Python cv2.CAP_PROP_POS_MSEC Examples

def extract_features(video_input_file_path, feature_output_file_path):
    if os.path.exists(feature_output_file_path):
        return np.load(feature_output_file_path)
    count = 0
    print('Extracting frames from video: ', video_input_file_path)
    vidcap = cv2.VideoCapture(video_input_file_path)
    success, image = vidcap.read()
    features = []
    success = True
    while success:
        vidcap.set(cv2.CAP_PROP_POS_MSEC, (count * 1000))  # added this line
        success, image = vidcap.read()
        # print('Read a new frame: ', success)
        if success:
            img = cv2.resize(image, (40, 40), interpolation=cv2.INTER_AREA)
            features.append(image)
            count = count + 1
    unscaled_features = np.array(features)
    print(unscaled_features.shape)
    np.save(feature_output_file_path, unscaled_features)
    return unscaled_features 

def get_video_frames(video_path, frames_path, start_time_ms, stop_time_ms, pace):
    try:
        cap = cv2.VideoCapture(video_path)
        # Set start position
        cap.set(cv2.CAP_PROP_POS_MSEC, start_time_ms)

        fps = cap.get(cv2.CAP_PROP_FPS)

        # If stop_time_ms == 0, get the entire video
        if stop_time_ms == 0:
            frame_count = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
            stop_time_ms = int(frame_count/fps)*1000

        # If pace == 0, get 1 image every FPS/10
        if pace == 0:
            pace = int(1000/(fps/10))

        frames_list = []
        ok = True
        current_frame = 1
        while ok and cap.get(cv2.CAP_PROP_POS_MSEC) <= stop_time_ms:
            ok, frame = cap.read()
            if not ok:
                break
            frame_path = '{}/frame_{:03}.jpg'.format(frames_path, current_frame)
            log.debug('Storing: {}'.format(frame_path))
            cv2.imwrite(frame_path, frame)
            frames_list.append(frame_path)
            current_frame += 1
            cap.set(cv2.CAP_PROP_POS_MSEC, cap.get(cv2.CAP_PROP_POS_MSEC) + pace)

        cap.release()
        cv2.destroyAllWindows()
        return True, frames_list
    except Exception as e:
        log.error(e)
        return False, [] 

def _read_frame_func(self):
        ret, frame = self.video_capture.read()
        if not ret:
            raise EOFError()

        if self.frame_skip_rt:
            systime_msec = self.get_tick()
            video_msec = self.video_capture.get(cv2.CAP_PROP_POS_MSEC)
            assert systime_msec >= 0

            skip = video_msec < systime_msec
            while skip:
                ret, frame_ = self.video_capture.read()

                if not ret:
                    break

                frame = frame_
                video_msec = self.video_capture.get(cv2.CAP_PROP_POS_MSEC)
                skip = video_msec < systime_msec

        return frame 

def extract_vgg16_features(model, video_input_file_path, feature_output_file_path):
    if os.path.exists(feature_output_file_path):
        return np.load(feature_output_file_path)
    count = 0
    print('Extracting frames from video: ', video_input_file_path)
    vidcap = cv2.VideoCapture(video_input_file_path)
    success, image = vidcap.read()
    features = []
    success = True
    while success:
        vidcap.set(cv2.CAP_PROP_POS_MSEC, (count * 1000))  # added this line
        success, image = vidcap.read()
        # print('Read a new frame: ', success)
        if success:
            img = cv2.resize(image, (224, 224), interpolation=cv2.INTER_AREA)
            input = img_to_array(img)
            input = np.expand_dims(input, axis=0)
            input = preprocess_input(input)
            feature = model.predict(input).ravel()
            features.append(feature)
            count = count + 1
    unscaled_features = np.array(features)
    np.save(feature_output_file_path, unscaled_features)
    return unscaled_features 

def _read_frame_func(self):
        ret, frame = self.video_capture.read()
        if not ret:
            raise EOFError()

        if self.frame_skip_rt:
            systime_msec = self.get_tick()
            video_msec = self.video_capture.get(cv2.CAP_PROP_POS_MSEC)
            assert systime_msec >= 0

            skip = video_msec < systime_msec
            while skip:
                ret, frame_ = self.video_capture.read()

                if not ret:
                    break

                frame = frame_
                video_msec = self.video_capture.get(cv2.CAP_PROP_POS_MSEC)
                skip = video_msec < systime_msec

        return frame

    # override 

def extract_vgg16_features_live(model, video_input_file_path):
    print('Extracting frames from video: ', video_input_file_path)
    vidcap = cv2.VideoCapture(video_input_file_path)
    success, image = vidcap.read()
    features = []
    success = True
    count = 0
    while success:
        vidcap.set(cv2.CAP_PROP_POS_MSEC, (count * 1000))  # added this line
        success, image = vidcap.read()
        # print('Read a new frame: ', success)
        if success:
            img = cv2.resize(image, (224, 224), interpolation=cv2.INTER_AREA)
            input = img_to_array(img)
            input = np.expand_dims(input, axis=0)
            input = preprocess_input(input)
            feature = model.predict(input).ravel()
            features.append(feature)
            count = count + 1
    unscaled_features = np.array(features)
    return unscaled_features 

def main():
    for video in glob.glob(VIDEO_FOLDER + "/*"):
        if ".srt" in video:
            continue
        print(video)
        video_name = os.path.splitext(os.path.basename(video))[0]

        cap = cv2.VideoCapture(video)
        max_frames = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
        cap.set(cv2.CAP_PROP_POS_FRAMES, max_frames // 4)

        srt_subtitle = parse_subtitle(os.path.join(VIDEO_FOLDER, video_name + ".srt"))
        if srt_subtitle:
            cap.set(cv2.CAP_PROP_POS_MSEC, srt_subtitle[0][0])

        pos_frame = 0
        i = 0
        pos_subtitle = 0
        while pos_frame < max_frames and i < MAX_IMAGES_PER_VIDEO:
            pos_frame = int(cap.get(cv2.CAP_PROP_POS_FRAMES))
            msec = cap.get(cv2.CAP_PROP_POS_MSEC)
            print("{}/{}".format(i + 1, MAX_IMAGES_PER_VIDEO), end="\r")
            _, frame = cap.read()

            if pos_frame % SKIP_FRAMES > 0:
                continue

            if not srt_subtitle or (msec >= srt_subtitle[pos_subtitle][0] and msec <= srt_subtitle[pos_subtitle][1]):
                cv2.imwrite(os.path.join(IMAGE_FOLDER, "{}_{}.jpg").format(video_name, pos_frame), frame)
                i += 1
            elif msec > srt_subtitle[pos_subtitle][1]:
                pos_subtitle += 1
                if pos_subtitle >= len(srt_subtitle):
                    break
                cap.set(cv2.CAP_PROP_POS_MSEC, srt_subtitle[pos_subtitle][0]) 

def current_time(self):
        return self.get(cv2.CAP_PROP_POS_MSEC) 

def extract_videos_for_conv2d(video_input_file_path, feature_output_file_path, max_frames):
    if feature_output_file_path is not None:
        if os.path.exists(feature_output_file_path):
            return np.load(feature_output_file_path)
    count = 0
    print('Extracting frames from video: ', video_input_file_path)
    vidcap = cv2.VideoCapture(video_input_file_path)
    success, image = vidcap.read()
    features = []
    success = True
    while success and count < max_frames:
        vidcap.set(cv2.CAP_PROP_POS_MSEC, (count * 1000))  # added this line
        success, image = vidcap.read()
        # print('Read a new frame: ', success)
        if success:
            image = cv2.resize(image, (240, 240), interpolation=cv2.INTER_AREA)
            channels = image.shape[2]
            for channel in range(channels):
                features.append(image[:, :, channel])
            count = count + 1
    unscaled_features = np.array(features)
    unscaled_features = np.transpose(unscaled_features, axes=(1, 2, 0))
    print(unscaled_features.shape)
    if feature_output_file_path is not None:
        np.save(feature_output_file_path, unscaled_features)
    return unscaled_features 

def extract_images(video_input_file_path, image_output_dir_path):
    if os.path.exists(image_output_dir_path):
        return
    count = 0
    print('Extracting frames from video: ', video_input_file_path)
    vidcap = cv2.VideoCapture(video_input_file_path)
    success, image = vidcap.read()
    success = True
    while success:
        vidcap.set(cv2.CAP_PROP_POS_MSEC, (count * 1000))  # added this line
        success, image = vidcap.read()
        # print('Read a new frame: ', success)
        if success:
            cv2.imwrite(image_output_dir_path + os.path.sep + "frame%d.jpg" % count, image)  # save frame as JPEG file
            count = count + 1 

def timestamps_sec(self):
        """ Get timestamp of each frame from video file """
        cap = cv2.VideoCapture(self.path_video)
        ret = True
        t = []
        while cap.isOpened() and ret:
            # Capture frame-by-frames
            t.append(cap.get(cv2.CAP_PROP_POS_MSEC) / 1000.)
            ret = cap.grab()
        # When everything done, release the capture
        cap.release()
        return t 

def getImage(self, frame_id):
        # retrieve the first image if its id is > 0 
        if self.is_init is False and frame_id > 0:
            self.is_init = True 
            self.cap.set(cv2.CAP_PROP_POS_FRAMES, frame_id)
        self.is_init = True
        ret, image = self.cap.read()
        #self._timestamp = time.time()  # rough timestamp if nothing else is available 
        self._timestamp = float(self.cap.get(cv2.CAP_PROP_POS_MSEC)*1000)
        self._next_timestamp = self._timestamp + self.Ts 
        if ret is False:
            print('ERROR while reading from file: ', self.filename)
        return image 

def jump(self, frame=None, ms=None):
        assert frame is not ms, "Use either frame or ms, not both!"
        if frame:
            if frame >= self.frames:
                raise ReadFrameException('Cannot jump to frame (frame does not exists)')
            self.vid.set(cv2.CAP_PROP_POS_FRAMES, frame)
        if ms:
            self.vid.set(cv2.CAP_PROP_POS_MSEC, ms)
        # print("jumped to frame %i" % self.vid.get(cv2.CAP_PROP_POS_FRAMES)) 

def extract_frame_cv2(cls, video_file):
        try:
            vidcap = cv2.VideoCapture(video_file)
            vidcap.set(cv2.CAP_PROP_POS_MSEC, 2000)  # just cue to 20 sec. position
            success, image = vidcap.read()
            if success:
                image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
                return image
        except:
            return None 

def get_current_frame_time(video_cap: cv2.VideoCapture) -> float:
    # same as get_current_frame_id, take good care of them
    return video_cap.get(cv2.CAP_PROP_POS_MSEC) / 1000 

def frame_iterator(filename, every_ms=1000, max_num_frames=300):
  """Uses OpenCV to iterate over all frames of filename at a given frequency.

  Args:
    filename: Path to video file (e.g. mp4)
    every_ms: The duration (in milliseconds) to skip between frames.
    max_num_frames: Maximum number of frames to process, taken from the
      beginning of the video.

  Yields:
    RGB frame with shape (image height, image width, channels)
  """
  video_capture = cv2.VideoCapture()
  if not video_capture.open(filename):
    print >> sys.stderr, 'Error: Cannot open video file ' + filename
    return
  last_ts = -99999  # The timestamp of last retrieved frame.
  num_retrieved = 0

  while num_retrieved < max_num_frames:
    # Skip frames
    while video_capture.get(CAP_PROP_POS_MSEC) < every_ms + last_ts:
      if not video_capture.read()[0]:
        return

    last_ts = video_capture.get(CAP_PROP_POS_MSEC)
    has_frames, frame = video_capture.read()
    if not has_frames:
      break
    yield frame
    num_retrieved += 1 

def _time_stamp(self):
        if self._use_wall_clock:
            now = time.time()
            return now - self._start_time
        time_s = self.capture.get(CAP_PROP_POS_MSEC) / 1e3
        return time_s 

def run(self):
        idx_frame = 0
        pbar = tqdm(total=self.total_frames + 1)
        while self.vdo.grab():
            if idx_frame % args.frame_interval == 0:
                _, ori_im = self.vdo.retrieve()
                timestamp = self.vdo.get(cv2.CAP_PROP_POS_MSEC)
                frame_id = int(self.vdo.get(cv2.CAP_PROP_POS_FRAMES))
                self.logger.add_frame(frame_id=frame_id, timestamp=timestamp)
                self.detection(frame=ori_im, frame_id=frame_id)
                self.save_frame(ori_im)
                idx_frame += 1
            pbar.update()
        self.logger.json_output(self.json_output) 

def split_visual(self,visual_video, fps, fps_ratio, output_folder='visual_frames'):
        '''
        Splits video into frames based on the actual fps, and time between frames of the thermal sequence.
        There is a sync issue where the thermal fps, and visual fps don't have an integer LCM/if LCM is v large. Have to try motion interpolation to fix this
        '''

        output_folder = Path(output_folder)
        output_folder.mkdir(exist_ok=True)
        vid = cv.VideoCapture(visual_video)
        skip_frames = round(fps_ratio)
        total_frames = vid.get(cv.CAP_PROP_FRAME_COUNT)
        current_frame = 0
        thermal_fps = fps * (1/fps_ratio)
        thermal_time = 1/thermal_fps
        logger.info(f'Time between frames for Thermal SEQ: {thermal_time}')
        # Uncomment below lines if you need total time of visual video
        # vid.set(cv.CAP_PROP_POS_AVI_RATIO,1)
        # total_time = vid.get(cv.CAP_PROP_POS_MSEC)
        last_save_time = -1*thermal_time #So that it saves the 0th frame
        idx=0
        while current_frame < total_frames:
            current_frame = vid.get(cv.CAP_PROP_POS_FRAMES)  
            try:
                current_time = (1/fps)*current_frame
            except:
                current_time = 0
            ret,frame = vid.read()
            if ret:
                if (current_time - last_save_time)*1000 >= ((thermal_time*1000)-5):
                    # logger.info(f'Current Time: {current_time}  Last save time: {last_save_time}')
                    cv.imwrite(str(output_folder/f"{idx}.jpg"), frame)
                    idx+=1
                    last_save_time=current_time        
        return True 

def frame_iterator(filename, every_ms=1000, max_num_frames=300):
  """Uses OpenCV to iterate over all frames of filename at a given frequency.

  Args:
    filename: Path to video file (e.g. mp4)
    every_ms: The duration (in milliseconds) to skip between frames.
    max_num_frames: Maximum number of frames to process, taken from the
      beginning of the video.

  Yields:
    RGB frame with shape (image height, image width, channels)
  """
  video_capture = cv2.VideoCapture()
  if not video_capture.open(filename):
    print >> sys.stderr, 'Error: Cannot open video file ' + filename
    return
  last_ts = -99999  # The timestamp of last retrieved frame.
  num_retrieved = 0

  while num_retrieved < max_num_frames:
    # Skip frames
    while video_capture.get(CAP_PROP_POS_MSEC) < every_ms + last_ts:
      if not video_capture.read()[0]:
        return

    last_ts = video_capture.get(CAP_PROP_POS_MSEC)
    has_frames, frame = video_capture.read()
    if not has_frames:
      break
    yield frame
    num_retrieved += 1 

def set_pos_msec(self, pos_msec):
        """Moves the video position to |pos_msec| in msec."""
        if self.video_capture:
            self.video_capture.set(cv2.CAP_PROP_POS_MSEC, pos_msec)

    # override 

def _get_current_timestamp_func(self):
        if self.video_capture is None:
            return self.get_tick()

        video_msec = self.video_capture.get(cv2.CAP_PROP_POS_MSEC)
        return video_msec or self.get_tick()


    # override 

def _get_current_timestamp_func(self):
        video_msec = self.video_capture.get(cv2.CAP_PROP_POS_MSEC)

        if video_msec is None:
            return self.get_tick()

        return video_msec

    # override 

def get_frame():
    """
    Get a frame from a video file.

    :return: (ndarray, float) (Loaded frame, time in seconds).
    """
    global _CAP, _FPS

    to_return_frame = None

    if _CAP is None:
        print("Error on getting frame. cv2.VideoCapture is not initialized.")
    else:
        try:
            if _CAP.isOpened():
                # Skip frames
                for i in range(int(_MAX_FPS / _FPS)):
                    _CAP.grab()

                is_valid_frame, to_return_frame = _CAP.retrieve()

                if not is_valid_frame:
                    to_return_frame = None
        except Exception as e:
            print("Error on getting a frame. Please, double-check if the video file is not corrupted.")
            print("Supported file format: MPEG-4 (*.mp4).")
            print("Check whether working versions of ffmpeg or gstreamer is installed.")
            raise e

    return to_return_frame, (_CAP.get(cv2.CAP_PROP_POS_MSEC) / 1000)