[ID3 Dev] Accessibilty extension draft is posted

[Scott Wheeler]

On Friday 16 June 2006 17:00, Ben Bennett wrote:
> Remeber, unsync only matters if the player can't understand the ID3v2
> format.  If it knows how to at least read the header it can get the
> tag length and skip it all.

Again, it's not quite that simple when working with an open-ended set of 
formats and an open-ended set of players.  A lot of decoding happens in 
layers.  The layer that understands the container format and handles demuxing 
probably won't know about tags; a tag parser would be done with data once the 
higher levels had figured out which data to throw at it.

I don't have a ready-made software/format combo that I'm sure this would not 
work on, but I can just say that it's not far fetched that it would break in 
some places.

(A little background in multimedia file formats:  MPEG is really, really easy.  
It barely deserves to be called a format since it's pretty much raw data -- a 
codec more than a file format.  But with things like AVI or Ogg files or more 
robust audio-only formats you often have more specific requirements on 
placement of data and what strings are "stream flags" and shouldn't occur 
randomly.)

> That is cute.  I was going to say that this breaks simple updates,
> e.g. case changes or the like.  But your example shows why you _want_
> to break on things like that.  It probably makes sense to do the
> lookups with "cleaned up" strings (lowercase, leading and trailing
> whitespace stripped, internal whitespace reduced to one space).

That might be appropriate, but mind you that normalizing strings is actually 
trickier than it sounds (since it requires knowledge of the character sets 
being used.)

> Though if there is a long string duplicating it entirely may be excessive.

Nah.  The string size relative to the audio content will be insignificantly 
small.

-Scott

-- 
The fact that an opinion has been widely held is no evidence whatever that it 
is not utterly absurd. 
--Bertrand Russell

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