python - 如何以特定 FPS 从视频中提取帧？

Question

我可以test.mp4使用以下代码提取某个文件的帧：

import cv2
def get_frames():
    cap = cv2.VideoCapture('test.mp4')
    i = 0
    while cap.isOpened():
        ret, frame = cap.read()
        if not ret:
            break
        cv2.imwrite('test_'+str(i)+'.jpg', frame)
        i += 1

    cap.release()
    cv2.destroyAllWindows()

提取的许多帧都是无用的（它们几乎相同）。我需要能够设置可以完成帧提取的特定速率。

标签： pythonopencv

Answer 1

我认为您只需要根据固定周期跳过帧即可。

import cv2

def get_frames():
    cap = cv2.VideoCapture('test.mp4')
    i = 0
    # a variable to set how many frames you want to skip
    frame_skip = 10
    # a variable to keep track of the frame to be saved
    frame_count = 0
    while cap.isOpened():
        ret, frame = cap.read()
        if not ret:
            break
        if i > frame_skip - 1:
            frame_count += 1
            cv2.imwrite('test_'+str(frame_count*frame_skip)+'.jpg', frame)
            i = 0
            continue
        i += 1

    cap.release()
    cv2.destroyAllWindows()