[FFmpeg-user] split output to predefined size while transcoding?

[Boštjan Strojan]

Say i have a long AVC.mp4 file as input and i'am converting this to some
editing format (like prores). Is it possible to make the output split into
several files, based on size maybe (or maybe based on position of original
I frames?), so i get:
file1.mov
file2.mov
file3 < still transcoding
and i can use file1 and 2 at once for editing, while the rest is still
generating?

thanks