Infinite Loop / The Apple Ecosystem

A peek inside an iTunes LP file

Is iTunes LP another proprietary format or something different? We peer …

On the shiny exterior, the new iTunes LP may seem like some sort of fancy proprietary format. In actuality it's an image-heavy, JavaScript-driven webpage that only renders correctly in iTunes or, with a bit of hackery, WebKit-based browsers such as Safari, Omniweb, or Google's Chrome. However, the system requirements for it may be a bit of a head scratcher—according to Apple's support document, the technology requires 1GB of RAM, a 2.0 GHz Core2Duo processor, and a screen resolution of at least 1280x800. Unfortunately, this means no iTunes LP on an iPhone or an AppleTV, which is odd because it seems like the LPs are perfect for the home theater device. If we had to guess, Apple will be adding iTunes LP support in future Apple TV updates—especially since there are allusions to HDTV in the code of the .itlp file.

Making use of an LP in iTunes is a no-brainer, but if you want to see what makes it tick, there is a fairly simple trick to view its dark, vast, innards. (Before you try this, we recommend you duplicate your LP before you go forward.) Just change the file extension from .itlp to .zip and make sure you accept the extension change. You will then have a normal directory with all of the contents freely viewable and editable.

In the LP we dissected, Big Whiskey and the GrooGrux King, the root directory consisted of 12 items. This included seven folders, an .xml and .plist file—which appears to point to full media files inside an iTunes library—an iTunesArtwork file, an .itlp file with a file size of 0KB, and a standard, run-of-the-the mill index.html file. Inside the HTML file, the doctype is HTML 4.01 with meta name properties set to "hdtv-fullscreen" and "hdtv-cursor-off". This particular one made use of three stylesheets and 34 JavaScript files, which were marked copyright of Apple Computer. 

The index file isn't complicated; it's largely made up of JavaScript calls and a single "div" tag. Most of the HTML is stored inside the "vues" sub-directory and called from within the JavaScript files. The most interesting part of the file are the comments referencing "TuneKit." What TuneKit is, exactly, is anyone's guess, but I'm willing to bet it has something to do with the "resource" Steve Jobs referred to during the September keynote that Apple makes available to artists to create these LPs.

The LP we dissected had a huge number of images. Keep in mind that the file is 206.5MB and it doesn't have any audio or video inside of it, short of a 484KB audio loop. That, of course, means there's an extraordinary number of images—in fact, the majority of the text is made up of images! Some users have complained that they can't scrape for the lyrics in each song because they are handled this way.

The last bit of interesting information is the inclusion of a font .svg file. Not every browser supports this feature, and WebKit only added the compatibility recently. SVG is the future--accept it, or be consumed.

The iTunes LP format can be as complicated or as simple as one wishes. The Dave Matthew's Band LP that we used was quite complicated, but the Door's LP looks much simpler by comparison. While the format is no doubt aimed at the big guys, I have very little question that someone could easily make his or her own LP and distribute it. There isn't much to the format, and the inner workings can be gleaned from just exploring an example. Of course Apple is probably fairly picky who gets to sell LPs in the iTunes Store, so fledgling artists will probably have to offer the format outside of iTunes.

The question is: just how easy is Apple making it on artists to actually create these LPs? A boring one could be made easily enough, but a complex one, such as the DMB album, takes some real knowledge. I envision some sort of iDVD-like application specifically for this purpose with drag-and-drop JavaScript transitions called TuneKit. If that's not the way Apple is doing it, I can't imagine a very high adoption rate. Right now, Apple only has a handful available to the public—if they require a lot of resources to make, there is no way these will replace physical albums for the hardcore music fan.

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