How to convert between Ros Bag and Apollo Record?
============================

How to convert Ros Bag into Apollo Record, and how to convert Apollo Record back into Ros Bag?

-  Maintainer：\ daohu527@gmail.com, yhuai@uci.edu
-  Version：1.0.0
-  Date：06/05/2024
-  Description：This document describes necessary tools and steps to convert data between Ros Bag and Apollo Record.

Answer
----

Ros Bag and Apollo Record are two different data storage formats.
Because these two formats have differences in file structure and message definition,
data conversion is required.

The process of conversion can be summarized into the following three key steps:

1. **Read ROS Bag Data**\ : First, we need to open the ROS Bag file using the corresponding tool or library,
   and read the stored ROS messages. In this step, we will get the type of ROS messages, and prepare for the subsequent conversion.

2. **Convert Message Format**\ : After reading the ROS messages, we need to convert these messages from ROS 
    format to the format supported by the Apollo. This usually involves parsing the content of ROS messages, 
    and reorganizing this data according to the message definition of Apollo.

3. **Save as Apollo Record**\ : After completing the conversion of the message format, we will save the new Apollo 
    messages as an Apollo Record file. By completing this step, messages collected from the original ROS system can
    now be read and used by Apollo.

To simplify the process described above, we provide the ``bag_convert`` tool. 
With this tool, users only need to specify the path of the ROS Bag file and the 
path of the output Apollo Record file, and the data format conversion can be easily completed.


Installation
~~~~

.. code:: shell

   pip3 install bag_convert

Ros Bag to Apollo Record
~~~~~~~~~~~~~~~~~~~~~

.. code:: shell

   bag_convert -m=b2r -b=data/input.bag -r=data/output.record

Apollo Record to Ros Bag
~~~~~~~~~~~~~~~~~~~~~

.. code:: shell

   bag_convert -m=r2b -r=data/input.record -b=data/output.bag