[dspillett]

> Base85 would probably be a better choice

Base64 has the advantage of relative ubiquity (though Base85 is hardly rare, being used in PDF and Git binary patches). It also doesn't contain characters (quotes, angled brackets, ...) that might cause problems if naively sent via some text protocols and/or embedded in XML/HTML mark-up.

> YouTube ... you'd need to find a resilient way of encoding the data [due to lossy re-encoding]

That should be easy enough: encode as blocks or lines of pixels (blocks of 4x4 should be more than sufficient) in a low enough number of colour values (I expect you'd get away with at least 4bits/channel/block with large enough blocks so 4096 values per block) and you should easily be able to survive anything the re-encoding does by averaging each block and taking the closest value to that result.

Add some form of error detection+correction code just for paranoia's sake. You are going to want to include some redundancy in the uploads anyway so you can combine these needs in a manner similar to RAID5/6 or the Parchive format that was (is?) popular on binary carrying Usenet groups.

[richrichardsson]

Would be cool to use the audio for some extra bandwidth too, get some Sinclair Spectrum-esque (albeit in stereo) bleeps to accompany the video.