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Freedom for Media in Java
There is a newer version: 1.0.2-jitsi
package net.sf.fmj.media;

import java.util.logging.*;

import net.sf.fmj.utility.*;

/**
 * Helps calculate and sleep based on buffer timestamps; useful for rendering
 * media at the correct rate. TODO: it is strange that we use this in the
 * RendererNode (which calls the Renderer), and in the RTPSyncBufferMux (but not
 * in the MuxNode). This implies that Multiplexers are responsible for timing
 * but not Renderers. This is perhaps a reasonable assumption, but needs to be
 * checked against JMF.
 *
 * @author Ken Larson
 *
 */
public class SleepHelper
{
    private static final Logger logger = LoggerSingleton.logger;

    private long mStart;
    private long tbStart;
    private boolean firstNonDiscard = true;

    /**
     * The number of nanoseconds in a millisecond.
     */
    public static long MILLI_TO_NANO = 1000000L;

    public long calculateSleep(long currentTimestamp)
    {
        final long tbNow = System.currentTimeMillis();

        // we don't want the first timestamp to be from a discarded frame.
        if (firstNonDiscard)
        {
            mStart = currentTimestamp;
            tbStart = tbNow;
            firstNonDiscard = false;
            return 0;
        }
        final long bufferTimeStamp = currentTimestamp;
        final float rate = 1; // TODO: support rates (controller/player rate)

        final long mTarget = bufferTimeStamp; // TODO: negative rates?
        // logger.fine("bufferTimeStamp=" + bufferTimeStamp + " tbNow=" +
        // tbNow);
        final long tbTarget = (long) ((mTarget - mStart) / ((double) rate * (double) MILLI_TO_NANO))
                + tbStart;
        final long sleep = tbTarget - tbNow;
        return sleep;

    }

    public void reset()
    {
        mStart = 0;
        tbStart = 0;
        firstNonDiscard = true;
    }

    public void sleep(long currentTimestamp) throws InterruptedException
    {
        final long sleep = calculateSleep(currentTimestamp);
        if (sleep > 0)
        {
            logger.finer("Sleeping " + sleep);
            // Sleep until the next frame
            // TODO: the way sleeping should really work is that we start
            // processing the next frame while sleeping on the current one
            // (double buffer the filter graph)
            // TODO: where does JMF sleep? It does not appear that the renderer
            // does any sleeping.
            Thread.sleep(sleep);
            // TODO: I think the correct way to do this is to check the time
            // when we wake up and re-sleep if awoken prematurely.

        }

    }
}