python 視頻轉換成圖片

import os
import cv2  ##加載OpenCV模塊


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：視頻的路徑，比如：F:\python_tutorials\test.mp4
    pathOut：設定提取的圖片保存在哪個文件夾下，比如：F:\python_tutorials\frames1\。如果該文件夾不存在，函數將自動創建它
    only_output_video_info：如果為True，只輸出視頻信息（長度、幀數和幀率），不提取圖片
    extract_time_points：提取的時間點，單位為秒，為元組數據，比如，(2, 3, 5)表示只提取視頻第2秒， 第3秒，第5秒圖片
    initial_extract_time：提取的起始時刻，單位為秒，默認為0（即從視頻最開始提取）
    end_extract_time：提取的終止時刻，單位為秒，默認為None（即視頻終點）
    extract_time_interval：提取的時間間隔，單位為秒，默認為-1（即輸出時間范圍內的所有幀）
    output_prefix：圖片的前綴名，默認為frame，圖片的名稱將為frame_000001.jpg、frame_000002.jpg、frame_000003.jpg......
    jpg_quality：設置圖片質量，范圍為0到100，默認為100（質量最佳）
    isColor：如果為False，輸出的將是黑白圖片
    '''

    cap = cv2.VideoCapture(pathIn)  ##打開視頻文件
    n_frames = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))  ##視頻的幀數
    fps = cap.get(cv2.CAP_PROP_FPS)  ##視頻的幀率
    dur = n_frames / fps  ##視頻的時間

    ##如果only_output_video_info=True, 只輸出視頻信息，不提取圖片
    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))

        ##提取特定時間點圖片
    elif extract_time_points is not None:
        if max(extract_time_points) > dur:  ##判斷時間點是否符合要求
            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)  ##轉化為黑白圖片
                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:
        ##判斷起始時間、終止時間參數是否符合要求
        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....')

        ##時間范圍內的每幀圖片都輸出
        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

        ##判斷提取時間間隔設置是否符合要求
        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....')

        ##時間范圍內每隔一段時間輸出一張圖片
        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


##### 測試
# 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)