From 9fee0ec4ca0c5b7a334cc29dbb58e76c7a4c736e Mon Sep 17 00:00:00 2001 From: Michiel Van Der Kolk Date: Mon, 11 Jul 2005 15:42:37 +0000 Subject: Songdb java version, source. only 1.5 compatible git-svn-id: svn://svn.rockbox.org/rockbox/trunk@7101 a1c6a512-1295-4272-9138-f99709370657 --- songdbj/javazoom/jl/decoder/Decoder.java | 357 +++++++++++++++++++++++++++++++ 1 file changed, 357 insertions(+) create mode 100644 songdbj/javazoom/jl/decoder/Decoder.java (limited to 'songdbj/javazoom/jl/decoder/Decoder.java') diff --git a/songdbj/javazoom/jl/decoder/Decoder.java b/songdbj/javazoom/jl/decoder/Decoder.java new file mode 100644 index 0000000..076f9de --- /dev/null +++ b/songdbj/javazoom/jl/decoder/Decoder.java @@ -0,0 +1,357 @@ +/* + * 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 Decoder 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 Decoder instance with default + * parameters. + */ + + public Decoder() + { + this(null); + } + + /** + * Creates a new Decoder instance with default + * parameters. + * + * @param params The Params 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 Params class presents the customizable + * aspects of the decoder. + *

+ * 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. + *

+ * The Equalizer 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 Equalizer used to initialize the + * EQ settings of the decoder. + */ + public Equalizer getInitialEqualizerSettings() + { + return equalizer; + } + + }; +} + -- cgit v1.1