matplotvideo - syncing video and matplotlib

What is it?

matplotvideo is a Python package providing an easy way to sync matplotlib plots to video. Some of the features:

Frame-accurate seeking forward and backward
Playback speed control between 0.01x and 4x
Auto frame-skip to maintain playback speed when plot takes to long
Seek with slider through entire video
Intuitive pause/play toggle using spacebar
Play all cv2 supported media types

Where to get it

The source code is currently hosted on GitHub at: https://github.com/PySport/matplotvideo

Installers for the latest released version are available at the Python package index.

# or PyPI
pip install matplotvideo

The package requires cv2 to be installed. When you don't have it installed yet, you can check out opencv-python.

Video player controls:

Sync between Scene Change data plot and video

'a' 1 frame back
'd' 1 frame forward
space toggle paused / play
esc quit video player
playback speed can be changed with the slider
playback position can be changed with the slider

Application examples

Verify data using video
Enrich video with additional data, like computer vision model output
Find interesting video/data frames

Usage

Import attach_video_player_to_figure and attach to matplotlib figure. You can pass additional keyword arguments to attach_video_player_to_figure that are passed to the on_frame callback on each invocation.

from matplotvideo import attach_video_player_to_figure
import matplotlib.pyplot as plt

# (timestamp, value) pairs

# sample: big bunny scene cuts
fancy_data = [
    (0, 1),
    (11.875, 1),
    (11.917, 2),
    (15.75, 2),
    (15.792, 3),
    (23.042, 3),
    (23.083, 4),
    (47.708, 4),
    (47.75, 5),
    (56.083, 5),
    (56.125, 6),
    (60, 6)
]


def on_frame(video_timestamp, line):
    timestamps, y = zip(*fancy_data)
    x = [timestamp - video_timestamp for timestamp in timestamps]

    line.set_data(x, y)
    line.axes.relim()
    line.axes.autoscale_view()
    line.axes.figure.canvas.draw()


def main():
    fig, ax = plt.subplots()
    plt.xlim(-15, 15)
    plt.axvline(x=0, color='k', linestyle='--')

    line, = ax.plot([], [], color='blue')

    attach_video_player_to_figure(fig, "BigBuckBunny.mp4", on_frame, line=line)

    plt.show()


main()