Play: start and end time

[dongfang-steven-yang]

Description

Hello,

I just wonder if ros2 bag play has functionality like -s as in rosbag play in ROS 1? I would like to debug my algorithm at a specific time in a big bag file. For example, the duration of my bag is 10 mins, when I start to replay the topics, I would like to directly jump into 6 mins, so that every time I open a bag, I don't have to wait.

If there is no such functionality, is there any plan to add it? Or is there any workaround to solve this issue?

Thanks, DF

[aprotyas]

I don't think the start/stop timestamp feature is exposed in the CLI tool yet, but the infrastructure exists following the work in https://github.com/ros2/rosbag2/issues/696 and https://github.com/ros2/rosbag2/issues/821.

[aprotyas]

Implementation question for maintainers: For the play start timestamp, can this feature boil down to adding a start timestamp to rosbag2_py.PlayOptions, which can then be used to invoke Player::seek(timepoint) after construction of a Player but before calling Player::play() on it? So, right after L115 here.

https://github.com/ros2/rosbag2/blob/2abc50904803a0eae58ee2094542977ec9262db7/rosbag2_py/src/rosbag2_py/_transport.cpp#L109-L128

Edit: In hindsight, this may not work because rosbag2_transport::Player seems to maintain a _starting_time from the reader metadata.

[emersonknapp]

These both make sense as additional PlayOption fields.

For starting time, it should be easy to implement by overriding Player::starting_time_ in Player::play.

The end time could be implemented in the dequeueing mechanism by returning nullptr from Player::peek_next_message_from_queue, which would stop playback at that time. Alternatively, it could be implemented in the enqueueing mechanism Player::enqueue_up_to_boundary, stopping enqueueing when a message past the given timestamp is reached. The result would be approximately the same - maybe slightly better performance to stop enqueueing messages, instead of adding messages to the queue that we don't intend to read.

[gbiggs]

We have a PR in our fork that adds "play until timestamp" functionality. We're planning on upstreaming it later this week or early next week. It might need some revision though.

[aprotyas]

We have [a PR in our fork[(https://github.com/gbiggs/pull/5) that adds "play until timestamp" functionality. We're planning on upstreaming it later this week or early next week. It might need some revision though.

~Oops, I didn't realize there was WIP on this. Feel free to close my PR to reduce the noise.~ I misread your comment, but https://github.com/gbiggs/rosbag2/pull/5 and https://github.com/ros2/rosbag2/pull/931 should cover both use-cases here. Nice!

[MichaelOrlov]

• Closing as done. Since --start-offset CLI parameter was added in https://github.com/ros2/rosbag2/pull/931