141 lines
4.1 KiB
Python
141 lines
4.1 KiB
Python
# -*- coding: utf-8 -*-
|
|
import io
|
|
import logging
|
|
import time
|
|
from abc import ABCMeta, abstractmethod
|
|
from collections import namedtuple
|
|
|
|
from labthings import ClientEvent, StrictLock
|
|
|
|
# Class to store a frames metadata
|
|
TrackerFrame = namedtuple("TrackerFrame", ["size", "time"])
|
|
|
|
|
|
class FrameStream(io.BytesIO):
|
|
"""
|
|
A file-like object used to analyse MJPEG frames.
|
|
|
|
Instead of analysing a load of real MJPEG frames
|
|
after they've been stored in a BytesIO stream,
|
|
we tell the camera to write frames to this class instead.
|
|
|
|
We then do analysis as the frames are written, and discard the heavier
|
|
image data.
|
|
"""
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
# Array of TrackerFrame objects
|
|
io.BytesIO.__init__(self, *args, **kwargs)
|
|
# Array of TrackerFramer objects
|
|
self.frames = []
|
|
# Last acquired TrackerFramer object
|
|
self.last = None
|
|
|
|
# Are we currently tracking frame sizes?
|
|
self.tracking = False
|
|
|
|
# Event to track if a new frame is available since the last getvalue() call
|
|
# We use a ClientEvent so that each thread can call getvalue() independantly
|
|
self.new_frame = ClientEvent()
|
|
|
|
def start_tracking(self):
|
|
if not self.tracking:
|
|
logging.debug("Started tracking frame data")
|
|
self.tracking = True
|
|
|
|
def stop_tracking(self):
|
|
if self.tracking:
|
|
logging.debug("Stopped tracking frame data")
|
|
self.tracking = False
|
|
|
|
def reset_tracking(self):
|
|
self.frames = []
|
|
|
|
def write(self, s):
|
|
"""
|
|
Write a new frame to the FrameStream. Does a few things:
|
|
1. If tracking frame size, store the size in self.frames
|
|
2. Rewind and truncate the stream (delete previous frame)
|
|
3. Store the new frame image
|
|
4. Set the new_frame event
|
|
"""
|
|
if self.tracking:
|
|
frame = TrackerFrame(size=len(s), time=time.time())
|
|
self.frames.append(frame)
|
|
self.last = frame
|
|
# Reset the stream for the next frame
|
|
super().seek(0)
|
|
super().truncate()
|
|
# Write the new frame
|
|
super().write(s)
|
|
# Set the new frame event
|
|
self.new_frame.set()
|
|
|
|
def getvalue(self) -> bytes:
|
|
"""
|
|
Clear tne new_frame event and return frame data
|
|
"""
|
|
self.new_frame.clear()
|
|
return super().getvalue()
|
|
|
|
def getframe(self) -> bytes:
|
|
"""Wait for a new frame to be available, then return it"""
|
|
self.new_frame.wait()
|
|
return self.getvalue()
|
|
|
|
|
|
class BaseCamera(metaclass=ABCMeta):
|
|
"""
|
|
Base implementation of StreamingCamera.
|
|
"""
|
|
|
|
def __init__(self):
|
|
self.camera = None
|
|
|
|
self.lock = StrictLock(name="Camera", timeout=None)
|
|
|
|
self.stream = FrameStream()
|
|
|
|
self.stream_active = False
|
|
self.record_active = False
|
|
self.preview_active = False
|
|
|
|
@property
|
|
@abstractmethod
|
|
def configuration(self):
|
|
"""The current camera configuration."""
|
|
|
|
@property
|
|
@abstractmethod
|
|
def state(self):
|
|
"""The current read-only camera state."""
|
|
|
|
@property
|
|
def settings(self):
|
|
return self.read_settings()
|
|
|
|
@abstractmethod
|
|
def update_settings(self, config: dict):
|
|
"""Update settings from a config dictionary"""
|
|
with self.lock(timeout=None):
|
|
# Apply valid config params to camera object
|
|
for key, value in config.items(): # For each provided setting
|
|
if hasattr(self, key): # If the instance has a matching property
|
|
setattr(self, key, value) # Set to the target value
|
|
|
|
@abstractmethod
|
|
def read_settings(self) -> dict:
|
|
"""Return the current settings as a dictionary"""
|
|
return {}
|
|
|
|
def __enter__(self):
|
|
"""Create camera on context enter."""
|
|
return self
|
|
|
|
def __exit__(self, exc_type, exc_value, traceback):
|
|
"""Close camera stream on context exit."""
|
|
self.close()
|
|
|
|
def close(self):
|
|
"""Close the BaseCamera and all attached StreamObjects."""
|
|
logging.info("Closed %s", (self))
|