How to get the duration of video using OpenCV

Question

I can only get the number of frames CAP_PROP_FRAME_COUNT using OpenCV.

However, I cannot find the parameter to get the duration of the video using OpenCV.

How to do that?

Thank you very much.

@Mathieu actually it's # of frames / frequency. (frequency has unit 1/sec) So a video with 60 frames and 30 Hz has a duration of 2 seconds. — Dorian, Apr 15 '20 at 12:26

score 57 · Answer 1 · edited Jul 23 '22 at 15:25

57

In OpenCV 3, the solution is:

import cv2 as cv

cap = cv.VideoCapture("./video.mp4")
fps = cap.get(cv.CAP_PROP_FPS)      # OpenCV v2.x used "CV_CAP_PROP_FPS"
frame_count = int(cap.get(cv.CAP_PROP_FRAME_COUNT))
duration = frame_count/fps

print('fps = ' + str(fps))
print('number of frames = ' + str(frame_count))
print('duration (S) = ' + str(duration))
minutes = int(duration/60)
seconds = duration%60
print('duration (M:S) = ' + str(minutes) + ':' + str(seconds))

cap.release()

edited Jul 23 '22 at 15:25

Christoph Rackwitz

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answered Aug 27 '18 at 03:55

Ryan Loggerythm

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Why do you import `cv2` when you begin your answer by saying that you are using OpenCV 3? Doesn't `cv2` mean OpenCV 2, or have I got this wrong? – HelloGoodbye Oct 29 '19 at 11:46
3

@HelloGoodbye, this page should explain it: https://stackoverflow.com/questions/44102738/why-cant-i-import-opencv3-even-though-the-package-is-installed – Ryan Loggerythm Oct 29 '19 at 17:14

score 37 · Accepted Answer · edited Jul 23 '22 at 15:26

37

OpenCV is not designed to explore video metadata, so VideoCapture doesn't have API to retrieve it directly.

You can instead "measure" the length of the stream: seek to the end, then get the timestamp:

>>> import cv2 as cv
>>> v = cv.VideoCapture('sample.avi')
>>> v.set(cv.CAP_PROP_POS_AVI_RATIO, 1)
True
>>> v.get(cv.CAP_PROP_POS_MSEC)
213400.0

Checking shows that this sets the point after the last frame (not before it), so the timestamp is indeed the exact total length of the stream:

>>> v.get(cv.CAP_PROP_POS_FRAMES)
5335.0
>>>> v.get(cv.CAP_PROP_FRAME_COUNT)
5335.0

>>> v.set(cv.CAP_PROP_POS_AVI_RATIO, 0)
>>> v.get(cv.CAP_PROP_POS_FRAMES)
0.0        # the 1st frame is frame 0, not 1, so "5335" means after the last frame

edited Jul 23 '22 at 15:26

Christoph Rackwitz

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answered Mar 01 '18 at 11:11

ivan_pozdeev

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The call to `v.get(cv2.CAP_PROP_POS_MSEC)` might not return correct value unless `v.read()` is called after setting a position, including seeking to the end. See https://github.com/opencv/opencv/issues/15749 – kfx Jun 29 '20 at 19:31
@kfx I see. So this is new behavior in `4.1.2`. [When I'm at the end, I get wrong number even after `read()`](https://github.com/opencv/opencv/issues/15749#issuecomment-651399016); from [the code](https://github.com/opencv/opencv/blob/master/modules/videoio/src/cap_ffmpeg_impl.hpp#L1590-L1609), it looks like it's not supposed to require calling `read()` because it sets `picture_pts`. So this is a bug in my book. – ivan_pozdeev Jun 29 '20 at 22:25
It seems like seeking to the end of the stream with `CAP_PROP_POS_AVI_RATIO` doesn't work all the time depending on the video type (e.g. doesn't work with QuickTime .mov files). I'd use this with caution. – Jack Jan 06 '22 at 22:40

score 7 · Answer 3 · edited Jul 23 '22 at 15:27

7

Capture the video and output the duration is seconds

import cv2 as cv
vidcapture = cv.VideoCapture('myvideo.mp4')
fps = vidcapture.get(cv.CAP_PROP_FPS)
totalNoFrames = vidcapture.get(cv.CAP_PROP_FRAME_COUNT)
durationInSeconds = totalNoFrames / fps

print("durationInSeconds:", durationInSeconds, "s")

edited Jul 23 '22 at 15:27

Christoph Rackwitz

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answered Apr 01 '20 at 16:51

lakjeewa Wijebandara

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score 4 · Answer 4 · edited Jul 23 '22 at 15:28

4

First calculate frame per second like this

import cv2 as cv
# cap = cv.VideoCapture...
fps = cap.get(cv.CAP_PROP_FPS)

Then duration can be calculated as (number of frames) / (frames per second)

 duration = float(num_frames) / float(fps) # in seconds

edited Jul 23 '22 at 15:28

Christoph Rackwitz

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answered Mar 01 '18 at 11:01

Mitiku

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Unfortunately, this does not always work. CAP_PROP_FPS comes from header data, it is not reliably calculated – Connor May 21 '19 at 05:53

score 2 · Answer 5 · edited Jul 23 '22 at 15:27

2

In my personal experience I've been using the OpenCV method. Try this code:

import cv2 as cv

def get_dur(filename):
    video = cv.VideoCapture(filename)
    fps = video.get(cv.CAP_PROP_FPS)
    frame_count = video.get(cv.CAP_PROP_FRAME_COUNT)
    seconds = frame_count / fps
    minutes = int(seconds / 60)
    rem_sec = int(seconds % 60)
    return f"{minutes}:{rem_sec}"

print(get_dur("dafuck.mp4"))

edited Jul 23 '22 at 15:27

Christoph Rackwitz

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answered Nov 21 '21 at 15:10

Joseph Yosoevsky

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You can use python's divmod function to calculate the quotient (minutes) and remainder (seconds) at once. For example for 100 s: minutes, seconds = divmod(100, 60) – Michael S. May 06 '23 at 21:35

score 1 · Answer 6 · edited Jul 23 '22 at 15:27

1

I noticed a weird phenomenon that many video DO NOT HAVE as much frames as the vid.get(cv.CAP_PROP_FRAME_COUNT) gets.

I suppose that the video duration should be the divided value of TOTAL FRAMES by FPS, but it always mismatch. The video duration would be longer than we calculated. Considering what FFMPEG does, the original video might has some empty frames.

Hope this help.

edited Jul 23 '22 at 15:27

Christoph Rackwitz

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answered Nov 19 '19 at 03:56

FantasyJXF

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How to get the duration of video using OpenCV

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