Use multiprocessing for writing Flir frames

[lwhite1]

Short PR that swaps multi-threading for multiprocesing to see if there's any improvement in write performance.

This change should be considered temporary, as it's not clear that this is an appropriate approach for image processing.

[divyadk]

Some changes in the stop process to clear the process and to avoid dangling reference just in case.

def stop(self): if self.open and self.recording: self.logger.debug('FLIR: Setting Record Stop Flag') self.recording = False if self.save_process is not None: #wait for child process to finish self.save_process.join(timeout=5) if self.save_process.is_alive(): self.logger.error('FLIR: Save process did not terminate in time.') #terminating the child process self.save_process.terminate() #clear the save_process reference just in case self.save_process = None self.streaming = False

[divyadk]

Minor change here -> passing the function object instead of calling the function.

self.save_process = multiprocessing.Process(target = self.camCaptureVid)

[divyadk]

Can create a video writer here (that gets created in the child process instead). this can be the rewritten function:

#rewritten function

def camCaptureVid(self):
    try:
        # Initializing VideoWriter in the child process instead
        fourcc = cv2.VideoWriter_fourcc(*"MJPG")
        video_out = cv2.VideoWriter(
            self.video_filename, fourcc,
            self.FRAME_RATE_OUT, self.frameSize
        )
        self.logger.debug('FLIR: Save Process Started')
 
       #write the frames from the queue as before
       while self.recording or not self.image_queue.empty():
            try:
                # Retrieve frame from the queue
                dequeuedImage = self.image_queue.get(block=True, timeout=1)
                # Write frame to the video file
                video_out.write(dequeuedImage)
            except queue.Empty:
                continue
    except Exception as e:
        self.logger.error(f'FLIR: Error in save process: {e}')
    finally:
        # Safely release video writer
        video_out.release()
        self.logger.debug('FLIR: Exiting Save Process')