The documentation on how to put your own bootanimation.zip together:
https://android.googlesource.com/pla...tion/FORMAT.md
The bootanimation starts running before the screen is fully configured.
So the beginning of the sequence will be missing.
I've always hated short sequences where it repeats a progress bar that starts over.
FWIW, here is a minimal bootanimation, just counting seconds in the lower right corner for Poke3 (or anything else that's 1072x1448).
I tried to get the trim.txt function to work, but I couldn't. It seems to be supported in libbootanimation.so I don't know what my problem is.
(The simple count up bootanimation is attached in post #5.)