python get image from video using cv2 (VIDEOIO ERROR: V4L: can't find camera device)

* MENTION : Ubuntu 16.05 LTS with python 2.7 installed on Azure.

This example works fine on my local. but doesn't work on my VM. so i'm keep messing up.

import cv2
 
def video2frame(invideofilename, save_path):
    vidcap = cv2.VideoCapture(invideofilename)
    count = 0
    while True:
        success,image = vidcap.read()
        if not success:
            break
        print ('Read a new frame: ', success)
        fname = "{}.jpg".format("{0:05d}".format(count))
        cv2.imwrite(save_path + fname, image) # save frame as JPEG file
        count += 1
    print("{} images are extracted in {}.". format(count, save_path))

but, finally i realized that my virtual machine doesn't have any carmera device.

Python 2.7.12 (default, Nov 12 2018, 14:36:49)
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
>>> cv2.VideoCapture(0)
VIDEOIO ERROR: V4L: can't open camera by index 0
<VideoCapture 0x7f44197b6810>
>>> cv2.VideoCapture(-1)
VIDEOIO ERROR: V4L: can't find camera device
<VideoCapture 0x7f44197b6770>
>>>

i'm try to install many things.

git clone https://github.com/opencv/opencv.git
 
mkdir build
 
cd build
 
cmake ../opencv
 
make

sudo apt-get install cheese libav-tools libavcodec-dev libavformat-dev libavutil-dev libswscale-dev libx264-dev

but finally resolve this problem when i install this opencv and many libs.

* additional : still doesn't work if i use cv2.VideoCapture from video url. so i have to change logic. just use local video path if you use get video meta from video url.

# don't use like this if you doing on VM with cv2 module.
import cv2
vid = cv2.VideoCapture("https://example.com/test.mp4")
success, img = vid.read()
if success:
    print len(img)
    print type(img)

# change from video url to local path.
import cv2
vid = cv2.VideoCapture("./video.mp4")
success, img = vid.read()
if success:
    print len(img)
    print type(img)

Don't use video url. if you doing on VM with cv2 module.