如何在Java应用程序中传输实时视频？

Question

我正在努力寻找方法来流Java应用程序中生成的实时视频。应用程序需要获取其自身的屏幕截图，并将其编码为视频流并发布该流。

到目前为止，我一直在使用夏格勒 (FFMPEG之上的Java库)将截图编码成视频文件。这个很好用。Xuggler声称能够通过RTMP传输实时视频，但我还没有找到任何关于如何以编程方式实现这一功能的文档。

1. 有谁知道如何以编程方式从Xuggler那里播放RTMP视频吗？
2. 有没有人对我可以用来达到同样结果的其他库有什么建议？我更喜欢通过RTP在MPEG2上播放视频。

我确实在这里上发现了其他人在问一个非常类似的问题，但没有回应。

我曾研究过JMF，但由于其他原因，这不是一种选择。

Answer 1

老实说，不要把你的时间浪费在JMF上，你可以认为这样做是徒劳的。下面是如何使用h.264对rtmp流进行屏幕切换(感谢tyreus@gmail.com的例子)。如果代码没有出现，这里有用于它的pastebin：http://pastebin.com/sJHwj0nW

import com.xuggle.xuggler.Configuration;
import com.xuggle.xuggler.ICodec;
import com.xuggle.xuggler.IContainer;
import com.xuggle.xuggler.IContainerFormat;
import com.xuggle.xuggler.IPacket;
import com.xuggle.xuggler.IPixelFormat;
import com.xuggle.xuggler.IRational;
import com.xuggle.xuggler.IStream;
import com.xuggle.xuggler.IStreamCoder;
import com.xuggle.xuggler.IVideoPicture;
import com.xuggle.xuggler.video.ConverterFactory;
import com.xuggle.xuggler.video.IConverter;
import java.awt.AWTException;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

public class XugglerRtmpReferenceImpl {

   private static String url = "rtmp://your.test.server/screen/";
   private static String fileName = "test/teststream";
   private static int framesToEncode = 60;
   private static int x = 0;
   private static int y = 0;
   private static int height = 480;
   private static int width = 640;

   public static void main(String[] args) {
       IContainer container = IContainer.make();
       IContainerFormat containerFormat_live = IContainerFormat.make();
       containerFormat_live.setOutputFormat("flv", url + fileName, null);
       container.setInputBufferLength(0);
       int retVal = container.open(url + fileName, IContainer.Type.WRITE, containerFormat_live);
       if (retVal < 0) {
           System.err.println("Could not open output container for live stream");
           System.exit(1);
       }
       IStream stream = container.addNewStream(0);
       IStreamCoder coder = stream.getStreamCoder();
       ICodec codec = ICodec.findEncodingCodec(ICodec.ID.CODEC_ID_H264);
       coder.setNumPicturesInGroupOfPictures(5);
       coder.setCodec(codec);
       coder.setBitRate(200000);
       coder.setPixelType(IPixelFormat.Type.YUV420P);
       coder.setHeight(height);
       coder.setWidth(width);
       System.out.println("[ENCODER] video size is " + width + "x" + height);
       coder.setFlag(IStreamCoder.Flags.FLAG_QSCALE, true);
       coder.setGlobalQuality(0);
       IRational frameRate = IRational.make(5, 1);
       coder.setFrameRate(frameRate);
       coder.setTimeBase(IRational.make(frameRate.getDenominator(), frameRate.getNumerator()));
       Properties props = new Properties();
       InputStream is = XugglerRtmpReferenceImpl.class.getResourceAsStream("/libx264-normal.ffpreset");
       try {
           props.load(is);
       } catch (IOException e) {
           System.err.println("You need the libx264-normal.ffpreset file from the Xuggle distribution in your classpath.");
           System.exit(1);
       }
       Configuration.configure(props, coder);
       coder.open();
       container.writeHeader();
       long firstTimeStamp = System.currentTimeMillis();
       long lastTimeStamp = -1;
       int i = 0;
       try {
           Robot robot = new Robot();
           while (i < framesToEncode) {
               //long iterationStartTime = System.currentTimeMillis();
               long now = System.currentTimeMillis();
               //grab the screenshot
               BufferedImage image = robot.createScreenCapture(new Rectangle(x, y, width, height));
               //convert it for Xuggler
               BufferedImage currentScreenshot = new BufferedImage(image.getWidth(), image.getHeight(), BufferedImage.TYPE_3BYTE_BGR);
               currentScreenshot.getGraphics().drawImage(image, 0, 0, null);
               //start the encoding process
               IPacket packet = IPacket.make();
               IConverter converter = ConverterFactory.createConverter(currentScreenshot, IPixelFormat.Type.YUV420P);
               long timeStamp = (now - firstTimeStamp) * 1000; 
               IVideoPicture outFrame = converter.toPicture(currentScreenshot, timeStamp);
               if (i == 0) {
                   //make first frame keyframe
                   outFrame.setKeyFrame(true);
               }
               outFrame.setQuality(0);
               coder.encodeVideo(packet, outFrame, 0);
               outFrame.delete();
               if (packet.isComplete()) {
                   container.writePacket(packet);
                   System.out.println("[ENCODER] writing packet of size " + packet.getSize() + " for elapsed time " + ((timeStamp - lastTimeStamp) / 1000));
                   lastTimeStamp = timeStamp;
               }
               System.out.println("[ENCODER] encoded image " + i + " in " + (System.currentTimeMillis() - now));
               i++;
               try {
                   Thread.sleep(Math.max((long) (1000 / frameRate.getDouble()) - (System.currentTimeMillis() - now), 0));
               } catch (InterruptedException e) {
                   e.printStackTrace();
               }
           }
       } catch (AWTException e) {
           e.printStackTrace();
       }
       container.writeTrailer();
    }
}