blakeblackshear.frigate/frigate/embeddings/maintainer.py

"""Maintain embeddings in Chroma."""

import base64
import io
import logging
import threading
from multiprocessing.synchronize import Event as MpEvent
from typing import Optional

import cv2
import numpy as np
from peewee import DoesNotExist
from PIL import Image

from frigate.comms.events_updater import EventEndSubscriber, EventUpdateSubscriber
from frigate.comms.inter_process import InterProcessRequestor
from frigate.config import FrigateConfig
from frigate.const import UPDATE_EVENT_DESCRIPTION
from frigate.events.types import EventTypeEnum
from frigate.genai import get_genai_client
from frigate.models import Event
from frigate.util.image import SharedMemoryFrameManager, calculate_region

from .embeddings import Embeddings, get_metadata

logger = logging.getLogger(__name__)


class EmbeddingMaintainer(threading.Thread):
    """Handle embedding queue and post event updates."""

    def __init__(
        self,
        config: FrigateConfig,
        stop_event: MpEvent,
    ) -> None:
        threading.Thread.__init__(self)
        self.name = "embeddings_maintainer"
        self.config = config
        self.embeddings = Embeddings()
        self.event_subscriber = EventUpdateSubscriber()
        self.event_end_subscriber = EventEndSubscriber()
        self.frame_manager = SharedMemoryFrameManager()
        # create communication for updating event descriptions
        self.requestor = InterProcessRequestor()
        self.stop_event = stop_event
        self.tracked_events = {}
        self.genai_client = get_genai_client(config.genai)

    def run(self) -> None:
        """Maintain a Chroma vector database for semantic search."""
        while not self.stop_event.is_set():
            self._process_updates()
            self._process_finalized()

        self.event_subscriber.stop()
        self.event_end_subscriber.stop()
        self.requestor.stop()
        logger.info("Exiting embeddings maintenance...")

    def _process_updates(self) -> None:
        """Process event updates"""
        update = self.event_subscriber.check_for_update()

        if update is None:
            return

        source_type, _, camera, data = update

        if not camera or source_type != EventTypeEnum.tracked_object:
            return

        camera_config = self.config.cameras[camera]
        if data["id"] not in self.tracked_events:
            self.tracked_events[data["id"]] = []

        # Create our own thumbnail based on the bounding box and the frame time
        try:
            frame_id = f"{camera}{data['frame_time']}"
            yuv_frame = self.frame_manager.get(frame_id, camera_config.frame_shape_yuv)

            if yuv_frame is not None:
                data["thumbnail"] = self._create_thumbnail(yuv_frame, data["box"])
                self.tracked_events[data["id"]].append(data)
                self.frame_manager.close(frame_id)
        except FileNotFoundError:
            pass

    def _process_finalized(self) -> None:
        """Process the end of an event."""
        while True:
            ended = self.event_end_subscriber.check_for_update()

            if ended == None:
                break

            event_id, camera, updated_db = ended
            camera_config = self.config.cameras[camera]

            if updated_db:
                try:
                    event: Event = Event.get(Event.id == event_id)
                except DoesNotExist:
                    continue

                # Skip the event if not an object
                if event.data.get("type") != "object":
                    continue

                # Extract valid event metadata
                metadata = get_metadata(event)
                thumbnail = base64.b64decode(event.thumbnail)

                # Embed the thumbnail
                self._embed_thumbnail(event_id, thumbnail, metadata)

                if (
                    camera_config.genai.enabled
                    and self.genai_client is not None
                    and event.data.get("description") is None
                ):
                    # Generate the description. Call happens in a thread since it is network bound.
                    threading.Thread(
                        target=self._embed_description,
                        name=f"_embed_description_{event.id}",
                        daemon=True,
                        args=(
                            event,
                            [
                                data["thumbnail"]
                                for data in self.tracked_events[event_id]
                            ]
                            if len(self.tracked_events.get(event_id, [])) > 0
                            else [thumbnail],
                            metadata,
                        ),
                    ).start()

            # Delete tracked events based on the event_id
            if event_id in self.tracked_events:
                del self.tracked_events[event_id]

    def _create_thumbnail(self, yuv_frame, box, height=500) -> Optional[bytes]:
        """Return jpg thumbnail of a region of the frame."""
        frame = cv2.cvtColor(yuv_frame, cv2.COLOR_YUV2BGR_I420)
        region = calculate_region(
            frame.shape, box[0], box[1], box[2], box[3], height, multiplier=1.4
        )
        frame = frame[region[1] : region[3], region[0] : region[2]]
        width = int(height * frame.shape[1] / frame.shape[0])
        frame = cv2.resize(frame, dsize=(width, height), interpolation=cv2.INTER_AREA)
        ret, jpg = cv2.imencode(".jpg", frame, [int(cv2.IMWRITE_JPEG_QUALITY), 100])

        if ret:
            return jpg.tobytes()

        return None

    def _embed_thumbnail(self, event_id: str, thumbnail: bytes, metadata: dict) -> None:
        """Embed the thumbnail for an event."""

        # Encode the thumbnail
        img = np.array(Image.open(io.BytesIO(thumbnail)).convert("RGB"))
        self.embeddings.thumbnail.upsert(
            images=[img],
            metadatas=[metadata],
            ids=[event_id],
        )

    def _embed_description(
        self, event: Event, thumbnails: list[bytes], metadata: dict
    ) -> None:
        """Embed the description for an event."""

        description = self.genai_client.generate_description(thumbnails, metadata)

        if description is None:
            logger.debug("Failed to generate description for %s", event.id)
            return

        # fire and forget description update
        self.requestor.send_data(
            UPDATE_EVENT_DESCRIPTION,
            {"id": event.id, "description": description},
        )

        # Encode the description
        self.embeddings.description.upsert(
            documents=[description],
            metadatas=[metadata],
            ids=[event.id],
        )

        logger.debug(
            "Generated description for %s (%d images): %s",
            event.id,
            len(thumbnails),
            description,
        )