output.py

"""Handle outputting raw frigate frames"""

import logging
import multiprocessing as mp
import os
import shutil
import signal
import threading
from typing import Optional
from wsgiref.simple_server import make_server

from setproctitle import setproctitle
from ws4py.server.wsgirefserver import (
    WebSocketWSGIHandler,
    WebSocketWSGIRequestHandler,
    WSGIServer,
)
from ws4py.server.wsgiutils import WebSocketWSGIApplication

from frigate.comms.detections_updater import DetectionSubscriber, DetectionTypeEnum
from frigate.comms.ws import WebSocket
from frigate.config import FrigateConfig
from frigate.const import CACHE_DIR, CLIPS_DIR
from frigate.output.birdseye import Birdseye
from frigate.output.camera import JsmpegCamera
from frigate.output.preview import PreviewRecorder
from frigate.util.image import SharedMemoryFrameManager

logger = logging.getLogger(__name__)


def output_frames(
    config: FrigateConfig,
):
    threading.current_thread().name = "output"
    setproctitle("frigate.output")

    stop_event = mp.Event()

    def receiveSignal(signalNumber, frame):
        logger.debug(f"Output frames process received signal {signalNumber}")
        stop_event.set()

    signal.signal(signal.SIGTERM, receiveSignal)
    signal.signal(signal.SIGINT, receiveSignal)

    frame_manager = SharedMemoryFrameManager()
    previous_frames = {}

    # start a websocket server on 8082
    WebSocketWSGIHandler.http_version = "1.1"
    websocket_server = make_server(
        "127.0.0.1",
        8082,
        server_class=WSGIServer,
        handler_class=WebSocketWSGIRequestHandler,
        app=WebSocketWSGIApplication(handler_cls=WebSocket),
    )
    websocket_server.initialize_websockets_manager()
    websocket_thread = threading.Thread(target=websocket_server.serve_forever)

    detection_subscriber = DetectionSubscriber(DetectionTypeEnum.video)

    jsmpeg_cameras: dict[str, JsmpegCamera] = {}
    birdseye: Optional[Birdseye] = None
    preview_recorders: dict[str, PreviewRecorder] = {}

    move_preview_frames("cache")

    for camera, cam_config in config.cameras.items():
        if not cam_config.enabled:
            continue

        jsmpeg_cameras[camera] = JsmpegCamera(cam_config, stop_event, websocket_server)
        preview_recorders[camera] = PreviewRecorder(cam_config)

    if config.birdseye.enabled:
        birdseye = Birdseye(config, frame_manager, stop_event, websocket_server)

    websocket_thread.start()

    while not stop_event.is_set():
        (topic, data) = detection_subscriber.get_data(timeout=1)

        if not topic:
            continue

        (
            camera,
            frame_time,
            current_tracked_objects,
            motion_boxes,
            regions,
        ) = data

        frame_id = f"{camera}{frame_time}"

        frame = frame_manager.get(frame_id, config.cameras[camera].frame_shape_yuv)

        # send camera frame to ffmpeg process if websockets are connected
        if any(
            ws.environ["PATH_INFO"].endswith(camera) for ws in websocket_server.manager
        ):
            # write to the converter for the camera if clients are listening to the specific camera
            jsmpeg_cameras[camera].write_frame(frame.tobytes())

        # send output data to birdseye if websocket is connected or restreaming
        if config.birdseye.enabled and (
            config.birdseye.restream
            or any(
                ws.environ["PATH_INFO"].endswith("birdseye")
                for ws in websocket_server.manager
            )
        ):
            birdseye.write_data(
                camera,
                current_tracked_objects,
                motion_boxes,
                frame_time,
                frame,
            )

        # send frames for low fps recording
        preview_recorders[camera].write_data(
            current_tracked_objects, motion_boxes, frame_time, frame
        )

        # delete frames after they have been used for output
        if camera in previous_frames:
            frame_manager.delete(f"{camera}{previous_frames[camera]}")

        previous_frames[camera] = frame_time

    move_preview_frames("clips")

    while True:
        (topic, data) = detection_subscriber.get_data(timeout=0)

        if not topic:
            break

        (
            camera,
            frame_time,
            current_tracked_objects,
            motion_boxes,
            regions,
        ) = data

        frame_id = f"{camera}{frame_time}"
        frame = frame_manager.get(frame_id, config.cameras[camera].frame_shape_yuv)
        frame_manager.delete(frame_id)

    detection_subscriber.stop()

    for jsmpeg in jsmpeg_cameras.values():
        jsmpeg.stop()

    for preview in preview_recorders.values():
        preview.stop()

    if birdseye is not None:
        birdseye.stop()

    websocket_server.manager.close_all()
    websocket_server.manager.stop()
    websocket_server.manager.join()
    websocket_server.shutdown()
    websocket_thread.join()
    logger.info("exiting output process...")


def move_preview_frames(loc: str):
    preview_holdover = os.path.join(CLIPS_DIR, "preview_restart_cache")
    preview_cache = os.path.join(CACHE_DIR, "preview_frames")

    try:
        if loc == "clips":
            shutil.move(preview_cache, preview_holdover)
        elif loc == "cache":
            if not os.path.exists(preview_holdover):
                return

            shutil.move(preview_holdover, preview_cache)

    except shutil.Error:
        logger.error("Failed to restore preview cache.")