2 * 11/19/04 : 1.0 moved to LGPL.
3 * VBRI header support added, E.B javalayer@javazoom.net
5 * 12/04/03 : VBR (XING) header support added, E.B javalayer@javazoom.net
7 * 02/13/99 : Java Conversion by JavaZOOM , E.B javalayer@javazoom.net
9 * Declarations for MPEG header class
10 * A few layer III, MPEG-2 LSF, and seeking modifications made by Jeff Tsay.
11 * Last modified : 04/19/97
13 * @(#) header.h 1.7, last edit: 6/15/94 16:55:33
14 * @(#) Copyright (C) 1993, 1994 Tobias Bading (bading@cs.tu-berlin.de)
15 * @(#) Berlin University of Technology
16 *-----------------------------------------------------------------------
17 * This program is free software; you can redistribute it and/or modify
18 * it under the terms of the GNU Library General Public License as published
19 * by the Free Software Foundation; either version 2 of the License, or
20 * (at your option) any later version.
22 * This program is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU Library General Public License for more details.
27 * You should have received a copy of the GNU Library General Public
28 * License along with this program; if not, write to the Free Software
29 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
30 *----------------------------------------------------------------------
34 * Class for extracting information from a frame header.
37 public final class Header {
39 public static final int[][] frequencies = { { 22050, 24000, 16000, 1 }, { 44100, 48000, 32000, 1 }, { 11025, 12000, 8000, 1 } }; // SZD:
43 * Constant for MPEG-2 LSF version
45 public static final int MPEG2_LSF = 0;
46 public static final int MPEG25_LSF = 2; // SZD
49 * Constant for MPEG-1 version
51 public static final int MPEG1 = 1;
53 public static final int STEREO = 0;
54 public static final int JOINT_STEREO = 1;
55 public static final int DUAL_CHANNEL = 2;
56 public static final int SINGLE_CHANNEL = 3;
57 public static final int FOURTYFOUR_POINT_ONE = 0;
58 public static final int FOURTYEIGHT = 1;
59 public static final int THIRTYTWO = 2;
63 private int h_protection_bit;
65 private int h_bitrate_index;
67 private int h_padding_bit;
69 private int h_mode_extension;
71 private int h_version;
75 private int h_sample_frequency;
77 private int h_number_of_subbands;
79 private int h_intensity_stereo_bound;
81 private boolean h_copyright;
83 private boolean h_original;
84 // VBR support added by E.B
86 private double[] h_vbr_time_per_frame = { -1.0, 384.0, 1152.0, 1152.0 };
88 private boolean h_vbr;
90 private int h_vbr_frames;
92 private int h_vbr_scale;
94 private int h_vbr_bytes;
96 private byte[] h_vbr_toc;
98 private byte syncmode = Bitstream.INITIAL_SYNC;
102 public short checksum;
104 public int framesize;
108 private int _headerstring = -1; // E.B
110 private SideInfoBuffer sib;
112 private BitReserve br;
119 public String toString() {
120 StringBuffer buffer = new StringBuffer(200);
121 buffer.append("Layer ");
122 buffer.append(layer_string());
123 buffer.append(" frame ");
124 buffer.append(mode_string());
126 buffer.append(version_string());
128 buffer.append(" no");
129 buffer.append(" checksums");
131 buffer.append(sample_frequency_string());
134 buffer.append(bitrate_string());
136 String s = buffer.toString();
141 * Read a 32-bit header from the bitstream.
143 int read_header(Bitstream stream, Crc16[] crcp) throws BitstreamException {
146 boolean sync = false;
148 headerstring = stream.syncHeader(syncmode);
149 if (headerstring == -1) {
152 _headerstring = headerstring; // E.B
153 if (syncmode == Bitstream.INITIAL_SYNC) {
154 h_version = ((headerstring >>> 19) & 1);
155 if (((headerstring >>> 20) & 1) == 0) // SZD: MPEG2.5 detection
156 if (h_version == MPEG2_LSF)
157 h_version = MPEG25_LSF;
159 throw stream.newBitstreamException(Bitstream.UNKNOWN_ERROR);
160 if ((h_sample_frequency = ((headerstring >>> 10) & 3)) == 3) {
161 throw stream.newBitstreamException(Bitstream.UNKNOWN_ERROR);
164 h_layer = 4 - (headerstring >>> 17) & 3;
165 h_protection_bit = (headerstring >>> 16) & 1;
166 h_bitrate_index = (headerstring >>> 12) & 0xF;
167 h_padding_bit = (headerstring >>> 9) & 1;
168 h_mode = ((headerstring >>> 6) & 3);
169 h_mode_extension = (headerstring >>> 4) & 3;
170 if (h_mode == JOINT_STEREO)
171 h_intensity_stereo_bound = (h_mode_extension << 2) + 4;
173 h_intensity_stereo_bound = 0; // should never be used
174 if (((headerstring >>> 3) & 1) == 1)
176 if (((headerstring >>> 2) & 1) == 1)
178 // calculate number of subbands:
180 h_number_of_subbands = 32;
182 channel_bitrate = h_bitrate_index;
183 // calculate bitrate per channel:
184 if (h_mode != SINGLE_CHANNEL)
185 if (channel_bitrate == 4)
188 channel_bitrate -= 4;
189 if ((channel_bitrate == 1) || (channel_bitrate == 2))
190 if (h_sample_frequency == THIRTYTWO)
191 h_number_of_subbands = 12;
193 h_number_of_subbands = 8;
194 else if ((h_sample_frequency == FOURTYEIGHT) || ((channel_bitrate >= 3) && (channel_bitrate <= 5)))
195 h_number_of_subbands = 27;
197 h_number_of_subbands = 30;
199 if (h_intensity_stereo_bound > h_number_of_subbands)
200 h_intensity_stereo_bound = h_number_of_subbands;
201 // calculate framesize and nSlots
202 calculate_framesize();
204 int framesizeloaded = stream.read_frame_data(framesize);
205 if ((framesize >= 0) && (framesizeloaded != framesize)) {
206 // Data loaded does not match to expected framesize,
207 // it might be an ID3v1 TAG. (Fix 11/17/04).
208 throw stream.newBitstreamException(Bitstream.INVALIDFRAME);
210 if (stream.isSyncCurrentPosition(syncmode)) {
211 if (syncmode == Bitstream.INITIAL_SYNC) {
212 syncmode = Bitstream.STRICT_SYNC;
213 stream.set_syncword(headerstring & 0xFFF80CC0);
217 stream.unreadFrame();
220 stream.parse_frame();
221 if (h_protection_bit == 0) {
222 // frame contains a crc checksum
223 checksum = (short) stream.get_bits(16);
226 crc.add_bits(headerstring, 16);
230 if (h_sample_frequency == FOURTYFOUR_POINT_ONE) {
232 * if (offset == null) { int max = max_number_of_frames(stream); offset =
233 * new int[max]; for(int i=0; i<max; i++) offset[i] = 0; } // E.B :
234 * Investigate more int cf = stream.current_frame(); int lf =
235 * stream.last_frame(); if ((cf > 0) && (cf == lf)) { offset[cf] =
236 * offset[cf-1] + h_padding_bit; } else { offset[0] = h_padding_bit; }
243 * Parse frame to extract optionnal VBR frame.
246 * @author E.B (javalayer@javazoom.net)
248 void parseVBR(byte[] firstframe) throws BitstreamException {
249 // Trying Xing header.
250 String xing = "Xing";
251 byte tmp[] = new byte[4];
253 // Compute "Xing" offset depending on MPEG version and channels.
254 if (h_version == MPEG1) {
255 if (h_mode == SINGLE_CHANNEL)
260 if (h_mode == SINGLE_CHANNEL)
266 System.arraycopy(firstframe, offset, tmp, 0, 4);
268 if (xing.equals(new String(tmp))) {
274 h_vbr_toc = new byte[100];
278 byte flags[] = new byte[4];
279 System.arraycopy(firstframe, offset + length, flags, 0, flags.length);
280 length += flags.length;
281 // Read number of frames (if available).
282 if ((flags[3] & (byte) (1 << 0)) != 0) {
283 System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
284 h_vbr_frames = (tmp[0] << 24) & 0xFF000000 | (tmp[1] << 16) & 0x00FF0000 | (tmp[2] << 8) & 0x0000FF00 | tmp[3] & 0x000000FF;
287 // Read size (if available).
288 if ((flags[3] & (byte) (1 << 1)) != 0) {
289 System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
290 h_vbr_bytes = (tmp[0] << 24) & 0xFF000000 | (tmp[1] << 16) & 0x00FF0000 | (tmp[2] << 8) & 0x0000FF00 | tmp[3] & 0x000000FF;
293 // Read TOC (if available).
294 if ((flags[3] & (byte) (1 << 2)) != 0) {
295 System.arraycopy(firstframe, offset + length, h_vbr_toc, 0, h_vbr_toc.length);
296 length += h_vbr_toc.length;
298 // Read scale (if available).
299 if ((flags[3] & (byte) (1 << 3)) != 0) {
300 System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
301 h_vbr_scale = (tmp[0] << 24) & 0xFF000000 | (tmp[1] << 16) & 0x00FF0000 | (tmp[2] << 8) & 0x0000FF00 | tmp[3] & 0x000000FF;
304 // System.out.println("VBR:"+xing+" Frames:"+ h_vbr_frames
305 // +" Size:"+h_vbr_bytes);
307 } catch (ArrayIndexOutOfBoundsException e) {
308 throw new BitstreamException("XingVBRHeader Corrupted", e);
311 // Trying VBRI header.
312 String vbri = "VBRI";
315 System.arraycopy(firstframe, offset, tmp, 0, 4);
317 if (vbri.equals(new String(tmp))) {
323 h_vbr_toc = new byte[100];
326 System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
327 h_vbr_bytes = (tmp[0] << 24) & 0xFF000000 | (tmp[1] << 16) & 0x00FF0000 | (tmp[2] << 8) & 0x0000FF00 | tmp[3] & 0x000000FF;
330 System.arraycopy(firstframe, offset + length, tmp, 0, tmp.length);
331 h_vbr_frames = (tmp[0] << 24) & 0xFF000000 | (tmp[1] << 16) & 0x00FF0000 | (tmp[2] << 8) & 0x0000FF00 | tmp[3] & 0x000000FF;
333 // System.out.println("VBR:"+vbri+" Frames:"+ h_vbr_frames
334 // +" Size:"+h_vbr_bytes);
338 } catch (ArrayIndexOutOfBoundsException e) {
339 throw new BitstreamException("VBRIVBRHeader Corrupted", e);
343 // Functions to query header contents:
348 public int version() {
361 * Returns bitrate index.
363 public int bitrate_index() {
364 return h_bitrate_index;
368 * Returns Sample Frequency.
371 public int sample_frequency() {
372 return h_sample_frequency;
379 public int frequency() {
380 return frequencies[h_version][h_sample_frequency];
392 * Returns Protection bit.
395 public boolean checksums() {
396 if (h_protection_bit == 0)
405 public boolean copyright() {
412 public boolean original() {
419 * @return true if VBR header is found
421 public boolean vbr() {
428 * @return scale of -1 if not available
430 public int vbr_scale() {
437 * @return vbr toc ot null if not available
439 public byte[] vbr_toc() {
444 * Returns Checksum flag. Compares computed checksum with stream checksum.
447 public boolean checksum_ok() {
448 return (checksum == crc.checksum());
451 // Seeking and layer III stuff
453 * Returns Layer III Padding bit.
455 public boolean padding() {
456 if (h_padding_bit == 0)
471 * Returns Mode Extension.
474 public int mode_extension() {
475 return h_mode_extension;
478 // E.B -> private to public
479 public static final int bitrates[][][] = { { { 0 /* free format */, 32000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 176000, 192000, 224000, 256000, 0 }, { 0 /*
482 */, 8000, 16000, 24000, 32000, 40000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 0 }, { 0 /*
485 */, 8000, 16000, 24000, 32000, 40000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 0 } },
487 { { 0 /* free format */, 32000, 64000, 96000, 128000, 160000, 192000, 224000, 256000, 288000, 320000, 352000, 384000, 416000, 448000, 0 }, { 0 /*
490 */, 32000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 160000, 192000, 224000, 256000, 320000, 384000, 0 }, { 0 /*
493 */, 32000, 40000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 160000, 192000, 224000, 256000, 320000, 0 } },
495 { { 0 /* free format */, 32000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 176000, 192000, 224000, 256000, 0 }, { 0 /*
498 */, 8000, 16000, 24000, 32000, 40000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 0 }, { 0 /*
501 */, 8000, 16000, 24000, 32000, 40000, 48000, 56000, 64000, 80000, 96000, 112000, 128000, 144000, 160000, 0 } },
505 // E.B -> private to public
507 * Calculate Frame size. Calculates framesize in bytes excluding header size.
509 public int calculate_framesize() {
512 framesize = (12 * bitrates[h_version][0][h_bitrate_index]) / frequencies[h_version][h_sample_frequency];
513 if (h_padding_bit != 0)
515 framesize <<= 2; // one slot is 4 bytes long
518 framesize = (144 * bitrates[h_version][h_layer - 1][h_bitrate_index]) / frequencies[h_version][h_sample_frequency];
519 if (h_version == MPEG2_LSF || h_version == MPEG25_LSF)
520 framesize >>= 1; // SZD
521 if (h_padding_bit != 0)
525 if (h_version == MPEG1) {
526 nSlots = framesize - ((h_mode == SINGLE_CHANNEL) ? 17 : 32) // side
529 - ((h_protection_bit != 0) ? 0 : 2) // CRC size
531 } else { // MPEG-2 LSF, SZD: MPEG-2.5 LSF
532 nSlots = framesize - ((h_mode == SINGLE_CHANNEL) ? 9 : 17) // side
535 - ((h_protection_bit != 0) ? 0 : 2) // CRC size
542 framesize -= 4; // subtract header size
547 * Returns the maximum number of frames in the stream.
550 * @return number of frames
552 public int max_number_of_frames(int streamsize) // E.B
557 if ((framesize + 4 - h_padding_bit) == 0)
560 return (streamsize / (framesize + 4 - h_padding_bit));
565 * Returns the maximum number of frames in the stream.
568 * @return number of frames
570 public int min_number_of_frames(int streamsize) // E.B
575 if ((framesize + 5 - h_padding_bit) == 0)
578 return (streamsize / (framesize + 5 - h_padding_bit));
585 * @return milliseconds per frame
588 public float ms_per_frame() // E.B
591 double tpf = h_vbr_time_per_frame[layer()] / frequency();
592 if ((h_version == MPEG2_LSF) || (h_version == MPEG25_LSF))
594 return ((float) (tpf * 1000));
596 float ms_per_frame_array[][] = { { 8.707483f, 8.0f, 12.0f }, { 26.12245f, 24.0f, 36.0f }, { 26.12245f, 24.0f, 36.0f } };
597 return (ms_per_frame_array[h_layer - 1][h_sample_frequency]);
605 * @return total milliseconds
607 public float total_ms(int streamsize) // E.B
609 return (max_number_of_frames(streamsize) * ms_per_frame());
613 * Returns synchronized header.
615 public int getSyncHeader() // E.B
617 return _headerstring;
620 // functions which return header informations as strings:
622 * Return Layer version.
625 public String layer_string() {
637 // E.B -> private to public
638 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" } },
640 { { "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" } },
642 { { "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" } }, };
647 * @return bitrate in bps
650 public String bitrate_string() {
651 String kbs = " kb/s";
653 return Integer.toString(bitrate() / 1000) + kbs;
655 return bitrate_str[h_version][h_layer - 1][h_bitrate_index];
662 * @return bitrate in bps and average bitrate for VBR header
665 public int bitrate() {
667 return ((int) ((h_vbr_bytes * 8) / (ms_per_frame() * h_vbr_frames))) * 1000;
669 return bitrates[h_version][h_layer - 1][h_bitrate_index];
674 * Return Instant Bitrate. Bitrate for VBR is not constant.
676 * @return bitrate in bps
678 public int bitrate_instant() {
679 return bitrates[h_version][h_layer - 1][h_bitrate_index];
685 * @return frequency string in kHz
688 public String sample_frequency_string() {
689 switch (h_sample_frequency) {
691 if (h_version == MPEG1)
693 else if (h_version == MPEG2_LSF)
698 case FOURTYFOUR_POINT_ONE:
699 if (h_version == MPEG1)
701 else if (h_version == MPEG2_LSF)
707 if (h_version == MPEG1)
709 else if (h_version == MPEG2_LSF)
722 public String mode_string() {
727 return "Joint stereo";
729 return "Dual channel";
731 return "Single channel";
739 * @return MPEG-1 or MPEG-2 LSF or MPEG-2.5 LSF
742 public String version_string() {
748 case MPEG25_LSF: // SZD
749 return "MPEG-2.5 LSF";
755 * Returns the number of subbands in the current frame.
757 * @return number of subbands
759 public int number_of_subbands() {
760 return h_number_of_subbands;
764 * Returns Intensity Stereo. (Layer II joint stereo only). Returns the number
765 * of subbands which are in stereo mode, subbands above that limit are in
766 * intensity stereo mode.
770 public int intensity_stereo_bound() {
771 return h_intensity_stereo_bound;
774 public void setSideInfoBuf(SideInfoBuffer sib) {
778 public void setBitReserve(BitReserve br) {
782 public SideInfoBuffer getSideInfoBuffer() {
786 public BitReserve getBitReserve() {
790 public int getIdx() {
794 public int setIdx(int idx) {
795 return this.idx = idx;