thongtruongvietsol
commented
3 months ago class VideoPlayer: def init(self, source, size=None, flip=False, fps=None, skip_first_frames=0): import cv2
self.cv2 = cv2 # This is done to access the package in class methods
self.__cap = cv2.VideoCapture(source)
if not self.__cap.isOpened():
raise RuntimeError(f"Cannot open {'camera' if isinstance(source, int) else ''} {source}")
# skip first N frames
self.__cap.set(cv2.CAP_PROP_POS_FRAMES, skip_first_frames)
# fps of input file
self.__input_fps = self.__cap.get(cv2.CAP_PROP_FPS)
if self.__input_fps <= 0:
self.__input_fps = 60
# target fps given by user
self.__output_fps = fps if fps is not None else self.__input_fps
self.__flip = flip
self.__size = None
self.__interpolation = None
if size is not None:
self.__size = size
# AREA better for shrinking, LINEAR better for enlarging
self.__interpolation = cv2.INTER_AREA if size[0] < self.__cap.get(cv2.CAP_PROP_FRAME_WIDTH) else cv2.INTER_LINEAR
# first frame
_, self.__frame = self.__cap.read()
self.__lock = threading.Lock()
self.__thread = None
self.__stop = False
"""
Start playing.
"""
def start(self):
self.__stop = False
self.__thread = threading.Thread(target=self.__run, daemon=True)
self.__thread.start()
"""
Stop playing and release resources.
"""
def stop(self):
self.__stop = True
if self.__thread is not None:
self.__thread.join()
self.__cap.release()
def __run(self):
prev_time = 0
while not self.__stop:
t1 = time.time()
ret, frame = self.__cap.read()
if not ret:
break
# fulfill target fps
if 1 / self.__output_fps < time.time() - prev_time:
prev_time = time.time()
# replace by current frame
with self.__lock:
self.__frame = frame
t2 = time.time()
# time to wait [s] to fulfill input fps
wait_time = 1 / self.__input_fps - (t2 - t1)
# wait until
time.sleep(max(0, wait_time))
self.__frame = None
"""
Get current frame.
"""
def next(self):
import cv2
with self.__lock:
if self.__frame is None:
return None
# need to copy frame, because can be cached and reused if fps is low
frame = self.__frame.copy()
if self.__size is not None:
frame = self.cv2.resize(frame, self.__size, interpolation=self.__interpolation)
if self.__flip:
frame = self.cv2.flip(frame, 1)
return frame
class VideoPlayer: