https://www.cnblogs.com/lovebay/p/11193388.html

1、.bag文件转.txt

将file_name.bag文件中topic_name话题的消息转换到Txt_name.txt文件中：

rostopic echo -b file_name.bag -p /topic_name > Txt_name.txt
2、rosbag remap

rosbag play ros.bag  /image_raw:=/camera/image_raw
3、使用rxplot画时间趋势曲线

在ROS系统中，标量数据可以根据消息中提供的时间戳作为时间序列绘制图形。

运行可以发布话题的节点后，可以通过rostopic list查看当前的发布的话题，现在，我们不再去使用rostopic echo ，而是通过rxplot命令就能够看到随时间变化的值的曲线。

rqt_plot /topic/data //单个话题，单个数据

rqt_plot /topic/x:y:z //单个话题，向量数据

rqt_plot /topic/x /topic/y /topic/z

123

或是先打开GUI界面：

rosrun rqt_plot rqt_plot
如何rosbag /录制无损的压缩图像
Libra

岁月腐蚀了曾经的青春，留下温顺苍老的影子。----------- ddb

rosbag record and play

话题录制：

录制所有发布出来的话题，此时默认将话题保存在一个以当时时间戳命名的文件夹中：
$ rosbag record -a1

录制指定话题：
$ rosbag record /topic1 /topic121
话题回放：

基本功能：
$ rosbag play 1

等待一定时间之后发布bag文件中的内容
$ rosbag play  -d 1

按一定频率回放，-r选项用来设定消息发布速率，如下面命令则表示以3倍原始速率发布话题

$ rosbag play -r 3 1

回放指定话题：

$ rosbag play  --topics 1

其他指令：

展示bag文件中所包含话题的名称、类型和消息数量:
$ rosbag info 1

更加灵活的回放方式，例如回放除了某个话题以外的所有话题：

参考：https://answers.ros.org/question/228676/exclude-some-topics-from-rosbag-play/
exclude some topics from rosbag play
注意：rosbag的remap方法-----------rosbag play ros.bag  /image_raw:=/camera/image_raw
How do you remap a topic?






**
在/ camera/image_raw以外的主题上发布rosbag图像
**


是否可以在/ camera/image_raw以外的主题上播放包含图像的rosbag文件？在/ camera/image_raw以外的主题上发布rosbag图像
来源
2017-04-20 Susan94
A

回答

1
是的，这是可能的，你可以简单地remap your arguments或remap your topic-tag。
您可以从终端层面做到这一点，当你玩一个节点：

rosbag play mybagfile.bag /camera/image_raw:=/dataset/name 

可以your rosbag play command之前，从roslaunch文件做到这一点。当你运行多个节点时，它很有用。

重映射例如：
<remap from = "/camera/image_raw" to = "/dataset/name" /> 

roslaunch例如：
<launch> 
<arg name = "pathToRosbag" default = "/home/path/to/Rosbag.bag" /> 
<remap from = "/camera/image_raw" to = "/dataset/name" /> 
<node pkg = "rosbag" 
     type = "play" 
     name = "player" 
     args = "$(arg pathToRosbag)"/> 
</launch> 

launch播放rosbag如下：

<launch>
 
  <node pkg="rosbag" type="play" name="player" output="screen" args="--clock /home/xx/xxx/xxx/xxx.bag"/>
  <!-- 注意这里bag文件的路径必须为绝对路径-->
</launch>

launch 录制rosbag如下：

<launch>
	<node pkg="rosbag" type="record" name="bag_record" args="topic-name1 topic-name1 -o /home/xx/xxx/xxx/xxx.bag"/>
  <!-- 注意这里bag文件的路径必须为绝对路径-->                                                                                             
</launch>

参考链接：

https://blog.csdn.net/u012423865/article/details/78278440/

https://blog.csdn.net/the_dream_runner/article/details/106922495

rosbag 主要用于记录、回放、分析 rostopic 中的数据。它可以将指定 rostopic 中的数据记录到 .bag 后缀的数据包中.

记录所有topic数据

rosbag record -a

将当前发布的所有 topic 数据都录制保存到一个 rosbag 文件中，录制的数据包名字为日期加时间。没有指定文件夹名字，生成的文件在工作空间所在目录。

指定文件夹名字

记录所有的
cd /home/xxx/bagfile
rosbag record -a

或者将指定的topic信息存到指定的文件夹下，并且打上时间戳命名，如：aaa_2021-04-06-10-09-20.bag。
rosbag record -o /home/xxx/bagfiles/aaa.bag topic_name

#多个topic
rosbag record -o /home/xxx/bagfiles/aaa.bag topic_name1 topic_name2

-O不会加时间戳，直接为：aaa.bag。
rosbag record -O /home/xxx/bagfiles/aaa.bag topic_name


使用roslaunch

<node pkg="rosbag" type="record" 
        name="bag_record" 
        args="topicname1 topicname2 -o /home/xxx/bagfiles/aaa.bag"/>

在roslaunch文件中添加上述语句，则在指定文件夹中生成aaa_2021-04-06-10-09-20.bag的文件，记录了主题名为topicname1和topicname2的相关信息.

1. 需求

前期录制的rosbag用以在office中做各种实验和测试，如ndt, lidar fusion等.现在切换ros2 环境，又不想去重新费时费力去重新录制ros2 bag，那么就引申了转换格式的需求.

2. 方法

I)通过ros1 bridge 转换topic

 

2)现成的模块rosbag2 v2 plugin

https://github.com/ros2/rosbag2/

https://github.com/ros2/rosbag2_bag_v2/

安装rosbag2  rosbag2 plugin

sudo  apt install -y ros-dashing-rosbag2-bag-v2-plugins	ros-dashing-rosbag2-converter-default-plugins ros-dashing-rosbag2-storage ros-dashing-rosbag2-transport ros-dashing-rosbag2-storage-default-plugins ros-dashing-ros2bag

 查看ros2 bag  info

ros2 bag info -s rosbag_v2  2019-12-20-18-00-27.bag
Files:             2019-12-20-18-00-27.bag
Bag size:          792.8 MiB
Storage id:        rosbag_v2
Duration:          6.492s
Start:             Dec 20 2019 10:00:33.878 (1576836033.878)
End                Dec 20 2019 10:00:40.371 (1576836040.371)
Messages:          7513
Topic information: 
                   Topic: /ns2/rslidar2 | Type: sensor_msgs/msg/PointCloud2 | Count: 75 | Serialization Format: rosbag_v2
                   Topic: /ns1/rslidar1 | Type: sensor_msgs/msg/PointCloud2 | Count: 76 | Serialization Format: rosbag_v2
                   Topic: /points_raw | Type: sensor_msgs/msg/PointCloud2 | Count: 65 | Serialization Format: rosbag_v2

播放

ros2 bag play -s rosbag_v2 3lidars.bag

与此同时，可以新开终端录制ros2bag 格式的文件

-XPS-15-9560:~$ ros2 bag record /points_raw /ns1/rslidar1 /ns2/rslidar2  -o 3.bag2
[INFO] [rosbag2_storage]: Opened database '3.bag2'.
[INFO] [rosbag2_transport]: Listening for topics...
[INFO] [rosbag2_transport]: Subscribed to topic '/ns2/rslidar2'
[INFO] [rosbag2_transport]: Subscribed to topic '/points_raw'
[INFO] [rosbag2_transport]: Subscribed to topic '/ns1/rslidar1'
[INFO] [rosbag2_transport]: All requested topics are subscribed. Stopping discovery...
^C[INFO] [rclcpp]: signal_handler(signal_value=2)
-XPS-15-9560:~$ ros2 bag info 3.bag2/

Files:             3.bag2.db3
Bag size:          268.9 MiB
Storage id:        sqlite3
Duration:          6.427s
Start:             Apr 13 2020 08:08:39.422 (1586765319.422)
End                Apr 13 2020 08:08:45.850 (1586765325.850)
Messages:          209
Topic information: Topic: /ns1/rslidar1 | Type: sensor_msgs/msg/PointCloud2 | Count: 73 | Serialization Format: cdr
                   Topic: /ns2/rslidar2 | Type: sensor_msgs/msg/PointCloud2 | Count: 73 | Serialization Format: cdr
                   Topic: /points_raw | Type: sensor_msgs/msg/PointCloud2 | Count: 63 | Serialization Format: cdr


但是录制下来的帧数有所减少,时间也有差异

看看录制下来的帧率

-XPS-15-9560:~$ ros2 topic hz /points_raw

WARNING: topic [/ns2/rslidar2] does not appear to be published yet
average rate: 14.224
	min: 0.006s max: 0.141s std dev: 0.04155s window: 15
average rate: 9.122
	min: 0.006s max: 0.694s std dev: 0.12617s window: 25
average rate: 8.281
	min: 0.006s max: 0.742s std dev: 0.16182s window: 31
average rate: 9.239
	min: 0.006s max: 0.742s std dev: 0.13851s window: 44
average rate: 9.189
	min: 0.006s max: 0.742s std dev: 0.12708s window: 53


帧率也有所降低

而我们用ros1 play和record的结果，是不会有这个现象的

 rosbag record  /points_raw /ns1/rslidar1 /ns2/rslidar2  
[ INFO] [1586768938.763631804]: Subscribing to /ns1/rslidar1
[ INFO] [1586768938.766971727]: Subscribing to /ns2/rslidar2
[ INFO] [1586768938.769629437]: Subscribing to /points_raw
[ INFO] [1586768938.772643391]: Recording to rosbag_2020-04-13-17-08-58.bag.


-XPS-15-9560:/tmp$ rosbag info rosbag_2020-04-13-17-08-58.bag 
path:        rosbag_2020-04-13-17-08-58.bag
version:     2.0
duration:    6.4s
start:       Apr 13 2020 17:09:03.83 (1586768943.83)
end:         Apr 13 2020 17:09:10.27 (1586768950.27)
size:        277.5 MB
messages:    216
compression: none [216/216 chunks]
types:       sensor_msgs/PointCloud2 [1158d486dd51d683ce2f1be655c3c181]
topics:      /ns1/rslidar1   76 msgs    : sensor_msgs/PointCloud2
             /ns2/rslidar2   75 msgs    : sensor_msgs/PointCloud2
             /points_raw     65 msgs    : sensor_msgs/PointCloud2


 对比autoware sample ros2bag 

 wget https://autoware-ai.s3.us-east-2.amazonaws.com/sample_moriyama_150324.bag2.tar.gz


时间，总帧数和ros1 bag完全一致

但是播放的时候，帧率也会下降

-XPS-15-9560:~$ ros2 topic hz /points_raw
average rate: 10.111
	min: 0.088s max: 0.105s std dev: 0.00447s window: 11
average rate: 9.575
	min: 0.088s max: 0.197s std dev: 0.02143s window: 20
average rate: 9.380
	min: 0.088s max: 0.211s std dev: 0.02691s window: 29
average rate: 9.282
	min: 0.088s max: 0.211s std dev: 0.02877s window: 38
average rate: 9.247
	min: 0.088s max: 0.211s std dev: 0.02910s window: 48
average rate: 8.898
	min: 0.088s max: 0.212s std dev: 0.03451s window: 56
average rate: 8.774
	min: 0.088s max: 0.212s std dev: 0.03623s window: 64
average rate: 8.696
	min: 0.088s max: 0.212s std dev: 0.03719s window: 73
average rate: 8.832
	min: 0.088s max: 0.212s std dev: 0.03521s window: 83
average rate: 8.844
	min: 0.088s max: 0.212s std dev: 0.03468s window: 92
average rate: 8.678

播放的时候，也许会出现

-XPS-15-9560:~$ ros2 bag  play sample_moriyama_150324.bag2
[ERROR] [rosbag2_storage]: Could not open 'sample_moriyama_150324.bag2' with 'sqlite3'. Error: Failed to read from bag 'sample_moriyama_150324.bag2': File 'sample_moriyama_150324.bag2/sample_moriyama_150324.bag2_0.db3' does not exist.
[ERROR] [rosbag2_storage]: Could not load/open plugin with storage id 'sqlite3'.
[ERROR] [rosbag2_transport]: Failed to play: No storage could be initialized. Abort
autoware@weilin-XPS-15-9560:~$ vim sample_moriyama_150324.bag2/


原因是对应的path要修改一下，如

vim metadata.yaml
 relative_file_paths:
    - ../sample_moriyama_150324.bag2/sample_moriyama_150324.bag2_0.db3