音视频：JavaCV AAC数据内存读写（PipedInputStream管道流）

需要进行简单的音视频编程，如果不是特别数据C/C++，那么JavaCV应该是比较好的选择，下面记录一下使用JavaCV AAC数据内存读写（PipedInputStream管道流）的方法。

使用管道流需要注意的是PipedInputStream和PipedOutputStream要在不同线程。

整体的流程就是：

1. FFmpegFrameRecorder将音频数据塞给PipedOutputStream
2. 程序从PipedInputStream中读取音频数据

实现代码：

public class Sample06 {

	public static void main(String[] args) throws IOException {
		FFmpegFrameGrabber grabber = new FFmpegFrameGrabber("E:\\lpl.mp4");
		grabber.start();

		PipedInputStream is = new PipedInputStream(1024 * 1024);
		PipedOutputStream os = new PipedOutputStream(is);
		FFmpegFrameRecorder recorder = new FFmpegFrameRecorder(os, grabber.getAudioChannels());
		recorder.setFormat("adts");
		recorder.start(grabber.getFormatContext());

		Thread readThread = new AudioReadThread(is);
		readThread.start();

		AVPacket packet;
		int audioStream = grabber.getAudioStream();
		while ((packet = grabber.grabPacket()) != null) {
			if (audioStream == packet.stream_index()) {
				recorder.recordPacket(packet);
			}
		}
		recorder.close();
		grabber.close();
	}
}

读取实现跟普通的读InputStream是一样的：

while (!Thread.interrupted()) {
  if (is.available() > 0) {
    byte[] bytes = new byte[is.available()];
    is.read(bytes);
    System.out.println("buff.size = " + bytes.length + ", "
      + Integer.toHexString(bytes[0] & 0xFF) + ","
      + Integer.toHexString(bytes[1] & 0xFF) + "," 
      + Integer.toHexString(bytes[2] & 0xFF) + ","
      + Integer.toHexString(bytes[3] & 0xFF));
  }
}

debug日志：

buff.size = 180, ff,f1,4c,80
buff.size = 176, ff,f1,4c,80
buff.size = 171, ff,f1,4c,80
buff.size = 178, ff,f1,4c,80
buff.size = 173, ff,f1,4c,80
buff.size = 193, ff,f1,4c,80