opencv将视频转成图片

傷城~ 2021-10-18 10:32 514阅读 0赞

最近在做图像处理与深度学习的实践，获得了视频数据，我要将它每隔几帧提取一张图片，然后对图片进行标注，下面分享一下视频提取图片的代码，使用python。

import os
    import cv2
    
    videos_src_path = "./video/"
    # video_formats = [".MP4", ".MOV"]          我的数据集都是.mp4所以不需要进行分类判断
    frames_save_path = "./image/"
    width = 2048
    height = 1536
    time_interval = 5
    
    
    def list_all_files(rootdir):
        import os
        _files = []
        list = os.listdir(rootdir) #列出文件夹下所有的目录与文件
        for i in range(0,len(list)):
               path = os.path.join(rootdir,list[i])
               if os.path.isdir(path):
                  _files.extend(list_all_files(path))
               if os.path.isfile(path):
                  _files.append(path)
        return _files
    
    def video2frame(video_src_path, frame_save_path, frame_width, frame_height, interval):
        """
        将视频按固定间隔读取写入图片
        :param video_src_path: 视频存放路径
        :param formats:　包含的所有视频格式
        :param frame_save_path:　保存路径
        :param frame_width:　保存帧宽
        :param frame_height:　保存帧高
        :param interval:　保存帧间隔
        :return:　帧图片
        """
    
        all_video = list_all_files(videos_src_path)
    
        videos = all_video
        # videos = os.listdir(video_src_path)
    
        # def filter_format(x, all_formats):      无需判断所以这部分代码也就不需要了
        #     if x[-4:] in all_formats:
        #         return True
        #     else:
        #         return False
        #
        # videos = filter(lambda x: filter_format(x, formats), videos)
    
        for each_video in videos:
            # print "正在读取视频：", each_video
    
            if each_video[-4:].lower() != '.mp4':
                print(each_video, "不是视频， 跳过")
                continue
            each_video = each_video[len(videos_src_path):]
            print("正在读取视频：", each_video)    # 我的是Python3.6
    
    
    
            each_video_name = each_video[:-4]
            # print('dir:', frame_save_path + each_video_name)
            # return
            if not os.path.exists(frame_save_path + each_video_name):
                os.makedirs(frame_save_path + each_video_name)
            each_video_save_full_path = os.path.join(frame_save_path, each_video_name) + "/"
    
    
            each_video_full_path = os.path.join(video_src_path, each_video)
    
            cap = cv2.VideoCapture(each_video_full_path)
            frame_index = 0
            frame_count = 0
            if cap.isOpened():
                success = True
            else:
                success = False
                print("读取失败!")
    
            while(success):
                success, frame = cap.read()
               # print "---> 正在读取第%d帧:" % frame_index, success
                # print("---> 正在读取第%d帧:" % frame_index, success)      # 我的是Python3.6
    
                if frame_index % interval == 0 and success:     # 如路径下有多个视频文件时视频最后一帧报错因此条件语句中加and success
                    resize_frame = cv2.resize(frame, (frame_width, frame_height), interpolation=cv2.INTER_AREA)
                    # cv2.imwrite(each_video_save_full_path + each_video_name + "_%d.jpg" % frame_index, resize_frame)
                    cv2.imwrite(each_video_save_full_path + "%d.jpg" % frame_count, resize_frame)
                    frame_count += 1
    
                frame_index += 1
    
            cap.release()		# 这行要缩一下(全局变量与局部变量)
    
    def main():
        # all_video = list_all_files(videos_src_path)
        # print(all_video)
        video2frame(videos_src_path, frames_save_path, width, height, time_interval)
    
    if __name__ == '__main__':
        main()