Finally, why go through all this trouble for a film from 2009? Because Avatar was filmed with dual-camera 3D rigs, not converted in post-production like many modern films (looking at you, Clash of the Titans ).
Indicates a vertical resolution of 1080 pixels, providing a "Full HD" foundation before the 3D horizontal split.
While files with these specific tags often circulate on file-sharing platforms like Google Drive , for the best quality and legal safety, you can find official versions of the film on Disney+ , which offers 4K and various audio tracks.