timestamp for multiple cameras

[lintong-zhang]

Hello. I am trying to run 3 cameras that are hardware synchronized by trigger at the same time. I created 3 nodes to run gscam for each camera. (I set use_gst_timestamps to True) However, I found that the timestamp are 10-20ms apart for these images.

In the below image, you can see the base time and time_offset_ calculated in the code are very similar, and the only difference is the buffer time (buf->pts). In this example, i am running them at 10Hz.

Can someone explain why this is the case? I thought all three camera images would have reached the buffer around a similar time, maybe 1-2ms apart but not 20ms apart.