extensvideo.cs

#!/usr/bin/env dotnet run
#:package OpenCvSharp4@4.*
#:package OpenCvSharp4.runtime.win@4.*

/*
    Video Extension Tool (.NET 10)
    Extends a video by adding extra time using the last frame.
    Usage: dotnet run extendvideo.cs

    Demo for El Bruno's YouTube channel: https://www.youtube.com/elbruno
*/

using OpenCvSharp;

// Supported video extensions
string[] videoExtensions = [".mp4", ".avi", ".mov", ".mkv", ".wmv", ".flv"];

Console.WriteLine(new string('=', 50));
Console.WriteLine("       🎥 Video Extension Tool (.NET)");
Console.WriteLine(new string('=', 50));

// Get videos from current folder
var videos = GetVideosFromFolder();

if (videos.Count == 0)
{
    Console.WriteLine("\n❌ No video files found in the current folder.");
    Console.WriteLine("   Supported formats: mp4, avi, mov, mkv, wmv, flv");
    return;
}

// Select video
var selectedVideo = SelectVideo(videos);
Console.WriteLine($"\n✅ Selected: {Path.GetFileName(selectedVideo)}");

// Select extra time
var extraTime = SelectExtraTime();
Console.WriteLine($"✅ Extra time: {extraTime} seconds");

// Extend the video
try
{
    var (outputPath, originalDuration, newDuration) = ExtendVideo(selectedVideo, extraTime);

    // Show results
    Console.WriteLine("\n" + new string('=', 50));
    Console.WriteLine("                 📊 Results");
    Console.WriteLine(new string('=', 50));
    Console.WriteLine($"  Original duration: {FormatDuration(originalDuration)}");
    Console.WriteLine($"  New duration:      {FormatDuration(newDuration)}");
    Console.WriteLine($"  New video:         {Path.GetFileName(outputPath)}");
    Console.WriteLine(new string('=', 50));
    Console.WriteLine("\n✅ Video extended successfully!");
}
catch (Exception ex)
{
    Console.WriteLine($"\n❌ Error processing video: {ex.Message}");
}

// --- Functions ---

List<string> GetVideosFromFolder(string folder = ".")
{
    var videos = new List<string>();
    foreach (var ext in videoExtensions)
    {
        videos.AddRange(Directory.GetFiles(folder, $"*{ext}", SearchOption.TopDirectoryOnly));
    }
    return videos.Take(5).ToList();
}

string SelectVideo(List<string> videoList)
{
    Console.WriteLine("\n📹 Available videos:");
    for (int i = 0; i < videoList.Count; i++)
    {
        var defaultLabel = i == 0 ? " (default)" : "";
        Console.WriteLine($"  {i + 1}. {Path.GetFileName(videoList[i])}{defaultLabel}");
    }

    Console.Write("\nSelect a video [1]: ");
    var choice = Console.ReadLine()?.Trim() ?? "";

    if (string.IsNullOrEmpty(choice) || !int.TryParse(choice, out int idx))
        return videoList[0];

    idx--;
    return (idx >= 0 && idx < videoList.Count) ? videoList[idx] : videoList[0];
}

int SelectExtraTime()
{
    int[] options = [5, 10, 15];
    Console.WriteLine("\n⏱️  Select extra time (seconds):");
    for (int i = 0; i < options.Length; i++)
    {
        var defaultLabel = options[i] == 5 ? " (default)" : "";
        Console.WriteLine($"  {i + 1}. {options[i]} seconds{defaultLabel}");
    }

    Console.Write("\nSelect extra time [1]: ");
    var choice = Console.ReadLine()?.Trim() ?? "";

    if (string.IsNullOrEmpty(choice) || !int.TryParse(choice, out int idx))
        return 5;

    idx--;
    return (idx >= 0 && idx < options.Length) ? options[idx] : 5;
}

(string outputPath, double originalDuration, double newDuration) ExtendVideo(string videoPath, int extraSeconds)
{
    Console.WriteLine($"\n🎬 Processing: {Path.GetFileName(videoPath)}");

    // Open the video
    using var cap = new VideoCapture(videoPath);
    if (!cap.IsOpened())
        throw new Exception($"Cannot open video: {videoPath}");

    // Get video properties
    var fps = cap.Fps;
    var width = (int)cap.Get(VideoCaptureProperties.FrameWidth);
    var height = (int)cap.Get(VideoCaptureProperties.FrameHeight);
    var totalFrames = (int)cap.Get(VideoCaptureProperties.FrameCount);
    var originalDuration = totalFrames / fps;

    // Generate output filename
    var directory = Path.GetDirectoryName(videoPath) ?? ".";
    var baseName = Path.GetFileNameWithoutExtension(videoPath);
    var ext = Path.GetExtension(videoPath);
    var outputPath = Path.Combine(directory, $"{baseName}_extended{ext}");

    // Set up video writer
    var fourcc = FourCC.MP4V;
    using var writer = new VideoWriter(outputPath, fourcc, fps, new Size(width, height));

    Console.WriteLine("📝 Writing extended video...");
    using var lastFrame = new Mat();
    var frameCount = 0;

    // Copy all original frames
    using var frame = new Mat();
    while (true)
    {
        if (!cap.Read(frame) || frame.Empty())
            break;

        frame.CopyTo(lastFrame);
        writer.Write(frame);
        frameCount++;

        if (frameCount % 100 == 0)
            Console.Write($"\r   Processed {frameCount}/{totalFrames} frames...");
    }
    Console.WriteLine($"\r   Processed {frameCount}/{totalFrames} frames...    ");

    // Add extra frames using the last frame
    var extraFrames = (int)(extraSeconds * fps);
    Console.WriteLine($"   Adding {extraFrames} extra frames ({extraSeconds}s)...");

    for (int i = 0; i < extraFrames; i++)
    {
        writer.Write(lastFrame);
        if ((i + 1) % 100 == 0)
            Console.Write($"\r   Added {i + 1}/{extraFrames} extra frames...");
    }
    Console.WriteLine($"\r   Added {extraFrames}/{extraFrames} extra frames...    ");

    var newDuration = originalDuration + extraSeconds;
    return (outputPath, originalDuration, newDuration);
}

string FormatDuration(double seconds)
{
    var minutes = (int)(seconds / 60);
    var secs = (int)(seconds % 60);
    return $"{minutes:D2}:{secs:D2}";
}