high fps lost frame

[thornsu]

I use downward camera , and set frame rate to 60 or 90 in snap_cam.cpp , use rosbag to record image_raw topic, but some frame lost about 3s, and error like
"ERROR: The requested frame_id(233) does not exist in the queue."
"[ERROR] [1531981032.768026411]: GetImageData() Unable to get Frame data for id: 233 rc: -2"