2013年3月22日星期五

C#使用libvlc实现万能视频播放器介绍

本人之前很多的文章中均提到了使用libvlc为播放器内核制作的播放器,也许有些朋友对此感兴趣,于是我用c#写了一个调用libvlc api实现的万能视频播放器,与大家分享一下。说它“万能”,当然是因为我们站在了vlc的肩膀上。
  vlc是一个 强大而且开源的多媒体播放器,也可以说是一个多媒体平台。它支持非常广泛的媒体格式的本地播放,完全可以媲美mplayer,其对视频网络流的处理能力更 是非常强悍。libvlc就是指的vlc的核心,它向外提供了一系列的接口,通过接口,来实现视频播放等复杂的功能。libvlc对外提供了c语言的接 口,也有其他语言,包括.net的绑定,在其官网上就有,不过已经“年久失修”。我之前用Qt, MFC实现过基于libvlc的播放器,不过鉴于园子里c#开发人员较多,遂用c#封装了一下libvlc的API接口,并实现了一个视频播放器。
  先上鉴赏图,外表很简单,不过,外表不是重点:)



 首先是libvlc的一些导出函数,我在注释里对它们的功能都有说明
 

  程序做好之后,需要带上libvlc.dlllibvlccore.dll,这两个是vlc的播放内核,因为vlc把编解码和格式解析的支持设计成了插件的形式,所以还必须要带上vlc的plugins目录里的插件。
  我把整个工程打包(包括libvlc.dlllibvlccore.dll)上传到了博客上,点击这里,就可以下载。
  plugins目录文件有点大(因为libvlc支持的格式和功能非常多,如果你不需要,删掉对应插件即可),我放到了115网盘,下载地址是http://115.com/file/dnre4jg7#plugins.7z。下载后放到“bin/Debug”目录即可调试运行。
// 创建一个libvlc实例,它是引用计数的 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] private static extern IntPtr libvlc_new(int argc, IntPtr argv); // 释放libvlc实例 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern void libvlc_release(IntPtr libvlc_instance); [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern String libvlc_get_version(); // 从视频来源(例如Url)构建一个libvlc_meida [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] private static extern IntPtr libvlc_media_new_location(IntPtr libvlc_instance, IntPtr path); // 从本地文件路径构建一个libvlc_media [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] private static extern IntPtr libvlc_media_new_path(IntPtr libvlc_instance, IntPtr path); [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern void libvlc_media_release(IntPtr libvlc_media_inst); // 创建libvlc_media_player(播放核心) [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern IntPtr libvlc_media_player_new(IntPtr libvlc_instance); // 将视频(libvlc_media)绑定到播放器上 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern void libvlc_media_player_set_media(IntPtr libvlc_media_player, IntPtr libvlc_media); // 设置图像输出的窗口 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern void libvlc_media_player_set_hwnd(IntPtr libvlc_mediaplayer, Int32 drawable); [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern void libvlc_media_player_play(IntPtr libvlc_mediaplayer); [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern void libvlc_media_player_pause(IntPtr libvlc_mediaplayer); [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern void libvlc_media_player_stop(IntPtr libvlc_mediaplayer); // 解析视频资源的媒体信息(如时长等) [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern void libvlc_media_parse(IntPtr libvlc_media); // 返回视频的时长(必须先调用libvlc_media_parse之后,该函数才会生效) [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern Int64 libvlc_media_get_duration(IntPtr libvlc_media); // 当前播放的时间 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern Int64 libvlc_media_player_get_time(IntPtr libvlc_mediaplayer); // 设置播放位置(拖动) [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern void libvlc_media_player_set_time(IntPtr libvlc_mediaplayer, Int64 time); [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern void libvlc_media_player_release(IntPtr libvlc_mediaplayer); // 获取和设置音量 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern int libvlc_audio_get_volume(IntPtr libvlc_media_player); [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern void libvlc_audio_set_volume(IntPtr libvlc_media_player, int volume); // 设置全屏 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)] [SuppressUnmanagedCodeSecurity] public static extern void libvlc_set_fullscreen(IntPtr libvlc_media_player, int isFullScreen);
要使用libvlc api进行播放,首先需要创建一个libvlc的实例,就是lbvlc_instance,之后所有的操作都是基于这个实例来完成。
  每一个播放窗口,对应一个libvlc_media_player,而每一个媒体文件,就是一个libvlc_media。所以,调用的步骤就是:
    1. 创建libvlc_instance
    2. 创建libvlc_media_player
    3. 开始播放时,创建libvlc_media,通知libvlc_media_player要播放的媒体文件,之后就可以释放libvlc_media了
    4. 操作libvlc_media_player,实现播放、暂停等功能
  下面对这些操作进行封装,以供上层使用。
class VlcPlayer { private IntPtr libvlc_instance_; private IntPtr libvlc_media_player_; private double duration_; public VlcPlayer(string pluginPath) { string plugin_arg = "--plugin-path=" + pluginPath; string[] arguments = { "-I", "dummy", "--ignore-config", "--no-video-title", plugin_arg }; libvlc_instance_ = LibVlcAPI.libvlc_new(arguments); libvlc_media_player_ = LibVlcAPI.libvlc_media_player_new(libvlc_instance_); } public void SetRenderWindow(int wndHandle) { if (libvlc_instance_ != IntPtr.Zero && wndHandle != 0) { LibVlcAPI.libvlc_media_player_set_hwnd(libvlc_media_player_, wndHandle); } } public void PlayFile(string filePath) { IntPtr libvlc_media = LibVlcAPI.libvlc_media_new_path(libvlc_instance_, filePath); if (libvlc_media != IntPtr.Zero) { LibVlcAPI.libvlc_media_parse(libvlc_media); duration_ = LibVlcAPI.libvlc_media_get_duration(libvlc_media) / 1000.0; LibVlcAPI.libvlc_media_player_set_media(libvlc_media_player_, libvlc_media); LibVlcAPI.libvlc_media_release(libvlc_media); LibVlcAPI.libvlc_media_player_play(libvlc_media_player_); } } public void Pause() { if (libvlc_media_player_ != IntPtr.Zero) { LibVlcAPI.libvlc_media_player_pause(libvlc_media_player_); } } public void Stop() { if (libvlc_media_player_ != IntPtr.Zero) { LibVlcAPI.libvlc_media_player_stop(libvlc_media_player_); } } public double GetPlayTime() { return LibVlcAPI.libvlc_media_player_get_time(libvlc_media_player_) / 1000.0; } public void SetPlayTime(double seekTime) { LibVlcAPI.libvlc_media_player_set_time(libvlc_media_player_, (Int64)(seekTime * 1000)); } public int GetVolume() { return LibVlcAPI.libvlc_audio_get_volume(libvlc_media_player_); } public void SetVolume(int volume) { LibVlcAPI.libvlc_audio_set_volume(libvlc_media_player_, volume); } public void SetFullScreen(bool istrue) { LibVlcAPI.libvlc_set_fullscreen(libvlc_media_player_, istrue ? 1 : 0); } public double Duration() { return duration_; } public string Version() { return LibVlcAPI.libvlc_get_version(); } }
封装为VlcPlayer之后,调用就会变得非常简单。
  • 首先确定好vlc的插件目录
  • 在你的代码里创建VlcPlayer对象
  • 调用SetRenderWindow,以设置视频显示的窗口,否则会变成一个独立的播放窗口
  • 调用PlayFile,即可开始播放

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