inference_stream_example.py

import cv2
import numpy as np
from inference import InferencePipeline
from inference.core.interfaces.camera.entities import VideoFrame
from utils.general import find_in_list, load_zones_config
from utils.timers import ClockBasedTimer

import supervision as sv

COLORS = sv.ColorPalette.from_hex(["#E6194B", "#3CB44B", "#FFE119", "#3C76D1"])
COLOR_ANNOTATOR = sv.ColorAnnotator(color=COLORS)
LABEL_ANNOTATOR = sv.LabelAnnotator(
    color=COLORS, text_color=sv.Color.from_hex("#000000")
)


class CustomSink:
    def __init__(self, zone_configuration_path: str, classes: list[int]):
        self.classes = classes
        self.tracker = sv.ByteTrack(minimum_matching_threshold=0.5)
        self.fps_monitor = sv.FPSMonitor()
        self.polygons = load_zones_config(file_path=zone_configuration_path)
        self.timers = [ClockBasedTimer() for _ in self.polygons]
        self.zones = [
            sv.PolygonZone(
                polygon=polygon,
                triggering_anchors=(sv.Position.CENTER,),
            )
            for polygon in self.polygons
        ]

    def on_prediction(self, result: dict, frame: VideoFrame) -> None:
        self.fps_monitor.tick()
        fps = self.fps_monitor.fps

        detections = sv.Detections.from_inference(result)
        detections = detections[find_in_list(detections.class_id, self.classes)]
        detections = self.tracker.update_with_detections(detections)

        annotated_frame = frame.image.copy()
        annotated_frame = sv.draw_text(
            scene=annotated_frame,
            text=f"{fps:.1f}",
            text_anchor=sv.Point(40, 30),
            background_color=sv.Color.from_hex("#A351FB"),
            text_color=sv.Color.from_hex("#000000"),
        )

        for idx, zone in enumerate(self.zones):
            annotated_frame = sv.draw_polygon(
                scene=annotated_frame, polygon=zone.polygon, color=COLORS.by_idx(idx)
            )

            detections_in_zone = detections[zone.trigger(detections)]
            time_in_zone = self.timers[idx].tick(detections_in_zone)
            custom_color_lookup = np.full(detections_in_zone.class_id.shape, idx)

            annotated_frame = COLOR_ANNOTATOR.annotate(
                scene=annotated_frame,
                detections=detections_in_zone,
                custom_color_lookup=custom_color_lookup,
            )
            labels = [
                f"#{tracker_id} {int(time // 60):02d}:{int(time % 60):02d}"
                for tracker_id, time in zip(detections_in_zone.tracker_id, time_in_zone)
            ]
            annotated_frame = LABEL_ANNOTATOR.annotate(
                scene=annotated_frame,
                detections=detections_in_zone,
                labels=labels,
                custom_color_lookup=custom_color_lookup,
            )
        cv2.imshow("Processed Video", annotated_frame)
        cv2.waitKey(1)


def main(
    zone_configuration_path: str,
    rtsp_url: str,
    model_id: str = "rfdetr-medium",
    confidence_threshold: float = 0.3,
    iou_threshold: float = 0.7,
    classes: list[int] = [],
    roboflow_api_key: str = "",
) -> None:
    """
    Calculating detections dwell time in zones, using RTSP stream.

    Args:
        zone_configuration_path: Path to the zone configuration JSON file
        rtsp_url: Complete RTSP URL for the video stream
        model_id: Roboflow model ID
        confidence_threshold: Confidence level for detections (0 to 1)
        iou_threshold: IOU threshold for non-max suppression
        classes: List of class IDs to track. If empty, all classes are tracked
        roboflow_api_key: Roboflow API key for accessing private models
    """
    sink = CustomSink(zone_configuration_path=zone_configuration_path, classes=classes)

    pipeline = InferencePipeline.init(
        model_id=model_id,
        video_reference=rtsp_url,
        on_prediction=sink.on_prediction,
        confidence=confidence_threshold,
        iou_threshold=iou_threshold,
        api_key=roboflow_api_key,
    )

    pipeline.start()

    try:
        pipeline.join()
    except KeyboardInterrupt:
        pipeline.terminate()


if __name__ == "__main__":
    from jsonargparse import auto_cli, set_parsing_settings

    set_parsing_settings(parse_optionals_as_positionals=True)
    auto_cli(main, as_positional=False)