The Twilight Saga: Breaking Dawn - Part 1 (2011)

StudioCanal 4K Blu-ray/Lionsgate Limited 4K Blu-ray (shared encode); slight improvement over the 2015 StudioCanal Blu-ray

StudioCanal/LG UHDs port the 1999 Criterion DVD, considered the best source

StudioCanal has a remastered Blu-ray, Lionsgate only a 4K Blu-ray

Bandai JP 4K Blu-ray

All 4K releases are sourced from the same mediocre transfer provided by Bandai, with various amounts of tweaks. Japanese disc presents it with the least tinkering.

The best attempt at improving it comes from the German/French releases from KSM/All the Anime, both of which use the same master with HDR regrading (original grade is SDR in HDR container), tasteful regraining and sharpening, in an attempt to breathe some life into the middling transfer, making for an arguably more pleasing viewing experience.

All earlier releases are from an even worse transfer, with significant black crush, with the exception of a Japanese TV airing, which doesn't suffer from that issue, but instead is heavily sharpened and suffers from poor encoding.

Comparisons: JPN UHD, USA UHD, FRA/GER UHD, ITA UHD (tonemapped), JPN UHD, USA UHD, FRA/GER UHD, ITA UHD, ESP UHD (PQ), All 1080p BDs, HDTV, HDTV filtered

Original matrixed stereo mix: Bandai JP 4K Blu-ray
Most discs include this track with comparable fidelity (which is excellent).

Dolby Atmos remix: Lionsgate US 4K / All the Anime FR 4K
6.1 remix (from Ghost in the Shell 2.0): KSM DE 4K / All the Anime FR 4K

All tracks on the Lionsgate US 4K replace the original ending song with the one heard on the English dub. As the Atmos track on the FR 4K is just a port, it also has this song replaced.

Japanese 4K includes English dub and subtitles.
French/German 4Ks are not English friendly, with no dub or subtitles.
French disc includes the Atmos track, but the German disc does not.