app.py

import cv2
import math
import numpy as np
from scipy import signal
from scipy.signal import find_peaks
import matplotlib.pyplot as plt
import io
import base64
import gradio as gr
import mediapipe as mp
import os

# Initialize MediaPipe Face Detection
mp_face_detection = mp.solutions.face_detection

def convert_video_if_needed(video_path):
    """Convert video to mp4 if it's in avi format"""
    if video_path.lower().endswith('.avi'):
        output_path = video_path.rsplit('.', 1)[0] + '.mp4'
        try:
            cap = cv2.VideoCapture(video_path)
            fourcc = cv2.VideoWriter_fourcc(*'mp4v')
            out = cv2.VideoWriter(output_path, fourcc, 30.0, 
                                (int(cap.get(3)), int(cap.get(4))))
            
            while cap.isOpened():
                ret, frame = cap.read()
                if not ret:
                    break
                out.write(frame)
                
            cap.release()
            out.release()
            return output_path
        except Exception as e:
            print(f"Error converting video: {e}")
            return video_path
    return video_path

def process_video(video_path):
    """Process video to calculate respiration rate"""
    cap = cv2.VideoCapture(video_path, cv2.CAP_FFMPEG)
    if not cap.isOpened():
        raise ValueError("Error opening video file. Please check the format or path.")

    points = (0, 0, 0, 0)
    fps = cap.get(cv2.CAP_PROP_FPS)
    if not fps or fps == 0:
        fps = 30.0  # Default FPS

    num_frames = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
    if not num_frames or num_frames <= 0:
        num_frames = 1  # Avoid division by zero

    # Detect face for the first frame
    with mp_face_detection.FaceDetection(model_selection=1, min_detection_confidence=0.5) as face_detection:
        while cap.isOpened():
            ret, frame = cap.read()
            if not ret:
                break
            rgb_frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
            results = face_detection.process(rgb_frame)
            if results.detections:
                for detection in results.detections:
                    bboxC = detection.location_data.relative_bounding_box
                    ih, iw, _ = frame.shape
                    x1, y1, w, h = int(bboxC.xmin * iw), int(bboxC.ymin * ih), \
                                  int(bboxC.width * iw), int(bboxC.height * ih)
                    x3 = math.ceil(x1 - (0.75 * w))
                    x4 = math.ceil(x1 + w + (0.75 * w))
                    y3 = math.ceil(y1 + h + (0.3 * h))
                    y4 = math.ceil(y3 + h)
                    w = x4 - x3
                    h = y4 - y3
                points = (x3, y3, w, h)
                break

    # Process frames to get intensity values
    val_list = []
    x, y, w, h = points
    while cap.isOpened():
        ret, frame = cap.read()
        if not ret:
            break
        frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
        cropped_frame = frame[y:y + h, x:x + w]
        int_frame = cv2.integral(cropped_frame)
        val_list.append(int_frame[-1][-1])

    cap.release()

    # Apply Band-Pass-Filter
    data = val_list
    lowcut = 0.16
    highcut = 0.5
    fs = 30  # Sampling frequency
    nyq = 0.5 * fs
    low = lowcut / nyq
    high = highcut / nyq
    order = 5
    b, a = signal.butter(order, [low, high], btype='band')
    filtered = signal.filtfilt(b, a, data)

    # Find peaks and calculate metrics
    peaks, _ = find_peaks(filtered)
    time_length = num_frames / fps if fps > 0 else 0.0
    if time_length == 0.0:
        raise ValueError("Unable to determine video duration.")

    respiration_times = peaks / fps
    rr = math.ceil((len(peaks) / time_length) * 60)

    # Create plot
    plt.figure(figsize=(10, 6))
    plt.plot(filtered, color='orange', label='Filtered Signal')
    plt.plot(peaks, filtered[peaks], "x", color='red', label='Peaks')
    plt.title('Respiratory Signal Analysis', color='darkorange')
    plt.xlabel('Frames', color='darkorange')
    plt.ylabel('Intensity', color='darkorange')
    plt.grid(True, color='lightcoral', alpha=0.3)
    plt.legend()

    # Save plot to BytesIO
    plot_output = io.BytesIO()
    plt.savefig(plot_output, format='png', facecolor='#001f3f', edgecolor='none')
    plt.close()
    plot_output.seek(0)
    plot_img = plot_output.getvalue()

    return {
        "fps": f"{fps:.2f}",
        "frames": str(num_frames),
        "respiration_times": respiration_times.tolist(),
        "duration": f"{time_length:.2f} seconds",
        "respiration_rate": f"{rr} breaths/minute",
        "plot": plot_img
    }

def process_input(video_path):
    """Handle input video processing with error handling"""
    try:
        if video_path is None:
            return ["Please upload a video file."] * 5 + [None]
        
        if not os.path.exists(video_path):
            return ["Video file not found."] * 5 + [None]
            
        # Convert video if needed
        video_path = convert_video_if_needed(video_path)
        result = process_video(video_path)
        
        return [
            result["fps"],
            result["frames"],
            result["respiration_times"],
            result["duration"],
            result["respiration_rate"],
            result["plot"]
        ]
    except Exception as e:
        error_msg = f"Error processing video: {str(e)}"
        return [error_msg] * 5 + [None]

# Create Gradio interface
interface = gr.Interface(
    fn=process_input,
    inputs=gr.Video(
        label="Upload or Stream Video", 
        format=["avi", "mp4", "webm", "mov"]
    ),
    outputs=[
        gr.Label(label="Frames per second"),
        gr.Label(label="Total number of frames"),
        gr.JSON(label="Respiration Times"),
        gr.Label(label="Time Length"),
        gr.Label(label="Respiration Rate (RR)"),
        gr.Image(label="Filtered Peaks Plot")
    ],
    title="Respiration Rate Analyzer",
    description="🫁 Analyze your respiration rate with ease!",
    theme="default",
    css="""
        body {
            background-color: #001f3f;
            color: #f0f8ff;
        }
        .output {
            font-size: 16px;
            color: #f0f8ff;
        }
        .label {
            font-weight: bold;
            color: #0074D9;
        }
        .plot {
            border: 2px solid #0074D9;
            border-radius: 10px;
        }
        .gradio-container {
            background-color: #002b57;
        }
        .output-markdown p {
            color: #f0f8ff !important;
        }
    """
)

interface.launch()