java - VLCJ 中的流式桌面

Question

我正在尝试编写一个Java程序，它允许一个用户充当服务器并流式传输其桌面(视频和音频)，然后其他用户充当客户端并观看其桌面的实时流(类似于Twitch， Webex、Skype 屏幕共享等)。我正在为此使用 VLCJ，尽管我没有 promise 使用它，所以如果有更好的解决方案，我会洗耳恭听。这是从我在下面提供的链接复制的代码:

package test.java;

import uk.co.caprica.vlcj.discovery.NativeDiscovery;
import uk.co.caprica.vlcj.player.MediaPlayerFactory;
import uk.co.caprica.vlcj.player.headless.HeadlessMediaPlayer;
import test.java.VlcjTest;

/**
* An example of how to stream a media file over HTTP.
* <p>
* The client specifies an MRL of <code>http://127.0.0.1:5555</code>
*/
public class StreamHttp extends VlcjTest {

    //when running this it requires an MRL (Media Resource Locator)
    //fancy term for saying the file you want to stream. This could be a url to another
    //location that streams media or a filepath to a media file you want to stream
    //on the system you are running this code on.
    public static void main(String[] args) throws Exception {
        new NativeDiscovery().discover();
        if(args.length != 1) {
            System.out.println("Specify a single MRL to stream");
            System.exit(1);
        }

        //the media you are wanting to stream
        String media = args[0];
        //this is the IP address and port you are wanting to stream at
        //this means clients will connect to http://127.0.0.1:5555
        //to watch the stream
        String options = formatHttpStream("127.0.0.1", 5555);

        System.out.println("Streaming '" + media + "' to '" + options + "'");

        //this creates a the actual media player that will make calls into the native
        //vlc libraries to actually play the media you supplied. It does it in
        //a headless fashion, as you are going to stream it over http to be watched
        //instead of playing it locally to be watched.    
        MediaPlayerFactory mediaPlayerFactory = new MediaPlayerFactory(args);
        HeadlessMediaPlayer mediaPlayer = mediaPlayerFactory.newHeadlessMediaPlayer();

        //this simply starts the player playing the media you gave it
        mediaPlayer.playMedia(media, options);

        // Don't exit
        //basically you don't want the thread to end and kill the player, 
        //so it just hangs around and waits for it to end.
        Thread.currentThread().join();
    }

    private static String formatHttpStream(String serverAddress, int serverPort) {
        StringBuilder sb = new StringBuilder(60);
        sb.append(":sout=#duplicate{dst=std{access=http,mux=ts,");
        sb.append("dst=");
        sb.append(serverAddress);
        sb.append(':');
        sb.append(serverPort);
        sb.append("}}");
        return sb.toString();
    }
}

我将“screen://”作为参数传递给该程序。当我运行代码时，我收到以下错误消息:

[000000000038b250] access_output_http access out: Consider passing --http-host=IP on the command line instead.
[000000001ccaa220] core mux error: cannot add this stream
[000000001cc72100] core decoder error: cannot create packetizer output (RV32)

我尝试寻找解决方案，但我所能找到的只是: Video Streaming in vlcj尽管该用户有相同的错误，但我无法从此链接解决我的问题，尽管我确实使用了其中的 StreamHttp 代码示例。我是一个相对缺乏经验的程序员，所以如果我错过了一个明显的解决方案，那么我深表歉意。我使用的是 Java 1.8、Windows 7 64 位。

Answer 1

你需要这样的东西:

String media = "screen://";
String[] options = {
    ":sout=#transcode{vcodec=FLV1,vb=4096,scale=0.500000}:http{mux=ffmpeg{mux=flv},dst=:5000/"
};

此处显示的关键内容是用于对视频进行转码的“sout”字符串，然后是另一个附加的“sout”字符串以进行流传输(在本例中通过 http)。

在此示例字符串中，对于 http 流，仅指定端口(5000，任意选择)。未指定主机，因此表示 localhost。您可以使用“dst=127.0.0.1:8080/”或任何您需要的内容。

您必须选择/试验您想要的特定转码/流媒体选项。没有一种方法适合所有这些选项。

脚注:

您实际上可以使用 VLC 本身来为您生成此字符串。

启动 VLC，然后选择您要播放的媒体。

不要按“播放”，而是使用小部件选择“流”。这将打开流媒体向导，您可以在其中选择所有选项。

在向导结束时，在您开始演奏之前，它会向您显示所需的字符串。