(I'm placing this in Troubleshooting because some of the problems encountered appear to be solvable bugs.)
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* Q. "What are BR repack?" ...These are large files (typically 40-60gb) which are lossless Blu-ray remuxes in 2160 resolution (i.e., 4k). Most 64-bit CPU desktops from 2009 onward are capable of playing them given more than rudimentary ram, with the player software being the primary impediment.
* Q. "What is a BPP?" ...Blu-ray Player Pro is a payware Mac application. Why it? --It's the first one I found when I went looking for alternative have-a-Mac-version players. (It has a free version, which overlays a watermark during playback.)
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Comparison materials:
Hardware: a mid-2011 27" iMac, 3.4ghz i7, 12gb ram, with original 1TB drive and stock 2gb video card. The machine's drive is mostly full, and the file to be played resides in the last 150gb of space (which is near the drive-spindle, or the slowest part of a mechanical drive). There are no external speakers. (The "thick-side" optical-drive aluminum iMacs had quite-nice stereo speakers, although not nearly as lush and rich-sounding as those in the now-obsolete "white" polycarbonate 24" iMacs, which were the real Cadillac models IMO. Either sound better than the current-generation "thin-side" iMacs, but I digress....)
Software: VLC 2.2.8, VLC 3.0.1, and BPP 3.2.22 ...each is installed without any adjustments to settings. I.e., they're default.
FIle: ...our favorite Asgardian hero's latest (2017) romp, in lossless MPEG-H Part2/HEVC H.265, 2.35:1 aspect-ratio letterboxed in 16x9 resolution 3840x2160 (which is exactly 50% over the pixel dimensions of my 2011 iMac's non-Retina screen, so the video will be auto-shrunk during playback). The audio track is 7:1, and will have to play on our stereo speaker set-up without missing anything important in my subjective estimation.
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Features: VLC (clear winner)
* VLC: you can fiddle with just about anything, although important stuff (such as brightness) are sometimes not where you'd expect it to be (brightness is located under Windows > Video Playback, rather than Preferences or the Video menu entry).
* BPP: ...as bare-bones as you can get. It lacks even taken-for-granted things like double-clicking-to-maximize and scrollwheel-to-adjust-volume. But it DOES auto-crop letterbox "black-bars" (which Blu-ray raw files actually do have, and they are noticeable as dark gray w/grain rather than pure black); this is something that VLC does not do.
Video playback: BPP (clear winner)
* VLC 2.2.8 Weatherwax: ...immediately choked playing back a 50gb repack, and so is excluded from further comparison.
* VLC 3.0.1: ...serious frame-dropping, even in "slow" scenes, such as when the character Skurge is showing off his M16s to the ladies, and is basically standing still and pivoting on his heels. The gun-barrels noticeably jerk, painfully so, as frames are dropped. It seems as if the playback is being cut to only 12 or 8fps. Oddly, this frame-loss doesn't appear dependent on the busy-ness (or lack thereof) of action scenes, but by VLC's inability to decompress the .265 quickly enough regardless.
* BPP: ...smooth as butter. It also appears to be degraining by default (and that is very welcome).
Video clarity: BPP (clear winner)
* ...aside from framerate, VLC's video playback was too dark. It was hard to see much in the opening scene in Surtur's cave, for example. I had to adjust VLC's brightness from the default 50% up to 60%-ish in order to match BPP's apparent default level.
Audio: (both adequate, but fail in the same annoying way, so no winner)
* ...neither one of these players has built-in default audio-normalization auto-set during playback on two-speaker systems (which are still the overwhelming majority of devices in 2018). Normalization is "old" tech (it was included in AutoGK back in 2004, which is why the now-crude 700mb AVI "rips" of the era nevertheless tended to have excellent stereo tracks), and any machine made in the last ten years can pretty much do it on-the-fly using a miniscule amount of horsepower. But nope, no such luck: "Whisper" dialogue is inaudible, so you scrollwheel the volume up, then immediately have your head blown clean off by a gazillion-decibel "Inception" blare sound-effect. Ouch....
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Final tally: VLC still needs work in order to be an adequate player of lossless Blu-ray files, and it should be noted that 2160p "rips" are rapidly becoming the new norm for film files, replacing 1080p just about...now. (VLC 3 could be a decent player of lossy, compressed 2160p, but it should work to close the gap with BPP.)