Google Play: Digital Distribution Service Announces New Algorithm to Reduce App Sizes

Google Play: Digital Distribution Service Announces New Algorithm to Reduce App Sizes


New Delta algorithm to reduce the size of app updates
For approximately 98% of app updates from the Play Store, only changes (deltas) to APK files are downloaded and merged with the existing files, reducing the size of updates. We recently rolled out a delta algorithm, bsdiff, that further reduces patches by up to 50% or more compared to the previous algorithm. Bsdiff is specifically targeted to produce more efficient deltas of native libraries by taking advantage of the specific ways in which compiled native code changes between versions. To be most effective, native libraries should be stored uncompressed (compression interferes with delta algorithms).

An example from Chrome:

Patch Description Previous patch size Bsdiff Size
M46 to M47 major update 22.8 MB 12.9 MB
M47 minor update 15.3 MB 3.6 MB
Apps that don’t have uncompressed native libraries can see a 5% decrease in size on average, compared to the previous delta algorithm.

Applying the delta algorithm to APK Expansion Files to further reduce update size
APK Expansion Files allow you to include additional large files up to 2GB in size (e.g. high resolution graphics or media files) with your app, which is especially popular with games. We have recently expanded our delta and compression algorithms to apply to these APK Expansion Files in addition to APKs, reducing the download size of initial installs by 12%, and updates by 65% on average.

Clearer size information in the Play Store
Alongside the improvements to reduce download size, we also made information displayed about data used and download sizes in the Play Store clearer. You can now see actual download sizes, not the APK file size, in the Play Store. If you already have an app, you will only see the update size. These changes are rolling out now. # New Algorithm to Reduce App Sizes