This is not bootanimation, this is the splash screen (the 'Mi' boot logo which is displayed when device is switched ON)
This is for Xiaomi Mi Max Only (Snapdragon Devices)..
For other devices, please send me your splash.img so that I can create a tool for you too.
1. Rooted Xiaomi Mi Max (any ROM)
2. Terminal Emulator app installed.
STEPS to create & install splash.img:
Click here for procedure
(It's the same procedure as that for Xiaomi Mi 5)
Hit the Thanks button if it worked for you