Nvbufsurface: mapping of memory type (0) not supported

Accelerated Computing Intelligent Video Analytics DeepStream SDK
1

Please provide complete information as applicable to your setup.

• Hardware Platform (Jetson / GPU) :T4
• DeepStream Version:5.0
• TensorRT Version:7.0.1
• NVIDIA GPU Driver Version (valid for GPU only):440.64

I have achieved save image in dsexample plugin, but I think it is a waste for doing only this thing, meanwhile it would get segmentation fault for a long time.

So I want to save image via osd sink/src pad prob in deepstream-app just like Access video frame and use opencv to draw on it in pad probe callback.

However I get error of nvbufsurface: mapping of memory type (0) not supported. Below is my probe code.

static GstPadProbeReturn
osd_bin_src_pad_prob (GstPad * pad, GstPadProbeInfo * info,
gpointer u_data)
{
GstBuffer *buf = (GstBuffer *) info->data;
GstMapInfo in_map_info;
NvBufSurface *surface = NULL;
NvDsBatchMeta *batch_meta = NULL;
NvDsMetaList *l_frame = NULL;
NvDsFrameMeta *frame_meta = NULL;
memset (&in_map_info, 0, sizeof (in_map_info));
if (gst_buffer_map (buf, &in_map_info, GST_MAP_READWRITE))
{
surface = (NvBufSurface *) in_map_info.data;
NvBufSurfaceMap(surface, -1, -1, NVBUF_MAP_READ_WRITE);
NvBufSurfaceSyncForCpu(surface, -1, -1);
batch_meta = gst_buffer_get_nvds_batch_meta(buf);
for (l_frame = batch_meta->frame_meta_list; l_frame != NULL;
l_frame = l_frame->next)
{
frame_meta = (NvDsFrameMeta *)(l_frame->data);
gint frame_width = (gint)surface->surfaceList[frame_meta->batch_id].width;
gint frame_height = (gint)surface->surfaceList[frame_meta->batch_id].height;
void *frame_data = surface->surfaceList[frame_meta->batch_id].mappedAddr.addr[0];
size_t frame_step = surface->surfaceList[frame_meta->batch_id].pitch;
// cv::Mat frame = cv::Mat(frame_height, frame_width, CV_8UC4, frame_data, frame_step);
}
NvBufSurfaceUnMap(surface, -1, -1);
}
gst_buffer_unmap (buf, &in_map_info);
}

Please give me some advices for this problems, and which way is better to save image.
Thanks!

3

Hi,
Please check the information of NvBufSurface:

typedef struct NvBufSurface {
  /** Holds a GPU ID. Valid only for a multi-GPU system. */
  uint32_t gpuId;
  /** Holds the batch size. */
  uint32_t batchSize;
  /** Holds the number valid and filled buffers. Initialized to zero when
   an instance of the structure is created. */
  uint32_t numFilled;
  /** Holds an "is contiguous" flag. If set, memory allocated for the batch
   is contiguous. */
  bool isContiguous;
  /** Holds type of memory for buffers in the batch. */
  NvBufSurfaceMemType memType;
  /** Holds a pointer to an array of batched buffers. */
  NvBufSurfaceParams *surfaceList;

  void * _reserved[STRUCTURE_PADDING];
} NvBufSurface;

More information should help on clarifying the issue.

4

Hi,
This might help:

May need to configure nvbuf_memory-type in some plugins.

5

Hi, @DaneLLL
Thanks for your anwser. I’ll have a try to set plugins nvbuf_memory_type.

But there is no same error when I use dsexample plugin, so I wonder the difference between probe function and plugin method in order to save images, and which way is recommanded from you.

Thanks!

6

Hi,
The default code in gstdsexample.cpp shoudl work fine. Do you hit the error in running the default code?

8