#-*- coding: utf-8 -*-

importosimport 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

ifonly_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 notNone: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)exceptOSError:passsuccess=True

count=0while success and count

cap.set(cv2.CAP_PROP_POS_MSEC, (1000*extract_time_points[count]))

success,image=cap.read()ifsuccess:if notisColor:

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 notNone: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)exceptOSError:pass

print('Converting a video into frames......')if end_extract_time is notNone:

N= (end_extract_time - initial_extract_time)*fps + 1success=True

count=0while success and count

success,image=cap.read()ifsuccess:if notisColor:

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=0whilesuccess:

success,image=cap.read()ifsuccess:if notisColor:

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)exceptOSError:pass

print('Converting a video into frames......')if end_extract_time is notNone:

N= (end_extract_time - initial_extract_time)/extract_time_interval + 1success=True

count=0while success and count

cap.set(cv2.CAP_PROP_POS_MSEC, (1000*initial_extract_time+count*1000*extract_time_interval))

success,image=cap.read()ifsuccess:if notisColor:

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=0whilesuccess:

cap.set(cv2.CAP_PROP_POS_MSEC, (1000*initial_extract_time+count*1000*extract_time_interval))

success,image=cap.read()ifsuccess:if notisColor:

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

pathIn = 'test.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)