Obtaining the Timestamp for Previous Frames from Tracker

Please provide complete information as applicable to your setup.

• Hardware Platform (Jetson / GPU)
Jetson Xavier
• DeepStream Version
5.0
• JetPack Version (valid for Jetson only)
4.5.1
• TensorRT Version
7.1.3.0
• Issue Type( questions, new requirements, bugs)
Question/Technical Query

Question -

We are adapting the “write_kitti_past_track_output” function from the deepstream reference app to get the previous object/frame data from the tracker (using NvDCF tracker). We are correctly getting the previous object data, including frame number etc.

Is it possible to get the timestamp from the tracker, so that we can associate a timestamp with the object ? We can get the current frame timestamp from “frame_meta->ntp_timestamp;” - is there an equivalent for the tracker data?

Since you have notice ntp_timestamp in NvDsFrameMeta, so please refer to buf_pts in NvDsFrameMeta to get the timestamp.

https://docs.nvidia.com/metropolis/deepstream/sdk-api/Meta/_NvDsFrameMeta.html

Thanks for the link - I understand that buf_pts is attached to the current frame in NvDsFrameMeta.

What I would like to do, is when I extract the previous objects from the tracker (with “_NvDsPastFrameObj”), to be able to associate a timestamp (either absolute, or pts) with that object. So that, for each object in the PastFrameObjList, we can get:

uint32_t frameNum
NvOSD_RectParams tBbox
float confidence
uint32_t age
// and add:
guint64 obj_timestamp

Is it possible to extract that information from the past tracked object ? Is it possible to configure the tracker (NvDCF) to include that information in the batch user meta data?

I don’t understand it? Timestamp is the time mark for every frame. The object will appear in many frames. How can we mark object’s timestamp? What does this mean?

Currently, there is no such data structure for timestamp of every object.