IMAX ratio (nearly square) is not commercially available for home release, as it would require "pillarboxing" (black bars on the sides) on modern TVs. Version Comparison 4K UHD Blu-ray Standard Blu-ray (1080p) Digital/Streaming Resolution 2160p (Ultra HD) 1080p (Full HD) Varies (up to 4K) Yes (HDR10) IMAX Scenes Yes (shifts to 1.78:1) Yes (shifts to 1.78:1) Often Locked to 2.39:1 DTS-HD Master Audio 5.1 DTS-HD Master Audio 5.1 Dolby Digital Plus/Atmos Buying Guide & Availability
Do not buy "digital downloads" from random websites offering a $3.99 MP4. These are usually pirated DVD screeners upscaled to fake 1080p. Most legitimate streaming services (iTunes, Vudu) do not support IMAX aspect ratio switching for Interstellar (they only offer the scope version).