[FFmpeg-devel] [PATCH] Shorten ID3v2 tags

[Anton Khirnov]

On Sat, Jul 03, 2010 at 01:02:50AM +0200, James Darnley wrote:
> Currently an unnecessary NULL byte is written at the end of each ID3v2
> tag.  The docs linked to here (
> http://www.id3.org/Developer_Information ) do not say that the NULL
> byte is necessary.  No other software writes this byte (lame.exe,
> Winamp, mp3tag).

As far as i understand the specs, strings should be NULL-terminated.
http://id3.org/id3v2.4.0-structure says:
4.   ID3v2 frame overview
[...]

   Frames that allow different types of text encoding contains a text
   encoding description byte. Possible encodings:

     $00   ISO-8859-1 [ISO-8859-1]. Terminated with $00.
     $01   UTF-16 [UTF-16] encoded Unicode [UNICODE] with BOM. All
           strings in the same frame SHALL have the same byteorder.
           Terminated with $00 00.
     $02   UTF-16BE [UTF-16] encoded Unicode [UNICODE] without BOM.
           Terminated with $00 00.
     $03   UTF-8 [UTF-8] encoded Unicode [UNICODE]. Terminated with $00.

   Strings dependent on encoding are represented in frame descriptions
   as <text string according to encoding>, or <full text string
   according to encoding> if newlines are allowed. Any empty strings of
   type $01 which are NULL-terminated may have the Unicode BOM followed
   by a Unicode NULL ($FF FE 00 00 or $FE FF 00 00).


Anton Khirnov
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