import time import av import cv2 import numpy as np import requests import base64 from requests_toolbelt.multipart.encoder import MultipartEncoder from zoneinfo import ZoneInfo from datetime import datetime from threading import Lock, Thread, Event DEBUG = False class FrameCapturer: def __init__( self, hls_url, cctv_name, lat, lon, interval=5, buffer_duration=15, buffer_size=600, time_zone="Asia/Seoul", endpoint="http://localhost:12345/cctv/infer" ): ''' :param hls_url: hls address :param cctv_name: CCTV_name gathered from ITS api :param interval: interval of sampling in seconds :param buffer_duration: video buffer, 15 seconds is default for ITS HLS video streaming :param time_zone: default Asia/Seoul :param endpoint: API endpoint ''' self.hls_url = hls_url self.interval = interval self.buffer_duration = buffer_duration self.buffer_size = buffer_size self.frame_buffer = [] self.current_frame = [] self.frame_buffer_lock = Lock() # for no memory sharing between receive_stream_packet and process_frames self.captured_frame_count = 0 self.last_capture_time = 0 self.start_time = time.time() self.stop_event = Event() self.input_stream = av.open(self.hls_url) self.video_stream = next(s for s in self.input_stream.streams if s.type == 'video') self.fps = self.video_stream.guessed_rate.numerator self.capture_interval = 1 / self.fps print(cctv_name) self.cctvid = cctv_name self.time_zone = ZoneInfo(time_zone) self.endpoint = endpoint self.lat = lat self.lon = lon def __call__(self, *args, **kwargs): return self.current_frame # ```receive_stream_packet``` and ```process_frames``` work asynchronously (called with Thread) # so that it always run as intended (for every '''interval''' sec, send a photo) # regardless of how you buffer frames as long as there are enough buffer. # They are triggered by ```start``` and halts by ```stop``` def receive_stream_packet(self): for packet in self.input_stream.demux(self.video_stream): for frame in packet.decode(): with self.frame_buffer_lock: self.frame_buffer.append(frame) time.sleep(self.capture_interval) #TODO Although there is no problems with how it works and how it was intended, because there seems to be an # unexpected behaivor on "if current_time - self.start_time >= self.buffer_duration:" line, # more inspection should be done def process_frames(self): while not self.stop_event.is_set(): current_time = time.time() if current_time - self.start_time >= self.buffer_duration: if self.last_capture_time == 0 or current_time - self.last_capture_time >= self.interval: with self.frame_buffer_lock: if self.frame_buffer: if len(self.frame_buffer) > self.buffer_size: self.frame_buffer = self.frame_buffer[-self.buffer_size:] buffered_frame = self.frame_buffer[-1] # print(len(self.frame_buffer)) self.current_frame = buffered_frame.to_image() self.current_frame = cv2.cvtColor(np.array(self.current_frame), cv2.COLOR_RGB2BGR) frame_name = f"captured_frame_{self.cctvid}_{self.captured_frame_count}.png" img_binary = cv2.imencode('.png', self.current_frame) img_binary = img_binary[1].tobytes() self.send_image_to_server(img_binary) if DEBUG: cv2.imwrite( f'hls_streaming/captured_frame_/{self.cctvid}_{datetime.now()}_{frame_name}', self.current_frame) self.last_capture_time = current_time # print(f"Captured {frame_name} of {self.cctvid} at time: {current_time - self.start_time:.2f}s") self.captured_frame_count += 1 time.sleep(0.1) def send_image_to_server(self, image, image_type="png"): time_sent = datetime.now(self.time_zone).strftime("yyyy-MM-dd'T'HH:mm:ss'Z'") header = { 'Content-Type': f'image/{image_type}', 'x-time-sent': time_sent, # Why are you encoding string? because post method has a problem with sending non-english chars. # (It defaults to latin-1 encoding and not straight forward to change) 'x-cctv-name': base64.b64encode(str(self.cctvid).encode('utf-8')).decode('ascii'), 'x-cctv-latitude': str(self.lat), 'x-cctv-longitude': str(self.lon), } session = requests.Session() try: multipart_data = MultipartEncoder( fields={ 'file': (f'frame_{self.cctvid}.{image_type}', image, f'image/{image_type}') } ) header["Content-Type"] = multipart_data.content_type response = session.post(self.endpoint, headers=header, data=multipart_data) except Exception as e: print(e) print("Can not connect to the analyzer server. Check the endpoint address or connection.\n" f"Can not connect to : {self.endpoint}") def start(self): self.receive_stream_packet = Thread(target=self.receive_stream_packet) self.process_thread = Thread(target=self.process_frames) self.receive_stream_packet.start() self.process_thread.start() def stop(self): self.stop_event.set() self.receive_stream_packet.join() self.process_thread.join() self.input_stream.close() # Example usage if __name__ == "__main__": capturer = FrameCapturer( 'http://cctvsec.ktict.co.kr/5545/LFkDslDT81tcSYh3G4306+mcGlLb3yShF9rx2vcPfltwUL4+I950kcBlD15uWm6K0cKCtAMlxsIptMkCDo5lGQiLlARP+SyUloz8vIMNB18=', "[국도] 테해란로", 10, 5 ) t1 = time.time() try: capturer.start() time.sleep(600000) finally: capturer.stop() del capturer t2 = time.time() with open("result.txt", "w") as file: file.write(f'{t2 - t1} seconds before terminating') exit()