[WhyIsItAlwaysHN]

Is this more efficient than putting all of that in say a 7z archive?

I'd expect video frames to be maximally efficient if you sorted the chunks by image similarity somehow.

Also isn't there a risk of losing data by doing this since for example h.265 is lossy?

[chatmasta]

h.265 is lossy but QR codes are redundant

[WhyIsItAlwaysHN]

Is the probability of lost data zero across eg. millions of documents?

I see there's a 30% redundancy per document, but I'm not sure every frame in a h265 file is guaranteed to have more than 70% of a qr code being readable. And if it's not readable, then that could mean losing an entire chunk of data.

I'd definitely calculate the probability of losing data if storing text with a lossy compression.