每 10 秒后从视频文件中捕获一帧

Question

我想每 10 秒后从视频文件中捕获一帧，所以如果有人可以帮助我，我将非常感激。我的python代码是这样的：

import cv2


print(cv2.__version__)
vidcap = cv2.VideoCapture('Standoff.avi')
vidcap.set(cv2.CAP_PROP_POS_MSEC,96000)  
success,image = vidcap.read()
count = 0
success = True
while success:
  success,image = vidcap.read()
  print 'Read a new frame: ', success
  cv2.imwrite("frame%d.jpg" % count, image)     # save frame as JPEG file
  cv2.waitKey(200)
  count += 1

Answer 1

在这里，我在 10 帧转换后捕获帧。您可以使用时间函数并在 if 条件语句中类似地捕获帧

import cv2

vidcap = cv2.VideoCapture('testing.mp4')
count = 0
success = True
fps = int(vidcap.get(cv2.CAP_PROP_FPS))

while success:
    success,image = vidcap.read()
    print('read a new frame:',success)
    if count%(10*fps) == 0 :
         cv2.imwrite('frame%d.jpg'%count,image)
         print('successfully written 10th frame')
    count+=1

Answer 2

如果您可以从文件中获取视频的帧率，则以下内容应该可以工作（您可能需要检查语法，因为我尚未对其进行测试）：

import cv2

cap = cv2.VideoCapture('Standoff.avi')
framerate = cap.get(cv2.cv.CV_CAP_PROP_FPS)
framecount = 0

while(True):
    # Capture frame-by-frame
    success, image = cap.read()
    framecount += 1

    # Check if this is the frame closest to 10 seconds
    if framecount == (framerate * 10)
      framecount = 0
      cv2.imshow('image',image)

    # Check end of video
    if cv2.waitKey(1) & 0xFF == ord('q'):
          break

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