提取关键帧| Python | Opencv的

Question

我目前正在从视频中提取关键帧。

代码：

while success:
    success, currentFrame = vidcap.read()
    isDuplicate = False
    limit = count if count <= 10  else (count - 10)
    for img in xrange(limit, count):
        previusFrame = cv2.imread("%sframe-%d.png" % (outputDir, img))
        try:
            difference = cv2.subtract(currentFrame, previusFrame)
        except:
            pass

这给了我很多相框。预期输出：计算帧之间的像素差异，然后将其与阈值进行比较并存储唯一的关键帧。

首次处理视频。请指导如何实现预期的输出

Answer 1

这是一个使用ffprobe和OpenCV提取I帧的脚本：

import os
import cv2
import subprocess

filename = '/home/andriy/Downloads/video.mp4'

def get_frame_types(video_fn):
    command = 'ffprobe -v error -show_entries frame=pict_type -of default=noprint_wrappers=1'.split()
    out = subprocess.check_output(command + [video_fn]).decode()
    frame_types = out.replace('pict_type=','').split()
    return zip(range(len(frame_types)), frame_types)

def save_i_keyframes(video_fn):
    frame_types = get_frame_types(video_fn)
    i_frames = [x[0] for x in frame_types if x[1]=='I']
    if i_frames:
        basename = os.path.splitext(os.path.basename(video_fn))[0]
        cap = cv2.VideoCapture(video_fn)
        for frame_no in i_frames:
            cap.set(cv2.CAP_PROP_POS_FRAMES, frame_no)
            ret, frame = cap.read()
            outname = basename+'_i_frame_'+str(frame_no)+'.jpg'
            cv2.imwrite(outname, frame)
            print ('Saved: '+outname)
        cap.release()
    else:
        print ('No I-frames in '+video_fn)

if __name__ == '__main__':
    save_i_keyframes(filename)

如果需要提取P帧'I'，'P'则可以更改为。