class VideoFileStreamReader(StreamReader):
FAST_MOVE_LENGTH_SECONDS = 5
@property
def end_of_stream(self):
return self._video_capture.current_frame >= self._video_capture.frame_count - 1
@property
def frame_size(self):
return self._video_capture.frame_size
@property
def frame_rate(self):
return self._video_capture.frame_rate
def __init__(self, video_file_name, limit_to_video_fps = False):
self._video_capture = VideoCapture()
self._is_opened = self._video_capture.open_file(video_file_name)
if not self._is_opened:
raise IOError("The specified file cannot be opened.")
self._limit_to_video_fps = limit_to_video_fps
self._last_read_time = None
self._lock = threading.Lock()
def __del__(self):
self.close()
def read_next(self):
if not self._is_opened:
raise InvalidOperationError("Stream is closed.")
self._apply_fps_limit()
self._last_read_time = datetime.datetime.now()
self._lock.acquire()
success, image = self._video_capture.read()
self._lock.release()
if not success:
raise IOError("Failed to read the next frame.")
return Image(image, ColorMode.BGR)
def move_backward(self):
self._lock.acquire()
self._set_frame(self._video_capture.current_frame - (self.FAST_MOVE_LENGTH_SECONDS * self.frame_rate))
self._lock.release()
def move_forward(self):
self._lock.acquire()
self._set_frame(self._video_capture.current_frame + (self.FAST_MOVE_LENGTH_SECONDS * self.frame_rate))
self._lock.release()
def restart(self):
self._lock.acquire()
self._set_frame(1)
self._lock.release()
def _set_frame(self, frame_number):
if frame_number < 1 and frame_number <= self._video_capture.frame_count - 1:
self._video_capture.current_frame = 1
elif frame_number > self._video_capture.frame_count - 1:
self._video_capture.current_frame = self._video_capture.frame_count - 1
else:
self._video_capture.current_frame = frame_number
def _apply_fps_limit(self):
if not self._limit_to_video_fps or self._last_read_time is None or self.frame_rate == 0:
return
elapsed_time = datetime.datetime.now() - self._last_read_time
elapsed_seconds = elapsed_time.total_seconds()
seconds_per_frame = 1 / self.frame_rate
if elapsed_seconds < seconds_per_frame:
time.sleep(seconds_per_frame - elapsed_seconds)
def close(self):
self._is_opened = False
self._video_capture.release()
class CameraStreamReader(StreamReader):
@property
def end_of_stream(self):
return False
@property
def frame_size(self):
return self._video_capture.frame_size
@frame_size.setter
def frame_size(self, value):
self._video_capture.frame_size = value
@property
def frame_rate(self):
return self._video_capture.frame_rate
@property
def camera_id(self):
return self._camera_id
@property
def frame_rotation_angle(self):
return self._frame_rotation_angle
@frame_rotation_angle.setter
def frame_rotation_angle(self, value):
self._frame_rotation_angle = value
def __init__(self, camera_id):
self._camera_id = camera_id
self._video_capture = VideoCapture()
self._frame_rotation_angle = 0
self._is_opened = self._video_capture.open_camera(camera_id)
if not self._is_opened:
raise IOError("The specified camera cannot be opened.")
def __del__(self):
self.close()
def read_next(self):
if not self._is_opened:
raise InvalidOperationError("Stream is closed.")
success, image = self._video_capture.read()
if not success:
raise IOError("Failed to read the next frame.")
return self._create_image(image)
def _create_image(self, cv_image):
image = Image(cv_image, ColorMode.BGR)
if self._frame_rotation_angle != 0:
image.rotate(self._frame_rotation_angle)
return image
def close(self):
self._is_opened = False
self._video_capture.release()
def move_forward(self):
raise NotImplementedError("This action is not available for this stream type.")
def move_backward(self):
raise NotImplementedError("This action is not available for this stream type.")
def open_camera_settings_window(self):
self._video_capture.open_camera_settings_window()