Added conversion option

Download.Designer.cs

@@ -70,7 +70,8 @@
             this.Controls.Add(this.lblStatus);
             this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedToolWindow;
             this.Name = "Download";
-            this.Text = "Download";
+            this.Text = "Downloading";
+            this.FormClosing += new System.Windows.Forms.FormClosingEventHandler(this.Download_FormClosing);
             this.Load += new System.EventHandler(this.Download_Load);
             this.ResumeLayout(false);
             this.PerformLayout();

Download.cs

@@ -5,6 +5,7 @@ using System.Data;
 using System.Drawing;
 using System.IO;
 using System.Linq;
+using System.Runtime.Remoting.Contexts;
 using System.Security.AccessControl;
 using System.Security.Policy;
 using System.Text;
@@ -16,10 +17,11 @@ namespace ytdlp_gui
 {
     public partial class Download : Form
     {
-        public Download(YTdlpProcess process, string workdir)
+        public Download(YTdlpProcess process, string workdir, string convert_to)
         {
             this.process = process;
             this.workdir = workdir;
+            this.convert_to = convert_to;
             InitializeComponent();
         }
 
@@ -60,14 +62,37 @@ namespace ytdlp_gui
                 if (File.Exists(newFilePath))
                     System.IO.File.Delete(newFilePath);
 
-                System.IO.File.Move(filePath, newFilePath);
-                System.IO.File.SetLastWriteTime(newFilePath, DateTime.Now);
+                if (convert_to == null || Path.GetExtension(filePath) == convert_to)
+                {
+                    System.IO.File.Move(filePath, newFilePath);
+                    System.IO.File.SetLastWriteTime(newFilePath, DateTime.Now);
+                    this.Close();
+                }
+                else
+                {
+                    newFilePath = Path.ChangeExtension(newFilePath, convert_to);
+                    convertion = (new FFmpeg()).Convert(filePath, newFilePath);
 
-                this.Close();
+                    convertion.Progress += (_ffmpeg, progress_event) =>
+                    {
+                        int progress = (int)(progress_event.progress * 100 + 0.5);
+                        this.Text = "Converting - " + progress.ToString() + "%";
+                        lblStatus.Text = "Converting to " + convert_to;
+                        progressBar.Value = progress;
+                    };
+
+                    convertion.Finished += (_ffmpeg, _ffmpeg_e) =>
+                    {
+                        System.IO.File.Delete(filePath);
+                        this.Close();
+                    };
+
+                    convertion.Run().ContinueWith(t => { MessageBox.Show(t.Exception.ToString(), "Error"); }, TaskContinuationOptions.OnlyOnFaulted); ;
+                }
             };
 
             // Can run in background :)
-            _ = process.Run();
+            process.Run().ContinueWith(t => { MessageBox.Show(t.Exception.ToString(), "Error"); }, TaskContinuationOptions.OnlyOnFaulted);
         }
 
         private void btnCancel_Click(object sender, EventArgs e)
@@ -75,7 +100,15 @@ namespace ytdlp_gui
             this.Close();
         }
 
-        protected readonly string workdir;
+        private void Download_FormClosing(object sender, FormClosingEventArgs e)
+        {
+            if (convertion != null)
+                convertion.Cancel();
+        }
+
         protected readonly YTdlpProcess process;
+        protected FFmpegProcess convertion;
+        protected readonly string workdir;
+        protected readonly string convert_to;
     }
 }

FFmpeg.cs

@@ -1,12 +1,133 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
+using System.Globalization;
+using System.IO;
 using System.Linq;
+using System.Security.Policy;
 using System.Text;
+using System.Text.RegularExpressions;
 using System.Threading.Tasks;
 
 namespace ytdlp_gui
 {
-    internal class FFmpeg
+    public class FFmpegProgressEventArgs : EventArgs
     {
+        public FFmpegProgressEventArgs(float progress)
+        {
+            this.progress = progress;
+        }
+
+        public readonly float progress;
+    }
+
+    public class FFmpegProcess
+    {
+        public FFmpegProcess(Process process, string output_file)
+        {
+            this.process = process;
+            this.output_file = output_file;
+            ci = (CultureInfo)CultureInfo.CurrentCulture.Clone();
+            ci.NumberFormat.CurrencyDecimalSeparator = ".";
+
+            this.header_regex = new Regex(@"Duration: (\d+):(\d+):(\d+)\.(\d+)");
+            this.progress_regex = new Regex(@"time=(\d+):(\d+):(\d+)\.(\d+)");
+        }
+
+        ~FFmpegProcess()
+        {
+            Cancel();
+        }
+
+        public async Task<string> Run()
+        {
+            if (File.Exists(output_file))
+                System.IO.File.Delete(output_file);
+            process.Start();
+
+            int duration = 0;
+            int progress = 0;
+            string line = null;
+            while ((line = await process.StandardError.ReadLineAsync()) != null)
+            {
+                Match match;
+
+                match = header_regex.Match(line);
+                if (match.Success)
+                {
+                    GroupCollection groups = match.Groups;
+                    duration =
+                          int.Parse(groups[1].Value) * 3600
+                        + int.Parse(groups[2].Value) * 60
+                        + int.Parse(groups[3].Value);
+                }
+
+                match = progress_regex.Match(line);
+                if (match.Success)
+                {
+                    GroupCollection groups = match.Groups;
+                    progress =
+                          int.Parse(groups[1].Value) * 3600
+                        + int.Parse(groups[2].Value) * 60
+                        + int.Parse(groups[3].Value);
+
+                    Progress?.Invoke(this, new FFmpegProgressEventArgs((float)progress / duration));
+                }
+            }
+
+            process.WaitForExit();
+            process.Close();
+            Finished?.Invoke(this, new EventArgs());
+
+            return null;
+        }
+
+        public void Cancel()
+        {
+            bool finished = true;
+            try // to kill the process before deleting the file
+            {
+                finished = process.HasExited;
+                process.Kill();
+                process.WaitForExit();
+                process.Close();
+            }
+            catch { }
+            // if (!finished && File.Exists(output_file))
+            //     System.IO.File.Delete(output_file);
+        }
+
+        private readonly Process process;
+        private readonly string output_file;
+        private readonly CultureInfo ci;
+        private readonly Regex header_regex;
+        private readonly Regex progress_regex;
+        public event EventHandler<FFmpegProgressEventArgs> Progress;
+        public event EventHandler Finished;
+    }
+
+    public class FFmpeg : Program
+    {
+        public FFmpeg() : base("ffmpeg")
+        {
+        }
+
+        public FFmpegProcess Convert(string from, string to)
+        {
+            Process process = new Process();
+            process.StartInfo.FileName = program;
+            process.StartInfo.Arguments = String.Format(
+                "-i \"{0}\" \"{1}\"",
+                from.Replace("\"", "\"\"\""),
+                to.Replace("\"", "\"\"\"")
+            );
+
+            process.StartInfo.UseShellExecute = false;
+            process.StartInfo.CreateNoWindow = true;
+            process.StartInfo.RedirectStandardOutput = true;
+            process.StartInfo.RedirectStandardError = true;
+
+            return new FFmpegProcess(process, to);
+        }
     }
 }

Main.Designer.cs

@@ -117,7 +117,6 @@
             this.groupBox2.Controls.Add(this.label3);
             this.groupBox2.Controls.Add(this.comboConvertFormat);
             this.groupBox2.Controls.Add(this.checkConvert);
-            this.groupBox2.Enabled = false;
             this.groupBox2.Location = new System.Drawing.Point(397, 58);
             this.groupBox2.Name = "groupBox2";
             this.groupBox2.Size = new System.Drawing.Size(391, 108);
@@ -157,6 +156,7 @@
             this.checkConvert.TabIndex = 0;
             this.checkConvert.Text = "Convert";
             this.checkConvert.UseVisualStyleBackColor = true;
+            this.checkConvert.CheckedChanged += new System.EventHandler(this.checkConvert_CheckedChanged);
             // 
             // btnDownload
             // 
@@ -188,6 +188,7 @@
             this.checkAudioOnly.TabIndex = 7;
             this.checkAudioOnly.Text = "Audio only";
             this.checkAudioOnly.UseVisualStyleBackColor = true;
+            this.checkAudioOnly.CheckedChanged += new System.EventHandler(this.checkAudioOnly_CheckedChanged);
             // 
             // Main
             // 

Main.cs

@@ -36,7 +36,11 @@ namespace ytdlp_gui
                 false,
                 workdir
             );
-            Download download = new Download(process, workdir);
+            Download download = new Download(
+                process,
+                workdir,
+                checkConvert.Checked ? comboConvertFormat.Text : null
+            );
 
             download.Show();
             downloads.Add(download);
@@ -57,6 +61,19 @@ namespace ytdlp_gui
             );
             e.Cancel = (window == DialogResult.No);
         }
+        
+        private void checkAudioOnly_CheckedChanged(object sender, EventArgs e)
+        {
+            if (checkAudioOnly.Checked)
+                comboConvertFormat.Text = "mp3";
+            else
+                comboConvertFormat.Text = "mp4";
+        }
+
+        private void checkConvert_CheckedChanged(object sender, EventArgs e)
+        {
+            comboConvertFormat.Enabled = checkConvert.Checked;
+        }
 
         protected List<Download> downloads;
         protected YTdlp ytdlp;