Control playback and drive the Viewer from code

Configure playback in the blueprint

The time panel of the blueprint controls playback:

import rerun as rr
import rerun.blueprint as rrb

rr.send_blueprint(
    rrb.Blueprint(
        rrb.Spatial3DView(origin="/world"),
        rrb.TimePanel(
            timeline="frame",
            playback_speed=2.0,
            fps=30.0,
            play_state="playing",
            loop_mode="all",
        ),
    )
)

Parameter	Meaning
`timeline`	The active timeline.
`playback_speed`	Playback speed multiplier.
`fps`	Frames per second, for sequence timelines.
`play_state`	`"paused"`, `"playing"`, or `"following"` (follow the newest data).
`loop_mode`	`"off"`, `"selection"`, or `"all"`. `"selection"` needs `time_selection`.
`time_selection`	A selected time range, as `rrb.components.AbsoluteTimeRange(min, max)`.
`state`	`"expanded"`, `"collapsed"`, or `"hidden"`.

The time panel blueprint has no field for the position of the time cursor. To start at a specific time, use one of the methods below.

Open a recording at a specific time

A Viewer URL can end with a #when= fragment that sets the time cursor, for example #when=frame@120. See Viewer URLs.

Drive a running Viewer from Python

rerun.experimental.ViewerClient connects to a running Viewer and controls it. This API is experimental and may change.

from rerun.experimental import ViewerClient

client = ViewerClient.connect()  # rerun+http://127.0.0.1:9876/proxy by default
client.open("recording.rrd")
client.set_time("frame", sequence=120, play_state="paused")
client.set_time(play_state="playing")
client.save_screenshot("viewer.png")  # The path is on the machine that runs the Viewer
client.close("current")

Other useful methods:

ViewerClient.spawn(headless=True) starts a new Viewer, for example for screenshots in CI.
get_state() returns the open recordings, the time cursor, and the views. It does not include the current selection.
take_screenshot() returns a PNG as bytes.
get_blueprint() and set_blueprint() read and replace the blueprint as a JSON-like dictionary.

In notebooks

The notebook Viewer has set_time_ctrl:

from rerun.notebook import Viewer

viewer = Viewer()
viewer.display()
viewer.set_time_ctrl(timeline="frame", sequence=120, play=True)

In the web Viewer

The JavaScript WebViewer has set_time:

await viewer.set_time({ timeline: "frame", sequence: 42, play_state: "playing" });

In the Viewer

Right-click in a time series view to move the time cursor to that time.
Press Space to play or pause.

Open a file in an already running Viewer

rerun recording.rrd sends the file to a Viewer that is already running on the default port, instead of starting a new one. To always start a new Viewer, use rerun --new recording.rrd (an alias for --port auto).