Investigate multi source tracker problem

[denisvmedyantsev]

There is a problem with nvtracker and sources connected in a loop. When using several sources sequentially, the tracker starts to output fewer objects at first, then stops outputting them. To prevent this, you can configure tracking-id-reset-mode, it defaults to 0, use 2 or 3 to reset the tracker on EOS.

A known issue is that in the Savant pipeline, elements do not receive GST_NVEVENT_PAD_DELETED, which the tracker uses to delete per source trackers. But that doesn't explain why we don't see a problem with multiple reconnected RTSP sources, for example.

To reproduce the issue, use the changed samples/peoplenet_detector, the code and video (short version of AVG-TownCentre.mp4) are attached. At the 12th iteration, you can notice that the tracker outputs fewer objects than usual, and at the 13th iteration, there are no objects left after the tracker. If you change the tracker config to samples/assets/tracker/config_tracker_NvDCF_perf.yml, it will happen faster, 5th and 6th iteration respectively.

test.zip

avg.mp4