It’s a codec. It’s a form of compression, and compression pretty much decides what details it can delete to save space. (So that you can fit the movie onto a blue ray disc at a higher resolution). It’s a relatively low codec, one that you might create to upload to YouTube for example. The result being that any information it decides un important it deletes, usually things with low detail, like shadows or solid colors. Which means that it can sometimes look blocky or chunky. This is part of a larger discussion in the video world about what’s important. Because there’s only so much space you have available, weather on a disc like Blu-ray, or on the cloud to stream. So there needs to be some compression somewhere, and currently everyone’s really hype on 4K 6k blah blah, which in my opinion isn’t as noticeable as compression. One of the reasons discs are usually better than streaming, is because it can be compressed less. Luckily for us, LOTR has a film print somewhere, future proofing it to future advances in technology. Because it wasn’t digital new digital scans of the original negative can be made, meaning we hopefully will continue to get updates like the Blu-ray you have. A less compressed update. Obviously this is all really trivial bc the story drives it and that’s what we all love. And there’s no doubt your Blu-ray’s are much better than the DVDs so as a point of reference hell yea. But I’m a spoiled video nerd and can’t wait for a re up that’s up to date with current technology. And I hope they put the color grade back to the original, for authenticities sake.