如何在不下载的情况下从 Google Cloud Storage 读取视频？ 使用视频网址

Question

I want to read a video file using opencv but the problem is that the video is on my Google Cloud Storage, and opencv.videocapture method won't recognize it. Is there any other way to access video file without downloading the video on a local disk?

I also tried with urllib.urlopen but it didn't work. Here's my code:

import urllib
import numpy as np
import cv2

uri = 'gs://call-gestures/dictionany/AIDS.mp4'
url = "https://storage.cloud.google.com/call- 
gestures/dictionany/AIDS.mp4?authuser=1"
# Open a sample video available in sample-videos
r = cv2.imread(url)
print('Result: ',r)
cap = cv2.VideoCapture(url)
print(cap)
if cap.isOpened():
    print ("File Can be Opened")
    while(True):
        # Capture frame-by-frame
        ret, frame = cap.read()
        #print cap.isOpened(), ret
        if frame is not None:
            # Display the resulting frame
            cv2.imshow('frame',frame)
            # Press q to close the video windows before it ends if you want
            if cv2.waitKey(22) & 0xFF == ord('q'):
                break
        else:
            print("Frame is None")
            break

    # When everything done, release the capture
    cap.release()
    cv2.destroyAllWindows()
    print ("Video stop")
else:
    print("Not Working")

Errors I got:

warning: Error opening file (/build/opencv/modules/videoio/src/cap_ffmpeg_impl.hpp:901)
warning: https://storage.cloud.google.com/call-gestures/dictionany/Asia.mp4?authuser=1 (/build/opencv/modules/videoio/src/cap_ffmpeg_impl.hpp:902)

Answer 1

Yes, there is a way to read a video file stored in google cloud storage without downloading it, via generating a signed url.

Google storage bucket structure :

Code (Tested):

import firebase_admin
from firebase_admin import credentials
from firebase_admin import storage
import datetime

import urllib.request as req
import cv2

cred = credentials.Certificate('Path\to\your\google-credential-file.json')
app = firebase_admin.initialize_app(cred, {'storageBucket': 'cnc-designs.appspot.com'}, name='storage')
bucket = storage.bucket(app=app)

def generate_image_url(blob_path):
    """ generate signed URL of a video stored on google storage. 
        Valid for 300 seconds in this case. You can increase this 
        time as per your requirement. 
    """                                                        
    blob = bucket.blob(blob_path) 
    return blob.generate_signed_url(datetime.timedelta(seconds=300), method='GET')


url = generate_image_url('sample1.mp4')
req.urlretrieve(url, "sample1.mp4")
cap = cv2.VideoCapture('sample1.mp4')

if cap.isOpened():
    print ("File Can be Opened")
    while(True):
        # Capture frame-by-frame
        ret, frame = cap.read()
        #print cap.isOpened(), ret
        if frame is not None:
            # Display the resulting frame
            cv2.imshow('frame',frame)
            # Press q to close the video windows before it ends if you want
            if cv2.waitKey(22) & 0xFF == ord('q'):
                break
        else:
            print("Frame is None")
            break
    # When everything done, release the capture
    cap.release()
    cv2.destroyAllWindows()
    print ("Video stop")
else:
    print("Not Working")

Library needs to be installed:

firebase_admin : pip install firebase_admin

Answer 2

yes. you need to use Google Storage Public URL

cap = cv2.VideoCapture('https://storage.googleapis.com//your_Bucket//sample1.mp4')