Nvstreammux frame drops and jitter (24.9 fps) when enabling ntp-sync in rtspsrc

[fanzh]

Please refer to this faq for hwo to set nvstreammux parameters.

1. How many sources are you testing? batch-size should be set to the number of sources. batched-push-timeout to the (1000000 us/maximum fps among the videos)
2. do you mean there is no “dropping late buffer” issue if ntp-sync is disabled?
3. ’ sync-inputs =1’ means sychronization of input frames using PTS. the late buffers will be dropped because the buffer is too late.