python視訊處理字幕_python 處理視訊輸入輸出

視訊的處理和圖檔的處理類似，隻不過視訊處理需要連續處理一系列圖檔。

一般有兩種視訊源，一種是直接從硬碟加載視訊，另一種是擷取攝像頭視訊。

0x00. 本地讀取視訊

核心函數:

cv.CaptureFromFile()

代碼示例：

import cv2.cv as cv

capture = cv.CaptureFromFile('myvideo.avi')

nbFrames = int(cv.GetCaptureProperty(capture, cv.CV_CAP_PROP_FRAME_COUNT))

#CV_CAP_PROP_FRAME_WIDTH Width of the frames in the video stream

#CV_CAP_PROP_FRAME_HEIGHT Height of the frames in the video stream

fps = cv.GetCaptureProperty(capture, cv.CV_CAP_PROP_FPS)

wait = int(1/fps * 1000/1)

duration = (nbFrames * fps) / 1000

print 'Num. Frames = ', nbFrames

print 'Frame Rate = ', fps, 'fps'

print 'Duration = ', duration, 'sec'

for f in xrange( nbFrames ):

frameImg = cv.QueryFrame(capture)

print cv.GetCaptureProperty(capture, cv.CV_CAP_PROP_POS_FRAMES)

cv.ShowImage("The Video", frameImg)

cv.WaitKey(wait)

cv2

import numpy as np

import cv2

cap = cv2.VideoCapture('vtest.avi')

while(cap.isOpened()):

ret, frame = cap.read()

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

cv2.imshow('frame',gray)

if cv2.waitKey(1) & 0xFF == ord('q'):

break

cap.release()

cv2.destroyAllWindows()

0x01. 攝像頭視訊讀取

核心函數：

cv.CaptureFromCAM()

示例代碼：

import cv2.cv as cv

capture = cv.CaptureFromCAM(0)

while True:

frame = cv.QueryFrame(capture)

cv.ShowImage("Webcam", frame)

c = cv.WaitKey(1)

if c == 27: #Esc on Windows

break

cv2

import numpy as np

import cv2

cap = cv2.VideoCapture(0)

while(True):

# Capture frame-by-frame

ret, frame = cap.read()

# Our 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()

0x02. 寫入視訊

攝像頭錄制視訊

import cv2.cv as cv

capture=cv.CaptureFromCAM(0)

temp=cv.QueryFrame(capture)

writer=cv.CreateVideoWriter("output.avi", cv.CV_FOURCC("D", "I", "B", " "), 5, cv.GetSize(temp), 1)

#On linux I used to take "M","J","P","G" as fourcc

count=0

while count<50:

print count

image=cv.QueryFrame(capture)

cv.WriteFrame(writer, image)

cv.ShowImage('Image_Window',image)

cv.WaitKey(1)

count+=1

從檔案中讀取視訊并儲存

import cv2.cv as cv

capture = cv.CaptureFromFile('img/mic.avi')

nbFrames = int(cv.GetCaptureProperty(capture, cv.CV_CAP_PROP_FRAME_COUNT))

width = int(cv.GetCaptureProperty(capture, cv.CV_CAP_PROP_FRAME_WIDTH))

height = int(cv.GetCaptureProperty(capture, cv.CV_CAP_PROP_FRAME_HEIGHT))

fps = cv.GetCaptureProperty(capture, cv.CV_CAP_PROP_FPS)

codec = cv.GetCaptureProperty(capture, cv.CV_CAP_PROP_FOURCC)

wait = int(1/fps * 1000/1) #Compute the time to wait between each frame query

duration = (nbFrames * fps) / 1000 #Compute duration

print 'Num. Frames = ', nbFrames

print 'Frame Rate = ', fps, 'fps'

writer=cv.CreateVideoWriter("img/new.avi", int(codec), int(fps), (width,height), 1) #Create writer with same parameters

cv.SetCaptureProperty(capture, cv.CV_CAP_PROP_POS_FRAMES,80) #Set the number of frames

for f in xrange( nbFrames - 80 ): #Just recorded the 80 first frames of the video

frame = cv.QueryFrame(capture)

print cv.GetCaptureProperty(capture, cv.CV_CAP_PROP_POS_FRAMES)

cv.WriteFrame(writer, frame)

cv.WaitKey(wait)

cv2

import numpy as np

import cv2

cap = cv2.VideoCapture(0)

# Define the codec and create VideoWriter object

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,0)

# 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()