This repository was archived by the owner on May 31, 2025. It is now read-only.
This repository was archived by the owner on May 31, 2025. It is now read-only.
rosbag filter adds two bytes per topic #736
Description
The bug occurs at least with ROS indigo, we did not test other versions.
cc @durko @dejanpan
$ rosbag info original.bag
path: original.bag
version: 2.0
duration: 11.0s
start: Mar 06 2015 14:32:21.02 (1425648741.02)
end: Mar 06 2015 14:32:32.04 (1425648752.04)
size: 60.8 KB
messages: 308
compression: none [1/1 chunks]
types: rosgraph_msgs/Log [acffd30cd6b6de30f120938c17c593fb]
std_msgs/String [992ce8a1687cec8c8bd883ec73ca41d1]
topics: /chatter 98 msgs : std_msgs/String
/rosout 106 msgs : rosgraph_msgs/Log (2 connections)
/rosout_agg 104 msgs : rosgraph_msgs/Log
$ rosbag filter original.bag x.bag True
$ rosbag filter x.bag y.bag True
$ rosbag filter y.bag z.bag True
$ du -bs *
62209 original.bag
59370 x.bag
59376 y.bag
59382 z.bag
The change of filesize from original.bag to x.bag is to be expected. After that the filesize (and md5sum) should remain the same. However, rosbag filter adds 2 bytes per topic.
At least one byte per topic we found: it's a \n (hex 0a) appended to pytype._full_text:
$ xxd x.bag |grep -A1 ^00014b0
00014b0: 7374 7269 6e67 2066 7261 6d65 5f69 640a string frame_id.
00014c0: 0a27 0000 006d 6435 7375 6d3d 6163 6666 .'...md5sum=acff
$ xxd y.bag |grep -A1 ^00014b0
00014b0: 7374 7269 6e67 2066 7261 6d65 5f69 640a string frame_id.
00014c0: 0a0a 2700 0000 6d64 3573 756d 3d61 6366 ..'...md5sum=acf
$ xxd z.bag |grep -A1 ^00014b0
00014b0: 7374 7269 6e67 2066 7261 6d65 5f69 640a string frame_id.
00014c0: 0a0a 0a27 0000 006d 6435 7375 6d3d 6163 ...'...md5sum=ac