import os import cv2 ##加载OpenCV模块 def video2frames(pathIn='', pathOut='', only_output_video_info=False, extract_time_points=None, initial_extract_time=0, end_extract_time=None, extract_time_interval=-1, output_prefix='frame', jpg_quality=100, isColor=True): ''' pathIn:视频的路径,比如:F:\python_tutorials\test.mp4 pathOut: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 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: pass success = True count = 0 while 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, "{}_{:06d}.jpg".format(output_prefix, count + 1)), image, [int(cv2.IMWRITE_JPEG_QUALITY), jpg_quality]) # save frame as JPEG file count = count + 1 else: ##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: pass print('Converting a video into frames......') if end_extract_time is not None: N = (end_extract_time - initial_extract_time) * fps + 1 success = True count = 0 while 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, "{}_{:06d}.jpg".format(output_prefix, count + 1)), image, [int(cv2.IMWRITE_JPEG_QUALITY), jpg_quality]) # save frame as JPEG file count = count + 1 else: success = True count = 0 while 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, "{}_{:06d}.jpg".format(output_prefix, count + 1)), image, [int(cv2.IMWRITE_JPEG_QUALITY), jpg_quality]) # save frame as JPEG file count = 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: pass print('Converting a video into frames......') if end_extract_time is not None: N = (end_extract_time - initial_extract_time) / extract_time_interval + 1 success = True count = 0 while 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, "{}_{:06d}.jpg".format(output_prefix, count + 1)), image, [int(cv2.IMWRITE_JPEG_QUALITY), jpg_quality]) # save frame as JPEG file count = count + 1 else: success = True count = 0 while 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, "{}_{:06d}.jpg".format(output_prefix, count + 1)), image, [int(cv2.IMWRITE_JPEG_QUALITY), jpg_quality]) # save frame as JPEG file count = count + 1 ##### 测试 # import cv2 as cv # cap = cv.VideoCapture("H:\pyImage\cs.mp4") pathIn = 'H:\pyImage\cs.mp4' video2frames(pathIn, only_output_video_info=True) pathOut = './frames1/' video2frames(pathIn, pathOut) pathOut = './frames2' video2frames(pathIn, pathOut, extract_time_points=(1, 2, 5)) pathOut = './frames3' video2frames(pathIn, pathOut, initial_extract_time=1, end_extract_time=3, extract_time_interval=0.5) pathOut = './frames4/' video2frames(pathIn, pathOut, extract_time_points=(0.3, 2), isColor=False) pathOut = './frames5/' video2frames(pathIn, pathOut, extract_time_points=(0.3, 2), jpg_quality=50)