[ID3 Dev] Apple iTunes complicance issues

Ben Bennett fiji at ayup.limey.net
Mon Feb 12 18:05:43 PST 2007


On Mon, Feb 12, 2007 at 05:42:50PM -0800, Ernest Prabhakar wrote:
> 
> I'm not trying to set an unreachable bar, but the more concrete the  
> usage scenario, the easier it is to justify the fix.  For example, it  
> sounds like the usage:
> 
> a) Add an MP3 file to Amarok
> b) Add a picture
> c) Import it into iTunes
> 
> will result in broken image.  Right?

Perhaps.  It is probably safer to add a long comment as well as an
image.  Or if possible, add two images.  But really, any frame (text
or image) that is larger than 127 will cause a problem.

The catch is that since iTunes misreads tag length as larger than it
ought to be, a trailing image will not cause problems sine it will hit
the end of the frame when looking for more tag data and stop.  Oh, and
an image in the middle of the tag will look correct, since the image
format will tell it when the data has ended (for jpg anyway).  It is
just the stuff following that frame that will be broken, so in a way
just having two long text frames makes it a little easier to see what
the problem is.

Do you want me to find a good example of a file with a broken tag?

> If so, then that's a nice, specific bug impacting iTunes users which  
> would generate more attention than merely "iTunes doesn't follow the  
> spec."

Ah, I see.  Sorry for getting a bit testy with you then.

> Especially if you can identify other compliant apps that would
> generate similar problems.

Any 2.4 app will do it... unfortunately I don't have a good survey of
what writes 2.4 vs. 2.3 :-(  I am sure that someone on this list will
be able to point to an OSX 2.4 tag app.  Although if it uses quicktime
to write tags, that may fall victim to the same syncsafe issue (I am
not sure if the Quicktime library is the issue, or if iTunes handles
it itself).

I know Amarok does... in fact it will only write 2.4, it will read 2.3
and 2.4 though.

		    -ben

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