import os
import cv2    ##加载OpenCV模块def video2frames(pathIn='', pathOut='', imgname='',only_output_video_info = False, extract_time_points = None, initial_extract_time = 0,end_extract_time = None,extract_time_interval = -1, output_prefix = 'img',jpg_quality = 100,isColor = True):'''pathIn：视频的路径，比如：F:\python_tutorials\test.mp4pathOut：设定提取的图片保存在哪个文件夹下，比如：F:\python_tutorials\frames1\。如果该文件夹不存在，函数将自动创建它only_output_video_info：如果为True，只输出视频信息（长度、帧数和帧率），不提取图片extract_time_points：提取的时间点，单位为秒，为元组数据，比如，(2, 3, 5)表示只提取视频第2秒， 第3秒，第5秒图片initial_extract_time：提取的起始时刻，单位为秒，默认为0（即从视频最开始提取）end_extract_time：提取的终止时刻，单位为秒，默认为None（即视频终点）extract_time_interval：提取的时间间隔，单位为秒，默认为-1（即输出时间范围内的所有帧）output_prefix：图片的前缀名，默认为frame，图片的名称将为frame_000001.jpg、frame_000002.jpg、frame_000003.jpg......jpg_quality：设置图片质量，范围为0到100，默认为100（质量最佳）isColor：如果为False，输出的将是黑白图片'''cap = cv2.VideoCapture(pathIn)  ##打开视频文件n_frames = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))  ##视频的帧数fps = cap.get(cv2.CAP_PROP_FPS)  ##视频的帧率print(fps)dur = n_frames/fps  ##视频的时间##如果only_output_video_info=True, 只输出视频信息，不提取图片if only_output_video_info:print('only output the video information (without extract frames)::::::')print("Duration of the video: {} seconds".format(dur))print("Number of frames: {}".format(n_frames))print("Frames per second (FPS): {}".format(fps)) ##提取特定时间点图片elif extract_time_points is not None:if max(extract_time_points) > dur:   ##判断时间点是否符合要求raise NameError('the max time point is larger than the video duration....')try:os.mkdir(pathOut)except OSError:passsuccess = Truecount = 0while success and count < len(extract_time_points):cap.set(cv2.CAP_PROP_POS_MSEC, (1000*extract_time_points[count])) success,image = cap.read()if success:if not isColor:image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)  ##转化为黑白图片print('Write a new frame: {}, {}th'.format(success, count+1))cv2.imwrite(os.path.join(pathOut, "{}_{}.jpg".format(output_prefix, imgname)), image, [int(cv2.IMWRITE_JPEG_QUALITY), jpg_quality])     # save frame as JPEG filecount = count + 1else:##判断起始时间、终止时间参数是否符合要求if initial_extract_time > dur:raise NameError('initial extract time is larger than the video duration....')if end_extract_time is not None:if end_extract_time > dur:raise NameError('end extract time is larger than the video duration....')if initial_extract_time > end_extract_time:raise NameError('end extract time is less than the initial extract time....')##时间范围内的每帧图片都输出if extract_time_interval == -1:if initial_extract_time > 0:cap.set(cv2.CAP_PROP_POS_MSEC, (1000*initial_extract_time)) try:os.mkdir(pathOut)except OSError:passprint('Converting a video into frames......')if end_extract_time is not None:N = (end_extract_time - initial_extract_time)*fps + 1success = Truecount = 0while success and count < N:success,image = cap.read()if success:if not isColor:image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)print('Write a new frame: {}, {}/{}'.format(success, count+1, n_frames))cv2.imwrite(os.path.join(pathOut, "{}_{}.jpg".format(output_prefix, imgname)), image, [int(cv2.IMWRITE_JPEG_QUALITY), jpg_quality])     # save frame as JPEG filecount =  count + 1else:success = Truecount = 0while success:success,image = cap.read()if success:if not isColor:image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)print('Write a new frame: {}, {}/{}'.format(success, count+1, n_frames))cv2.imwrite(os.path.join(pathOut, "{}_{}.jpg".format(output_prefix, imgname)), image, [int(cv2.IMWRITE_JPEG_QUALITY), jpg_quality])     # save frame as JPEG filecount =  count + 1##判断提取时间间隔设置是否符合要求    elif extract_time_interval > 0 and extract_time_interval < 1/fps:raise NameError('extract_time_interval is less than the frame time interval....')elif extract_time_interval > (n_frames/fps):raise NameError('extract_time_interval is larger than the duration of the video....')##时间范围内每隔一段时间输出一张图片else:try:os.mkdir(pathOut)except OSError:passprint('Converting a video into frames......')if end_extract_time is not None:N = (end_extract_time - initial_extract_time)/extract_time_interval + 1success = Truecount = 0while success and count < N:cap.set(cv2.CAP_PROP_POS_MSEC, (1000*initial_extract_time+count*1000*extract_time_interval)) success,image = cap.read()if success:if not isColor:image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)print('Write a new frame: {},{}th'.format(success, count+1))cv2.imwrite(os.path.join(pathOut, "{}_{}.jpg".format(output_prefix,imgname)), image, [int(cv2.IMWRITE_JPEG_QUALITY), jpg_quality])     # save frame as JPEG filecount = count + 1else:success = Truecount = 0while success:cap.set(cv2.CAP_PROP_POS_MSEC, (1000*initial_extract_time+count*1000*extract_time_interval)) success,image = cap.read()if success:if not isColor:image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)print('Write a new frame: {}, {}th'.format(success, count+1))cv2.imwrite(os.path.join(pathOut, "{}_{}.jpg".format(output_prefix, imgname)), image, [int(cv2.IMWRITE_JPEG_QUALITY), jpg_quality])     # save frame as JPEG filecount = count + 1if __name__ == "__main__":pathIn = 'C:/Users/Administrator/www/video_back/video_back/upload/1.mp4'pathOut = 'C:/Users/Administrator/www/video_back/video_back/upload/'imgname = 'dog'video2frames(pathIn,pathOut,imgname,extract_time_points=(1,))