Difference between split binary and asset bundles?

Questions & Answers
1

Hi all

I’m trying to get an app under 50mb for google play but i’m not quite sure whats the difference between split binary and asset bundles. I always thought i needed unity pro to release a game over 50mb on google play but it doesn’t seems to be the case with split binary.

So… :

  1. Whats the difference between split binary and asset bundles?
  2. How automated is the process of downloading the extra content on each variant for the user? Does it download inside the app and continues after the download?
  3. Why is split binary free and assets bundles a pro feature?
  4. How do i get an uncompressed obb for faster load times?

thx in advance

2

This documentation explains how to use split binaries: Unity - Manual: APK expansion files

Split binaries are a feature provided by Android and Google Play to support large APK files, whereas Asset Bundles is a Unity feature for delivering downloadable game content. They are similar, but the split binary functionality operates on a lower level than asset bundles.

As you’ll notice in the document linked, splitting the binary causes the main game APK to be only your application code and the first scene. For the rest of your game to be runnable, you’ll need to retrieve the OBB file either from Google’s server, or from your own server. Unity expects the OBB file to be located in a particular location on the device, so the main task of your first game scene should be to retrieve the OBB file from the external server and then continue on with booting up the game. If the OBB file is already available, you can quickly skip to the rest of your game.

Unity actually provides a free plugin on the asset store which helps with loading the OBB files and all that: Google Play OBB Downloader | Utilities Tools | Unity Asset Store. I believe the plugin should help you automate the process as much as possible. However, there is probably some logic you’d need to write as part of your startup scene.

A split binary would be used when your game is too big to be hosted on the Google Play store as a single APK (over 50MB). You’d probably want to use a split binary if all the stuff required to run your game is too big to host in a single APK. Asset bundles, on the other hand, are mainly meant for add-on content that is “extra” for the game, like DLC. Maybe your players can make an in-app purchase and you deliver some special artwork to the game. Personally, I prefer to include that stuff in the main bundle if possible (less complicated than hosting it remotely), but sometimes the content you want to deliver as add-on content is too big to include in the main bundle.