How to get the duration of a video in Python?

As reported here https://www.reddit.com/r/moviepy/comments/2bsnrq/is_it_possible_to_get_the_length_of_a_video/

you could use the moviepy module

from moviepy.editor import VideoFileClip
clip = VideoFileClip("my_video.mp4")
print( clip.duration )

(year 2020 answer)

Solutions:

1. opencv 0.0065 sec ✔
2. ffprobe 0.0998 sec
3. moviepy 2.8239 sec

✔ OpenCV method:

def with_opencv(filename):
    import cv2
    video = cv2.VideoCapture(filename)

    duration = video.get(cv2.CAP_PROP_POS_MSEC)
    frame_count = video.get(cv2.CAP_PROP_FRAME_COUNT)

    return duration, frame_count

Usage: print(with_opencv('my_video.webm'))

---

Other:

ffprobe method:

def with_ffprobe(filename):
    import subprocess, json

    result = subprocess.check_output(
            f'ffprobe -v quiet -show_streams -select_streams v:0 -of json "{filename}"',
            shell=True).decode()
    fields = json.loads(result)['streams'][0]

    duration = fields['tags']['DURATION']
    fps      = eval(fields['r_frame_rate'])
    return duration, fps

moviepy method:

def with_moviepy(filename):
    from moviepy.editor import VideoFileClip
    clip = VideoFileClip(filename)
    duration       = clip.duration
    fps            = clip.fps
    width, height  = clip.size
    return duration, fps, (width, height)

You can use the external command ffprobe for this. Specifically, run this bash command from the FFmpeg Wiki:

import subprocess

def get_length(filename):
    result = subprocess.run(["ffprobe", "-v", "error", "-show_entries",
                             "format=duration", "-of",
                             "default=noprint_wrappers=1:nokey=1", filename],
        stdout=subprocess.PIPE,
        stderr=subprocess.STDOUT)
    return float(result.stdout)