Hi , I'm trying to start a discussion about what type should uint8[] be converted to Background: In ROS1 , `uint8[]` is transported into `string` while other `uint` is transported to `list` . In Ros 2 , all the `uint` types are transported into list. But in our tests , we find that when we transport the images using uint8 , the `list` type shows high latency , cause the transport to `list` takes a lot of time So we changed some codes and transport the `uint8` type to `bytes` and test again , the result is much better Test comparison result: copy data in cpp to `list` : 10ms transport 2M image in ROS2 in type `list` in python : 270ms copy data in cpp tp 'byte' : 0-1ms transport 2M image in ROS2 using cv_bridge in type 'bytes' in python : 10ms issue description : In our program , low time latency is very important , and bytes is more suitable in python too . So whether it's better to let the `uint8`` type convert to `bytes` instead of `list` in ROS2. (Just like in ROS) Our attempts 1. change the code in rosidl to make `uint8` convert to `bytes`` directly 2. trying to add a new Primitive type like `imguint8` to convert to `bytes` and `uint8` is still `list` , but i have some problems in codes link to the [attempt 2](https://discourse.ros.org/t/discussion-about-how-to-add-a-new-primitive-types-to-rosidl-msg/4607/6) Opinion Invitation: @dirk-thomas @marguedas Appreciating your opinion ! --- [Visit Topic](https://discourse.ros.org/t/discussion-about-uint8-type-transport-in-ros2-python/4633/1) or reply to this email to respond. If you do not want to receive messages from ros-users please use the unsubscribe link below. If you use the one above, you will stop all of ros-users from receiving updates. ______________________________________________________________________________ ros-users mailing list ros-users@lists.ros.org http://lists.ros.org/mailman/listinfo/ros-users Unsubscribe: