Trying to service callback fails initially in ROS [closed]

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Hi,

I ported some code for a camera in C++ for ROS and subscribing to another node to capture images from it. This camera node has a start method that issues a callback function that delivers the frames. The first captured frame from the camera is very critical as I plan to do this across multiple cameras so the first frame would be ideally at the same time ( assuming the camera nodes are time synced ). 1.First question , is it possible to expect that the ROS system can respond to the callback in this way ? 2. I am observing that within the camera node , the camera driver drops the first few frames complaining that USBIO Bulk transfer failed. After printing this out for the first few frames, it works fine. I am guessing that ROS is not able to service my callback on time. The camera driver by itself doesn’t show this problem, when it is working outside the ROS environment. 3. I am calling ros::SpinOnce() , within my code just before I call the start method on the camera.

I am relatively new to ROS and was trying to dig around but couldn’t find or understand anything conclusive. If some one could share some code explanation with some code example for this case it would be great!

-Best CN