rawpushbufferparser.java

FMJ（freedom media for java)是java视频开发的新选择

package net.sf.fmj.media.parser;

import java.io.IOException;
import java.io.InterruptedIOException;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.media.BadHeaderException;
import javax.media.Buffer;
import javax.media.Format;
import javax.media.IncompatibleSourceException;
import javax.media.Track;
import javax.media.protocol.BufferTransferHandler;
import javax.media.protocol.ContentDescriptor;
import javax.media.protocol.DataSource;
import javax.media.protocol.PushBufferDataSource;
import javax.media.protocol.PushBufferStream;

import com.lti.utils.synchronization.SynchronizedBoolean;

import net.sf.fmj.media.AbstractDemultiplexer;
import net.sf.fmj.media.AbstractTrack;
import net.sf.fmj.utility.LoggerSingleton;

/**
 * Demux that doesn't really do much - since the stream does all the work of providing the buffers.
 * It may be that similar sun classes actually do something meaningful.
 * Very similar code could be used for PullBufferDataSource.
 * 
 * @author Ken Larson
 *
 */
public class RawPushBufferParser extends AbstractDemultiplexer 
{
	private static final Logger logger = LoggerSingleton.logger;

	private ContentDescriptor[] supportedInputContentDescriptors = new ContentDescriptor[] {new ContentDescriptor(ContentDescriptor.RAW)};

	private PushBufferDataSource source;
	
	private PushBufferStreamTrack[] tracks;
	//@Override
	public ContentDescriptor[] getSupportedInputContentDescriptors()
	{
		return supportedInputContentDescriptors;
	}

	//@Override
	public Track[] getTracks() throws IOException, BadHeaderException
	{
		return tracks;
	}

	//@Override
	public void setSource(DataSource source) throws IOException, IncompatibleSourceException
	{
		if (!(source instanceof PushBufferDataSource))
			throw new IncompatibleSourceException();
		
		this.source = (PushBufferDataSource) source;
		
	}
	
	//@Override
	public void start() throws IOException
	{
		source.start();
		if (tracks == null)
		{
			// we assume that streams do not change if we stop and restart.  TODO: is this true?
			
			final PushBufferStream[] streams = source.getStreams();
			
			tracks = new PushBufferStreamTrack[streams.length];
			for (int i = 0; i < streams.length; ++i)
			{
				tracks[i] = new PushBufferStreamTrack(streams[i]);
			}
		}
	}
	
	// @Override
	public void stop()
	{
		try 
		{
			source.stop();
		} catch (IOException e) 
		{
			logger.log(Level.WARNING, "" + e, e);
		}
	}
	
	private static final boolean USE_BUFFER_TRANSFER_HANDLER = true;
	private static final int POLL_INTERVAL = 1000;	// how often to wake up and read anyway, even if not notified by handler.  Kind of an insurance policy.
	
	private class PushBufferStreamTrack extends AbstractTrack implements BufferTransferHandler
	{
		private final PushBufferStream stream;
		
		public PushBufferStreamTrack(PushBufferStream stream)
		{
			super();
			this.stream = stream;
			if (USE_BUFFER_TRANSFER_HANDLER)
				stream.setTransferHandler(this);
		}

		public Format getFormat()
		{
			return stream.getFormat();
		}

		private SynchronizedBoolean dataAvailable = new SynchronizedBoolean();
		
		public void transferData(PushBufferStream stream)
		{
			dataAvailable.setValue(true);
			
		}

		public void readFrame(Buffer buffer)
		{

			// TODO: use setTransferHandler to know when to read?
			// the transfer handler is not as useful as it might seem, since
			// read is (I think) a blocking method, and the reading all occurs within
			// its own thread anyway.  KAL.
			try
			{
				if (USE_BUFFER_TRANSFER_HANDLER)
				{
					try
					{
						synchronized (dataAvailable)
						{
							dataAvailable.waitUntil(true, POLL_INTERVAL);
							dataAvailable.setValue(false);
						}
					}
					catch (InterruptedException e)
					{	throw new InterruptedIOException();
					}
				}
				
				stream.read(buffer);
				
			} catch (IOException e)
			{
				buffer.setEOM(true);	// TODO
				buffer.setDiscard(true);	// TODO
				buffer.setLength(0);
				if (!(e instanceof InterruptedIOException))	// logging interruptions is noisy.
					logger.log(Level.WARNING, "" + e, e);
			}
			
		}


	}



}