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
1 // 创建一个libvlc实例，它是引用计数的
2 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
3 [SuppressUnmanagedCodeSecurity]
4 private static extern IntPtr libvlc_new(int argc, IntPtr argv);
5
6 // 释放libvlc实例
7 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
8 [SuppressUnmanagedCodeSecurity]
9 public static extern void libvlc_release(IntPtr libvlc_instance);
10
11 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
12 [SuppressUnmanagedCodeSecurity]
13 public static extern String libvlc_get_version();
14
15 // 从视频来源(例如Url)构建一个libvlc_meida
16 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
17 [SuppressUnmanagedCodeSecurity]
18 private static extern IntPtr libvlc_media_new_location(IntPtr libvlc_instance, IntPtr path);
19
20 // 从本地文件路径构建一个libvlc_media
21 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
22 [SuppressUnmanagedCodeSecurity]
23 private static extern IntPtr libvlc_media_new_path(IntPtr libvlc_instance, IntPtr path);
24
25 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
26 [SuppressUnmanagedCodeSecurity]
27 public static extern void libvlc_media_release(IntPtr libvlc_media_inst);
28
29 // 创建libvlc_media_player(播放核心)
30 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
31 [SuppressUnmanagedCodeSecurity]
32 public static extern IntPtr libvlc_media_player_new(IntPtr libvlc_instance);
33
34 // 将视频(libvlc_media)绑定到播放器上
35 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
36 [SuppressUnmanagedCodeSecurity]
37 public static extern void libvlc_media_player_set_media(IntPtr libvlc_media_player, IntPtr libvlc_media);
38
39 // 设置图像输出的窗口
40 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
41 [SuppressUnmanagedCodeSecurity]
42 public static extern void libvlc_media_player_set_hwnd(IntPtr libvlc_mediaplayer, Int32 drawable);
43
44 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
45 [SuppressUnmanagedCodeSecurity]
46 public static extern void libvlc_media_player_play(IntPtr libvlc_mediaplayer);
47
48 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
49 [SuppressUnmanagedCodeSecurity]
50 public static extern void libvlc_media_player_pause(IntPtr libvlc_mediaplayer);
51
52 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
53 [SuppressUnmanagedCodeSecurity]
54 public static extern void libvlc_media_player_stop(IntPtr libvlc_mediaplayer);
55
56 // 解析视频资源的媒体信息(如时长等)
57 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
58 [SuppressUnmanagedCodeSecurity]
59 public static extern void libvlc_media_parse(IntPtr libvlc_media);
60
61 // 返回视频的时长(必须先调用libvlc_media_parse之后，该函数才会生效)
62 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
63 [SuppressUnmanagedCodeSecurity]
64 public static extern Int64 libvlc_media_get_duration(IntPtr libvlc_media);
65
66 // 当前播放的时间
67 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
68 [SuppressUnmanagedCodeSecurity]
69 public static extern Int64 libvlc_media_player_get_time(IntPtr libvlc_mediaplayer);
70
71 // 设置播放位置(拖动)
72 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
73 [SuppressUnmanagedCodeSecurity]
74 public static extern void libvlc_media_player_set_time(IntPtr libvlc_mediaplayer, Int64 time);
75
76 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
77 [SuppressUnmanagedCodeSecurity]
78 public static extern void libvlc_media_player_release(IntPtr libvlc_mediaplayer);
79
80 // 获取和设置音量
81 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
82 [SuppressUnmanagedCodeSecurity]
83 public static extern int libvlc_audio_get_volume(IntPtr libvlc_media_player);
84
85 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
86 [SuppressUnmanagedCodeSecurity]
87 public static extern void libvlc_audio_set_volume(IntPtr libvlc_media_player, int volume);
88
89 // 设置全屏
90 [DllImport("libvlc", CallingConvention = CallingConvention.StdCall, ExactSpelling = true)]
91 [SuppressUnmanagedCodeSecurity]
92 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。
1 class VlcPlayer
2 {
3 private IntPtr libvlc_instance_;
4 private IntPtr libvlc_media_player_;
5
6 private double duration_;
7
8 public VlcPlayer(string pluginPath)
9 {
10 string plugin_arg = "--plugin-path=" + pluginPath;
11 string[] arguments = { "-I", "dummy", "--ignore-config", "--no-video-title", plugin_arg };
12 libvlc_instance_ = LibVlcAPI.libvlc_new(arguments);
13
14 libvlc_media_player_ = LibVlcAPI.libvlc_media_player_new(libvlc_instance_);
15 }
16
17 public void SetRenderWindow(int wndHandle)
18 {
19 if (libvlc_instance_ != IntPtr.Zero && wndHandle != 0)
20 {
21 LibVlcAPI.libvlc_media_player_set_hwnd(libvlc_media_player_, wndHandle);
22 }
23 }
24
25 public void PlayFile(string filePath)
26 {
27 IntPtr libvlc_media = LibVlcAPI.libvlc_media_new_path(libvlc_instance_, filePath);
28 if (libvlc_media != IntPtr.Zero)
29 {
30 LibVlcAPI.libvlc_media_parse(libvlc_media);
31 duration_ = LibVlcAPI.libvlc_media_get_duration(libvlc_media) / 1000.0;
32
33 LibVlcAPI.libvlc_media_player_set_media(libvlc_media_player_, libvlc_media);
34 LibVlcAPI.libvlc_media_release(libvlc_media);
35
36 LibVlcAPI.libvlc_media_player_play(libvlc_media_player_);
37 }
38 }
39
40 public void Pause()
41 {
42 if (libvlc_media_player_ != IntPtr.Zero)
43 {
44 LibVlcAPI.libvlc_media_player_pause(libvlc_media_player_);
45 }
46 }
47
48 public void Stop()
49 {
50 if (libvlc_media_player_ != IntPtr.Zero)
51 {
52 LibVlcAPI.libvlc_media_player_stop(libvlc_media_player_);
53 }
54 }
55
56 public double GetPlayTime()
57 {
58 return LibVlcAPI.libvlc_media_player_get_time(libvlc_media_player_) / 1000.0;
59 }
60
61 public void SetPlayTime(double seekTime)
62 {
63 LibVlcAPI.libvlc_media_player_set_time(libvlc_media_player_, (Int64)(seekTime * 1000));
64 }
65
66 public int GetVolume()
67 {
68 return LibVlcAPI.libvlc_audio_get_volume(libvlc_media_player_);
69 }
70
71 public void SetVolume(int volume)
72 {
73 LibVlcAPI.libvlc_audio_set_volume(libvlc_media_player_, volume);
74 }
75
76 public void SetFullScreen(bool istrue)
77 {
78 LibVlcAPI.libvlc_set_fullscreen(libvlc_media_player_, istrue ? 1 : 0);
79 }
80
81 public double Duration()
82 {
83 return duration_;
84 }
85
86 public string Version()
87 {
88 return LibVlcAPI.libvlc_get_version();
89 }
90 }
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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