Back when I had some interest in doing a custom boot animation, I read different posts about what the contents of the bootanimation.zip file meant. I came across some info that explains it pretty well.

In 2.0, the android boot animation has been changed to enable easy replacement or customization.

There is a file called bootanimation.zip stored in /system/media/ in the root file system (or /data/local). This file contains two things:

1) A description file (desc.txt) that outlines how the animation progresses, what images to use, image size etc.
2) Folder(s) that contain the images for the animation.

The basic structure of the bootanimation.zip file is as follows:

bootanimation.zip
|-- desc.txt
|-- part0
`-- part1


part0 and part1 are directories that contain a series of images for example, in part 0 there is:

part0
|-- boot_00001.png
|-- boot_00002.png
|-- boot_00003.png
|-- boot_00004.png
|-- boot_00005.png
|-- boot_00006.png
|-- boot_00007.png
|-- boot_00008.png
|-- boot_00009.png
`-- boot_00010.png

And in part 1 there are:

part1
|-- boot_00011.png
|-- boot_00012.png
|-- boot_00013.png
|-- boot_00014.png
|-- boot_00015.png
|-- boot_00016.png
|-- boot_00017.png
|-- boot_00018.png
|-- boot_00019.png
`-- boot_00020.png

These images form the 'part0' and 'part1' animations that are combined as outlined in the 'desc.txt' file to form the overall startup animation. The images are ordered by number and run in sequence.
The 'desc.txt' file outlines how the animation progresses and a sample is as follows:

512 256 30
p 1 0 part0
p 0 0 part1

'523' is the width of the animation
'256' is the height of the animation
'30' is the desired fps of the animation
'p' defines a animation part
'1' how many times this animation part loops
'0' defines a pause (max 10)
'part0' is the folder name where the animation images are
'p' defines another animation part
'0' defines that it loops forever (until android starts)
'0' defines a pause
'part1' is the folder for the second animation part.

Hope this helps those looking to create their own boot animations.

Hello, thank you for this instruction posting, and sorry to revive this older topic.
I have a Vodafone 845 (made by Huawei) and used the original bootanimation.zip to create my own, custom animation.
Unfortunaly it will not work:
I used 240x320 PNG files but it will not show. If I take the original ZIP file and replace single frames, the animation will stop as it reaches the modified frame number, and loop back to file 000.png.

I tried everything:
- PNG with 8 bit ans 24 bit (as both types are used in different parts of the original animation)
- PNG with different compression levels (0-9)
- Regular and Interlaced PNG

For editing and such I am using 7zip. As deleting single frames of the original file work, the bootanimation.zip is valid.

Is there anything I have not thought of?

I Know this is a highly old post but might as well answer your question for future users. But the reason it will not work is because you are reziping the files wrong just as i did the first time i made one, but i recommend using winrar instead of 7zip and you half to zip the files as store not as compress or anything eles or youll get a blank screen.

hope that helps somebody