hello：
I can save a frame of image using the following method
GstMapInfo in_map_info;
NvBufSurface *surface = NULL;
struct timeval start, start1, start2,start3,start4,start5;
memset (&in_map_info, 0, sizeof (in_map_info));
if (!gst_buffer_map (buf, &in_map_info, GST_MAP_READ)) {
g_print ("Error: Failed to map gst buffer\n");
gst_buffer_unmap (buf, &in_map_info);
return -1;
}
// cudaError_t cuda_err;
gettimeofday(&start, NULL);
NvBufSurfTransformRect src_rect, dst_rect;
surface = (NvBufSurface *) in_map_info.data;
int batch_size= surface->batchSize;
// printf("\nBatch Size : %d, resolution : %dx%d \n",batch_size,
// surface->surfaceList[0].width, surface->surfaceList[0].height);
scale_height = surface->surfaceList[0].height;
scale_width = src_rect.width;
src_rect.top = 0;
src_rect.left = 0;
src_rect.width = (guint) surface->surfaceList[0].width;
src_rect.height= (guint) surface->surfaceList[0].height;
dst_rect.top = 0;
dst_rect.left = 0;
// dst_rect.width = (guint) surface->surfaceList[0].width;
// dst_rect.height= (guint) surface->surfaceList[0].height;
dst_rect.width = 1920;
dst_rect.height= 1080;
NvBufSurfTransformParams nvbufsurface_params;
nvbufsurface_params.src_rect = &src_rect;
nvbufsurface_params.dst_rect = &dst_rect;
nvbufsurface_params.transform_flag = NVBUFSURF_TRANSFORM_CROP_SRC | NVBUFSURF_TRANSFORM_CROP_DST;
nvbufsurface_params.transform_filter = NvBufSurfTransformInter_Default;
NvBufSurface *dst_surface = NULL;
NvBufSurfaceCreateParams nvbufsurface_create_params;
/* An intermediate buffer for NV12/RGBA to BGR conversion will be
* required. Can be skipped if custom algorithm can work directly on NV12/RGBA. */
nvbufsurface_create_params.gpuId = surface->gpuId;
nvbufsurface_create_params.width = (gint) surface->surfaceList[0].width;
nvbufsurface_create_params.height = (gint) surface->surfaceList[0].height;
nvbufsurface_create_params.size = 0;
nvbufsurface_create_params.colorFormat = NVBUF_COLOR_FORMAT_RGBA;
nvbufsurface_create_params.layout = NVBUF_LAYOUT_PITCH;
nvbufsurface_create_params.memType = NVBUF_MEM_DEFAULT;
cudaSetDevice (surface->gpuId);
cudaStream_t cuda_stream;
cudaStreamCreate (&cuda_stream);
gettimeofday(&start1, NULL);
int create_result = NvBufSurfaceCreate(&dst_surface,batch_size,&nvbufsurface_create_params);
NvBufSurfTransformConfigParams transform_config_params;
NvBufSurfTransform_Error err;
transform_config_params.compute_mode = NvBufSurfTransformCompute_Default;
transform_config_params.gpu_id = surface->gpuId;
err = NvBufSurfTransformSetSessionParams (&transform_config_params);
NvBufSurfaceMemSet (dst_surface, 0, 0, 0);
err = NvBufSurfTransform (surface, dst_surface, &nvbufsurface_params);
if (err != NvBufSurfTransformError_Success) {
g_print ("NvBufSurfTransform failed with error %d while converting buffer\n", err);
}
gettimeofday(&start2, NULL);
NvBufSurfaceMap (dst_surface, 0, 0, NVBUF_MAP_READ);
NvBufSurfaceSyncForCpu (dst_surface, 0, 0);
gettimeofday(&start3, NULL);
cv::Mat bgr_frame = cv::Mat (cv::Size(nvbufsurface_create_params.width, nvbufsurface_create_params.height), CV_8UC3);
cv::Mat in_mat =
cv::Mat (nvbufsurface_create_params.height, nvbufsurface_create_params.width,
CV_8UC4, dst_surface->surfaceList[0].mappedAddr.addr[0],
dst_surface->surfaceList[0].pitch);//矩阵一行占用的字节数 cv::Mat in_mat =
cv::cvtColor (in_mat, bgr_frame, CV_RGBA2BGR);
char* filename = new char[64];
snprintf(filename, 64, "./img/image%03d_%u.jpg", frame_meta->frame_num,dst_surface->surfaceList[0].pitch);
cv::imwrite(filename,bgr_frame);
，but when I use NvBufSurfaceMap (dst_surface, 0, 0, NVBUF_MAP_READ);
NvBufSurfaceSyncForCpu (dst_surface, 0, 0);
These two functions take 40ms, which is too slow. Can you provide me with a method that is not so slow? Thank you