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https://github.com/EyeTrackVR/EyeTrackVR.git
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fix: identify and mitigate latency issues
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parent
b3f444ee3a
commit
295f10476d
@ -18,6 +18,11 @@ class CameraState(Enum):
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DISCONNECTED = 2
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# Find JPEG frames based on start and end bytes.
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FRAME_JPEG_BEGIN = b'\xff\xd8'
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FRAME_JPEG_END = b'\xff\xd9'
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class Camera:
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def __init__(
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self,
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@ -43,7 +48,7 @@ class Camera:
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self.frame_number = 0
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self.fps = 0
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self.start = True
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self.serialByteBuffer = b''
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self.buffer = b''
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self.error_message = "\033[93m[WARN] Capture source {} not found, retrying...\033[0m"
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@ -120,43 +125,58 @@ class Camera:
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self.camera_status = CameraState.DISCONNECTED
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pass
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def get_next_frame_bounds(self):
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beg = -1
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end = -1
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# Initial read.
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self.buffer += self.serial_connection.read(4096)
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while beg == -1 or end == -1:
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# Find the jpeg begin bytes.
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if beg == -1:
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beg = self.buffer.find(FRAME_JPEG_BEGIN)
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continue
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# Discard any data before the jpeg frame.
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if beg > 0:
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self.buffer = self.buffer[beg:]
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beg = 0
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continue
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# Find the jpeg end bytes.
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end = self.buffer.find(FRAME_JPEG_END)
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# Read more data when no jpeg end bytes found.
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if end == -1:
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self.buffer += self.serial_connection.read(2048)
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return beg, end
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def get_next_jpeg_frame(self):
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beg, end = self.get_next_frame_bounds()
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# Extract jpeg from the buffer.
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jpeg = self.buffer[beg:end+2]
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# Remove jpeg from the buffer.
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self.buffer = self.buffer[end+2:]
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return jpeg
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def get_serial_camera_picture(self, should_push):
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start = time.time()
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try:
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bytes = self.serialByteBuffer
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if self.serial_connection.in_waiting:
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bytes += self.serial_connection.read(4096) # Read in initial bytes
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a = bytes.find(b'\xff\xd8') # Find start byte for jpeg image
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b = bytes.find(b'\xff\xd9') # Fine end byte for jpeg image
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# If the first found end byte is before the start byte, keep reading in serial
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# data and discarding the old data until the start byte is before the end byte
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while a > b:
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bytes = bytes[a:]
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a = bytes.find(b'\xff\xd8')
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b = bytes.find(b'\xff\xd9')
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if a == -1 or b == -1:
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bytes += self.serial_connection.read(2048)
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if a != -1 and b != -1: # If there is jpeg data
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jpg = bytes[a:b + 2] # Create the string of bytes for the current jpeg
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bytes = bytes[b + 2:] # Clear the buffer until the end of our current jpeg
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self.serialByteBuffer = bytes
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if jpg:
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# Create jpeg frame from byte string
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image = cv2.imdecode(np.fromstring(jpg, dtype=np.uint8), cv2.IMREAD_UNCHANGED)
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if image is None:
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print("image not found")
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return
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else:
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self.frame_number = self.frame_number + 1
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delta_time = time.time() - start
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if delta_time > 0:
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self.fps = 1 / delta_time
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if should_push:
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self.push_image_to_queue(image, self.frame_number, self.fps)
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jpeg = self.get_next_jpeg_frame()
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if jpeg:
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# Create jpeg frame from byte string
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image = cv2.imdecode(np.fromstring(jpeg, dtype=np.uint8), cv2.IMREAD_UNCHANGED)
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if image is None:
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print("image not found")
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return
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# Discard the serial buffer. This is due to the fact that it
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# may build up some outdated frames. A bit of a workaround here tbh.
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self.serial_connection.reset_input_buffer()
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self.buffer = b''
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# Calculate the fps.
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delta_time = time.time() - start
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if delta_time > 0:
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self.fps = 1 / delta_time
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self.frame_number = self.frame_number + 1
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if should_push:
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self.push_image_to_queue(image, self.frame_number, self.fps)
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except UnboundLocalError as ex:
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print(ex)
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@ -179,22 +199,25 @@ class Camera:
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if not any(p for p in com_ports if port in p):
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return
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try:
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conn = serial.Serial()
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conn.baudrate = 3000000
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conn.port = port
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conn.setDTR(False)
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conn.setRTS(False)
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conn.open()
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conn = serial.Serial(
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baudrate = 3000000,
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port = port,
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xonxoff=False,
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dsrdtr=False,
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rtscts=False)
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conn.reset_input_buffer()
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print(f"\033[94m[INFO] Serial Tracker successfully connected on {port}\033[0m")
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self.serial_connection = conn
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self.camera_status = CameraState.CONNECTED
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except Exception as e:
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except Exception:
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self.camera_status = CameraState.DISCONNECTED
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def push_image_to_queue(self, image, frame_number, fps):
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# If there's backpressure, just yell. We really shouldn't have this unless we start getting
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# some sort of capture event conflict though.
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print(f"N {frame_number} FPS {fps}")
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qsize = self.camera_output_outgoing.qsize()
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if qsize > 1:
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print(
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