The leftmost strip is Sony Dynamic Digital Sound, the square between the sprocket holes (which give you an idea just small these are) is Dolby Digital. Each barcode encodes all the different surround channels. Sadly no open source formats though, unless you consider the two analog waveforms on the right.
IDK, sorry and feel free to remove if this breaks the community rules, I just thought it was really cool. I've always just assumed they had a separate medium for storing the sound and just timed them to play in sync.
That would be a real fun hackaday project. Even better, encode DMX512 on film.