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<DIV><FONT face=Arial size=2>I'm not sure about that. I know that appended
tags MUST have a footer but there is nothing that says a prepended tag can't
have a footer. (At least nothing that I know of. Am I wrong about
that?)</FONT></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=andy@andy-k.co.uk href="mailto:andy@andy-k.co.uk">Andy</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=id3v2@id3.org
href="mailto:id3v2@id3.org">id3v2@id3.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Tuesday, November 14, 2006 3:46
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [ID3 Dev] Why is footer not
included in total size?</DIV>
<DIV><BR></DIV>I am pretty sure that footers are only to be written to a file
when the tag is appended, not pre-pended.<BR><BR><BR>
<DIV><SPAN class=gmail_quote>On 14/11/06, <B class=gmail_sendername>Jim</B>
<<A href="mailto:jmartin92@comcast.net"> jmartin92@comcast.net</A>>
wrote:</SPAN>
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<DIV bgcolor="#ffffff">
<DIV><FONT face=Arial size=2>Hi.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I am wondering what the reasoning was
behind the size stored in ID3v2.4 tags not including the size of the footer
(if present). </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I've been looking through the source code for
some utilities for MP3 files and some other audio file types. Many of
these utilities use a simple method for skipping over the ID3v2 tag if it is
there. They read the first 10 bytes of the file, do some simple
checking (look for 'ID3', check that version bytes are less than $FF and in
some cases check that size bytes are syncsafe, i.e. < $80) and if it
looks like a tag, convert the size and skip that many bytes ahead (+ 10
bytes for header). Most of these utilities would be broken if the
tag has a footer. They don't do any specific version checking or
checking of the flags byte. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>If the size stored in ID3v2.4 tags included the
footer size (if it is present), it would make these tags much more backwards
compatible. (I know it is a pretty easy change to add
checking for the footer flag but wouldn't it have been better
to make it compatible with older apps that don't really need to
read the tag, just skip it?) Were there reasons that came
up during development why it was done the way it is? If so, I'd
appreciate if someone could share them with me. Or if there is
somewhere I can read about this (like some archive of the mailing list) I
would appreciate someone pointing me in the right direction.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Thanks.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Jim Martin</FONT></DIV>
<DIV><FONT face=Verdana color=#808080 size=1><FONT face=Arial color=#000000
size=2></FONT></FONT> </DIV></DIV></BLOCKQUOTE></DIV><BR><BR
clear=all><BR>-- <BR>Andy. </BLOCKQUOTE></BODY></HTML>