c#万能视频播放器
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
// 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：
- 创建libvlc_instance
- 创建libvlc_media_player
- 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
- 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 != )
{
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 * ));
}
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 ? : );
}
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
程序做好之后，需要带上libvlc.dll和libvlccore.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.dll和libvlccore.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。
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