372 lines
12 KiB
Python
372 lines
12 KiB
Python
# -*- coding: utf-8 -*-
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import time
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import os
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import threading
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import datetime
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import logging
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try:
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from greenlet import getcurrent as get_ident
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except ImportError:
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try:
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from thread import get_ident
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except ImportError:
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from _thread import get_ident
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from .capture import CaptureObject, BASE_CAPTURE_PATH, TEMP_CAPTURE_PATH
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from openflexure_microscope.utilities import entry_by_id
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from openflexure_microscope.lock import StrictLock
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def last_entry(object_list: list):
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"""Return the last entry of a list, if the list contains items."""
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if object_list: # If any images have been captured
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return object_list[-1] # Return the latest captured image
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else:
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return None
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def generate_basename():
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"""Return a default filename based on the capture datetime"""
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return datetime.datetime.now().strftime("%Y-%m-%d_%H-%M-%S")
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def generate_numbered_basename(obj_list: list) -> str:
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initial_basename = generate_basename()
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basename = initial_basename
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# Handle clashing
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iterator = 1
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while basename in [obj.basename for obj in obj_list]:
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basename = initial_basename + "_{}".format(iterator)
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iterator += 1
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return basename
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class CameraEvent(object):
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"""
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A frame-signaller object used by any instances or subclasses of BaseCamera.
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An event-like class that signals all active clients when a new frame is available.
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"""
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def __init__(self):
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self.events = {}
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def wait(self, timeout: int = 5):
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"""Wait for the next frame (invoked from each client's thread)."""
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ident = get_ident()
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if ident not in self.events:
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# this is a new client
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# add an entry for it in the self.events dict
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# each entry has two elements, a threading.Event() and a timestamp
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self.events[ident] = [threading.Event(), time.time()]
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return self.events[ident][0].wait(timeout)
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def set(self):
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"""Signal that a new frame is available."""
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now = time.time()
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remove = None
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for ident, event in self.events.items():
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if not event[0].isSet():
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# if this client's event is not set, then set it
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# also update the last set timestamp to now
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event[0].set()
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event[1] = now
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else:
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# if the client's event is already set, it means the client
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# did not process a previous frame
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# if the event stays set for more than 5 seconds, then assume
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# the client is gone and remove it
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if now - event[1] > 5:
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remove = ident
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if remove:
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del self.events[remove]
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def clear(self):
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"""Clear frame event, once processed."""
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self.events[get_ident()][0].clear()
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class BaseCamera(object):
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"""
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Base implementation of StreamingCamera.
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Attributes:
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thread: Background thread reading frames from camera
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camera: Camera object
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lock (:py:class:`openflexure_microscope.lock.StrictLock`): Strict lock controlling thread
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access to stage hardware
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frame (bytes): Current frame is stored here by background thread
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last_access (time): Time of last client access to the camera
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state (dict): Dictionary for capture state
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config (dict): Dictionary of base camera config
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paths (dict): Dictionary of capture paths
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images (list): List of image capture objects
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videos (list): List of video capture objects
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"""
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def __init__(self):
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self.thread = None
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self.camera = None
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self.lock = StrictLock(timeout=1)
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self.frame = None
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self.last_access = 0
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self.event = CameraEvent()
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self.state = {}
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self.config = {}
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self.paths = {
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'image': BASE_CAPTURE_PATH,
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'video': BASE_CAPTURE_PATH,
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'image_tmp': TEMP_CAPTURE_PATH,
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'video_tpm': TEMP_CAPTURE_PATH
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}
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# Capture data
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self.images = []
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self.videos = []
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def apply_config(self, config):
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"""Update settings from a config dictionary"""
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self.config.update(config)
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def read_config(self, config):
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"""Return the current settings as a dictionary"""
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return self.config
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def __enter__(self):
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"""Create camera on context enter."""
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return self
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def __exit__(self, exc_type, exc_value, traceback):
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"""Close camera stream on context exit."""
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self.close()
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def close(self):
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"""Close the BaseCamera and all attached StreamObjects."""
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logging.info("Closing {}".format(self))
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# Close all StreamObjects
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for capture_list in [self.images, self.videos]:
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for stream_object in capture_list:
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stream_object.close()
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# Stop worker thread
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self.stop_worker()
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logging.info("Closed {}".format(self))
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def wait_for_camera(self, timeout=5):
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"""Wait for camera object, with 5 second timeout."""
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timeout_time = time.time() + timeout
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while not self.camera:
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if time.time() > timeout_time:
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raise TimeoutError("Timeout waiting for camera")
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else:
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pass
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# START AND STOP WORKER THREAD
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def start_worker(self, timeout: int = 5) -> bool:
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"""Start the background camera thread if it isn't running yet."""
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timeout_time = time.time() + timeout
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self.last_access = time.time()
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self.stop = False
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if not self.state['stream_active']:
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# start background frame thread
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self.thread = threading.Thread(target=self._thread)
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self.thread.daemon = True
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self.thread.start()
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# wait until frames are available
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logging.info("Waiting for frames")
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while self.get_frame() is None:
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if time.time() > timeout_time:
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raise TimeoutError("Timeout waiting for frames.")
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else:
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time.sleep(0.1)
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return True
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def stop_worker(self, timeout: int = 5) -> bool:
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"""Flag worker thread for stop. Waits for thread close or timeout."""
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logging.debug("Stopping worker thread")
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timeout_time = time.time() + timeout
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if self.state['stream_active']:
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self.stop = True
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self.thread.join() # Wait for stream thread to exit
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logging.debug("Waiting for stream thread to exit.")
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while self.state['stream_active']:
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if time.time() > timeout_time:
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logging.debug("Timeout waiting for worker thread close.")
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raise TimeoutError("Timeout waiting for worker thread close.")
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else:
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time.sleep(0.1)
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return True
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# HANDLE STREAM FRAMES
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def get_frame(self):
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"""Return the current camera frame."""
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self.last_access = time.time()
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# wait for a signal from the camera thread
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self.event.wait()
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self.event.clear()
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return self.frame
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def frames(self):
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"""Create generator that returns frames from the camera."""
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raise RuntimeError('Must be implemented by subclasses.')
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# RETURNING CAPTURES
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@property
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def image(self):
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"""Return the latest captured image."""
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return last_entry(self.images)
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@property
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def video(self):
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"""Return the latest recorded video."""
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return last_entry(self.videos)
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def image_from_id(self, image_id):
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"""Return an image StreamObject with a matching ID."""
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return entry_by_id(image_id, self.images)
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def video_from_id(self, video_id):
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"""Return a video StreamObject with a matching ID."""
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return entry_by_id(video_id, self.videos)
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# CREATING NEW CAPTURES
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def shunt_captures(self, target_list: list):
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for obj in target_list: # For each older capture
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obj.shunt() # Shunt capture from memory to storage
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def new_image(
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self,
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write_to_file: bool = True,
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temporary: bool = True,
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filename: str = None,
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folder: str = "",
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fmt: str = 'jpeg'):
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"""
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Create a new image capture object. Adds to the image list, and shunt all others.
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Args:
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write_to_file (bool): Should the StreamObject write to a file, or an in-memory byte stream.
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temporary (bool): Should the data be deleted after session ends.
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Creating the capture with a content manager sets this to true.
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filename (str): Name of the stored file. Defaults to timestamp.
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fmt (str): Format of the capture.
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"""
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# Generate file name
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if not filename:
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filename = generate_numbered_basename(self.images)
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logging.debug(filename)
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filename = "{}.{}".format(filename, fmt)
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# Generate folder
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base_folder = self.paths['image_tmp'] if temporary else self.paths['image']
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folder = os.path.join(base_folder, folder)
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# Generate file path
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filepath = os.path.join(folder, filename)
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# Create capture object
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output = CaptureObject(
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write_to_file=write_to_file,
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temporary=temporary,
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filepath=filepath)
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# Update capture list
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self.shunt_captures(self.images)
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self.images.append(output)
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return output
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def new_video(
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self,
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write_to_file: bool = True,
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temporary: bool = False,
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filename: str = None,
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folder: str = "",
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fmt: str = 'h264'):
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"""
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Create a new video capture object. Adds to the image list, and shunt all others.
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Args:
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write_to_file (bool): Should the StreamObject write to a file, or an in-memory byte stream.
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temporary (bool): Should the data be deleted after session ends.
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Creating the capture with a content manager sets this to true.
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filename (str): Name of the stored file. Defaults to timestamp.
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fmt (str): Format of the capture.
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"""
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# Generate file name
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if not filename:
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filename = generate_numbered_basename(self.videos)
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logging.debug(filename)
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filename = "{}.{}".format(filename, fmt)
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# Generate folder
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base_folder = self.paths['video_tmp'] if temporary else self.paths['video']
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folder = os.path.join(base_folder, folder)
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# Generate file path
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filepath = os.path.join(folder, filename)
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# Create capture object
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output = CaptureObject(
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write_to_file=write_to_file,
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temporary=temporary,
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filepath=filepath)
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# Update capture list
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self.shunt_captures(self.videos)
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self.videos.append(output)
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return output
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# WORKER THREAD
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def _thread(self):
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"""Camera background thread."""
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self.frames_iterator = self.frames()
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logging.debug("Entering worker thread.")
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self.state['stream_active'] = True
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for frame in self.frames_iterator:
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self.frame = frame
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self.event.set() # send signal to clients
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time.sleep(0)
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# Handle timeout
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if (
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self.stream_timeout_enabled and # If using timeout
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(time.time() - self.last_access > self.stream_timeout) and # And timeout time
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not self.state['preview_active'] # And GPU preview is not active
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):
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self.frames_iterator.close()
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break
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try:
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if self.stop is True:
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logging.debug("Worker thread flagged for stop.")
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self.frames_iterator.close()
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break
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except AttributeError:
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pass
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logging.debug("BaseCamera worker thread exiting...")
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# Set stream_activate state
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self.state['stream_active'] = False
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