/*
* 11/19/04 : 1.0 moved to LGPL.
* VBRI header support added, E.B javalayer@javazoom.net
*
* 12/04/03 : VBR (XING) header support added, E.B javalayer@javazoom.net
*
* 02/13/99 : Java Conversion by JavaZOOM , E.B javalayer@javazoom.net
*
* Declarations for MPEG header class
* A few layer III, MPEG-2 LSF, and seeking modifications made by Jeff Tsay.
* Last modified : 04/19/97
*
* @(#) header.h 1.7, last edit: 6/15/94 16:55:33
* @(#) Copyright (C) 1993, 1994 Tobias Bading (bading@cs.tu-berlin.de)
* @(#) Berlin University of Technology
*-----------------------------------------------------------------------
* 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;
import java.util.Arrays;
/**
* Class for extracting information from a frame header.
*/
public final class Header {
public static final int[][] frequencies =
{{22050, 24000, 16000, 1},
{44100, 48000, 32000, 1},
{11025, 12000, 8000, 1}}; // SZD: MPEG25
/**
* Constant for MPEG-2 LSF version
*/
public static final int MPEG2_LSF = 0;
public static final int MPEG25_LSF = 2; // SZD
/**
* Constant for MPEG-1 version
*/
public static final int MPEG1 = 1;
public static final int STEREO = 0;
public static final int JOINT_STEREO = 1;
public static final int DUAL_CHANNEL = 2;
public static final int SINGLE_CHANNEL = 3;
public static final int FOURTYFOUR_POINT_ONE = 0;
public static final int FOURTYEIGHT = 1;
public static final int THIRTYTWO = 2;
private int h_layer, h_protection_bit, h_bitrate_index, h_padding_bit, h_mode_extension;
private int h_version;
private int h_mode;
private int h_sample_frequency;
private int h_number_of_subbands, h_intensity_stereo_bound;
private boolean h_copyright, h_original;
// VBR support added by E.B
private double[] h_vbr_time_per_frame = {-1, 384, 1152, 1152};
private boolean h_vbr;
private int h_vbr_frames;
private int h_vbr_scale;
private int h_vbr_bytes;
private byte[] h_vbr_toc;
private byte syncmode = Bitstream.INITIAL_SYNC;
private Crc16 crc;
public short checksum;
public int framesize;
public int nSlots;
private int _headerstring = -1; // E.B
private int encDelay;
private int encPadding;
private static final int GAPLESS_DELAY = 529;
Header() {
}
/**
* Read a 32-bit header from the bitstream.
*/
void readHeader(Bitstream stream, Crc16[] crcp) throws BitstreamException {
int headerstring;
int channel_bitrate;
boolean sync = false;
do {
headerstring = stream.syncHeader(syncmode);
_headerstring = headerstring; // E.B
if (syncmode == Bitstream.INITIAL_SYNC) {
h_version = ((headerstring >>> 19) & 1);
if (((headerstring >>> 20) & 1) == 0) // SZD: MPEG2.5 detection
{
if (h_version == MPEG2_LSF) {
h_version = MPEG25_LSF;
} else {
throw stream.newBitstreamException(Bitstream.UNKNOWN_ERROR);
}
}
if ((h_sample_frequency = ((headerstring >>> 10) & 3)) == 3) {
throw stream.newBitstreamException(Bitstream.UNKNOWN_ERROR);
}
}
h_layer = 4 - (headerstring >>> 17) & 3;
h_protection_bit = (headerstring >>> 16) & 1;
h_bitrate_index = (headerstring >>> 12) & 0xF;
h_padding_bit = (headerstring >>> 9) & 1;
h_mode = ((headerstring >>> 6) & 3);
h_mode_extension = (headerstring >>> 4) & 3;
if (h_mode == JOINT_STEREO) {
h_intensity_stereo_bound = (h_mode_extension << 2) + 4;
} else {
h_intensity_stereo_bound = 0; // should never be used
}
if (((headerstring >>> 3) & 1) == 1) {
h_copyright = true;
}
if (((headerstring >>> 2) & 1) == 1) {
h_original = true;
}
// calculate number of subbands:
if (h_layer == 1) {
h_number_of_subbands = 32;
} else {
channel_bitrate = h_bitrate_index;
// calculate bitrate per channel:
if (h_mode != SINGLE_CHANNEL) {
if (channel_bitrate == 4) {
channel_bitrate = 1;
} else {
channel_bitrate -= 4;
}
}
if ((channel_bitrate == 1) || (channel_bitrate == 2)) {
if (h_sample_frequency == THIRTYTWO) {
h_number_of_subbands = 12;
} else {
h_number_of_subbands = 8;
}
} else if ((h_sample_frequency == FOURTYEIGHT) || ((channel_bitrate >= 3) && (channel_bitrate <= 5))) {
h_number_of_subbands = 27;
} else {
h_number_of_subbands = 30;
}
}
if (h_intensity_stereo_bound > h_number_of_subbands) {
h_intensity_stereo_bound = h_number_of_subbands;
}
// calculate framesize and nSlots
calculate_framesize();
// read framedata:
int framesizeloaded = stream.read_frame_data(framesize);
if ((framesize >= 0) && (framesizeloaded != framesize)) {
// Data loaded does not match to expected framesize,
// it might be an ID3v1 TAG. (Fix 11/17/04).
throw stream.newBitstreamException(Bitstream.INVALIDFRAME);
}
if (stream.isSyncCurrentPosition(syncmode)) {
if (syncmode == Bitstream.INITIAL_SYNC) {
syncmode = Bitstream.STRICT_SYNC;
stream.setSyncword(headerstring & 0xFFF80CC0);
}
sync = true;
} else {
//Denis Tulskiy: previous code skips last frame, trying to fix it
if (syncmode != Bitstream.INITIAL_SYNC) {
sync = true;
} else {
stream.unreadFrame();
}
}
} while (!sync);
stream.parse_frame();
if (h_protection_bit == 0) {
// frame contains a crc checksum
checksum = (short) stream.get_bits(16);
if (crc == null) {
crc = new Crc16();
}
crc.add_bits(headerstring, 16);
crcp[0] = crc;
} else {
crcp[0] = null;
}
}
/**
* Parse frame to extract optionnal VBR frame.
*
* @param firstframe
* @author E.B (javalayer@javazoom.net)
*/
boolean checkHeader(byte[] firstframe) throws BitstreamException {
// Trying Xing header.
String xing = "Xing";
String info = "Info";
encDelay = GAPLESS_DELAY;
byte tmp[] = new byte[4];
int offset = 0;
// Compute "Xing" offset depending on MPEG version and channels.
if (h_version == MPEG1) {
if (h_mode == SINGLE_CHANNEL) {
offset = 21 - 4;
} else {
offset = 36 - 4;
}
} else {
if (h_mode == SINGLE_CHANNEL) {
offset = 13 - 4;
} else {
offset = 21 - 4;
}
}
try {
System.arraycopy(firstframe, offset, tmp, 0, 4);
// Is "Xing" ?
if (xing.equals(new String(tmp)) || info.equals(new String(tmp))) {
//Yes.
// if (xing.equals(new String(tmp)))
h_vbr = true;
h_vbr_frames = -1;
h_vbr_bytes = -1;
h_vbr_scale = -1;
h_vbr_toc = new byte[100];
int length = 4;
// Read flags.
byte flags[] = new byte[4];
System.arraycopy(firstframe, offset + length, flags, 0, flags.length);
length += flags.length;
// Read number of frames (if available).
if ((flags[3] & (byte) (1 << 0)) != 0) {
System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
h_vbr_frames = (tmp[0] << 24) & 0xFF000000 | (tmp[1] << 16) & 0x00FF0000 | (tmp[2] << 8) & 0x0000FF00 | tmp[3] & 0x000000FF;
length += 4;
}
// Read size (if available).
if ((flags[3] & (byte) (1 << 1)) != 0) {
System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
h_vbr_bytes = (tmp[0] << 24) & 0xFF000000 | (tmp[1] << 16) & 0x00FF0000 | (tmp[2] << 8) & 0x0000FF00 | tmp[3] & 0x000000FF;
length += 4;
}
// Read TOC (if available).
if ((flags[3] & (byte) (1 << 2)) != 0) {
System.arraycopy(firstframe, offset + length, h_vbr_toc, 0, h_vbr_toc.length);
length += h_vbr_toc.length;
}
// Read scale (if available).
if ((flags[3] & (byte) (1 << 3)) != 0) {
System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
h_vbr_scale = (tmp[0] << 24) & 0xFF000000 | (tmp[1] << 16) & 0x00FF0000 | (tmp[2] << 8) & 0x0000FF00 | tmp[3] & 0x000000FF;
length += 4;
}
if (offset + length < firstframe.length) {
//parse LAME Header
System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
if (Arrays.equals(tmp, "LAME".getBytes())) {
// System.out.println("Found Lame header");
length += 21;
System.arraycopy(firstframe, offset + length, tmp, 0, 3);
encDelay += tmp[0] << 4 | (tmp[1] >> 4 & 0x0F);
encPadding = (tmp[1] & 0x0F) << 8 | (tmp[2] & 0xFF);
encPadding -= GAPLESS_DELAY;
length += 3;
// System.out.printf("EncDelay: %d, EncPadding: %d\n", encDelay, encPadding);
}
}
//System.out.println("VBR:"+xing+" Frames:"+ h_vbr_frames +" Size:"+h_vbr_bytes);
return true;
}
}
catch (ArrayIndexOutOfBoundsException e) {
throw new BitstreamException("XingVBRHeader Corrupted", e);
}
// Trying VBRI header.
String vbri = "VBRI";
offset = 36 - 4;
try {
System.arraycopy(firstframe, offset, tmp, 0, 4);
// Is "VBRI" ?
if (vbri.equals(new String(tmp))) {
//Yes.
h_vbr = true;
h_vbr_frames = -1;
h_vbr_bytes = -1;
h_vbr_scale = -1;
h_vbr_toc = new byte[100];
// Bytes.
int length = 4 + 6;
System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
h_vbr_bytes = (tmp[0] << 24) & 0xFF000000 | (tmp[1] << 16) & 0x00FF0000 | (tmp[2] << 8) & 0x0000FF00 | tmp[3] & 0x000000FF;
length += 4;
// Frames.
System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
h_vbr_frames = (tmp[0] << 24) & 0xFF000000 | (tmp[1] << 16) & 0x00FF0000 | (tmp[2] << 8) & 0x0000FF00 | tmp[3] & 0x000000FF;
length += 4;
//System.out.println("VBR:"+vbri+" Frames:"+ h_vbr_frames +" Size:"+h_vbr_bytes);
// TOC
// TODO
return true;
}
}
catch (ArrayIndexOutOfBoundsException e) {
throw new BitstreamException("VBRIVBRHeader Corrupted", e);
}
return false;
}
public int getEncPadding() {
return encPadding;
}
public int getEncDelay() {
return encDelay;
}
// Functions to query header contents:
/**
* Returns version.
*/
public int version() {
return h_version;
}
/**
* Returns Layer ID.
*/
public int layer() {
return h_layer;
}
/**
* Returns bitrate index.
*/
public int bitrate_index() {
return h_bitrate_index;
}
/**
* Returns Sample Frequency.
*/
public int sample_frequency() {
return h_sample_frequency;
}
/**
* Returns Frequency.
*/
public int frequency() {
return frequencies[h_version][h_sample_frequency];
}
/**
* Returns Mode.
*/
public int mode() {
return h_mode;
}
/**
* Returns Protection bit.
*/
public boolean checksums() {
return h_protection_bit == 0;
}
/**
* Returns Copyright.
*/
public boolean copyright() {
return h_copyright;
}
/**
* Returns Original.
*/
public boolean original() {
return h_original;
}
/**
* Return VBR.
*
* @return true if VBR header is found
*/
public boolean vbr() {
return h_vbr;
}
/**
* Return VBR scale.
*
* @return scale of -1 if not available
*/
public int vbr_scale() {
return h_vbr_scale;
}
/**
* Return VBR TOC.
*
* @return vbr toc ot null if not available
*/
public byte[] vbr_toc() {
return h_vbr_toc;
}
/**
* Returns Checksum flag.
* Compares computed checksum with stream checksum.
*/
public boolean checksum_ok() {
return (checksum == crc.checksum());
}
// Seeking and layer III stuff
/**
* Returns Layer III Padding bit.
*/
public boolean padding() {
return h_padding_bit != 0;
}
/**
* Returns Slots.
*/
public int slots() {
return nSlots;
}
/**
* Returns Mode Extension.
*/
public int mode_extension() {
return h_mode_extension;
}
// E.B -> private to public
public static final int bitrates[][][] = {
{{0 /*free format*/, 32000, 48000, 56000, 64000, 80000, 96000,
112000, 128000, 144000, 160000, 176000, 192000, 224000, 256000, 0},
{0 /*free format*/, 8000, 16000, 24000, 32000, 40000, 48000,
56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 0},
{0 /*free format*/, 8000, 16000, 24000, 32000, 40000, 48000,
56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 0}},
{{0 /*free format*/, 32000, 64000, 96000, 128000, 160000, 192000,
224000, 256000, 288000, 320000, 352000, 384000, 416000, 448000, 0},
{0 /*free format*/, 32000, 48000, 56000, 64000, 80000, 96000,
112000, 128000, 160000, 192000, 224000, 256000, 320000, 384000, 0},
{0 /*free format*/, 32000, 40000, 48000, 56000, 64000, 80000,
96000, 112000, 128000, 160000, 192000, 224000, 256000, 320000, 0}},
// SZD: MPEG2.5
{{0 /*free format*/, 32000, 48000, 56000, 64000, 80000, 96000,
112000, 128000, 144000, 160000, 176000, 192000, 224000, 256000, 0},
{0 /*free format*/, 8000, 16000, 24000, 32000, 40000, 48000,
56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 0},
{0 /*free format*/, 8000, 16000, 24000, 32000, 40000, 48000,
56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 0}},
};
// E.B -> private to public
/**
* Calculate Frame size.
* Calculates framesize in bytes excluding header size.
*/
public int calculate_framesize() {
if (h_layer == 1) {
framesize = (12 * bitrates[h_version][0][h_bitrate_index]) /
frequencies[h_version][h_sample_frequency];
if (h_padding_bit != 0) {
framesize++;
}
framesize <<= 2; // one slot is 4 bytes long
nSlots = 0;
} else {
framesize = (144 * bitrates[h_version][h_layer - 1][h_bitrate_index]) /
frequencies[h_version][h_sample_frequency];
if (h_version == MPEG2_LSF || h_version == MPEG25_LSF) {
framesize >>= 1; // SZD
}
if (h_padding_bit != 0) {
framesize++;
}
// Layer III slots
if (h_layer == 3) {
if (h_version == MPEG1) {
nSlots = framesize - ((h_mode == SINGLE_CHANNEL) ? 17 : 32) // side info size
- ((h_protection_bit != 0) ? 0 : 2) // CRC size
- 4; // header size
} else { // MPEG-2 LSF, SZD: MPEG-2.5 LSF
nSlots = framesize - ((h_mode == SINGLE_CHANNEL) ? 9 : 17) // side info size
- ((h_protection_bit != 0) ? 0 : 2) // CRC size
- 4; // header size
}
} else {
nSlots = 0;
}
}
framesize -= 4; // subtract header size
return framesize;
}
/**
* Returns the maximum number of frames in the stream.
*
* @param streamsize
* @return number of frames
*/
public int max_number_of_frames(long streamsize) // E.B
{
if (h_vbr) {
return h_vbr_frames;
} else {
if ((framesize + 4 - h_padding_bit) == 0) {
return 0;
} else {
return (int) (streamsize / (framesize + 4 - h_padding_bit));
}
}
}
/**
* Returns the maximum number of frames in the stream.
*
* @param streamsize
* @return number of frames
*/
public int min_number_of_frames(long streamsize) // E.B
{
if (h_vbr) {
return h_vbr_frames;
} else {
if ((framesize + 5 - h_padding_bit) == 0) {
return 0;
} else {
return (int) (streamsize / (framesize + 5 - h_padding_bit));
}
}
}
/**
* Returns ms/frame.
*
* @return milliseconds per frame
*/
public float ms_per_frame() // E.B
{
if (h_vbr) {
double tpf = h_vbr_time_per_frame[layer()] / frequency();
if ((h_version == MPEG2_LSF) || (h_version == MPEG25_LSF)) {
tpf /= 2;
}
return ((float) (tpf * 1000));
} else {
float ms_per_frame_array[][] = {{8.707483f, 8.0f, 12.0f},
{26.12245f, 24.0f, 36.0f},
{26.12245f, 24.0f, 36.0f}};
return (ms_per_frame_array[h_layer - 1][h_sample_frequency]);
}
}
/**
* Returns total ms.
*
* @param streamsize
* @return total milliseconds
*/
public float total_ms(int streamsize) // E.B
{
return (max_number_of_frames(streamsize) * ms_per_frame());
}
/**
* Returns synchronized header.
*/
public int getSyncHeader() // E.B
{
return _headerstring;
}
// functions which return header informations as strings:
/**
* Return Layer version.
*/
public String layer_string() {
switch (h_layer) {
case 1:
return "I";
case 2:
return "II";
case 3:
return "III";
}
return null;
}
// E.B -> private to public
public static final String bitrate_str[][][] = {
{{"free format", "32 kbit/s", "48 kbit/s", "56 kbit/s", "64 kbit/s",
"80 kbit/s", "96 kbit/s", "112 kbit/s", "128 kbit/s", "144 kbit/s",
"160 kbit/s", "176 kbit/s", "192 kbit/s", "224 kbit/s", "256 kbit/s",
"forbidden"},
{"free format", "8 kbit/s", "16 kbit/s", "24 kbit/s", "32 kbit/s",
"40 kbit/s", "48 kbit/s", "56 kbit/s", "64 kbit/s", "80 kbit/s",
"96 kbit/s", "112 kbit/s", "128 kbit/s", "144 kbit/s", "160 kbit/s",
"forbidden"},
{"free format", "8 kbit/s", "16 kbit/s", "24 kbit/s", "32 kbit/s",
"40 kbit/s", "48 kbit/s", "56 kbit/s", "64 kbit/s", "80 kbit/s",
"96 kbit/s", "112 kbit/s", "128 kbit/s", "144 kbit/s", "160 kbit/s",
"forbidden"}},
{{"free format", "32 kbit/s", "64 kbit/s", "96 kbit/s", "128 kbit/s",
"160 kbit/s", "192 kbit/s", "224 kbit/s", "256 kbit/s", "288 kbit/s",
"320 kbit/s", "352 kbit/s", "384 kbit/s", "416 kbit/s", "448 kbit/s",
"forbidden"},
{"free format", "32 kbit/s", "48 kbit/s", "56 kbit/s", "64 kbit/s",
"80 kbit/s", "96 kbit/s", "112 kbit/s", "128 kbit/s", "160 kbit/s",
"192 kbit/s", "224 kbit/s", "256 kbit/s", "320 kbit/s", "384 kbit/s",
"forbidden"},
{"free format", "32 kbit/s", "40 kbit/s", "48 kbit/s", "56 kbit/s",
"64 kbit/s", "80 kbit/s", "96 kbit/s", "112 kbit/s", "128 kbit/s",
"160 kbit/s", "192 kbit/s", "224 kbit/s", "256 kbit/s", "320 kbit/s",
"forbidden"}},
// SZD: MPEG2.5
{{"free format", "32 kbit/s", "48 kbit/s", "56 kbit/s", "64 kbit/s",
"80 kbit/s", "96 kbit/s", "112 kbit/s", "128 kbit/s", "144 kbit/s",
"160 kbit/s", "176 kbit/s", "192 kbit/s", "224 kbit/s", "256 kbit/s",
"forbidden"},
{"free format", "8 kbit/s", "16 kbit/s", "24 kbit/s", "32 kbit/s",
"40 kbit/s", "48 kbit/s", "56 kbit/s", "64 kbit/s", "80 kbit/s",
"96 kbit/s", "112 kbit/s", "128 kbit/s", "144 kbit/s", "160 kbit/s",
"forbidden"},
{"free format", "8 kbit/s", "16 kbit/s", "24 kbit/s", "32 kbit/s",
"40 kbit/s", "48 kbit/s", "56 kbit/s", "64 kbit/s", "80 kbit/s",
"96 kbit/s", "112 kbit/s", "128 kbit/s", "144 kbit/s", "160 kbit/s",
"forbidden"}},
};
/**
* Return Bitrate.
*
* @return bitrate in bps
*/
public String bitrate_string() {
if (h_vbr) {
return Integer.toString(bitrate() / 1000) + " kb/s";
} else {
return bitrate_str[h_version][h_layer - 1][h_bitrate_index];
}
}
/**
* Return Bitrate.
*
* @return bitrate in bps and average bitrate for VBR header
*/
public int bitrate() {
if (h_vbr) {
return ((int) ((h_vbr_bytes * 8) / (ms_per_frame() * h_vbr_frames))) * 1000;
} else {
return bitrates[h_version][h_layer - 1][h_bitrate_index];
}
}
/**
* Return Instant Bitrate.
* Bitrate for VBR is not constant.
*
* @return bitrate in bps
*/
public int bitrate_instant() {
return bitrates[h_version][h_layer - 1][h_bitrate_index];
}
/**
* Returns Frequency
*
* @return frequency string in kHz
*/
public String sample_frequency_string() {
switch (h_sample_frequency) {
case THIRTYTWO:
if (h_version == MPEG1) {
return "32 kHz";
} else if (h_version == MPEG2_LSF) {
return "16 kHz";
} else // SZD
{
return "8 kHz";
}
case FOURTYFOUR_POINT_ONE:
if (h_version == MPEG1) {
return "44.1 kHz";
} else if (h_version == MPEG2_LSF) {
return "22.05 kHz";
} else // SZD
{
return "11.025 kHz";
}
case FOURTYEIGHT:
if (h_version == MPEG1) {
return "48 kHz";
} else if (h_version == MPEG2_LSF) {
return "24 kHz";
} else // SZD
{
return "12 kHz";
}
}
return (null);
}
/**
* Returns Mode.
*/
public String mode_string() {
switch (h_mode) {
case STEREO:
return "Stereo";
case JOINT_STEREO:
return "Joint stereo";
case DUAL_CHANNEL:
return "Dual channel";
case SINGLE_CHANNEL:
return "Single channel";
}
return null;
}
/**
* Returns Version.
*
* @return MPEG-1 or MPEG-2 LSF or MPEG-2.5 LSF
*/
public String version_string() {
switch (h_version) {
case MPEG1:
return "MPEG-1";
case MPEG2_LSF:
return "MPEG-2 LSF";
case MPEG25_LSF: // SZD
return "MPEG-2.5 LSF";
}
return (null);
}
/**
* Returns the number of subbands in the current frame.
*
* @return number of subbands
*/
public int number_of_subbands() {
return h_number_of_subbands;
}
/**
* Returns Intensity Stereo.
* (Layer II joint stereo only).
* Returns the number of subbands which are in stereo mode,
* subbands above that limit are in intensity stereo mode.
*
* @return intensity
*/
public int intensity_stereo_bound() {
return h_intensity_stereo_bound;
}
}