How to add metadata to the output result?

[image-rcdat]

Hi everyone, I've written a plugin to convert video frames to base64 format and I could attach this data as new field to the GStructure using:
gst_structure_set(structure, "base64img", G_TYPE_STRING, base64Buffer, NULL);

I can see this field that is attached to my structure, by gvametaconvert doesn't recognize it, is there anyway to force this block to recognize custom defined fields in the structure?

[brmarkus]

From the discussions in the issue "#445" it looks like the JSON-part of gvametaconvert is done in "https://github.com/dlstreamer/dlstreamer/blob/350a6a4fd480628332fc000e04df37322738a939/src/monolithic/gst/elements/gvametaconvert/jsonconverter.cpp".

Do you see a chance to "fake" your additional "base64img" data as e.g. a detection or classification? Then the existing JSON code could add it to the JSON metadata (file). Otherwise you might need to extend the code.
Or write your base64img data into a file/datastructure in parallel to the JSON metadata (file) (with timestamp, detecgtion/classification/tracking-ID as a reference to what it belongs to)?

[image-rcdat]

Thanks for the advice @brmarkus
Yes, I tried to add my data to a predefined field such as layer-name and it worked, but the problem is that this field is specified for each object, but I want to add a base64 for the full-frame and beside this kind of work is not so clean and clear

[brmarkus]

Have a look into these older issues:

• Not able to add some custom data in gvametaconvert0 of Gvametaconvert element of DL streamer #329
• How to attach and extract custom metadata generated by custom written plugin? #178

[image-rcdat]

so, let me change my question!
How can we access json message generated by gvametaconvert and at our custom result to the json object, I mean we can put our custom plugin between gvametaconvert and gvametapublish and add our result

[brmarkus]

So far I haven't looked into gvametapublish, it's quite a long chain before it gets finally written into a JSON-file in "https://github.com/dlstreamer/dlstreamer/blob/350a6a4fd480628332fc000e04df37322738a939/src/monolithic/gst/elements/gvametapublish/file/gvametapublishfile.cpp".

Have you checked the two issues mentioned above, how others have managed to add custom metadata?