I record a bag "test.bag", and it has the same topic with stereo_outdoorA.bag . topics:

        /stereo_camera/left/image_raw_throttle/compressed 
        /stereo_camera/right/image_raw_throttle/compressed 
        /stereo_camera/left/camera_info_throttle 
        /stereo_camera/right/camera_info_throttle 
        /tf

when run "rosbag info stereo_outdoorA.bag"

 path:        stereo_outdoorA.bag
 version:     2.0
 duration:    3:55s (235s)
 start:       Nov 12 2014 04:28:20.90 (1415737700.90)
 end:         Nov 12 2014 04:32:16.65 (1415737936.65)
 size:        668.3 MB
 messages:    54083
compression: none [848/848 chunks]
types:       sensor_msgs/CameraInfo      [c9a58c1b0b154e0e6da7578cb991d214]
         sensor_msgs/CompressedImage [8f7a12909da2c9d3332d540a0977563f]
         tf2_msgs/TFMessage          [94810edda583a504dfda3829e70d7eec]
topics:      /stereo_camera/left/camera_info_throttle              3741 msgs    : sensor_msgs/CameraInfo     
         /stereo_camera/left/image_raw_throttle/compressed     3753 msgs    : sensor_msgs/CompressedImage
         /stereo_camera/right/camera_info_throttle             3741 msgs    : sensor_msgs/CameraInfo     
         /stereo_camera/right/image_raw_throttle/compressed    3745 msgs    : sensor_msgs/CompressedImage
         /tf                                                  39103 msgs    : tf2_msgs/TFMessage          (2 connections)

But when I run " rosbag info test.bag"

path:        test.bag
version:     2.0
duration:    51.6s
start:       Sep 27 2015 22:47:01.06 (1443365221.06)
end:         Sep 27 2015 22:47:52.63 (1443365272.63)
size:        81.9 MB
messages:    2096
compression: none [101/101 chunks]
 types:       sensor_msgs/CameraInfo      [c9a58c1b0b154e0e6da7578cb991d214]
         sensor_msgs/CompressedImage [8f7a12909da2c9d3332d540a0977563f]
         tf2_msgs/TFMessage          [94810edda583a504dfda3829e70d7eec]
       topics:      /stereo_camera/left/camera_info_throttle             395 msgs    : sensor_msgs/CameraInfo     
         /stereo_camera/left/image_raw_throttle/compressed    395 msgs    : sensor_msgs/CompressedImage
         /stereo_camera/right/camera_info_throttle            395 msgs    : sensor_msgs/CameraInfo     
         /stereo_camera/right/image_raw_throttle/compressed   395 msgs    : sensor_msgs/CompressedImage
         /tf                                                  516 msgs    : tf2_msgs/TFMessage

They are different about /tf. So what's the "2 connections" in the stereo_outdoorA.bag?

After

       roslaunch rtabmap_ros demo_stereo_outdoor.launch

then

       rosbag play --clock  test.bag

At last it gives an error message.

        [stereo_odometry-6] process has died [pid 17233, exit code -6, cmd /home/exbot/catkin_ws/devel/lib/rtabmap_ros/stereo_odometry left/image_rect:=/stereo_camera/left/image_rect_color right/image_rect:=/stereo_camera/right/image_rect left/camera_info:=/stereo_camera/left/camera_info_throttle right/camera_info:=/stereo_camera/right/camera_info_throttle odom:=/odometry __name:=stereo_odometry __log:=/home/exbot/.ros/log/662c6f46-6679-11e5-84f1-3ca9f4a1fe90/stereo_odometry-6.log].   log file: /home/exbot/.ros/log/662c6f46-6679-11e5-84f1-3ca9f4a1fe90/stereo_odometry-6*.log

what should I do with this error? Your replies are much appreciated!