How to get the duration of a video in Python?

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)

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)

To make things a little bit easier, the following codes put the output to JSON.

You can use it by using probe(filename), or get duration by using duration(filename):

json_info     = probe(filename)
secondes_dot_ = duration(filename) # float number of seconds

It works on Ubuntu 14.04 where of course ffprobe installed. The code is not optimized for speed or beautiful purposes but it works on my machine hope it helps.

#
# Command line use of 'ffprobe':
#
# ffprobe -loglevel quiet -print_format json \
#         -show_format    -show_streams \
#         video-file-name.mp4
#
# man ffprobe # for more information about ffprobe
#

import subprocess32 as sp
import json


def probe(vid_file_path):
    ''' Give a json from ffprobe command line

    @vid_file_path : The absolute (full) path of the video file, string.
    '''
    if type(vid_file_path) != str:
        raise Exception('Gvie ffprobe a full file path of the video')
        return

    command = ["ffprobe",
            "-loglevel",  "quiet",
            "-print_format", "json",
             "-show_format",
             "-show_streams",
             vid_file_path
             ]

    pipe = sp.Popen(command, stdout=sp.PIPE, stderr=sp.STDOUT)
    out, err = pipe.communicate()
    return json.loads(out)


def duration(vid_file_path):
    ''' Video's duration in seconds, return a float number
    '''
    _json = probe(vid_file_path)

    if 'format' in _json:
        if 'duration' in _json['format']:
            return float(_json['format']['duration'])

    if 'streams' in _json:
        # commonly stream 0 is the video
        for s in _json['streams']:
            if 'duration' in s:
                return float(s['duration'])

    # if everything didn't happen,
    # we got here because no single 'return' in the above happen.
    raise Exception('I found no duration')
    #return None


if __name__ == "__main__":
    video_file_path = "/tmp/tt1.mp4"
    duration(video_file_path) # 10.008