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.

[awesomebytes]

What's the interface for the cameras? USB? Ethernet? Something else?

…

On Tue, Jun 11, 2024, 18:10 Lintong ***@***.***> wrote: 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. 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. image.png (view on web) <https://github.com/ros-drivers/gscam/assets/72497274/e8a58c7c-f14a-4c98-892a-ff758776d0d6> 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. — Reply to this email directly, view it on GitHub <#98>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AANEK5ADWSCZCGWZBH7U2ZLZG4VQ3AVCNFSM6AAAAABJEYB2FCVHI2DSMVQWIX3LMV43ASLTON2WKOZSGM2DMOJQHAYDINA> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[lintong-zhang]

They are Framos cameras IMX296 connected to Nvidia Jetson NX board with Framos connector . The cameras are configured as master and slaves through the driver, so they are triggered at the same time.