how can I record the same number of massages from different topics?

edit

I want to build a database that takes each image with its joy and IMU (angles) data, so I need to receive the same number of messages for each topic to have a synchronized data.
I run the below command in order to record RGB images, depth images, joystick commands, and IMU data.

$> rosbag record -O subset /camera/depth/image_raw /camera/rgb/image_raw /joy /mobile_base/sensors/imu_data_raw

then

 $> rosbag info subset.bag

which show me the information about my recorded bag file

path:        subset.bag
version:     2.0
duration:    21.9s
start:       Mar 11 2018 16:31:17.29 (1520771477.29)
end:         Mar 11 2018 16:31:39.20 (1520771499.20)
size:        857.5 MB
messages:    3113
compression: none [605/605 chunks]
types:       sensor_msgs/Image [060021388200f6f0f447d0fcd9c64743]
             sensor_msgs/Imu   [6a62c6daae103f4ff57a132d6f95cec2]
             sensor_msgs/Joy   [5a9ea5f83505693b71e785041e67a8bb]
topics:      /camera/depth/image_raw             652 msgs    : sensor_msgs/Image
             /camera/rgb/image_raw               540 msgs    : sensor_msgs/Image
             /joy                                991 msgs    : sensor_msgs/Joy  
             /mobile_base/sensors/imu_data_raw   930 msgs    : sensor_msgs/Imu

as you see there are a diffrente number of messegas for each topic. So, how can I receive the same number of it?
and one more thing

any help please?
Thanks in advance