ROS使用教程--关于rosbag
原文：https://blog.csdn.net/wendox/article/details/52373488
overview
rosbag package提供了一个命令行工具以及cpp类和python的API. rosbag使用命令行能够：录制，从包重新发布，获取包的概括信息，检查包的消息类型，使用Python表达式过滤包中信息，压缩解压缩包，重新索引包
命令行工具
This is the current list of supported commands:
- record. Record a bag file with the contents of specified topics.
1 $ rosbag record rosout tf cmd_vel
info. Summarize the contents of a bag file.
play. Play back the contents of one or more bag files.
check. Determine whether a bag is playable in the current system, or if it can be migrated.
fix. Repair the messages in a bag file so that it can be played in the current system.
filter. Convert a bag file using Python expressions.
compress. Compress one or more bag files.
decompress. Decompress one or more bag files.
reindex. Reindex one or more broken bag files.
如果记录一个高带宽的信息,例如图像信息,最好是在同一个相机节点运行的机器上记录,并指定文件的目的地所属的机器的硬盘
可以使用regex, 指令是-e, -regex
1 $ rosbag record -e "/(.*)_stereo/(left|right)/image_rect_color"
rosbage info
该工具将保存的bag文件显示出来,包含起止时间,toppics以及其类型,信息数量等.
rqt_bag
提供全方位的图形化界面，具有录制，播放，显示，保存，加载文件，暂停等功能
refer
https://zhenshenglee.github.io/2016/08/16/160816ROS-Bag%E4%BB%8B%E7%BB%8D/
http://chenjunjun.bitbucket.org/2016/03/22/ROS-%E6%B6%88%E6%81%AF%E5%BD%95%E5%88%B6%E5%92%8C%E5%9B%9E%E6%94%BE/
rosbag文件中提取视频
方法1
[refer ros wiki page]http://wiki.ros.org/rosbag/Tutorials/Exporting%20image%20and%20video%20data#CA-b03834a5a0917593e18fb84cfab917fbab79f52a_1
1 <launch> 2 <node pkg="rosbag" type="play" name="rosbag" args="-d 2 $(find image_view)/test.bag"/> 3 <node name="extract" pkg="image_view" type="extract_images" respawn="false" output="screen" cwd="ROS_HOME"> 4 <remap from="image" to="/camera/image_raw"/> 5 </node> 6 </launch>
$(find image_view)/test.bag在使用的时候换成自己的bag文件的路径,然后生成一些文件,文件名统一格式为’frame%04d.jpg’,位置在.ros文件中.因此执行一下命令,移动文件,并录制成视频.
1 cd ~ 2 mkdir test 3 mv ~/.ros/frame*.jpg test/ 4 5 cd ~/test 6 mencoder "mf://*.jpg" -mf type=jpg:fps=15 -o output.mpg -speed 1 -ofps 30 -ovc lavc -lavcopts vcodec=mpeg2video:vbitrate=2500 -oac copy -of mpeg
