int ff_vdpau_common_init(AVCodecContext *avctx, VdpDecoderProfile profile,

                         int level)

{

    VDPAUHWContext *hwctx = avctx->hwaccel_context;

    VDPAUContext *vdctx = avctx->internal->hwaccel_priv_data;

    VdpVideoSurfaceQueryCapabilities *surface_query_caps;

    VdpDecoderQueryCapabilities *decoder_query_caps;

    VdpDecoderCreate *create;



    void *func;

    VdpStatus status;

    VdpBool supported;

    uint32_t max_level, max_mb, max_width, max_height;

    VdpChromaType type;

    uint32_t width;

    uint32_t height;



    vdctx->width            = UINT32_MAX;

    vdctx->height           = UINT32_MAX;



    if (av_vdpau_get_surface_parameters(avctx, &type, &width, &height))

        return AVERROR(ENOSYS);



    if (hwctx) {

        hwctx->reset            = 0;



        if (hwctx->context.decoder != VDP_INVALID_HANDLE) {

            vdctx->decoder = hwctx->context.decoder;

            vdctx->render  = hwctx->context.render;

            vdctx->device  = VDP_INVALID_HANDLE;

            return 0; /* Decoder created by user */

        }



        vdctx->device           = hwctx->device;

        vdctx->get_proc_address = hwctx->get_proc_address;



        if (hwctx->flags & AV_HWACCEL_FLAG_IGNORE_LEVEL)

            level = 0;



        if (!(hwctx->flags & AV_HWACCEL_FLAG_ALLOW_HIGH_DEPTH) &&

            type != VDP_CHROMA_TYPE_420)

            return AVERROR(ENOSYS);

    } else {

        AVHWFramesContext *frames_ctx = NULL;

        AVVDPAUDeviceContext *dev_ctx;



        // We assume the hw_frames_ctx always survives until ff_vdpau_common_uninit

        // is called. This holds true as the user is not allowed to touch

        // hw_device_ctx, or hw_frames_ctx after get_format (and ff_get_format

        // itself also uninits before unreffing hw_frames_ctx).

        if (avctx->hw_frames_ctx) {

            frames_ctx = (AVHWFramesContext*)avctx->hw_frames_ctx->data;

        } else if (avctx->hw_device_ctx) {

            int ret;



            avctx->hw_frames_ctx = av_hwframe_ctx_alloc(avctx->hw_device_ctx);

            if (!avctx->hw_frames_ctx)

                return AVERROR(ENOMEM);



            frames_ctx            = (AVHWFramesContext*)avctx->hw_frames_ctx->data;

            frames_ctx->format    = AV_PIX_FMT_VDPAU;

            frames_ctx->sw_format = avctx->sw_pix_fmt;

            frames_ctx->width     = avctx->coded_width;

            frames_ctx->height    = avctx->coded_height;



            ret = av_hwframe_ctx_init(avctx->hw_frames_ctx);

            if (ret < 0) {

                av_buffer_unref(&avctx->hw_frames_ctx);

                return ret;

            }

        }



        if (!frames_ctx) {

            av_log(avctx, AV_LOG_ERROR, "A hardware frames context is "

                   "required for VDPAU decoding.\n");

            return AVERROR(EINVAL);

        }



        dev_ctx = frames_ctx->device_ctx->hwctx;



        vdctx->device           = dev_ctx->device;

        vdctx->get_proc_address = dev_ctx->get_proc_address;



        if (avctx->hwaccel_flags & AV_HWACCEL_FLAG_IGNORE_LEVEL)

            level = 0;

    }



    if (level < 0)

        return AVERROR(ENOTSUP);



    status = vdctx->get_proc_address(vdctx->device,

                                     VDP_FUNC_ID_GET_INFORMATION_STRING,

                                     &func);

    if (status != VDP_STATUS_OK)

        return vdpau_error(status);

    else

        info = func;



    status = info(&info_string);

    if (status != VDP_STATUS_OK)

        return vdpau_error(status);

    if (avctx->codec_id == AV_CODEC_ID_HEVC && strncmp(info_string, "NVIDIA ", 7) == 0 &&

        !(avctx->hwaccel_flags & AV_HWACCEL_FLAG_ALLOW_PROFILE_MISMATCH)) {

        av_log(avctx, AV_LOG_VERBOSE, "HEVC with NVIDIA VDPAU drivers is buggy, skipping.\n");

        return AVERROR(ENOTSUP);

    }



    status = vdctx->get_proc_address(vdctx->device,

                                     VDP_FUNC_ID_VIDEO_SURFACE_QUERY_CAPABILITIES,

                                     &func);

    if (status != VDP_STATUS_OK)

        return vdpau_error(status);

    else

        surface_query_caps = func;



    status = surface_query_caps(vdctx->device, type, &supported,

                                &max_width, &max_height);

    if (status != VDP_STATUS_OK)

        return vdpau_error(status);

    if (supported != VDP_TRUE ||

        max_width < width || max_height < height)

        return AVERROR(ENOTSUP);



    status = vdctx->get_proc_address(vdctx->device,

                                     VDP_FUNC_ID_DECODER_QUERY_CAPABILITIES,

                                     &func);

    if (status != VDP_STATUS_OK)

        return vdpau_error(status);

    else

        decoder_query_caps = func;



    status = decoder_query_caps(vdctx->device, profile, &supported, &max_level,

                                &max_mb, &max_width, &max_height);

#ifdef VDP_DECODER_PROFILE_H264_CONSTRAINED_BASELINE

    if ((status != VDP_STATUS_OK || supported != VDP_TRUE) && profile == VDP_DECODER_PROFILE_H264_CONSTRAINED_BASELINE) {

        profile = VDP_DECODER_PROFILE_H264_MAIN;

        status = decoder_query_caps(vdctx->device, profile, &supported,

                                    &max_level, &max_mb,

                                    &max_width, &max_height);

    }

#endif

    if (status != VDP_STATUS_OK)

        return vdpau_error(status);



    if (supported != VDP_TRUE || max_level < level ||

        max_width < width || max_height < height)

        return AVERROR(ENOTSUP);



    status = vdctx->get_proc_address(vdctx->device, VDP_FUNC_ID_DECODER_CREATE,

                                     &func);

    if (status != VDP_STATUS_OK)

        return vdpau_error(status);

    else

        create = func;



    status = vdctx->get_proc_address(vdctx->device, VDP_FUNC_ID_DECODER_RENDER,

                                     &func);

    if (status != VDP_STATUS_OK)

        return vdpau_error(status);

    else

        vdctx->render = func;



    status = create(vdctx->device, profile, width, height, avctx->refs,

                    &vdctx->decoder);

    if (status == VDP_STATUS_OK) {

        vdctx->width  = avctx->coded_width;

        vdctx->height = avctx->coded_height;

    }



    return vdpau_error(status);

}