Minecraft Stop-Motion Movie Creator - too many frames

This post is a work in progress.

My kids love using the "Minecraft Stop-Motion Movie Creator". They've just finished putting together an epic animation (> 400 frames) and went to save the movie but were greeted with "Too many frames - please remove 91 frames". They were crestfallen. Surely this limit should be advertised somewhere?

Anyway, I attached the device to my computer to take a look - with the idea of downloading all the frames myself and using different software to stitch them together.

This was done on a Mac - I used androidfiletransfer to connect and browse the device (a Hudl2 in this case).
For any of you who want to do the same the relevant files are in: Android->data->com.mattel.MCSMMC->files->Movie. Each movie has it's own number and each frame of each movie is in an individual, numbered, folder. e.g. Movie->9->Frame->11 contains the files for frame 11 of movie 9.

I'll update this post when I've figured out how to resolve the issue - probably by creating the movie using separate software or by splitting the movie on the device.