[ID3 Dev] Apple iTunes complicance issues

Jud White jwhite at cdtag.com
Sun Feb 11 17:58:16 PST 2007

Please correct me if I'm wrong... do you have to purchase a membership 
to report a bug?

I have a few things to report:

1. In ID3v2.4, non-syncsafe sizes are written to frames (ie, bit 7 is 
used).  The spec has changed in regards to how frame sizes are written 
from ID3v2.3 to ID3v2.4.  Also, iTunes does not read frames written with 
syncsafe sizes correctly.  See http://id3.org/id3v2.4.0-structure, 
section 4, paragraph 3.  Frame sizes should be written the same way as 
the total tag size is written in the header in ID3v2.4.  Also, it's easy 
enough to determine which size-encoding method was used by attempting to 
seek to the next position and testing for a valid frame signature/end of 
tag; in other words, it's not too late to correct this behavior.
2. Reading APIC frames with a text encoding of anything other than 
ISO-8859-1 results in "No artwork" (all ID3v2 version).

3. APIC frames need the "MIME Type" field set (in ID3v2.3 and ID3v2.4) 
and the "File Extension" field set (in ID3v2.2) in order to display an 
image.  However, it only seems to be checking that the MIME Type/File 
Extension are recognized - for example, a JPEG can be saved with a File 
Extension of "jpg", "png", or "bmp" and still be displayed.  I think the 
point here is some implementations may not write the MIME Type/File 
Extension at all to APIC frames, in which case iTunes will not display them.

Also, Dale owned up to have HUA syndrome - what he found was not a bug. :)


Ernest Prabhakar wrote:
> Have you filed a bug? 
> http://developer.apple.com/bugreporter/bugbestpractices.html
> If you can file a specific bug explaining the concrete, real-world 
> interoperability consequences, I can help escalate it to the iTunes team.
> -- Ernie P.
> On Feb 9, 2007, at 6:46 PM, Dale Preston wrote:
>> Apple iTunes suffers from the same problem as Windows Media Player 11 
>> when it comes to ID3V2.2 TYE and ID3V2.3 TYER frames.  In both tag 
>> versions iTunes adds a leading and trailing zero byte to the frame.
>> And, of course, there’s the issue of iTunes defaulting to the 
>> obsolete ID3V2.2 tag in the first place.
>> Dale

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