx = NULL;
         }
         cuda_free_functions(&hwctx->internal->cuda_dl);
     }

     av_freep(&hwctx->internal);
 }

 static int cuda_device_init(AVHWDeviceContext *ctx)
 {
     AVCUDADeviceContext *hwctx = ctx->hwctx;
     int ret;

     if (!hwctx->internal) {
         hwctx->internal = av_mallocz(sizeof(*hwctx->internal));
         if (!hwctx->internal)
             return AVERROR(ENOMEM);
     }

     if (!hwctx->internal->cuda_dl) {
         ret = cuda_load_functions(&hwctx->internal->cuda_dl, ctx);
         if (ret < 0) {
             av_log(ctx, AV_LOG_ERROR, "Could not dynamically load CUDA\n");
             goto error;
         }
     }

     return 0;

 error:
     cuda_device_uninit(ctx);
     return ret;
 }

 static int cuda_device_create(AVHWDeviceContext *ctx, const char *device,
                               AVDictionary *opts, int flags)
 {
     AVCUDADeviceContext *hwctx = ctx->hwctx;
     CudaFunctions *cu;
     CUdevice cu_device;
     CUcontext dummy;
     CUresult err;
     int device_idx = 0;

     if (device)
         device_idx = strtol(device, NULL, 0);

     if (cuda_device_init(ctx) < 0)
         goto error;

     cu = hwctx->internal->cuda_dl;

     err = cu->cuInit(0);
     if (err != CUDA_SUCCESS) {
         av_log(ctx, AV_LOG_ERROR, "Could not initialize the CUDA driver API\n");
         goto error;
     }

     err = cu->cuDeviceGet(&cu_device, device_idx);
     if (err != CUDA_SUCCESS) {
         av_log(ctx, AV_LOG_ERROR, "Could not get the device number %d\n", device_idx);
         goto error;
     }

     err = cu->cuCtxCreate(&hwctx->cuda_ctx, CU_CTX_SCHED_BLOCKING_SYNC, cu_device);
     if (err != CUDA_SUCCESS) {
         av_log(ctx, AV_LOG_ERROR, "Error creating a CUDA context\n");
         goto error;
     }

     // Setting stream to NULL will make functions automatically use the default CUstream
     hwctx->stream = NULL;

     cu->cuCtxPopCurrent(&dummy);

     hwctx->internal->is_allocated = 1;

     return 0;

 error:
     cuda_device_uninit(ctx);
     return AVERROR_UNKNOWN;
 }

 const HWContextType ff_hwcontext_type_cuda = {
     .type                 = AV_HWDEVICE_TYPE_CUDA,
     .name                 = "CUDA",

     .device_hwctx_size    = sizeof(AVCUDADeviceContext),
     .frames_priv_size     = sizeof(CUDAFramesContext),

     .device_create        = cuda_device_create,
     .device_init          = cuda_device_init,
     .device_uninit        = cuda_device_uninit,
     .frames_get_constraints = cuda_frames_get_constraints,
     .frames_init          = cuda_frames_init,
     .frames_get_buffer    = cuda_get_buffer,
     .transfer_get_formats = cuda_transfer_get_formats,
     .transfer_data_to     = cuda_transfer_data_to,
     .transfer_data_from   = cuda_transfer_data_from,

     .pix_fmts             = (const enum AVPixelFormat[]){ AV_PIX_FMT_CUDA, AV_PIX_FMT_NONE },
 };
	/*
	* 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
	*/

	#include "buffer.h"
	#include "common.h"
	#include "hwcontext.h"
	#include "hwcontext_internal.h"
	#include "hwcontext_cuda_internal.h"
	#include "mem.h"
	#include "pixdesc.h"
	#include "pixfmt.h"
	#include "imgutils.h"

	#define CUDA_FRAME_ALIGNMENT 256

	typedef struct CUDAFramesContext {
	int shift_width, shift_height;
	} CUDAFramesContext;

	static const enum AVPixelFormat supported_formats[] = {
	AV_PIX_FMT_NV12,
	AV_PIX_FMT_YUV420P,
	AV_PIX_FMT_YUV444P,
	AV_PIX_FMT_P010,
	AV_PIX_FMT_P016,
	AV_PIX_FMT_YUV444P16,
	AV_PIX_FMT_0RGB32,
	AV_PIX_FMT_0BGR32,
	};

	static int cuda_frames_get_constraints(AVHWDeviceContext *ctx,
	const void *hwconfig,
	AVHWFramesConstraints *constraints)
	{
	int i;

	constraints->valid_sw_formats = av_malloc_array(FF_ARRAY_ELEMS(supported_formats) + 1,
	sizeof(*constraints->valid_sw_formats));
	if (!constraints->valid_sw_formats)
	return AVERROR(ENOMEM);

	for (i = 0; i < FF_ARRAY_ELEMS(supported_formats); i++)
	constraints->valid_sw_formats[i] = supported_formats[i];
	constraints->valid_sw_formats[FF_ARRAY_ELEMS(supported_formats)] = AV_PIX_FMT_NONE;

	constraints->valid_hw_formats = av_malloc_array(2, sizeof(*constraints->valid_hw_formats));
	if (!constraints->valid_hw_formats)
	return AVERROR(ENOMEM);

	constraints->valid_hw_formats[0] = AV_PIX_FMT_CUDA;
	constraints->valid_hw_formats[1] = AV_PIX_FMT_NONE;

	return 0;
	}

	static void cuda_buffer_free(void opaque, uint8_t data)
	{
	AVHWFramesContext *ctx = opaque;
	AVCUDADeviceContext *hwctx = ctx->device_ctx->hwctx;
	CudaFunctions *cu = hwctx->internal->cuda_dl;

	CUcontext dummy;

	cu->cuCtxPushCurrent(hwctx->cuda_ctx);

	cu->cuMemFree((CUdeviceptr)data);

	cu->cuCtxPopCurrent(&dummy);
	}

	static AVBufferRef cuda_pool_alloc(void opaque, int size)
	{
	AVHWFramesContext *ctx = opaque;
	AVCUDADeviceContext *hwctx = ctx->device_ctx->hwctx;
	CudaFunctions *cu = hwctx->internal->cuda_dl;

	AVBufferRef *ret = NULL;
	CUcontext dummy = NULL;
	CUdeviceptr data;
	CUresult err;

	err = cu->cuCtxPushCurrent(hwctx->cuda_ctx);
	if (err != CUDA_SUCCESS) {
	av_log(ctx, AV_LOG_ERROR, "Error setting current CUDA context\n");
	return NULL;
	}

	err = cu->cuMemAlloc(&data, size);
	if (err != CUDA_SUCCESS)
	goto fail;

	ret = av_buffer_create((uint8_t*)data, size, cuda_buffer_free, ctx, 0);
	if (!ret) {
	cu->cuMemFree(data);
	goto fail;
	}

	fail:
	cu->cuCtxPopCurrent(&dummy);
	return ret;
	}

	static int cuda_frames_init(AVHWFramesContext *ctx)
	{
	CUDAFramesContext *priv = ctx->internal->priv;
	int i;

	for (i = 0; i < FF_ARRAY_ELEMS(supported_formats); i++) {
	if (ctx->sw_format == supported_formats[i])
	break;
	}
	if (i == FF_ARRAY_ELEMS(supported_formats)) {
	av_log(ctx, AV_LOG_ERROR, "Pixel format '%s' is not supported\n",
	av_get_pix_fmt_name(ctx->sw_format));
	return AVERROR(ENOSYS);
	}

	av_pix_fmt_get_chroma_sub_sample(ctx->sw_format, &priv->shift_width, &priv->shift_height);

	if (!ctx->pool) {
	int size = av_image_get_buffer_size(ctx->sw_format, ctx->width, ctx->height, CUDA_FRAME_ALIGNMENT);
	if (size < 0)
	return size;

	ctx->internal->pool_internal = av_buffer_pool_init2(size, ctx, cuda_pool_alloc, NULL);
	if (!ctx->internal->pool_internal)
	return AVERROR(ENOMEM);
	}

	return 0;
	}

	static int cuda_get_buffer(AVHWFramesContext ctx, AVFrame frame)
	{
	int res;

	frame->buf[0] = av_buffer_pool_get(ctx->pool);
	if (!frame->buf[0])
	return AVERROR(ENOMEM);

	res = av_image_fill_arrays(frame->data, frame->linesize, frame->buf[0]->data,
	ctx->sw_format, ctx->width, ctx->height, CUDA_FRAME_ALIGNMENT);
	if (res < 0)
	return res;

	// YUV420P is a special case.
	// Nvenc expects the U/V planes in swapped order from how ffmpeg expects them, also chroma is half-aligned
	if (ctx->sw_format == AV_PIX_FMT_YUV420P) {
	frame->linesize[1] = frame->linesize[2] = frame->linesize[0] / 2;
	frame->data[2] = frame->data[1];
	frame->data[1] = frame->data[2] + frame->linesize[2] * ctx->height / 2;
	}

	frame->format = AV_PIX_FMT_CUDA;
	frame->width = ctx->width;
	frame->height = ctx->height;

	return 0;
	}

	static int cuda_transfer_get_formats(AVHWFramesContext *ctx,
	enum AVHWFrameTransferDirection dir,
	enum AVPixelFormat **formats)
	{
	enum AVPixelFormat *fmts;

	fmts = av_malloc_array(2, sizeof(*fmts));
	if (!fmts)
	return AVERROR(ENOMEM);

	fmts[0] = ctx->sw_format;
	fmts[1] = AV_PIX_FMT_NONE;

	*formats = fmts;

	return 0;
	}

	static int cuda_transfer_data_from(AVHWFramesContext ctx, AVFrame dst,
	const AVFrame *src)
	{
	CUDAFramesContext *priv = ctx->internal->priv;
	AVCUDADeviceContext *device_hwctx = ctx->device_ctx->hwctx;
	CudaFunctions *cu = device_hwctx->internal->cuda_dl;

	CUcontext dummy;
	CUresult err;
	int i;

	err = cu->cuCtxPushCurrent(device_hwctx->cuda_ctx);
	if (err != CUDA_SUCCESS)
	return AVERROR_UNKNOWN;

	for (i = 0; i < FF_ARRAY_ELEMS(src->data) && src->data[i]; i++) {
	CUDA_MEMCPY2D cpy = {
	.srcMemoryType = CU_MEMORYTYPE_DEVICE,
	.dstMemoryType = CU_MEMORYTYPE_HOST,
	.srcDevice = (CUdeviceptr)src->data[i],
	.dstHost = dst->data[i],
	.srcPitch = src->linesize[i],
	.dstPitch = dst->linesize[i],
	.WidthInBytes = FFMIN(src->linesize[i], dst->linesize[i]),
	.Height = src->height >> (i ? priv->shift_height : 0),
	};

	err = cu->cuMemcpy2DAsync(&cpy, device_hwctx->stream);
	if (err != CUDA_SUCCESS) {
	av_log(ctx, AV_LOG_ERROR, "Error transferring the data from the CUDA frame\n");
	return AVERROR_UNKNOWN;
	}
	}

	err = cu->cuStreamSynchronize(device_hwctx->stream);
	if (err != CUDA_SUCCESS) {
	av_log(ctx, AV_LOG_ERROR, "Error synchronizing CUDA stream\n");
	return AVERROR_UNKNOWN;
	}

	cu->cuCtxPopCurrent(&dummy);

	return 0;
	}

	static int cuda_transfer_data_to(AVHWFramesContext ctx, AVFrame dst,
	const AVFrame *src)
	{
	CUDAFramesContext *priv = ctx->internal->priv;
	AVCUDADeviceContext *device_hwctx = ctx->device_ctx->hwctx;
	CudaFunctions *cu = device_hwctx->internal->cuda_dl;

	CUcontext dummy;
	CUresult err;
	int i;

	err = cu->cuCtxPushCurrent(device_hwctx->cuda_ctx);
	if (err != CUDA_SUCCESS)
	return AVERROR_UNKNOWN;

	for (i = 0; i < FF_ARRAY_ELEMS(src->data) && src->data[i]; i++) {
	CUDA_MEMCPY2D cpy = {
	.srcMemoryType = CU_MEMORYTYPE_HOST,
	.dstMemoryType = CU_MEMORYTYPE_DEVICE,
	.srcHost = src->data[i],
	.dstDevice = (CUdeviceptr)dst->data[i],
	.srcPitch = src->linesize[i],
	.dstPitch = dst->linesize[i],
	.WidthInBytes = FFMIN(src->linesize[i], dst->linesize[i]),
	.Height = src->height >> (i ? priv->shift_height : 0),
	};

	err = cu->cuMemcpy2DAsync(&cpy, device_hwctx->stream);
	if (err != CUDA_SUCCESS) {
	av_log(ctx, AV_LOG_ERROR, "Error transferring the data to the CUDA frame\n");
	return AVERROR_UNKNOWN;
	}
	}

	err = cu->cuStreamSynchronize(device_hwctx->stream);
	if (err != CUDA_SUCCESS) {
	av_log(ctx, AV_LOG_ERROR, "Error synchronizing CUDA stream\n");
	return AVERROR_UNKNOWN;
	}

	cu->cuCtxPopCurrent(&dummy);

	return 0;
	}

	static void cuda_device_uninit(AVHWDeviceContext *ctx)
	{
	AVCUDADeviceContext *hwctx = ctx->hwctx;

	if (hwctx->internal) {
	if (hwctx->internal->is_allocated && hwctx->cuda_ctx) {
	hwctx->internal->cuda_dl->cuCtxDestroy(hwctx->cuda_ctx);
	hwctx->cuda_ctx = NULL;
	}
	cuda_free_functions(&hwctx->internal->cuda_dl);
	}

	av_freep(&hwctx->internal);
	}

	static int cuda_device_init(AVHWDeviceContext *ctx)
	{
	AVCUDADeviceContext *hwctx = ctx->hwctx;
	int ret;

	if (!hwctx->internal) {
	hwctx->internal = av_mallocz(sizeof(*hwctx->internal));
	if (!hwctx->internal)
	return AVERROR(ENOMEM);
	}

	if (!hwctx->internal->cuda_dl) {
	ret = cuda_load_functions(&hwctx->internal->cuda_dl, ctx);
	if (ret < 0) {
	av_log(ctx, AV_LOG_ERROR, "Could not dynamically load CUDA\n");
	goto error;
	}
	}

	return 0;

	error:
	cuda_device_uninit(ctx);
	return ret;
	}

	static int cuda_device_create(AVHWDeviceContext ctx, const char device,
	AVDictionary *opts, int flags)
	{
	AVCUDADeviceContext *hwctx = ctx->hwctx;
	CudaFunctions *cu;
	CUdevice cu_device;
	CUcontext dummy;
	CUresult err;
	int device_idx = 0;

	if (device)
	device_idx = strtol(device, NULL, 0);

	if (cuda_device_init(ctx) < 0)
	goto error;

	cu = hwctx->internal->cuda_dl;

	err = cu->cuInit(0);
	if (err != CUDA_SUCCESS) {
	av_log(ctx, AV_LOG_ERROR, "Could not initialize the CUDA driver API\n");
	goto error;
	}

	err = cu->cuDeviceGet(&cu_device, device_idx);
	if (err != CUDA_SUCCESS) {
	av_log(ctx, AV_LOG_ERROR, "Could not get the device number %d\n", device_idx);
	goto error;
	}

	err = cu->cuCtxCreate(&hwctx->cuda_ctx, CU_CTX_SCHED_BLOCKING_SYNC, cu_device);
	if (err != CUDA_SUCCESS) {
	av_log(ctx, AV_LOG_ERROR, "Error creating a CUDA context\n");
	goto error;
	}

	// Setting stream to NULL will make functions automatically use the default CUstream
	hwctx->stream = NULL;

	cu->cuCtxPopCurrent(&dummy);

	hwctx->internal->is_allocated = 1;

	return 0;

	error:
	cuda_device_uninit(ctx);
	return AVERROR_UNKNOWN;
	}

	const HWContextType ff_hwcontext_type_cuda = {
	.type = AV_HWDEVICE_TYPE_CUDA,
	.name = "CUDA",

	.device_hwctx_size = sizeof(AVCUDADeviceContext),
	.frames_priv_size = sizeof(CUDAFramesContext),

	.device_create = cuda_device_create,
	.device_init = cuda_device_init,
	.device_uninit = cuda_device_uninit,
	.frames_get_constraints = cuda_frames_get_constraints,
	.frames_init = cuda_frames_init,
	.frames_get_buffer = cuda_get_buffer,
	.transfer_get_formats = cuda_transfer_get_formats,
	.transfer_data_to = cuda_transfer_data_to,
	.transfer_data_from = cuda_transfer_data_from,

	.pix_fmts = (const enum AVPixelFormat[]){ AV_PIX_FMT_CUDA, AV_PIX_FMT_NONE },
	};