OpenCV 教程(2) -- 基本視頻處理

import numpy as np
import cv2

# Capture Video from Camera
cap = cv2.VideoCapture(0)
while(True):
    # Capture frame-by-frame
    ret, frame = cap.read()

    # Out operations on the frame come here
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    # Display the resulting frame
    cv2.imshow('frame', gray)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# When everything done, release the capture
cap.release()
cv2.destroyAllWindows()

# Play Video from File
cap = cv2.VideoCapture('output.avi')

while(cap.isOpened()):
    ret, frame = cap.read()

    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    cv2.imshow('frame', gray)
    if cv2.waitKey(10) & 0xFF == ord('q'):
        break

cap.release()
cv2.destroyAllWindows()

# Saving a Video
cap = cv2.VideoCapture(0)

# Define the codec and create VideoWriter object

# FourCC is a 4-byte code used to specify the video codec.
# In Fedora: DIVX, XVID, MJPG, X264, WMV1, WMV2. 
# (XVID is more preferable. MJPG results in high size video. 
# X264 gives very small size video)
fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('output.avi', fourcc, 20.0, (640,480))

while(cap.isOpened()):
    ret, frame = cap.read()
    if ret == True:
        frame = cv2.flip(frame,1)

        # write the flipped frame
        out.write(frame)

        cv2.imshow('frame', frame)
        if cv2.waitKey(1) & 0xFF == ord('q'):
            break
    else:
        break

# Release everything if job is finished
cap.release()
out.release()
cv2.destroyAllWindows()