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package com.sun.media.sound;

import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;

import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;

A jitter corrector to be used with SoftAudioPusher.
Author:Karl Helgason
/** * A jitter corrector to be used with SoftAudioPusher. * * @author Karl Helgason */
public final class SoftJitterCorrector extends AudioInputStream { private static class JitterStream extends InputStream { static int MAX_BUFFER_SIZE = 1048576; boolean active = true; Thread thread; AudioInputStream stream; // Cyclic buffer int writepos = 0; int readpos = 0; byte[][] buffers; private final Object buffers_mutex = new Object(); // Adapative Drift Statistics int w_count = 1000; int w_min_tol = 2; int w_max_tol = 10; int w = 0; int w_min = -1; // Current read buffer int bbuffer_pos = 0; int bbuffer_max = 0; byte[] bbuffer = null; public byte[] nextReadBuffer() { synchronized (buffers_mutex) { if (writepos > readpos) { int w_m = writepos - readpos; if (w_m < w_min) w_min = w_m; int buffpos = readpos; readpos++; return buffers[buffpos % buffers.length]; } w_min = -1; w = w_count - 1; } while (true) { try { Thread.sleep(1); } catch (InterruptedException e) { //e.printStackTrace(); return null; } synchronized (buffers_mutex) { if (writepos > readpos) { w = 0; w_min = -1; w = w_count - 1; int buffpos = readpos; readpos++; return buffers[buffpos % buffers.length]; } } } } public byte[] nextWriteBuffer() { synchronized (buffers_mutex) { return buffers[writepos % buffers.length]; } } public void commit() { synchronized (buffers_mutex) { writepos++; if ((writepos - readpos) > buffers.length) { int newsize = (writepos - readpos) + 10; newsize = Math.max(buffers.length * 2, newsize); buffers = new byte[newsize][buffers[0].length]; } } } JitterStream(AudioInputStream s, int buffersize, int smallbuffersize) { this.w_count = 10 * (buffersize / smallbuffersize); if (w_count < 100) w_count = 100; this.buffers = new byte[(buffersize/smallbuffersize)+10][smallbuffersize]; this.bbuffer_max = MAX_BUFFER_SIZE / smallbuffersize; this.stream = s; Runnable runnable = new Runnable() { @Override public void run() { AudioFormat format = stream.getFormat(); int bufflen = buffers[0].length; int frames = bufflen / format.getFrameSize(); long nanos = (long) (frames * 1000000000.0 / format.getSampleRate()); long now = System.nanoTime(); long next = now + nanos; int correction = 0; while (true) { synchronized (JitterStream.this) { if (!active) break; } int curbuffsize; synchronized (buffers) { curbuffsize = writepos - readpos; if (correction == 0) { w++; if (w_min != Integer.MAX_VALUE) { if (w == w_count) { correction = 0; if (w_min < w_min_tol) { correction = (w_min_tol + w_max_tol) / 2 - w_min; } if (w_min > w_max_tol) { correction = (w_min_tol + w_max_tol) / 2 - w_min; } w = 0; w_min = Integer.MAX_VALUE; } } } } while (curbuffsize > bbuffer_max) { synchronized (buffers) { curbuffsize = writepos - readpos; } synchronized (JitterStream.this) { if (!active) break; } try { Thread.sleep(1); } catch (InterruptedException e) { //e.printStackTrace(); } } if (correction < 0) correction++; else { byte[] buff = nextWriteBuffer(); try { int n = 0; while (n != buff.length) { int s = stream.read(buff, n, buff.length - n); if (s < 0) throw new EOFException(); if (s == 0) Thread.yield(); n += s; } } catch (IOException e1) { //e1.printStackTrace(); } commit(); } if (correction > 0) { correction--; next = System.nanoTime() + nanos; continue; } long wait = next - System.nanoTime(); if (wait > 0) { try { Thread.sleep(wait / 1000000L); } catch (InterruptedException e) { //e.printStackTrace(); } } next += nanos; } } }; thread = new Thread(null, runnable, "JitterCorrector", 0, false); thread.setDaemon(true); thread.setPriority(Thread.MAX_PRIORITY); thread.start(); } @Override public void close() throws IOException { synchronized (this) { active = false; } try { thread.join(); } catch (InterruptedException e) { //e.printStackTrace(); } stream.close(); } @Override public int read() throws IOException { byte[] b = new byte[1]; if (read(b) == -1) return -1; return b[0] & 0xFF; } public void fillBuffer() { bbuffer = nextReadBuffer(); bbuffer_pos = 0; } @Override public int read(byte[] b, int off, int len) { if (bbuffer == null) fillBuffer(); int bbuffer_len = bbuffer.length; int offlen = off + len; while (off < offlen) { if (available() == 0) fillBuffer(); else { byte[] bbuffer = this.bbuffer; int bbuffer_pos = this.bbuffer_pos; while (off < offlen && bbuffer_pos < bbuffer_len) b[off++] = bbuffer[bbuffer_pos++]; this.bbuffer_pos = bbuffer_pos; } } return len; } @Override public int available() { return bbuffer.length - bbuffer_pos; } } public SoftJitterCorrector(AudioInputStream stream, int buffersize, int smallbuffersize) { super(new JitterStream(stream, buffersize, smallbuffersize), stream.getFormat(), stream.getFrameLength()); } }