code request for youtube downloader

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C#

Been some time since I last posted something here so I thought I could post my latest project.

It's a youtube downloader written in C#.

Some code, I started with making a DLL which should contain all youtube functions I needed.

YoutubeDownload.DLL

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.IO;
using System.Diagnostics;

namespace YoutubeDownloadDLL
{
    static public class YoutubeDownload
    {
        public enum formatType
        {
            mp3 = 0,
            mp4 = 1,
            flv = 2,
            mpg = 3,
            avi = 4
        }

        /// <summary>
        /// Gets a downloadable youtube link
        /// </summary>
        /// <param name="strUrl">the url to the video</param>
        /// <returns>returns the link on success, else it returns string.empty</returns>
        static public string GetYoutubeLink(string strUrl)
        {
            try
            {
                //Get the key from the url
                string strKey = strUrl.Substring(strUrl.LastIndexOf("v=") + 2, 11);

                if (strKey == string.Empty)
                    throw new ArgumentException();

                //Get the token from the video info
                Uri infoUri = new Uri("http://youtube.com/get_video_info?video_id=" + strKey);
                string strToken = getTokenFromUri(infoUri);

                if (strToken == string.Empty)
                    return string.Empty;

                string strDownloadLink =
                    "http://www.youtube.com/get_video.php?video_id=" + strKey + "&t=" + strToken + "&fmt=18";
                
                return strDownloadLink;
            }
            catch (Exception ex)
            {
                //Handle exception
            }
            return string.Empty;
        }

        /// <summary>
        /// This function requires ffmpeg, make a folder called ffmpeg in your project folder
        /// </summary>
        /// <param name="strInputFile">path to input file, .mp4 (e.g. file1.mp4)</param>
        /// <param name="strOutPutFile">path to output file, .mp3 (e.g. file2.mp3)</param>
        /// <returns></returns>
        static public int EncodeFormatFromMp4ToMp3(string strInputFile,
                                                    string strOutPutFile,
                                                    bool bolKeepInputFile)
        {
            ProcessStartInfo startInfo = new ProcessStartInfo();
            startInfo.FileName = "ffmpeg.EXE";
            startInfo.Arguments = "-i \"" + strInputFile + "\" -vn -ac 1 \"" + strOutPutFile + "\"";
            startInfo.CreateNoWindow = true;
            startInfo.WindowStyle = ProcessWindowStyle.Hidden;
            Process prcProcess = new Process();
            prcProcess.StartInfo = startInfo;
            prcProcess.Start();

            prcProcess.WaitForExit();
            prcProcess.Close();

            if (!bolKeepInputFile)
            {
                File.Delete(strInputFile);
            }

            return 0;
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="strDownloadLink">download link</param>
        /// <param name="objFormat">the format you want to save the file as</param>
        /// <param name="strOutputFileName">output file name</param>
        /// <returns></returns>
        static public int CreateFileFromYoutubeDownloadLink(string strDownloadLink,
                                                            string strOutputFileName)
        {
            Uri objUri = new Uri(strDownloadLink);

            //Get file content
            WebRequest wrRequest = WebRequest.Create(objUri);
            WebResponse wrResponse = wrRequest.GetResponse();
            Stream objStream = wrResponse.GetResponseStream();

            FileStream fsStream = new FileStream(strOutputFileName, FileMode.Create);
            byte[] bteRead = new byte[256];

            int iCount = objStream.Read(bteRead, 0, bteRead.Length);

            while (iCount > 0)
            {
                fsStream.Write(bteRead, 0, iCount);
                iCount = objStream.Read(bteRead, 0, bteRead.Length);
            }

            fsStream.Close();
            objStream.Close();
            wrResponse.Close();


            return 0;
        }

        /// <summary>
        /// Gets the title of the youtube link
        /// </summary>
        /// <param name="strUrl">url to youtube video</param>
        /// <returns>return title on success</returns>
        static public string GetTitleFromYoutubeLink(string strUrl)
        {
            try
            {
                Uri objUri = new Uri(strUrl);

                //Get file content
                WebRequest wrRequest = WebRequest.Create(objUri);
                WebResponse wrResponse = wrRequest.GetResponse();
                Stream objStream = wrResponse.GetResponseStream();
                StreamReader objReader = new StreamReader(objStream);

                //Hopefully got it!
                string strFileContent = objReader.ReadToEnd();

                //Calculate the title length
                int iTitlePos = strFileContent.LastIndexOf("<meta name=\"title\" content=\"") + 28;
                int iEndTitlePos = strFileContent.IndexOf("\">", iTitlePos);
                int iDifference = iEndTitlePos - iTitlePos;

                //Moving on to finding the title
                string strTitle = strFileContent.Substring(iTitlePos, iDifference);

                objStream.Close();
                objReader.Close();
                wrResponse.Close();

                return strTitle;
            }
            catch (Exception ex)
            {
                //ex
            }
            return string.Empty;
        }

        static private string getTokenFromUri(Uri objUri)
        {
            //Get file content
            WebRequest wrRequest = WebRequest.Create(objUri);
            WebResponse wrResponse = wrRequest.GetResponse();
            Stream objStream = wrResponse.GetResponseStream();
            StreamReader objReader = new StreamReader(objStream);

            //Hopefully got it!
            string strFileContent = objReader.ReadToEnd();

            //Calculate the token length
            int iTokenPos = strFileContent.LastIndexOf("&token=") + 7;
            int iThumbPos = strFileContent.LastIndexOf("&thumbnail_url=");
            int iDifference = iThumbPos - iTokenPos;

            //Moving on to finding the token
            string strToken = strFileContent.Substring(iTokenPos, iDifference);

            objReader.Close();
            objStream.Close();
            wrResponse.Close();

            if (strToken == string.Empty)
                return string.Empty;
            else
                return strToken;
        }
    }
}

As you can see I use ffmpeg to convert from mp4 to mp3, do you guys have any better ways of converting files other than using ffmpeg.exe?
Here is a picture of the application running:
Screen shot:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Net;
using System.Threading;
using YoutubeDownloadDLL;

namespace KekTube_Downloader
{
    public partial class frmMain : Form
    {
        private static int iPercentProgress;
        private delegate void UpdateProgessCallback(Int64 BytesRead, Int64 TotalBytes);
        private delegate void SetTextCallback(string strText);
        private Thread thrDownload;

        public frmMain()
        {
            InitializeComponent();
        }

        private void txtYoutubeLink_Enter(object sender, EventArgs e)
        {
            this.txtYoutubeLink.Text = "";
        }

        private void txtYoutubeLink_Leave(object sender, EventArgs e)
        {
            if (this.txtYoutubeLink.Text == "")
                this.txtYoutubeLink.Text = "URL to Youtube movie";
        }

        private void txtYoutubeLink_TextChanged(object sender, EventArgs e)
        {
            if (this.txtYoutubeLink.Text.IndexOf("watch") > 0)
            {
                this.lblTitle.Text = YoutubeDownload.GetTitleFromYoutubeLink(this.txtYoutubeLink.Text);
                this.lblOrgTitle.Text = "video4.mp4";

                string strFormat = string.Empty;

                if (cboMp3.Checked)
                    strFormat = ".mp3";
                else if (cboMp4.Checked)
                    strFormat = ".mp4";
                else
                    strFormat = ".mp4";

                if (this.cboCustom.Checked)
                {
                    this.lblSaveAs.Text = this.txtCustomName.Text + strFormat;
                }
                else
                {
                    this.lblSaveAs.Text = this.lblTitle.Text + strFormat;
                }
            }
        }

        private void cboMp4_CheckedChanged(object sender, EventArgs e)
        {
            if (this.cboMp4.Checked)
            {
                //Set all to false except for the format the user wants
                this.cboMp3.Checked = false;

                this.lblSaveAs.Text = this.lblSaveAs.Text.Substring(0, this.lblSaveAs.Text.Length - 1) + "4";
            }
        }

        private void cboMp3_CheckedChanged(object sender, EventArgs e)
        {
            if (this.cboMp3.Checked)
            {
                //Set all to false except for the format the user wants
                this.cboMp4.Checked = false;

                this.lblSaveAs.Text = this.lblSaveAs.Text.Substring(0, this.lblSaveAs.Text.Length - 1) + "3";
            }
        }

        private void cboCustom_CheckedChanged(object sender, EventArgs e)
        {
            string strFormat = string.Empty;

            if (cboMp3.Checked)
                strFormat = ".mp3";
            else if (cboMp4.Checked)
                strFormat = ".mp4";
            else
                strFormat = ".mp4";

            if (this.cboCustom.Checked)
            {
                this.cboOrg.Checked = false;
                this.txtCustomName.Enabled = true;
                this.lblSaveAs.Text = this.txtCustomName.Text + strFormat;
            }
            else
            {
                this.lblSaveAs.Text = this.lblTitle.Text + strFormat;
                this.txtCustomName.Enabled = false;
            }
        }

        private void txtCustomName_TextChanged(object sender, EventArgs e)
        {
            string strFormat = string.Empty;

            if (cboMp3.Checked)
                strFormat = ".mp3";
            else if (cboMp4.Checked)
                strFormat = ".mp4";
            else
                strFormat = ".mp4";

            this.lblSaveAs.Text = this.txtCustomName.Text + strFormat;

        }

        private void cboOrg_CheckedChanged(object sender, EventArgs e)
        {
            string strFormat = string.Empty;

            if (cboMp3.Checked)
                strFormat = ".mp3";
            else if (cboMp4.Checked)
                strFormat = ".mp4";
            else
                strFormat = ".mp4";

            if (this.cboOrg.Checked)
            {
                this.cboCustom.Checked = false;
                this.lblSaveAs.Text = "video4" + strFormat;
            }
            else
            {
                if (!this.cboCustom.Checked)
                {
                    this.lblSaveAs.Text = this.lblTitle.Text + strFormat;
                }
            }
        }

        private void lblTitle_TextChanged(object sender, EventArgs e)
        {
            if (this.lblTitle.Text != "")
            {

            }
        }

        private void btnDownload_Click(object sender, EventArgs e)
        {
            tboLog.Text += "[*] Checking if download link is valid..." + Environment.NewLine;
            //Check so that we have a valid link
            if (this.txtYoutubeLink.Text.IndexOf("watch?v=") > 0)
            {
                tboLog.Text += "[*] Download link is valid, starting download..." + Environment.NewLine;
                thrDownload = new Thread(Download);
                thrDownload.Start();
            }
        }

        private void Download()
        {
            try
            {
                Uri objUri = new Uri(YoutubeDownload.GetYoutubeLink(this.txtYoutubeLink.Text));

                //Get file content
                WebRequest wrRequest = WebRequest.Create(objUri);
                WebResponse wrResponse = wrRequest.GetResponse();
                Stream objStream = wrResponse.GetResponseStream();

                Int64 fileSize = wrResponse.ContentLength;

                if (!Directory.Exists(Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\\KekTube"))
                {
                    Directory.CreateDirectory(Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\\KekTube");
                }

                FileStream fsStream = new FileStream(Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\\KekTube\\" + this.lblOrgTitle.Text, FileMode.Create, FileAccess.Write);
                byte[] bteRead = new byte[256];

                int iCount = objStream.Read(bteRead, 0, bteRead.Length);

                while (iCount > 0)
                {
                    fsStream.Write(bteRead, 0, iCount);
                    iCount = objStream.Read(bteRead, 0, bteRead.Length);

                    this.Invoke(new UpdateProgessCallback(this.UpdateProgress), new object[] { fsStream.Length, fileSize });
                }

                fsStream.Close();
                objStream.Close();
                wrResponse.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            finally
            {
                if (this.cboMp3.Checked)
                {
                    YoutubeDownload.EncodeFormatFromMp4ToMp3(Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\\KekTube\\" + this.lblOrgTitle.Text,
                        Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\\KekTube\\" + this.lblSaveAs.Text, false);
                }
                else
                {
                    File.Copy(Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\\KekTube\\" + this.lblOrgTitle.Text,
                        Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\\KekTube\\" + this.lblSaveAs.Text, true);
                    File.Delete(Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\\KekTube\\video4.mp4");
                }
                if (this.tboLog.InvokeRequired)
                {
                    string strUpdateText = "[*] File completly downloaded, it can be accessed at " + Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\\KekTube\\";
                    // It's on a different thread, so use Invoke.
                    SetTextCallback d = new SetTextCallback(updateLog);
                    this.Invoke
                        (d, new object[] { strUpdateText });
                }

            }
        }

        private void updateLog(string strText)
        {
            this.tboLog.Text += strText;
        }

        private void UpdateProgress(Int64 BytesRead, Int64 TotalBytes)
        {
            iPercentProgress = Convert.ToInt32((BytesRead * 100) / TotalBytes);
            this.pgbDownloadFile.Value = iPercentProgress;
        }
    }
}

Am getting the error “URI is empty & URI is Invalid

an I downloaded many projects from your website but I am getting the errors always

am using the Microsoft Visual studio 2010