c# 视频播放之Vlc.DotNet.Forms

先说下优缺点

优点：与电脑无关，能播放主流编码格式视频。

缺点：只能播放本地视频，网络视频播放不了。

下面是具体操作和代码

1. 安装Vlc.DotNet.Forms 和 VideoLAN.LibVLC.Windows

Vlc.DotNet.Forms 是播放库，VideoLAN.LibVLC.Windows用于播放显示

2. 界面布局

用到 vlcControl： 视频播放组件 ；滑块 TrackBar ：自定义控件，用于显示视频播放进度和音量；button：视频播放和快进

我播放是网上的视频， 所以调用线程先将视频下载到本地，下载完成后在播放。

lTrackBar_vedio 和 lTrackBar_voice 是我自定义的滑块，可以直接用系统默认的滑块控件。

 public partial class Form1 : Form
    {
        private string url = @"http://www.xxxxx.com/video/20240111155329.mp4";
        private string vedioPath = AppDomain.CurrentDomain.BaseDirectory + @"Vedio\123.mp4";
        private long vedioLength = 0;
        private string vedioTime;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            if (!Directory.Exists(AppDomain.CurrentDomain.BaseDirectory + @"\Vedio"))
                Directory.CreateDirectory(AppDomain.CurrentDomain.BaseDirectory + @"\Vedio");

            if (!File.Exists(vedioPath))
            {
                VedioDownloader urlDownloader = new VedioDownloader(vedioPath, url);
                new Thread(new ThreadStart(urlDownloader.DownloadFileAsync)).Start(); ;
            }
            else
            {
                InitVedio();  
            }
        }

        private void InitVedio()
        {
            vlcControl1.Play(new FileInfo(vedioPath));
            button_play.BackgroundImage = Properties.Resources.audioPlay;
            vlcControl1.Audio.Volume = this.lTrackBar_voice.L_Value;
            lTrackBar_vedio.L_Maximum = this.lTrackBar_vedio.Width;
            lTrackBar_vedio.L_Minimum = 0;
        }

        //加载播放需要的库
        private void vlcControl1_VlcLibDirectoryNeeded(object sender, Vlc.DotNet.Forms.VlcLibDirectoryNeededEventArgs e)
        {
            var currentAssembly = Assembly.GetEntryAssembly();
            var currentDirectory = new FileInfo(currentAssembly.Location).DirectoryName;

            if (currentDirectory != null)
            {
                if (IntPtr.Size == 4)
                {
                    e.VlcLibDirectory = new DirectoryInfo(Path.GetFullPath(@".\libvlc\win-x86"));
                }
                else
                {
                    e.VlcLibDirectory = new DirectoryInfo(Path.GetFullPath(@".\libvlc\win-x64"));
                }
            }

            if (!e.VlcLibDirectory.Exists)
            {
                var folderBrowserDialog = new System.Windows.Forms.FolderBrowserDialog();
                folderBrowserDialog.Description = "Select Vlc libraries folder.";
                folderBrowserDialog.RootFolder = Environment.SpecialFolder.Desktop;
                folderBrowserDialog.ShowNewFolderButton = true;
                if (folderBrowserDialog.ShowDialog() == DialogResult.OK)
                {
                    e.VlcLibDirectory = new DirectoryInfo(folderBrowserDialog.SelectedPath);
                }
            }
        }

        private void vlcControl1_TimeChanged(object sender, Vlc.DotNet.Core.VlcMediaPlayerTimeChangedEventArgs e)
        {
            vedioLength = vlcControl1.VlcMediaPlayer.Length;

            string allTime = ConvertTimeStampToDateTime(vedioLength);
            string current = ConvertTimeStampToDateTime(vlcControl1.VlcMediaPlayer.Time);

            this.lTrackBar_vedio.L_Value = Convert.ToInt32(1.0f * (lTrackBar_vedio.L_Maximum - lTrackBar_vedio.L_Minimum) * vlcControl1.VlcMediaPlayer.Time / vedioLength);
           
            vedioTime = current + " / " + allTime;

            SetVedioTime(vedioTime);
        }

        /// 

        /// 使用委托显示视频时间
        /// 
        /// 
        delegate void SetTextCallBack(string text);
        private void SetVedioTime(string vedioTime)
        {
            if (this.label_vedioTime.InvokeRequired)
            {
                SetTextCallBack stcb = new SetTextCallBack(SetVedioTime);
                this.BeginInvoke(stcb, new object[] { vedioTime });
            }
            else
            {
                this.label_vedioTime.Text = vedioTime;
            }
        }

        private string ConvertTimeStampToDateTime(long vedioLength)
        {
            DateTime dt = new DateTime(vedioLength * 10000);
            return dt.Hour.ToString().PadLeft(2, '0') + ":" + dt.Minute.ToString().PadLeft(2, '0') + ":" + dt.Second.ToString().PadLeft(2, '0');
        }

        private void button_play_Click(object sender, EventArgs e)
        {
            if (vlcControl1.State == Vlc.DotNet.Core.Interops.Signatures.MediaStates.Playing)
            {
                vlcControl1.Pause();
                button_play.BackgroundImage = Properties.Resources.audioPause2;
            }
            else
            {
                if (vlcControl1.State == Vlc.DotNet.Core.Interops.Signatures.MediaStates.Ended)
                {
                    InitVedio();
                }
                else
                {
                    button_play.BackgroundImage = Properties.Resources.audioPlay;
                    vlcControl1.Play();
                }
            }
        }

        private void button_voice_Click(object sender, EventArgs e)
        {
            if (lTrackBar_voice.L_Value != 0)
            {
                lTrackBar_voice.L_Value = 0;
                button_voice.BackgroundImage = Properties.Resources.voice_close;
            }
            else
            {
                lTrackBar_voice.L_Value = 80;
                button_voice.BackgroundImage = Properties.Resources.voice_open;
            }
        }

        private void lTrackBar_voice_LValueChanged(object sender, LEventArgs e)
        {
            vlcControl1.Audio.Volume = lTrackBar_voice.L_Value;
        }

        private void vlcControl1_Stopped(object sender, Vlc.DotNet.Core.VlcMediaPlayerStoppedEventArgs e)
        {
            button_play.BackgroundImage = Properties.Resources.audioPause2;
        }

        private void lTrackBar_vedio_MouseMove(object sender, MouseEventArgs e)
        {
            PlayInNewLocation(sender,e);
        }

        private void lTrackBar_vedio_MouseDown(object sender, MouseEventArgs e)
        {
            PlayInNewLocation(sender,e);
        }

        private void PlayInNewLocation(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                if (vlcControl1.State == Vlc.DotNet.Core.Interops.Signatures.MediaStates.Ended)
                {
                    InitVedio();
                }

                vlcControl1.VlcMediaPlayer.Time = this.lTrackBar_vedio.L_Value * vedioLength / (lTrackBar_vedio.L_Maximum - lTrackBar_vedio.L_Minimum);
            }
        }

        private void button1_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
                vlcControl1.Rate = 2.5f;
        }

        private void button1_MouseUp(object sender, MouseEventArgs e)
        {
            vlcControl1.Rate = 1;
        }

        private void Form1_FormClosed(object sender, FormClosedEventArgs e)
        {
            // vlcControl在stop的过程中可能会产生子窗口消息，然而子窗口消息是在主线程（UI线程）中处理的，而stop()方法也是在主线程中调用的，这就造成了竞争性死锁。所以先释放掉主窗体，在释放vlcControl
            this.Dispose();

            if (vlcControl1.State != Vlc.DotNet.Core.Interops.Signatures.MediaStates.Stopped)
                vlcControl1.Stop();
            vlcControl1.Dispose();
        }
    }