What's Inside An iPod Game?

I’m interested in developing iPod games, but Apple doesn’t have any developer information available. I emailed them and they replied promptly:

Hello Ben,

Thank you for contacting the Apple Developer Connection regarding developing for the iPod.

Please know that, at this time, we have no plans to offer an SDK for the iPod. We have, however, posted documentation on using the “NotesOnly” mode, also called Museum Mode, which allows you to create custom or restricted user interfaces for special purposes. This is available for download from our iPod Developer web page:

iPod Developer
http://developer.apple.com/hardware/ipod/

Also available on the above page are dimensional drawings for developers who wish to develop carrying cases for the iPod. If you are interested in developing an accessory for the iPod and need more information on the connectors and technical specifications, please send an email to:

I hope that the above information is of help to you. Please let me know if you have any questions.

Best regards,

Brunon Rogowski
Apple Developer Connection
Worldwide Developer Relations

Thanks Apple! Perhaps sewing a carrying case will be just as much fun! Knitting is popular these days, maybe I’ll switch careers.

So anyway, Nate downloaded the iPod Mini Golf game and let me take a look. The .IPG file is actually just a ZIP archive.

The archive contains many files, including AAC and WAV audio, XML, executables, language files, and more. I just started looking things over, but here are some of the interesting things I’ve found so far.

The iTunesMetaData file contains information such as the game title for use in iTunes itself. If you modify the strings in there, you can rename the game from iTunes’ point of view. iTunesArtwork is a JPEG file that is used for the game screenshot in iTunes.

Also used by iTunes is Description.xml and its associated images found in Resources/en (where en is your language). It tells iTunes how to display the help image.

Manifest.plist seems to contain information used by the iPod itself, but possibly iTunes. It contains references to the Description.xml files used by iTunes. It also references the executable used by the iPod, and apparently the loading artwork. I’m sure it does a lot more, but I haven’t gotten too far into it.

Mini Golf contains several non-DRM AAC files that are used for background sounds. Sound effects are in the various bank folders and are in WAV format.

The files with .en, .no, and other language names are language files for displaying text in the game.

If you’re bored, you could swap out the image files or change some of the text, then rezip and rename the file to .IPG, then import into iTunes. For example, Mini Golf is more fun if it’s called Maxi Golf and instead of help, you get an image of Randy Savage:

I’m sure enterprising iPod game hackers will be able to do more. The games feature could be used to create all kinds of homebrew applications. The iPodLinux Project might be able to do something with this.

One more thing…

iTunes apparently generates a copy of the game just for you when downloading. It inserts your name and email address (iTunes store user name) into the archive.

The .bin.sinf file in Resources contains your name, and iTunesMetaData contains your email address.

Other content purchased from the music store contains your information as well, so this is no surprise.