The article doesn’t explain why it’s faster to use the Video LAN decoding library versus Google’s.

Looking at the code repo, it looks like the reason is because the new library has lots of hand-optimized assembly code to perform the decoding for a wide variety of platforms. This will help ease the transition to the new codec especially for economy devices that lack the hardware support.

If you want to see how you’re decoding different audio and video formats on your device, you can open this app to view your decoder capabilities: https://play.google.com/store/apps/details?id=com.parseus.codecinfo