Android boot animation is composed of a series of PNG pictures that act as frames of a continuous animation. Each PNG frame is saved in a compressed format.

The boot animation file name is bootanimation.zip, the format is .zip and the compression method is store.

The animation file includes one desc.txt file and directories labelled part0 to part4.

-rw-rw-rw- 1 lxx lxx   74 Aug 17  2015 desc.txt
drwxrwxrwx 2 lxx lxx 4096 Mar 18 11:10 part0
drwxrwxrwx 2 lxx lxx 4096 Mar 18 11:11 part1
drwxrwxrwx 2 lxx lxx 4096 Mar 18 11:11 part2
drwxrwxrwx 2 lxx lxx 4096 Mar 18 13:41 part3
drwxrwxrwx 2 lxx lxx 4096 Mar 18 13:42 part4

• desc.txt: animation property description file. Used to set the animation pixel (size), number of frames, number of cycles, file name, etc.

• Part0: folder containing first stage animation frames.
• Part1: folder containing second stage animation frames.

desc.txt file contents:

543 143 60
c 1 30 part0
c 1 0 part1
c 0 0 part2
c 1 64 part3
c 1 15 part4

543 143 60:

• 543: the pixel width of the picture
• 143: the pixel height of the picture
• 60 : frame rate

c 1 30 part0:

• c : the flag bit
• 1 : the number of cycles is 1 (0 for infinite loop)
• 30: the number of frames contained within part0
• part0: the directory of the picture

We can there calculate the time-duration of part0 as: 30 * (1 / 60) seconds.

After you create the part folders and desc.txt, you can use following Linux command to generate bootanimation.zip:

zip -r -X -Z store bootanimation part*/* desc.txt 

Push bootanimation.zip to system/media, and restart your SBC for changes to take effect.

adb root
adb remount