package org.kc7bfi.jflac.frame;
/**
* libFLAC - Free Lossless Audio Codec library
* Copyright (C) 2001,2002,2003 Josh Coalson
*
* This library 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 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
import java.io.IOException;
import org.kc7bfi.jflac.Constants;
import org.kc7bfi.jflac.io.BitInputStream;
import org.kc7bfi.jflac.metadata.StreamInfo;
import org.kc7bfi.jflac.util.ByteData;
import org.kc7bfi.jflac.util.CRC8;
/**
* Frame header class.
* @author kc7bfi
*/
public class Header {
/** The number of samples per subframe. */
public int blockSize;
/** The sample rate in Hz. */
public int sampleRate;
/** The number of channels (== number of subframes). */
public int channels;
/** The channel assignment for the frame. */
public int channelAssignment;
/** The sample resolution. */
public int bitsPerSample;
/**
* The frame number or sample number of first sample in frame.
* use the number_type value to determine which to use.
*/
public int frameNumber = -1;
/**
* The sample number for the first sample in the frame.
*/
public long sampleNumber = -1;
/**
* CRC-8 (polynomial = x^8 + x^2 + x^1 + x^0, initialized with 0).
* of the raw frame header bytes, meaning everything before the CRC byte
* including the sync code.
*/
protected byte crc;
/**
* The constructor.
* @param is The InputBitStream
* @param headerWarmup The header warm-up bytes
* @param streamInfo The FLAC Stream Info
* @throws IOException Thrown on error reading InputBitStream
* @throws BadHeaderException Thrown if header is bad
*/
public Header(BitInputStream is, byte[] headerWarmup, StreamInfo streamInfo) throws IOException, BadHeaderException {
int blocksizeHint = 0;
int sampleRateHint = 0;
ByteData rawHeader = new ByteData(16); // MAGIC NUMBER based on the maximum frame header size, including CRC
boolean isKnownVariableBlockSizeStream = (streamInfo != null && streamInfo.getMinBlockSize() != streamInfo.getMaxBlockSize());
boolean isKnownFixedBlockSizeStream = (streamInfo != null && streamInfo.getMinBlockSize() == streamInfo.getMaxBlockSize());
// init the raw header with the saved bits from synchronization
rawHeader.append(headerWarmup[0]);
rawHeader.append(headerWarmup[1]);
// check to make sure that the reserved bits are 0
if ((rawHeader.getData(1) & 0x03) != 0) { // MAGIC NUMBER
throw new BadHeaderException("Bad Magic Number: " + (rawHeader.getData(1) & 0xff));
}
// Note that along the way as we read the header, we look for a sync
// code inside. If we find one it would indicate that our original
// sync was bad since there cannot be a sync code in a valid header.
// read in the raw header as bytes so we can CRC it, and parse it on the way
for (int i = 0; i < 2; i++) {
if (is.peekRawUInt(8) == 0xff) { // MAGIC NUMBER for the first 8 frame sync bits
throw new BadHeaderException("Found sync byte");
}
rawHeader.append((byte) is.readRawUInt(8));
}
int bsType = (rawHeader.getData(2) >> 4) & 0x0f;
switch (bsType) {
case 0 :
if (!isKnownFixedBlockSizeStream)
throw new BadHeaderException("Unknown Block Size (0)");
blockSize = streamInfo.getMinBlockSize();
break;
case 1 :
blockSize = 192;
break;
case 2 :
case 3 :
case 4 :
case 5 :
blockSize = 576 << (bsType - 2);
break;
case 6 :
case 7 :
blocksizeHint = bsType;
break;
case 8 :
case 9 :
case 10 :
case 11 :
case 12 :
case 13 :
case 14 :
case 15 :
blockSize = 256 << (bsType - 8);
break;
default :
break;
}
//System.out.println("BSType="+bsType+" BS="+blockSize);
int srType = rawHeader.getData(2) & 0x0f;
switch (srType) {
case 0 :
if (streamInfo == null)
throw new BadHeaderException("Bad Sample Rate (0)");
sampleRate = streamInfo.getSampleRate();
break;
case 1 :
case 2 :
case 3 :
throw new BadHeaderException("Bad Sample Rate (" + srType + ")");
case 4 :
sampleRate = 8000;
break;
case 5 :
sampleRate = 16000;
break;
case 6 :
sampleRate = 22050;
break;
case 7 :
sampleRate = 24000;
break;
case 8 :
sampleRate = 32000;
break;
case 9 :
sampleRate = 44100;
break;
case 10 :
sampleRate = 48000;
break;
case 11 :
sampleRate = 96000;
break;
case 12 :
case 13 :
case 14 :
sampleRateHint = srType;
break;
case 15 :
throw new BadHeaderException("Bad Sample Rate (" + srType + ")");
default :
}
int asgnType = (int) ((rawHeader.getData(3) >> 4) & 0x0f);
//System.out.println("AsgnType="+asgnType+" "+(rawHeader.space[3] >> 4));
if ((asgnType & 8) != 0) {
channels = 2;
switch (asgnType & 7) {
case 0 :
channelAssignment = Constants.CHANNEL_ASSIGNMENT_LEFT_SIDE;
break;
case 1 :
channelAssignment = Constants.CHANNEL_ASSIGNMENT_RIGHT_SIDE;
break;
case 2 :
channelAssignment = Constants.CHANNEL_ASSIGNMENT_MID_SIDE;
break;
default :
throw new BadHeaderException("Bad Channel Assignment (" + asgnType + ")");
}
} else {
channels = (int) asgnType + 1;
channelAssignment = Constants.CHANNEL_ASSIGNMENT_INDEPENDENT;
}
int bpsType = (int) (rawHeader.getData(3) & 0x0e) >> 1;
switch (bpsType) {
case 0 :
if (streamInfo != null)
bitsPerSample = streamInfo.getBitsPerSample();
else
throw new BadHeaderException("Bad BPS (" + bpsType + ")");
break;
case 1 :
bitsPerSample = 8;
break;
case 2 :
bitsPerSample = 12;
break;
case 4 :
bitsPerSample = 16;
break;
case 5 :
bitsPerSample = 20;
break;
case 6 :
bitsPerSample = 24;
break;
case 3 :
case 7 :
throw new BadHeaderException("Bad BPS (" + bpsType + ")");
default :
break;
}
if ((rawHeader.getData(3) & 0x01) != 0) { // this should be a zero padding bit
throw new BadHeaderException("this should be a zero padding bit");
}
if ((blocksizeHint != 0) && isKnownVariableBlockSizeStream) {
sampleNumber = is.readUTF8Long(rawHeader);
if (sampleNumber == 0xffffffffffffffffL) { // i.e. non-UTF8 code...
throw new BadHeaderException("Bad Sample Number");
}
} else {
int lastFrameNumber = is.readUTF8Int(rawHeader);
if (lastFrameNumber == 0xffffffff) { // i.e. non-UTF8 code...
throw new BadHeaderException("Bad Last Frame");
}
sampleNumber = (long) streamInfo.getMinBlockSize() * (long) lastFrameNumber;
}
if (blocksizeHint != 0) {
int blockSizeCode = is.readRawUInt(8);
rawHeader.append((byte) blockSizeCode);
if (blocksizeHint == 7) {
int blockSizeCode2 = is.readRawUInt(8);
rawHeader.append((byte) blockSizeCode2);
blockSizeCode = (blockSizeCode << 8) | blockSizeCode2;
}
blockSize = blockSizeCode + 1;
}
if (sampleRateHint != 0) {
int sampleRateCode = is.readRawUInt(8);
rawHeader.append((byte) sampleRateCode);
if (sampleRateHint != 12) {
int sampleRateCode2 = is.readRawUInt(8);
rawHeader.append((byte) sampleRateCode2);
sampleRateCode = (sampleRateCode << 8) | sampleRateCode2;
}
if (sampleRateHint == 12)
sampleRate = sampleRateCode * 1000;
else if (sampleRateHint == 13)
sampleRate = sampleRateCode;
else
sampleRate = sampleRateCode * 10;
}
// read the CRC-8 byte
byte crc8 = (byte) is.readRawUInt(8);
if (CRC8.calc(rawHeader.getData(), rawHeader.getLen()) != crc8) {
throw new BadHeaderException("STREAM_DECODER_ERROR_STATUS_BAD_HEADER");
}
}
/**
* Return a descriptive string for this object.
* @return the string description
* @see java.lang.Object#toString()
*/
public String toString() {
return "FrameHeader:"
+ " BlockSize=" + blockSize
+ " SampleRate=" + sampleRate
+ " Channels=" + channels
+ " ChannelAssignment=" + channelAssignment
+ " BPS=" + bitsPerSample
+ " SampleNumber=" + sampleNumber;
}
}