path: root/www/docs/mpeghdr.t

#define _PAGE_ MPEG Audio Frame Header
#include "head.t"

<P>This is a brief and informal document targeted to those who want to deal
with the MPEG format. If you are one of them, you probably already know what
is MPEG audio. If not, jump to <A
HREF="http://www.mp3.com/">http://www.mp3.com/</A> or <A
HREF="http://www.layer3.org/">http://www.layer3.org/</A> where you will find
more details and also more links. This document does not cover compression and
decompression algorithm.

<P>NOTE: You cannot just search the Internet and find the MPEG audio specs. It 
is copyrighted and you will have to pay quite a bit to get the Paper. That's why 
I made this. Information I got is gathered from the Internet, and mostly originate 
from program sources I found available for free. Despite my intention to always 
specify the information sources, I am not able to do it this time. Sorry, I did 
not maintain the list. :-( 
<P><B>These are not a decoding specs, it just informs you how to read the </B><A
HREF="#MPEG HEADER"><B>MPEG headers</B></A><B> and the </B> <A HREF="#MPEGTAG" 
TARGET=""><B>MPEG TAG</B></A><B>. MPEG Version 1, 2 and 2.5 and Layer I, II 
and III are supported, the MP3 TAG (ID3v1 and ID3v1.1) also.</B>. Those of you 
who use Delphi may find <A 
HREF="http://www.dv.co.yu/mpgscript/mpgtools.htm">MPGTools Delphi unit (freeware source)</A> 
useful, it is where I implemented this stuff. 

<P>I do not claim information presented in this document is accurate. At first 
I just gathered it from different sources. It was not an easy task but I needed 
it. Later, I received lots of comments as feedback when I published this document. 
I think this last release is highly accurate due to comments and corrections I 
received. 
<P>This document is last updated on December 22, 1999. 
<P ALIGN="center"><FONT SIZE="5"><B>MPEG Audio Compression Basics</B></FONT>

<P>This is one of many methods to compress audio in digital form trying to consume 
as little space as possible but keep audio quality as good as possible. MPEG compression 
showed up as one of the best achievements in this area. 
<P>This is a lossy compression, which means, you will certainly loose some audio 
information when you use this compression methods. But, this lost can hardly be 
noticed because the compression method tries to control it. By using several quite 
complicate and demanding mathematical algorithms it will only loose those parts 
of sound that are hard to be heard even in the original form. This leaves more 
space for information that is important. This way you can compress audio up to 
12 times (you may choose compression ratio) which is really significant. Due to 
its quality MPEG audio became very popular. 
<P>MPEG standards MPEG-1, MPEG-2 and MPEG-4 are known but this document covers 
first two of them. There is an unofficial MPEG-2.5 which is rarely used. It is 
also covered. 
<P><B>MPEG-1 audio</B> (described in ISO/IEC 11172-3) describes three Layers of audio coding with the following properties:
<LI>one or two audio channels
<LI>sample rate 32kHz, 44.1kHz or 48kHz.
<LI>bit rates from 32kbps up to 448kbps<BR>
Each layer has its merits.

<P><B>MPEG-2 audio</B> (described in ISO/IEC 13818-3) has two extensions to MPEG-1, usually referred as MPEG-2/LSF and MPEG-2/Multichannel.
<P>MPEG-2/LSF has the following properties:
<LI>one or two audio channels
<LI>sample rates half those of MPEG-1
<LI>bit rates from 8 kbps up to 256kbps.

<P>MPEG-2/Multichannel has the following properties:
<LI>up to 5 full range audio channels and an LFE-channel (Low Frequency
Enhancement <> subwoofer!)
<LI>sample rates the same as those of MPEG-1
<LI>highest possible bitrate goes up to about 1Mbps for 5.1


<P ALIGN="center"><A NAME="MPEG HEADER"></A><FONT SIZE="5"><B>MPEG Audio Frame
Header</B></FONT>

<P>An MPEG audio file is built up from smaller parts called frames. Generally, 
frames are independent items. Each frame has its own header and audio informations. 
There is no file header. Therefore, you can cut any part of MPEG file and play 
it correctly (this should be done on frame boundaries but most applications will 
handle incorrect headers). For Layer III, this is not 100% correct. Due to internal 
data organization in MPEG version 1 Layer III files, frames are often dependent 
of each other and they cannot be cut off just like that. 
<P>When you want to read info about an MPEG file, it is usually enough to find 
the first frame, read its header and assume that the other frames are the same 
This may not be always the case. Variable bitrate MPEG files may use so called 
bitrate switching, which means that bitrate changes according to the content of 
each frame. This way lower bitrates may be used in frames where it will not reduce 
sound quality. This allows making better compression while keeping high quality 
of sound. 
<P>The frame header is constituted by the very first four bytes (32bits) in a 
frame. The first eleven bits (or first twelve bits, see below about frame sync) 
of a frame header are always set and they are called &quot;frame sync&quot;. Therefore, 
you can search through the file for the first occurence of frame sync (meaning 
that you have to find a byte with a value of 255, and followed by a byte with 
its three (or four) most significant bits set). Then you read the whole header 
and check if the values are correct. You will see in the following table the exact 
meaning of each bit in the header, and which values may be checked for validity. 
Each value that is specified as reserved, invalid, bad, or not allowed should 
indicate an invalid header. Remember, this is not enough, frame sync can be easily 
(and very frequently) found in any binary file. Also it is likely that MPEG file 
contains garbage on it's beginning which also may contain false sync. Thus, you 
have to check two or more frames in a row to assure you are really dealing with 
MPEG audio file. 
<P>Frames may have a CRC check. The CRC is 16 bits long
and, if it exists, it follows the frame header. After the CRC comes the audio
data. You may calculate the length of the frame and use it if you need to read
other headers too or just want to calculate the CRC of the frame, to compare
it with the one you read from the file. This is actually a very good method to
check the MPEG header validity.

<P>Here is &quot;graphical&quot; presentation of the header content. Characters 
from A to M are used to indicate different fields. In the table, you can see 
details about the content of each field. 
<P ALIGN="center">
<B><TT><FONT SIZE="5">
AAAAAAAA AAABBCCD EEEEFFGH IIJJKLMM
</FONT>
</TT></B>

<P><CENTER>

<TABLE BORDER="0" CELLSPACING=7>
<TR VALIGN=TOP BGCOLOR="#E2E2E2">
<TD>Sign</TD><TD>Length<BR>(bits)</TD><TD>Position<BR>(bits)</TD><TD>Description</TD>
</TR>

<TR VALIGN=TOP>
<TD>A</TD><TD>11</TD><TD>(31-21)</TD><TD>Frame sync (all bits set)</TD>
</TR>

<TR VALIGN=TOP>
<TD>B</TD><TD>2</TD><TD>(20,19)</TD><TD>MPEG Audio version ID<BR>          
00 - MPEG Version 2.5<BR>01 - reserved<BR>10 - MPEG Version 2 (ISO/IEC 13818-3)<BR>11 - MPEG Version 1 (ISO/IEC 11172-3)
<P>Note: MPEG Version 2.5 is not official standard. Bit No 20 in frame header 
is used to indicate version 2.5. Applications that do not support this MPEG version 
expect this bit always to be set, meaning that frame sync (A) is twelve bits long, 
not eleve as stated here. Accordingly, B is one bit long (represents only bit 
No 19). I recommend using methodology presented here, since this allows you to 
distinguish all three versions and keep full compatibility.
</TD>
</TR>

<TR VALIGN=TOP><TD>C</TD><TD>2</TD><TD>(18,17)</TD>
<TD>Layer description<BR>          
00 - reserved<BR>
01 - Layer III<BR>
10 - Layer II<BR>
11 - Layer I</TD>
</TR>

<TR VALIGN=TOP>
<TD>D</TD><TD>1</TD><TD>(16)</TD>
<TD>Protection bit<BR>          
0 - Protected by CRC (16bit crc follows header)<BR>
1 - Not protected</TD>
</TR>
<TR VALIGN=TOP><TD>E</TD><TD>4</TD><TD>(15,12)</TD><TD>Bitrate index<BR>     
<TABLE BORDER="1" CELLSPACING="0" CELLPADING="0">
<TR><TD>bits</TD><TD>V1,L1</TD><TD>V1,L2</TD><TD>V1,L3</TD><TD>V2,L1</TD><TD>V2, L2 &amp; L3</TD></TR>
<TR><TD>0000</TD><TD>free</TD><TD>free</TD><TD>free</TD><TD>free</TD><TD>free</TD></TR>
<TR><TD>0001</TD><TD>32</TD><TD>32</TD><TD>32</TD><TD>32</TD><TD>8</TD></TR>
<TR><TD>0010</TD><TD>64</TD><TD>48</TD><TD>40</TD><TD>48</TD><TD>16</TD></TR>
<TR><TD>0011</TD><TD>96</TD><TD>56</TD><TD>48</TD><TD>56</TD><TD>24</TD></TR>
<TR><TD>0100</TD><TD>128</TD><TD>64</TD><TD>56</TD><TD>64</TD><TD>32</TD></TR>
<TR><TD>0101</TD><TD>160</TD><TD>80</TD><TD>64</TD><TD>80</TD><TD>40</TD></TR>
<TR><TD>0110</TD><TD>192</TD><TD>96</TD><TD>80</TD><TD>96</TD><TD>48</TD></TR>
<TR><TD>0111</TD><TD>224</TD><TD>112</TD><TD>96</TD><TD>112</TD><TD>56</TD></TR>
<TR><TD>1000</TD><TD>256</TD><TD>128</TD><TD>112</TD><TD>128</TD><TD>64</TD></TR>
<TR><TD>1001</TD><TD>288</TD><TD>160</TD><TD>128</TD><TD>144</TD><TD>80</TD></TR>
<TR><TD>1010</TD><TD>320</TD><TD>192</TD><TD>160</TD><TD>160</TD><TD>96</TD></TR>
<TR><TD>1011</TD><TD>352</TD><TD>224</TD><TD>192</TD><TD>176</TD><TD>112</TD></TR>
<TR><TD>1100</TD><TD>384</TD><TD>256</TD><TD>224</TD><TD>192</TD><TD>128</TD></TR>
<TR><TD>1101</TD><TD>416</TD><TD>320</TD><TD>256</TD><TD>224</TD><TD>144</TD></TR>
<TR><TD>1110</TD><TD>448</TD><TD>384</TD><TD>320</TD><TD>256</TD><TD>160</TD></TR>
<TR><TD>1111</TD><TD>bad</TD><TD>bad</TD><TD>bad</TD><TD>bad</TD><TD>bad</TD></TR>
</TABLE>
<P>
NOTES: All values are in kbps<BR>
V1 - MPEG Version 1<BR>
V2 - MPEG Version 2 and Version 2.5<BR>
L1 - Layer I<BR>
L2 - Layer II<BR>
L3 - Layer III<BR>
&quot;free&quot; means free format. If the correct fixed bitrate (such files cannot 
use variable bitrate) is different than those presented in upper table it must 
be determined by the application. This may be implemented only for internal purposes 
since third party applications have no means to find out correct bitrate. Howewer, 
this is not impossible to do but demands lot's of efforts.<BR>
&quot;bad&quot; means that this is not an allowed value

<P>MPEG files may have variable bitrate (VBR). This means that bitrate in the file may change. I have learned about two used methods:
<LI>bitrate switching. Each frame may be created with different bitrate. It may be used in all layers. Layer III decoders must support this method. Layer I & II decoders may support it.
<LI>bit reservoir. Bitrate may be borrowed (within limits) from previous frames 
in order to provide more bits to demanding parts of the input signal. This causes, 
however, that the frames are no longer independent, which means you should not 
cut this files. This is supported only in Layer III. 
<P>More about VBR you may find on <A HREF="http://www.xingtech.com/">Xing Tech 
site</A>
<P>For Layer II there are some combinations of bitrate and mode which are not 
allowed. Here is a list of allowed combinations. 
<TABLE BORDER=1 CELLSPACING=0>
<TR> 
<TD>bitrate</TD>
<TD>allowed modes</TD>
</TR>
<TR> 
<TD>free</TD>
<TD>all</TD>
</TR>
<TR> 
<TD>32</TD>
<TD>single channel</TD>
</TR>
<TR> 
<TD>48</TD>
<TD>single channel</TD>
</TR>
<TR> 
<TD>56</TD>
<TD>single channel</TD>
</TR>
<TR> 
<TD>64</TD>
<TD>all</TD>
</TR>
<TR> 
<TD>80</TD>
<TD>single channel</TD>
</TR>
<TR> 
<TD>96</TD>
<TD>all</TD>
</TR>
<TR> 
<TD>112</TD>
<TD>all</TD>
</TR>
<TR> 
<TD>128</TD>
<TD>all</TD>
</TR>
<TR> 
<TD>160</TD>
<TD>all</TD>
</TR>
<TR> 
<TD>192</TD>
<TD>all</TD>
</TR>
<TR> 
<TD>224</TD>
<TD>stereo, intensity stereo, dual channel</TD>
</TR>
<TR> 
<TD>256</TD>
<TD>stereo, intensity stereo, dual channel</TD>
</TR>
<TR> 
<TD>320</TD>
<TD>stereo, intensity stereo, dual channel</TD>
</TR>
<TR> 
<TD>384</TD>
<TD>stereo, intensity stereo, dual channel</TD>
</TR>
</TABLE>
</TD></TR>
<TR VALIGN=TOP>
<TD>F</TD><TD>2</TD><TD>(11,10)</TD>
<TD>Sampling rate frequency index (values are in Hz) 
<TABLE BORDER="1" CELLSPACING="0" CELLPADING="0">
<TR><TD>bits</TD><TD>MPEG1</TD><TD>MPEG2</TD><TD>MPEG2.5</TD></TR>
<TR><TD>00</TD><TD>44100</TD><TD>22050</TD><TD>11025</TD></TR>
<TR><TD>01</TD><TD>48000</TD><TD>24000</TD><TD>12000</TD></TR>
<TR><TD>10</TD><TD>32000</TD><TD>16000</TD><TD>8000</TD></TR>
<TR><TD>11</TD><TD>reserv.</TD><TD>reserv.</TD><TD>reserv.</TD></TR>
</TABLE>
</TD></TR>

<TR VALIGN=TOP>
<TD>G</TD><TD>1</TD><TD>(9)</TD>
<TD>Padding bit<BR>          
0 - frame is not padded<BR>
1 - frame is padded with one extra slot<BR>

Padding is used to fit the bit rates exactly. For an example: 128k 44.1kHz layer II uses a lot of 418 bytes and some of 417 bytes long frames to get the exact 128k bitrate. For Layer I slot is 32 bits long, for Layer II and Layer III slot is 8 bits long.



<P><B>How to calculate frame length</B>

<P>First, let's distinguish two terms frame size and frame length. Frame size 
is the number of samples contained in a frame. It is constant and always 384 samples 
for Layer I and 1152 samples for Layer II and Layer III. Frame length is length 
of a frame when compressed. It is calculated in slots. One slot is 4 bytes long 
for Layer I, and one byte long for Layer II and Layer III. When you are reading 
MPEG file you must calculate this to be able to find each consecutive frame. Remember, 
frame length may change from frame to frame due to padding or bitrate switching. 
<P>Read the BitRate, SampleRate and Padding of the frame header. 
<P>For Layer I files us this formula: 
<P ALIGN=CENTER>FrameLengthInBytes = (12 * BitRate / SampleRate + Padding) * 4
<P ALIGN=LEFT>For Layer II & III files use this formula:
<P ALIGN=CENTER>FrameLengthInBytes = 144 * BitRate / SampleRate + Padding 
<P>Example:<BR>
Layer III, BitRate=128000, SampleRate=44100, Padding=0<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ==&gt;&nbsp; FrameSize=417 bytes 
</TD></TR>

<TR VALIGN=TOP><TD>H</TD><TD>1</TD><TD>(8)</TD>
<TD>Private bit. It may be freely used for specific needs of an application, i.e. if it has to trigger some application specific events.</TD>
</TR>

<TR VALIGN=TOP><TD>I</TD><TD>2</TD><TD>(7,6)</TD>
<TD>Channel Mode<BR>          
00 - Stereo<BR>
01 - Joint stereo (Stereo)<BR>
10 - Dual channel (Stereo)<BR>
11 - Single channel (Mono)</TD>
</TR>

<TR VALIGN=TOP><TD>J</TD><TD>2</TD><TD>(5,4)</TD>
<TD>Mode extension (Only if Joint stereo)
<P>Mode extension is used to join informations that are of no use for stereo effect, thus reducing needed resources. These bits are dynamically determined by an encoder in Joint stereo mode.

<P>Complete frequency range of MPEG file is divided in subbands There are 32 subbands. For Layer I & II these two bits determine frequency range (bands) where intensity stereo is applied. For Layer III these two bits determine which type of joint stereo 

is used (intensity stereo or m/s stereo). Frequency range is determined within decompression algorythm.

<TABLE BORDER="0" CELLSPACING="2" CELLPADDING="0">
<TR><TD ALIGN=CENTER>Layer I and II</TD><TD ALIGN=CENTER>Layer III</TD></TR>
<TR VALIGN=TOP><TD> 
<TABLE BORDER="1" CELLSPACING="0" CELLPADING="0">
<TR><TD>value</TD><TD>Layer I &amp; II</TD></TR>
<TR><TD>00</TD><TD>bands 4 to 31</TD></TR>
<TR><TD>01</TD><TD>bands 8 to 31</TD></TR>
<TR><TD>10</TD><TD>bands 12 to 31</TD></TR>
<TR><TD>11</TD><TD>bands 16 to 31</TD></TR></TABLE>
</TD>

<TD> 
<TABLE BORDER="1" CELLSPACING="0" CELLPADING="0" WIDTH="212">
<TR ALIGN=CENTER><TD>Intensity stereo</TD><TD>MS stereo</TD></TR>
<TR ALIGN=CENTER><TD>off</TD><TD>off</TD></TR>
<TR ALIGN=CENTER><TD>on</TD><TD>off</TD></TR>
<TR ALIGN=CENTER><TD>off</TD><TD>on</TD></TR>
<TR ALIGN=CENTER><TD>on</TD><TD>on</TD></TR></TABLE>
</TD></TR></TABLE>
</TD></TR>

<TR VALIGN=TOP><TD>K</TD><TD>1</TD><TD>(3)</TD>
<TD>Copyright<BR>          
0 - Audio is not copyrighted<BR>
1 - Audio is copyrighted</TD>
</TR>

<TR VALIGN=TOP><TD>L</TD><TD>1</TD><TD>(2)</TD>
<TD>Original<BR>          
0 - Copy of original media<BR>
1 - Original media</TD>
</TR>

<TR VALIGN=TOP>
<TD>M</TD><TD>2</TD><TD>(1,0)</TD>
<TD>Emphasis<BR>          
00 - none<BR>
01 - 50/15 ms<BR>
10 - reserved<BR>
11 - CCIT J.17</TD>
</TR></TABLE>
<P>&nbsp;</P></CENTER>

<P ALIGN="center"><A NAME="MPEGTAG"></A><FONT SIZE="5"><B>MPEG Audio Tag ID3v1</B></FONT> 
<P>The TAG is used to describe the MPEG Audio file. It contains information
about artist, title, album, publishing year and genre. There is some extra
space for comments. It is exactly 128 bytes long and is located at very end of
the audio data. You can get it by reading the last 128 bytes of the MPEG audio
file.

<P ALIGN="center"><FONT SIZE="5"><B><TT>
AAABBBBB BBBBBBBB BBBBBBBB BBBBBBBB<BR>
BCCCCCCC CCCCCCCC CCCCCCCC CCCCCCCD<BR>
DDDDDDDD DDDDDDDD DDDDDDDD DDDDDEEE<BR>
EFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFG<BR>
</TT></B></FONT>

<CENTER>

<TABLE BORDER="0" WIDTH="500">
<TR VALIGN=TOP BGCOLOR=#E2E2E2>
<TD>Sign</TD><TD>Length<BR>(bytes)</TD><TD>Position<BR>
(bytes)</TD><TD>Description</TD></TR>
<TR VALIGN=TOP><TD>A</TD><TD>3</TD><TD>(0-2)</TD>
<TD>Tag identification. Must contain 'TAG' if tag exists and is 
correct.</TD>
</TR>
<TR><TD>B</TD><TD>30</TD><TD>(3-32)</TD><TD>Title</TD></TR>
<TR><TD>C</TD><TD>30</TD><TD>(33-62)</TD><TD>Artist</TD></TR>
<TR><TD>D</TD><TD>30</TD><TD>(63-92)</TD><TD>Album</TD></TR>
<TR><TD>E</TD><TD>4</TD><TD>(93-96)</TD><TD>Year</TD></TR>
<TR><TD>F</TD><TD>30</TD><TD>(97-126)</TD><TD>Comment</TD></TR>
<TR><TD>G</TD><TD>1</TD><TD>(127)</TD><TD>Genre</TD></TR></TABLE>
</CENTER>

<P>The specification asks for all fields to be padded with null character
(ASCII 0). However, not all applications respect this (an example is WinAmp
which pads fields with &lt;space&gt;, ASCII 32).

<P>There is a small change proposed in <B>ID3v1.1</B> structure. The last byte 
of the Comment field may be used to specify the track number of a song in an 
album. It should contain a null character (ASCII 0) if the information is 
unknown.

<P>Genre is a numeric field which may have one of the following values:

<CENTER>
<TABLE BORDER="0" WIDTH="90%">
<TR>
<TD WIDTH="1%">0</TD>
<TD WIDTH="20%">'Blues'</TD>
<TD WIDTH="1%">20</TD>
<TD WIDTH="20%">'Alternative'</TD>
<TD WIDTH="1%">40</TD>
<TD WIDTH="20%">'AlternRock'</TD>
<TD WIDTH="1%">60</TD>
<TD WIDTH="20%">'Top 40'</TD>
</TR>
<TR>
<TD>1</TD>
<TD>'Classic Rock'</TD>
<TD>21</TD>
<TD>'Ska'</TD>
<TD>41</TD>
<TD>'Bass'</TD>
<TD>61</TD>
<TD>'Christian Rap'</TD>
</TR>
<TR>
<TD>2</TD>
<TD>'Country'</TD>
<TD>22</TD>
<TD>'Death Metal'</TD>
<TD>42</TD>
<TD>'Soul'</TD>
<TD>62</TD>
<TD>'Pop/Funk'</TD>
</TR>
<TR>
<TD>3</TD>
<TD>'Dance'</TD>
<TD>23</TD>
<TD>'Pranks'</TD>
<TD>43</TD>
<TD>'Punk'</TD>
<TD>63</TD>
<TD>'Jungle'</TD>
</TR>
<TR>
<TD>4</TD>
<TD>'Disco'</TD>
<TD>24</TD>
<TD>'Soundtrack'</TD>
<TD>44</TD>
<TD>'Space'</TD>
<TD>64</TD>
<TD>'Native American'</TD>
</TR>
<TR>
<TD>5</TD>
<TD>'Funk'</TD>
<TD>25</TD>
<TD>'Euro-Techno'</TD>
<TD>45</TD>
<TD>'Meditative'</TD>
<TD>65</TD>
<TD>'Cabaret'</TD>
</TR>
<TR>
<TD>6</TD>
<TD>'Grunge'</TD>
<TD>26</TD>
<TD>'Ambient'</TD>
<TD>46</TD>
<TD>'Instrumental Pop'</TD>
<TD>66</TD>
<TD>'New Wave'</TD>
</TR>
<TR>
<TD>7</TD>
<TD>'Hip-Hop'</TD>
<TD>27</TD>
<TD>'Trip-Hop'</TD>
<TD>47</TD>
<TD>'Instrumental Rock'</TD>
<TD>67</TD>
<TD>'Psychadelic'</TD>
</TR>
<TR>
<TD>8</TD>
<TD>'Jazz'</TD>
<TD>28</TD>
<TD>'Vocal'</TD>
<TD>48</TD>
<TD>'Ethnic'</TD>
<TD>68</TD>
<TD>'Rave'</TD>
</TR>
<TR>
<TD>9</TD>
<TD>'Metal'</TD>
<TD>29</TD>
<TD>'Jazz+Funk'</TD>
<TD>49</TD>
<TD>'Gothic'</TD>
<TD>69</TD>
<TD>'Showtunes'</TD>
</TR>
<TR>
<TD>10</TD>
<TD>'New Age'</TD>
<TD>30</TD>
<TD>'Fusion'</TD>
<TD>50</TD>
<TD>'Darkwave'</TD>
<TD>70</TD>
<TD>'Trailer'</TD>
</TR>
<TR>
<TD>11</TD>
<TD>'Oldies'</TD>
<TD>31</TD>
<TD>'Trance'</TD>
<TD>51</TD>
<TD>'Techno-Industrial'</TD>
<TD>71</TD>
<TD>'Lo-Fi'</TD>
</TR>
<TR>
<TD>12</TD>
<TD>'Other'</TD>
<TD>32</TD>
<TD>'Classical'</TD>
<TD>52</TD>
<TD>'Electronic'</TD>
<TD>72</TD>
<TD>'Tribal'</TD>
</TR>
<TR>
<TD>13</TD>
<TD>'Pop'</TD>
<TD>33</TD>
<TD>'Instrumental'</TD>
<TD>53</TD>
<TD>'Pop-Folk'</TD>
<TD>73</TD>
<TD>'Acid Punk'</TD>
</TR>
<TR>
<TD>14</TD>
<TD>'R&amp;B'</TD>
<TD>34</TD>
<TD>'Acid'</TD>
<TD>54</TD>
<TD>'Eurodance'</TD>
<TD>74</TD>
<TD>'Acid Jazz'</TD>
</TR>
<TR>
<TD>15</TD>
<TD>'Rap'</TD>
<TD>35</TD>
<TD>'House'</TD>
<TD>55</TD>
<TD>'Dream'</TD>
<TD>75</TD>
<TD>'Polka'</TD>
</TR>
<TR>
<TD>16</TD>
<TD>'Reggae'</TD>
<TD>36</TD>
<TD>'Game'</TD>
<TD>56</TD>
<TD>'Southern Rock'</TD>
<TD>76</TD>
<TD>'Retro'</TD>
</TR>
<TR>
<TD>17</TD>
<TD>'Rock'</TD>
<TD>37</TD>
<TD>'Sound Clip'</TD>
<TD>57</TD>
<TD>'Comedy'</TD>
<TD>77</TD>
<TD>'Musical'</TD>
</TR>
<TR>
<TD>18</TD>
<TD>'Techno'</TD>
<TD>38</TD>
<TD>'Gospel'</TD>
<TD>58</TD>
<TD>'Cult'</TD>
<TD>78</TD>
<TD>'Rock &amp; Roll'</TD>
</TR>
<TR>
<TD>19</TD>
<TD>'Industrial'</TD>
<TD>39</TD>
<TD>'Noise'</TD>
<TD>59</TD>
<TD>'Gangsta'</TD>
<TD>79</TD>
<TD>'Hard Rock'</TD>
</TR>
</TABLE>
<DIV ALIGN="LEFT"><BR>
WinAmp expanded this table with next codes: </DIV>
<TABLE BORDER="0" WIDTH="90%">
<TR> 
<TD WIDTH="1%">80</TD>
<TD WIDTH="20%">'Folk'</TD>
<TD>92</TD>
<TD>'Progressive Rock'</TD>
<TD>104</TD>
<TD>'Chamber Music'</TD>
<TD>116</TD>
<TD>'Ballad'</TD>
</TR>
<TR> 
<TD>81</TD>
<TD>'Folk-Rock'</TD>
<TD WIDTH="1%">93</TD>
<TD WIDTH="20%">'Psychedelic Rock'</TD>
<TD>105</TD>
<TD>'Sonata'</TD>
<TD>117</TD>
<TD>'Poweer Ballad'</TD>
</TR>
<TR> 
<TD>82</TD>
<TD>'National Folk'</TD>
<TD>94</TD>
<TD>'Symphonic Rock'</TD>
<TD WIDTH="1%">106</TD>
<TD WIDTH="20%">'Symphony'</TD>
<TD>118</TD>
<TD>'Rhytmic Soul'</TD>
</TR>
<TR> 
<TD>83</TD>
<TD>'Swing'</TD>
<TD>95</TD>
<TD>'Slow Rock'</TD>
<TD>107</TD>
<TD>'Booty Brass'</TD>
<TD WIDTH="1%">119</TD>
<TD WIDTH="20%">'Freestyle'</TD>
</TR>
<TR> 
<TD>84</TD>
<TD>'Fast Fusion'</TD>
<TD>96</TD>
<TD>'Big Band'</TD>
<TD>108</TD>
<TD>'Primus'</TD>
<TD>120</TD>
<TD>'Duet'</TD>
</TR>
<TR> 
<TD>85</TD>
<TD>'Bebob'</TD>
<TD>97</TD>
<TD>'Chorus'</TD>
<TD>109</TD>
<TD>'Porn Groove'</TD>
<TD>121</TD>
<TD>'Punk Rock'</TD>
</TR>
<TR> 
<TD>86</TD>
<TD>'Latin'</TD>
<TD>98</TD>
<TD>'Easy Listening'</TD>
<TD>110</TD>
<TD>'Satire'</TD>
<TD>122</TD>
<TD>'Drum Solo'</TD>
</TR>
<TR> 
<TD>87</TD>
<TD>'Revival'</TD>
<TD>99</TD>
<TD>'Acoustic'</TD>
<TD>111</TD>
<TD>'Slow Jam'</TD>
<TD>123</TD>
<TD>'A Capela'</TD>
</TR>
<TR> 
<TD>88</TD>
<TD>'Celtic'</TD>
<TD>100</TD>
<TD>'Humour'</TD>
<TD>112</TD>
<TD>'Club'</TD>
<TD>124</TD>
<TD>'Euro-House'</TD>
</TR>
<TR> 
<TD>89</TD>
<TD>'Bluegrass'</TD>
<TD>101</TD>
<TD>'Speech'</TD>
<TD>113</TD>
<TD>'Tango'</TD>
<TD>125</TD>
<TD>'Dance Hall'</TD>
</TR>
<TR> 
<TD>90</TD>
<TD>'Avantgarde'</TD>
<TD>102</TD>
<TD>'Chanson'</TD>
<TD>114</TD>
<TD>'Samba'</TD>
<TD>&nbsp;</TD>
<TD>&nbsp;</TD>
</TR>
<TR> 
<TD>91</TD>
<TD>'Gothic Rock'</TD>
<TD>103</TD>
<TD>'Opera'</TD>
<TD>115</TD>
<TD>'Folklore'</TD>
<TD>&nbsp;</TD>
<TD>&nbsp;</TD>
</TR>
<TR> 
<TD COLSPAN=8>Any other value should be considered as 'Unknown' 
</TABLE>
<P>&nbsp;</P></CENTER>

<P ALIGN="center"><A NAME="MPEG TAG"></A><FONT SIZE="5"><B>MPEG Audio Tag ID3v2</B></FONT> 
<P>This is new proposed TAG format which is different than ID3v1 and ID3v1.1. 
Complete tech specs for it may be found at <A 
HREF="http://www.id3.org/">http://www.id3.org/</A>. 
<P><CENTER>
<HR>
<P><FONT SIZE="-1"> Created on September 1998. by <A HREF="http://www.dv.co.yu/broker/">Predrag 
Supurovic</A>.<BR>
Thanks to <A HREF="http://www.jps.net/kyunghi/">Jean</A> for debugging and polishing 
of this document, <A HREF="http://members.tripod.com/~videoripper/home.htm">Peter 
Luijer</A>, Guwani, Rob Leslie and Franc Zijderveld<BR>
for valuable comments and corrections.</FONT></P>
<P>&copy; 1998, 1999 Copyright by DataVoyage</P>
<P><FONT SIZE="-1">This document may be changed. Check <A
HREF="http://www.dv.co.yu/mpgscript/mpeghdr.htm">http://www.dv.co.yu/mpgscript/mpeghdr.htm</A> 
for updates.<BR>
You may use it freely. Distribution is allowed only in unaltered form. If you 
can help me make it more accurate, please do. </FONT></P>
<P>&nbsp;</P>
</CENTER>

#include "foot.t"