/*
* Entagged Audio Tag library
* Copyright (c) 2003-2005 Raphaël Slinckx <raphael@slinckx.net>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.jaudiotagger.audio.flac.metadatablock;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.util.logging.Logger;
/**
* Stream Info
* <p/>
* <p>This block has information about the whole stream, like sample rate, number of channels, total number of samples,
* etc. It must be present as the first metadata block in the stream. Other metadata blocks may follow, and ones
* that the decoder doesn't understand, it will skip.
* Format:
* <Size in bits> Info
* <16> The minimum block size (in samples) used in the stream.
* <16> The maximum block size (in samples) used in the stream. (Minimum blocksize == maximum blocksize) implies a fixed-blocksize stream.
* <24> The minimum frame size (in bytes) used in the stream. May be 0 to imply the value is not known.
* <24> The maximum frame size (in bytes) used in the stream. May be 0 to imply the value is not known.
* <20> Sample rate in Hz. Though 20 bits are available, the maximum sample rate is limited by the structure of frame headers to 655350Hz. Also,
* a value of 0 is invalid.
* <3> (number of channels)-1. FLAC supports from 1 to 8 channels
* <5> (bits per sample)-1. FLAC supports from 4 to 32 bits per sample. Currently the reference encoder and decoders only support up to 24 bits per sample.
* <36> Total samples in stream. 'Samples' means inter-channel sample,
* i.e. one second of 44.1Khz audio will have 44100 samples regardless of the number of channels.
* A value of zero here means the number of total samples is unknown.
* <128> MD5 signature of the unencoded audio data. This allows the decoder to determine if an error exists in the audio data
* even when the error does not result in an invalid bitstream.
* NOTES
* * FLAC specifies a minimum block size of 16 and a maximum block size of 65535, meaning the bit patterns corresponding to the numbers 0-15 in the minimum blocksize and maximum blocksize fields are invalid.
*/
public class MetadataBlockDataStreamInfo implements MetadataBlockData
{
public static final int STREAM_INFO_DATA_LENGTH = 34;
// Logger Object
public static Logger logger = Logger.getLogger("org.jaudiotagger.audio.flac.MetadataBlockDataStreamInfo");
private int minBlockSize, maxBlockSize, minFrameSize, maxFrameSize, samplingRate, samplingRatePerChannel, bitsPerSample, channelNumber, totalNumberOfSamples;
private float songLength;
private boolean isValid = true;
private ByteBuffer rawdata;
public MetadataBlockDataStreamInfo(MetadataBlockHeader header, RandomAccessFile raf) throws IOException
{
rawdata = ByteBuffer.allocate(header.getDataLength());
int bytesRead = raf.getChannel().read(rawdata);
if (bytesRead < header.getDataLength())
{
throw new IOException("Unable to read required number of databytes read:" + bytesRead + ":required:" + header.getDataLength());
}
rawdata.rewind();
minBlockSize = rawdata.getShort();
maxBlockSize = rawdata.getShort();
minFrameSize = readThreeByteInteger(rawdata.get(), rawdata.get(), rawdata.get());
maxFrameSize = readThreeByteInteger(rawdata.get(), rawdata.get(), rawdata.get());
samplingRate = readSamplingRate(rawdata.get(), rawdata.get(), rawdata.get());
channelNumber = ((u(rawdata.get(12)) & 0x0E) >>> 1) + 1;
samplingRatePerChannel = samplingRate / channelNumber;
bitsPerSample = ((u(rawdata.get(12)) & 0x01) << 4) + ((u(rawdata.get(13)) & 0xF0) >>> 4) + 1;
totalNumberOfSamples = readTotalNumberOfSamples(rawdata.get(13), rawdata.get(14), rawdata.get(15), rawdata.get(16), rawdata.get(17));
songLength = (float) ((double) totalNumberOfSamples / samplingRate);
logger.config(this.toString());
}
/**
* @return the rawdata as it will be written to file
*/
public byte[] getBytes()
{
return rawdata.array();
}
public int getLength()
{
return getBytes().length;
}
public String toString()
{
return "MinBlockSize:" + minBlockSize + "MaxBlockSize:" + maxBlockSize + "MinFrameSize:" + minFrameSize + "MaxFrameSize:" + maxFrameSize + "SampleRateTotal:" + samplingRate + "SampleRatePerChannel:" + samplingRatePerChannel + ":Channel number:" + channelNumber + ":Bits per sample: " + bitsPerSample + ":TotalNumberOfSamples: " + totalNumberOfSamples + ":Length: " + songLength;
}
public int getSongLength()
{
return (int) songLength;
}
public float getPreciseLength()
{
return songLength;
}
public int getChannelNumber()
{
return channelNumber;
}
public int getSamplingRate()
{
return samplingRate;
}
public int getSamplingRatePerChannel()
{
return samplingRatePerChannel;
}
public String getEncodingType()
{
return "FLAC " + bitsPerSample + " bits";
}
public boolean isValid()
{
return isValid;
}
private int readThreeByteInteger(byte b1, byte b2, byte b3)
{
int rate = (u(b1) << 16) + (u(b2) << 8) + (u(b3));
return rate;
}
//TODO this code seems to be give a sampling rate over 21 bytes instead of 20 bytes but attempt to change
//to 21 bytes give wrong value
private int readSamplingRate(byte b1, byte b2, byte b3)
{
int rate = (u(b1) << 12) + (u(b2) << 4) + ((u(b3) & 0xF0) >>> 4);
return rate;
}
private int readTotalNumberOfSamples(byte b1, byte b2, byte b3, byte b4, byte b5)
{
int nb = u(b5);
nb += u(b4) << 8;
nb += u(b3) << 16;
nb += u(b2) << 24;
nb += (u(b1) & 0x0F) << 32;
return nb;
}
private int u(int i)
{
return i & 0xFF;
}
}
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