inference/core/interfaces/stream/stream.py

import json
import threading
import time
import traceback
from typing import Callable, Union

import cv2
import numpy as np
import supervision as sv
from PIL import Image

import inference.core.entities.requests.inference
from inference.core.active_learning.middlewares import (
    NullActiveLearningMiddleware,
    ThreadingActiveLearningMiddleware,
)
from inference.core.cache import cache
from inference.core.env import (
    ACTIVE_LEARNING_ENABLED,
    API_KEY,
    API_KEY_ENV_NAMES,
    CLASS_AGNOSTIC_NMS,
    CONFIDENCE,
    ENABLE_BYTE_TRACK,
    ENFORCE_FPS,
    IOU_THRESHOLD,
    JSON_RESPONSE,
    MAX_CANDIDATES,
    MAX_DETECTIONS,
    MODEL_ID,
    STREAM_ID,
)
from inference.core.interfaces.base import BaseInterface
from inference.core.interfaces.camera.camera import WebcamStream
from inference.core.logger import logger
from inference.core.registries.roboflow import get_model_type
from inference.models.utils import get_roboflow_model


class Stream(BaseInterface):
    """Roboflow defined stream interface for a general-purpose inference server.

    Attributes:
        model_manager (ModelManager): The manager that handles model inference tasks.
        model_registry (RoboflowModelRegistry): The registry to fetch model instances.
        api_key (str): The API key for accessing models.
        class_agnostic_nms (bool): Flag for class-agnostic non-maximum suppression.
        confidence (float): Confidence threshold for inference.
        iou_threshold (float): The intersection-over-union threshold for detection.
        json_response (bool): Flag to toggle JSON response format.
        max_candidates (float): The maximum number of candidates for detection.
        max_detections (float): The maximum number of detections.
        model (str|Callable): The model to be used.
        stream_id (str): The ID of the stream to be used.
        use_bytetrack (bool): Flag to use bytetrack,

    Methods:
        init_infer: Initialize the inference with a test frame.
        preprocess_thread: Preprocess incoming frames for inference.
        inference_request_thread: Manage the inference requests.
        run_thread: Run the preprocessing and inference threads.
    """

    def __init__(
        self,
        api_key: str = API_KEY,
        class_agnostic_nms: bool = CLASS_AGNOSTIC_NMS,
        confidence: float = CONFIDENCE,
        enforce_fps: bool = ENFORCE_FPS,
        iou_threshold: float = IOU_THRESHOLD,
        max_candidates: float = MAX_CANDIDATES,
        max_detections: float = MAX_DETECTIONS,
        model: Union[str, Callable] = MODEL_ID,
        source: Union[int, str] = STREAM_ID,
        use_bytetrack: bool = ENABLE_BYTE_TRACK,
        use_main_thread: bool = False,
        output_channel_order: str = "RGB",
        on_prediction: Callable = None,
        on_start: Callable = None,
        on_stop: Callable = None,
    ):
        """Initialize the stream with the given parameters.
        Prints the server settings and initializes the inference with a test frame.
        """
        logger.info("Initializing server")

        self.frame_count = 0
        self.byte_tracker = sv.ByteTrack() if use_bytetrack else None
        self.use_bytetrack = use_bytetrack

        if source == "webcam":
            stream_id = 0
        else:
            stream_id = source

        self.stream_id = stream_id
        if self.stream_id is None:
            raise ValueError("STREAM_ID is not defined")
        self.model_id = model
        if not self.model_id:
            raise ValueError("MODEL_ID is not defined")
        self.api_key = api_key

        self.active_learning_middleware = NullActiveLearningMiddleware()
        if isinstance(model, str):
            self.model = get_roboflow_model(model, self.api_key)
            if ACTIVE_LEARNING_ENABLED:
                self.active_learning_middleware = (
                    ThreadingActiveLearningMiddleware.init(
                        api_key=self.api_key,
                        model_id=self.model_id,
                        cache=cache,
                    )
                )
            self.task_type = get_model_type(
                model_id=self.model_id, api_key=self.api_key
            )[0]
        else:
            self.model = model
            self.task_type = "unknown"

        self.class_agnostic_nms = class_agnostic_nms
        self.confidence = confidence
        self.iou_threshold = iou_threshold
        self.max_candidates = max_candidates
        self.max_detections = max_detections
        self.use_main_thread = use_main_thread
        self.output_channel_order = output_channel_order

        self.inference_request_type = (
            inference.core.entities.requests.inference.ObjectDetectionInferenceRequest
        )

        self.webcam_stream = WebcamStream(
            stream_id=self.stream_id, enforce_fps=enforce_fps
        )
        logger.info(
            f"Streaming from device with resolution: {self.webcam_stream.width} x {self.webcam_stream.height}"
        )

        self.on_start_callbacks = []
        self.on_stop_callbacks = [
            lambda: self.active_learning_middleware.stop_registration_thread()
        ]
        self.on_prediction_callbacks = []

        if on_prediction:
            self.on_prediction_callbacks.append(on_prediction)

        if on_start:
            self.on_start_callbacks.append(on_start)

        if on_stop:
            self.on_stop_callbacks.append(on_stop)

        self.init_infer()
        self.preproc_result = None
        self.inference_request_obj = None
        self.queue_control = False
        self.inference_response = None
        self.stop = False

        self.frame = None
        self.frame_cv = None
        self.frame_id = None
        logger.info("Server initialized with settings:")
        logger.info(f"Stream ID: {self.stream_id}")
        logger.info(f"Model ID: {self.model_id}")
        logger.info(f"Enforce FPS: {enforce_fps}")
        logger.info(f"Confidence: {self.confidence}")
        logger.info(f"Class Agnostic NMS: {self.class_agnostic_nms}")
        logger.info(f"IOU Threshold: {self.iou_threshold}")
        logger.info(f"Max Candidates: {self.max_candidates}")
        logger.info(f"Max Detections: {self.max_detections}")

        self.run_thread()

    def on_start(self, callback):
        self.on_start_callbacks.append(callback)

        unsubscribe = lambda: self.on_start_callbacks.remove(callback)
        return unsubscribe

    def on_stop(self, callback):
        self.on_stop_callbacks.append(callback)

        unsubscribe = lambda: self.on_stop_callbacks.remove(callback)
        return unsubscribe

    def on_prediction(self, callback):
        self.on_prediction_callbacks.append(callback)

        unsubscribe = lambda: self.on_prediction_callbacks.remove(callback)
        return unsubscribe

    def init_infer(self):
        """Initialize the inference with a test frame.

        Creates a test frame and runs it through the entire inference process to ensure everything is working.
        """
        frame = Image.new("RGB", (640, 640), color="black")
        self.model.infer(
            frame, confidence=self.confidence, iou_threshold=self.iou_threshold
        )
        self.active_learning_middleware.start_registration_thread()

    def preprocess_thread(self):
        """Preprocess incoming frames for inference.

        Reads frames from the webcam stream, converts them into the proper format, and preprocesses them for
        inference.
        """
        webcam_stream = self.webcam_stream
        webcam_stream.start()
        # processing frames in input stream
        try:
            while True:
                if webcam_stream.stopped is True or self.stop:
                    break
                else:
                    self.frame_cv, frame_id = webcam_stream.read_opencv()
                    if frame_id > 0 and frame_id != self.frame_id:
                        self.frame_id = frame_id
                        self.frame = cv2.cvtColor(self.frame_cv, cv2.COLOR_BGR2RGB)
                        self.preproc_result = self.model.preprocess(self.frame_cv)
                        self.img_in, self.img_dims = self.preproc_result
                        self.queue_control = True

        except Exception as e:
            traceback.print_exc()
            logger.error(e)

    def inference_request_thread(self):
        """Manage the inference requests.

        Processes preprocessed frames for inference, post-processes the predictions, and sends the results
        to registered callbacks.
        """
        last_print = time.perf_counter()
        print_ind = 0
        while True:
            if self.webcam_stream.stopped is True or self.stop:
                while len(self.on_stop_callbacks) > 0:
                    # run each onStop callback only once from this thread
                    cb = self.on_stop_callbacks.pop()
                    cb()
                break
            if self.queue_control:
                while len(self.on_start_callbacks) > 0:
                    # run each onStart callback only once from this thread
                    cb = self.on_start_callbacks.pop()
                    cb()

                self.queue_control = False
                frame_id = self.frame_id
                inference_input = np.copy(self.frame_cv)
                start = time.perf_counter()
                predictions = self.model.predict(
                    self.img_in,
                )
                predictions = self.model.postprocess(
                    predictions,
                    self.img_dims,
                    class_agnostic_nms=self.class_agnostic_nms,
                    confidence=self.confidence,
                    iou_threshold=self.iou_threshold,
                    max_candidates=self.max_candidates,
                    max_detections=self.max_detections,
                )[0]

                self.active_learning_middleware.register(
                    inference_input=inference_input,
                    prediction=predictions.dict(by_alias=True, exclude_none=True),
                    prediction_type=self.task_type,
                )
                if self.use_bytetrack:
                    detections = sv.Detections.from_roboflow(
                        predictions.dict(by_alias=True, exclude_none=True)
                    )
                    detections = self.byte_tracker.update_with_detections(detections)

                    if detections.tracker_id is None:
                        detections.tracker_id = np.array([], dtype=int)

                    for pred, detect in zip(predictions.predictions, detections):
                        pred.tracker_id = int(detect[4])
                predictions.frame_id = frame_id
                predictions = predictions.dict(by_alias=True, exclude_none=True)

                self.inference_response = predictions
                self.frame_count += 1

                for cb in self.on_prediction_callbacks:
                    if self.output_channel_order == "BGR":
                        cb(predictions, self.frame_cv)
                    else:
                        cb(predictions, np.asarray(self.frame))

                current = time.perf_counter()
                self.webcam_stream.max_fps = 1 / (current - start)
                logger.debug(f"FPS: {self.webcam_stream.max_fps:.2f}")

                if time.perf_counter() - last_print > 1:
                    print_ind = (print_ind + 1) % 4
                    last_print = time.perf_counter()

    def run_thread(self):
        """Run the preprocessing and inference threads.

        Starts the preprocessing and inference threads, and handles graceful shutdown on KeyboardInterrupt.
        """
        preprocess_thread = threading.Thread(target=self.preprocess_thread)
        preprocess_thread.start()

        if self.use_main_thread:
            self.inference_request_thread()
        else:
            # start a thread that looks for the predictions
            # and call the callbacks
            inference_request_thread = threading.Thread(
                target=self.inference_request_thread
            )
            inference_request_thread.start()