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gaminghorror
Member
I came up with a theory on how to get close to actually calculating any App's size after App Store approval. I would appreciate your help to test this theory. Please read my blog post and let me know what you think:
http://www.gaminghorror.net/steffenj/how-to-calculate-the-size-of-an-iphone-app-after-approval/
Thanks!
See also http://forum.unity3d.com/viewtopic.php?t=43187, which comes to about the same conclusion as you did.
gaminghorror
Member
I think Unity executables contain a lot of repetitive code or uniform data (eg. bunches of zero padding and what not, lots of strings, and so on). That compresses well normally but if you encrypt the file it'll compress almost as bad as 100% random data. A 10 MB executable may normally compress to 3 MB but with encryption it could easily be 9 MB.
I would expect that the latest Unity iPhone version which features reduced binary sizes fixes some of these issues.
too bad it doesnt compress first, then encrypt.
The encryption is for DRM purposes -- to protect your apps from you (a.k.a. the bad guy, a.k.a. Mallory in cryptographic scenarios). The usual compress-then-encrypt steps would require a decrypt-then-expand step later, and that's a no-no in DRM land. Instead, they probably decompress the package when installing it on the device (mostly as a convenient transport format rather than to save bandwidth), then leave it in the encrypted state in flash memory. It's likely decrypted on the fly -- at late as possible -- to execute the code, but the OS doesn't ever lay the whole image out there in plaintext where you might be able to have a look at it.
Hey,
I have been doing some research on this and I thought about sharing my findings here too.
- 20MB limit on final size is very important for casual games as they follow impulse buying trends.
- Trivial but worth mentioning: The final size is not the size of the app on the BUILD folder. It is the size of the compressed app.
- The compressed app to be submitted is a ZIP file, however the final one will be a IPA that they produce for the AppStore.
- You can create a ZIP version of your app by right clicking on the .app on your release for device build folder
- You can create an IPA of your app on XCode by doing "Build And Archive" then go to Organizer and select your app on the Archived Applications area. Press "Share" to save to file. You can skip the signing here by selecting "Don't Resign" on the dropmenu.
- IPA on Xcode is very similar size to ZIP to submit (zipped from build folder)
- IPA on Xcode won't produce exactly the same results as the one they create (there's will be bigger). They add iTunesArtwork and some other files that people say (http://bit.ly/qwZVC1) count up to 100k extra. However the binary compression is different and people have reported growing far more than expected (doubled in some cases - Unity3D). This is precisely where we all get lost. How much bigger?
- I can't confirm this, but I've read in some forums that Apple states 1MB as 1000 Bytes as opposed to the rest of the world convention of 1MB = 1024 Bytes.
- And finally, and according to this source: http://bit.ly/oQEgyp you can get close to know the final size of your game by doing this:
FinalSize = (uncompressed executable size) + (app bundle compressed but without executable) + 0,1 MBSee this post for more theory on this formula: http://bit.ly/pjX1g3 by @gaminghorror
I hope it helps.
letmeknow
Member
Thanks @jotajota.
Could you please give me a simple conclusion about your research? Just simple like, with cocos2d app, your zip file should be about ???mb - ???mb, your final ipa will be a little bit less than 20Mb, something like that should be very very helpful for me and other people. Thank you.
@letmeknow (love your user name)
I wish I had an answer for that myself! However, I'm going to believe that the formula I found is accurate to calculate the final size and even then I'll still push to be under 19MB just in case.
As stated in this link http://bit.ly/oQEgyp, and I'm quoting the source, to know the final size of your app you do:
1. open the .app bundle via right-click -> Show Package Contents (on Mac)
2. locate the executable file and remember its (uncompressed) size (Size A)
3. delete the executable from the bundle
4. zip the bundle and remember the bundles compressed size (Size B)
5. Size C are the 100 KB from the additional files added to the bundle by Apple. The final calculation for the maximum size of your App is as follows:
maximum size of your App after approval = A + B + CThis will take you 5 minutes.
letmeknow
Member
Thanks @jotajota.
I know doing some math do not cost much time but it's easy and useful to know the draft idea about the app 'ideal' size, we do not need to calculate and recalculate many times. (Most of the time I don't need the accurate calculation)
Yes, it should be good if we know keep your zipped app size less than 19Mb you would have no problem with the final ipa. Thank you for that info.
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