Songdb java version, source. only 1.5 compatible

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@7101 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 357 insertions, 0 deletions

diff --git a/songdbj/javazoom/jl/decoder/Decoder.java b/songdbj/javazoom/jl/decoder/Decoder.java
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+/*
+ * 11/19/04		1.0 moved to LGPL.
+ * 01/12/99		Initial version.	mdm@techie.com
+ *-----------------------------------------------------------------------
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU Library General Public License as published
+ *   by the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU Library General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Library General Public
+ *   License along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *----------------------------------------------------------------------
+ */
+ 
+package javazoom.jl.decoder;
+
+/**
+ * The <code>Decoder</code> class encapsulates the details of
+ * decoding an MPEG audio frame. 
+ * 
+ * @author	MDM	
+ * @version 0.0.7 12/12/99
+ * @since	0.0.5
+ */
+public class Decoder implements DecoderErrors
+{
+	static private final Params DEFAULT_PARAMS = new Params();
+	
+	/**
+	 * The Bistream from which the MPEG audio frames are read.
+	 */
+	//private Bitstream				stream;
+	
+	/**
+	 * The Obuffer instance that will receive the decoded
+	 * PCM samples.
+	 */
+	private Obuffer			output;
+		
+	/**
+	 * Synthesis filter for the left channel.
+	 */
+	private SynthesisFilter			filter1;
+	
+	/**
+	 * Sythesis filter for the right channel.
+	 */
+	private SynthesisFilter			filter2;	
+			
+	/**
+	 * The decoder used to decode layer III frames.
+	 */
+	private LayerIIIDecoder			l3decoder;
+	private LayerIIDecoder			l2decoder;
+	private LayerIDecoder			l1decoder;
+	
+	private int						outputFrequency;
+	private int						outputChannels;
+	
+	private Equalizer				equalizer = new Equalizer();
+	
+	private Params					params;
+	
+	private boolean					initialized;
+		
+	
+	/**
+	 * Creates a new <code>Decoder</code> instance with default 
+	 * parameters.
+	 */
+	
+	public Decoder()
+	{
+		this(null);
+	}
+
+	/**
+	 * Creates a new <code>Decoder</code> instance with default 
+	 * parameters.
+	 * 
+	 * @param params	The <code>Params</code> instance that describes
+	 *					the customizable aspects of the decoder.  
+	 */
+	public Decoder(Params params0)
+	{
+		if (params0==null)
+			params0 = DEFAULT_PARAMS;
+	
+		params = params0;
+		
+		Equalizer eq = params.getInitialEqualizerSettings();
+		if (eq!=null)
+		{
+			equalizer.setFrom(eq);
+		}
+	}
+	
+	static public Params getDefaultParams()
+	{
+		return (Params)DEFAULT_PARAMS.clone();
+	}
+	
+	public void setEqualizer(Equalizer eq)
+	{
+		if (eq==null)
+			eq = Equalizer.PASS_THRU_EQ;
+		
+		equalizer.setFrom(eq);
+		
+		float[] factors = equalizer.getBandFactors();
+
+		if (filter1!=null)
+			filter1.setEQ(factors);
+		
+		if (filter2!=null)
+			filter2.setEQ(factors);			
+	}
+	
+	/**
+	 * Decodes one frame from an MPEG audio bitstream.
+	 * 
+	 * @param header		The header describing the frame to decode.
+	 * @param bitstream		The bistream that provides the bits for te body of the frame. 
+	 * 
+	 * @return A SampleBuffer containing the decoded samples.
+	 */
+	public Obuffer decodeFrame(Header header, Bitstream stream)
+		throws DecoderException
+	{
+		if (!initialized)
+		{
+			initialize(header);
+		}
+		
+		int layer = header.layer();
+		
+		output.clear_buffer();
+		
+		FrameDecoder decoder = retrieveDecoder(header, stream, layer);
+		
+		decoder.decodeFrame();
+				
+		output.write_buffer(1);
+		
+		return output;	
+	}
+	
+	/**
+	 * Changes the output buffer. This will take effect the next time
+	 * decodeFrame() is called. 
+	 */
+	public void setOutputBuffer(Obuffer out)
+	{
+		output = out;
+	}
+	
+	/**
+	 * Retrieves the sample frequency of the PCM samples output
+	 * by this decoder. This typically corresponds to the sample
+	 * rate encoded in the MPEG audio stream.
+	 * 
+	 * @param the sample rate (in Hz) of the samples written to the
+	 *		output buffer when decoding. 
+	 */
+	public int getOutputFrequency()
+	{
+		return outputFrequency;
+	}
+	
+	/**
+	 * Retrieves the number of channels of PCM samples output by
+	 * this decoder. This usually corresponds to the number of
+	 * channels in the MPEG audio stream, although it may differ.
+	 * 
+	 * @return The number of output channels in the decoded samples: 1 
+	 *		for mono, or 2 for stereo.
+	 *		
+	 */
+	public int getOutputChannels()
+	{
+		return outputChannels;	
+	}
+	
+	/**
+	 * Retrieves the maximum number of samples that will be written to
+	 * the output buffer when one frame is decoded. This can be used to
+	 * help calculate the size of other buffers whose size is based upon 
+	 * the number of samples written to the output buffer. NB: this is
+	 * an upper bound and fewer samples may actually be written, depending
+	 * upon the sample rate and number of channels.
+	 * 
+	 * @return The maximum number of samples that are written to the 
+	 *		output buffer when decoding a single frame of MPEG audio.
+	 */
+	public int getOutputBlockSize()
+	{
+		return Obuffer.OBUFFERSIZE;
+	}
+	
+	
+	protected DecoderException newDecoderException(int errorcode)
+	{
+		return new DecoderException(errorcode, null);
+	}
+	
+	protected DecoderException newDecoderException(int errorcode, Throwable throwable)
+	{
+		return new DecoderException(errorcode, throwable);
+	}
+	
+	protected FrameDecoder retrieveDecoder(Header header, Bitstream stream, int layer)
+		throws DecoderException
+	{
+		FrameDecoder decoder = null;
+		
+		// REVIEW: allow channel output selection type
+		// (LEFT, RIGHT, BOTH, DOWNMIX)
+		switch (layer)
+		{
+		case 3:
+			if (l3decoder==null)
+			{
+				l3decoder = new LayerIIIDecoder(stream, 
+					header, filter1, filter2, 
+					output, OutputChannels.BOTH_CHANNELS);
+			}						
+			
+			decoder = l3decoder;
+			break;
+		case 2:
+			if (l2decoder==null)
+			{
+				l2decoder = new LayerIIDecoder();
+				l2decoder.create(stream, 
+					header, filter1, filter2, 
+					output, OutputChannels.BOTH_CHANNELS);				
+			}
+			decoder = l2decoder;
+			break;
+		case 1:
+			if (l1decoder==null)
+			{
+				l1decoder = new LayerIDecoder();
+				l1decoder.create(stream, 
+					header, filter1, filter2, 
+					output, OutputChannels.BOTH_CHANNELS);				
+			}
+			decoder = l1decoder;
+			break;
+		}
+						
+		if (decoder==null)
+		{
+			throw newDecoderException(UNSUPPORTED_LAYER, null);
+		}
+		
+		return decoder;
+	}
+	
+	private void initialize(Header header)
+		throws DecoderException
+	{
+		
+		// REVIEW: allow customizable scale factor
+		float scalefactor = 32700.0f;
+		
+		int mode = header.mode();
+		int layer = header.layer();
+		int channels = mode==Header.SINGLE_CHANNEL ? 1 : 2;
+
+					
+		// set up output buffer if not set up by client.
+		if (output==null)
+			output = new SampleBuffer(header.frequency(), channels);
+		
+		float[] factors = equalizer.getBandFactors();
+		filter1 = new SynthesisFilter(0, scalefactor, factors);
+   		
+		// REVIEW: allow mono output for stereo
+		if (channels==2) 
+			filter2 = new SynthesisFilter(1, scalefactor, factors);
+
+		outputChannels = channels;
+		outputFrequency = header.frequency();
+		
+		initialized = true;
+	}
+	
+	/**
+	 * The <code>Params</code> class presents the customizable
+	 * aspects of the decoder. 
+	 * <p>
+	 * Instances of this class are not thread safe. 
+	 */
+	public static class Params implements Cloneable
+	{
+		private OutputChannels	outputChannels = OutputChannels.BOTH;
+		
+		private Equalizer		equalizer = new Equalizer();
+		
+		public Params()
+		{			
+		}
+		
+		public Object clone()
+		{
+			try
+			{
+				return super.clone();
+			}
+			catch (CloneNotSupportedException ex)
+			{				
+				throw new InternalError(this+": "+ex);
+			}
+		}
+				
+		public void setOutputChannels(OutputChannels out)
+		{
+			if (out==null)
+				throw new NullPointerException("out");
+			
+			outputChannels = out;
+		}
+		
+		public OutputChannels getOutputChannels()
+		{
+			return outputChannels;
+		}
+		
+		/**
+		 * Retrieves the equalizer settings that the decoder's equalizer
+		 * will be initialized from.
+		 * <p>
+		 * The <code>Equalizer</code> instance returned 
+		 * cannot be changed in real time to affect the 
+		 * decoder output as it is used only to initialize the decoders
+		 * EQ settings. To affect the decoder's output in realtime,
+		 * use the Equalizer returned from the getEqualizer() method on
+		 * the decoder. 
+		 * 
+		 * @return	The <code>Equalizer</code> used to initialize the
+		 *			EQ settings of the decoder. 
+		 */
+		public Equalizer getInitialEqualizerSettings()
+		{
+			return equalizer;	
+		}
+				
+	};
+}
+