How to add system timestamps to metadata#

This tutorial will help you add timestamp to metadata of each frame. This tutorial shows how to use the GST element ‘timecodestamper’ that adds timestamps to frames.

Steps#

Update default config.json present at [WORKDIR]/edge-ai-libraries/microservices/dlstreamer-pipeline-server/configs/default/config.json with below configurations.

Update “pipeline” variable as follows -

"pipeline": "{auto_source} name=source  ! decodebin ! timecodestamper set=always ! videoconvert ! gvadetect name=detection model-instance-id=inst0 ! queue ! gvafpscounter ! gvametaconvert add-empty-results=true name=metaconvert ! gvametapublish name=destination ! appsink name=appsink",

NOTE Make sure that proprety set of timecodestamper is set to always. timecodestamper element follows SMPTE format of storing data (hours:minutes:seconds:frames).

set property can have anyone of the 3 values shown below

Value	Description
never	Never set timecodes
keep	Keep upstream timecodes and only set if no upstream timecode
always	Always set timecode and remove upstream timecode

Ensure that the changes made to the config.json are reflected in the container by volume mounting it as mentioned in this tutorial

Start the DLStreamer pipeline server

cd [WORKDIR]/edge-ai-libraries/microservices/dlstreamer-pipeline-server/docker/    
docker compose up

Open another terminal and run the following curl command to start the pipeline.

curl http://localhost:8080/pipelines/user_defined_pipelines/pallet_defect_detection -X POST -H 'Content-Type: application/json' -d '{
    "source": {
        "uri": "file:///home/pipeline-server/resources/videos/warehouse.avi",
        "type": "uri"
    },
    "destination": {
        "metadata": {
            "type": "file",
            "path": "/tmp/results.jsonl",
            "format": "json-lines"
        }
    },
    "parameters": {
        "detection-properties": {
            "model": "/home/pipeline-server/resources/models/geti/pallet_defect_detection/deployment/Detection/model/model.xml",
            "device": "CPU"
        }
    }
}'

To view the metadata, open another terminal and run the following command

tail -f /tmp/results.jsonl

You should see an attribute called system_timestamp in the metadata of each frame. Sample output of a metadata from one frame shown below -

{"objects":[{"detection":{"bounding_box":{"x_max":0.37195673026144505,"x_min":0.02789940871298313,"y_max":0.7120070457458496,"y_min":0.17735711733500162},"confidence":0.9217351078987122,"label":"box","label_id":0},"h":257,"region_id":2319,"roi_type":"box","w":220,"x":18,"y":85},{"detection":{"bounding_box":{"x_max":0.17977098003029823,"x_min":0.06219940260052681,"y_max":0.42195435365041095,"y_min":0.3419050375620524},"confidence":0.9094383120536804,"label":"shipping_label","label_id":1},"h":38,"region_id":2320,"roi_type":"shipping_label","w":75,"x":40,"y":164}],"resolution":{"height":480,"width":640},"system_timestamp":"2025-06-02T08:15:14.870:+0000","tags":{},"timestamp":7766666666}