app.py

import cv2
import numpy as np
import torch
from ultralytics import YOLO
import gradio as gr
from scipy.interpolate import interp1d
import uuid
import os

# Load the trained YOLOv8n model from the Space's root directory
model = YOLO("best.pt")  # Assumes best.pt is in the same directory as app.py

# Constants for LBW decision and video processing
STUMPS_WIDTH = 0.2286  # meters (width of stumps)
BALL_DIAMETER = 0.073  # meters (approx. cricket ball diameter)
FRAME_RATE = 30  # Input video frame rate
SLOW_MOTION_FACTOR = 6  # For very slow motion (6x slower)
CONF_THRESHOLD = 0.3  # Lowered confidence threshold for better detection

def process_video(video_path):
    # Initialize video capture
    if not os.path.exists(video_path):
        return [], [], "Error: Video file not found"
    cap = cv2.VideoCapture(video_path)
    frames = []
    ball_positions = []
    debug_log = []

    frame_count = 0
    while cap.isOpened():
        ret, frame = cap.read()
        if not ret:
            break
        frame_count += 1
        frames.append(frame.copy())  # Store original frame
        # Detect ball using the trained YOLOv8n model
        results = model.predict(frame, conf=CONF_THRESHOLD)
        detections = 0
        for detection in results[0].boxes:
            if detection.cls == 0:  # Assuming class 0 is the ball
                detections += 1
                x1, y1, x2, y2 = detection.xyxy[0].cpu().numpy()
                ball_positions.append([(x1 + x2) / 2, (y1 + y2) / 2])
                # Draw bounding box on frame for visualization
                cv2.rectangle(frame, (int(x1), int(y1)), (int(x2), int(y2)), (0, 255, 0), 2)
        frames[-1] = frame  # Update frame with bounding box
        debug_log.append(f"Frame {frame_count}: {detections} ball detections")
    cap.release()

    if not ball_positions:
        debug_log.append("No balls detected in any frame")
    else:
        debug_log.append(f"Total ball detections: {len(ball_positions)}")

    return frames, ball_positions, "\n".join(debug_log)

def estimate_trajectory(ball_positions, frames):
    # Simplified physics-based trajectory projection
    if len(ball_positions) < 2:
        return None, None, "Error: Fewer than 2 ball detections for trajectory"
    # Extract x, y coordinates
    x_coords = [pos[0] for pos in ball_positions]
    y_coords = [pos[1] for pos in ball_positions]
    times = np.arange(len(ball_positions)) / FRAME_RATE

    # Interpolate to smooth trajectory
    try:
        fx = interp1d(times, x_coords, kind='linear', fill_value="extrapolate")
        fy = interp1d(times, y_coords, kind='quadratic', fill_value="extrapolate")
    except Exception as e:
        return None, None, f"Error in trajectory interpolation: {str(e)}"

    # Project trajectory forward (0.5 seconds post-impact)
    t_future = np.linspace(times[-1], times[-1] + 0.5, 10)
    x_future = fx(t_future)
    y_future = fy(t_future)

    return list(zip(x_future, y_future)), t_future, "Trajectory estimated successfully"

def lbw_decision(ball_positions, trajectory, frames):
    # Simplified LBW logic
    if not frames:
        return "Error: No frames processed", None
    if not trajectory or len(ball_positions) < 2:
        return "Not enough data (insufficient ball detections)", None

    # Assume stumps are at the bottom center of the frame (calibration needed)
    frame_height, frame_width = frames[0].shape[:2]
    stumps_x = frame_width / 2
    stumps_y = frame_height * 0.9  # Approximate stumps position
    stumps_width_pixels = frame_width * (STUMPS_WIDTH / 3.0)  # Assume 3m pitch width

    # Check pitching point (first detected position)
    pitch_x, pitch_y = ball_positions[0]
    if pitch_x < stumps_x - stumps_width_pixels / 2 or pitch_x > stumps_x + stumps_width_pixels / 2:
        return "Not Out (Pitched outside line)", None

    # Check impact point (last detected position)
    impact_x, impact_y = ball_positions[-1]
    if impact_x < stumps_x - stumps_width_pixels / 2 or impact_x > stumps_x + stumps_width_pixels / 2:
        return "Not Out (Impact outside line)", None

    # Check trajectory hitting stumps
    for x, y in trajectory:
        if abs(x - stumps_x) < stumps_width_pixels / 2 and abs(y - stumps_y) < frame_height * 0.1:
            return "Out", trajectory
    return "Not Out (Missing stumps)", trajectory

def generate_slow_motion(frames, trajectory, output_path):
    # Generate very slow-motion video with ball detection and trajectory overlay
    if not frames:
        return None
    fourcc = cv2.VideoWriter_fourcc(*'mp4v')
    out = cv2.VideoWriter(output_path, fourcc, FRAME_RATE / SLOW_MOTION_FACTOR, (frames[0].shape[1], frames[0].shape[0]))

    for frame in frames:
        if trajectory:
            for x, y in trajectory:
                cv2.circle(frame, (int(x), int(y)), 5, (255, 0, 0), -1)  # Blue dots for trajectory
        for _ in range(SLOW_MOTION_FACTOR):  # Duplicate frames for very slow motion
            out.write(frame)
    out.release()
    return output_path

def drs_review(video):
    # Process video and generate DRS output
    frames, ball_positions, debug_log = process_video(video)
    if not frames:
        return f"Error: Failed to process video\nDebug Log:\n{debug_log}", None
    trajectory, _, trajectory_log = estimate_trajectory(ball_positions, frames)
    decision, trajectory = lbw_decision(ball_positions, trajectory, frames)

    # Generate slow-motion replay even if Trajectory fails
    output_path = f"output_{uuid.uuid4()}.mp4"
    slow_motion_path = generate_slow_motion(frames, trajectory, output_path)

    # Combine debug logs for output
    debug_output = f"{debug_log}\n{trajectory_log}"
    return f"DRS Decision: {decision}\nDebug Log:\n{debug_output}", slow_motion_path

# Gradio interface
iface = gr.Interface(
    fn=drs_review,
    inputs=gr.Video(label="Upload Video Clip"),
    outputs=[
        gr.Textbox(label="DRS Decision and Debug Log"),
        gr.Video(label="Very Slow-Motion Replay with Ball Detection and Trajectory")
    ],
    title="AI-Powered DRS for LBW in Local Cricket",
    description="Upload a video clip of a cricket delivery to get an LBW decision and very slow-motion replay showing ball detection (green boxes) and trajectory (blue dots)."
)

if __name__ == "__main__":
    iface.launch()