BD Image Quality

That's a pretty odd question... there's probably only one person on this board that would say bitrate is the most important factor. Though it's certainly a major factor in transparency to the source.

I want high quality to be carried through the entire process, from what film elements are scanned, how they're scanned, the digital mastering, scaling to 1080p, compression, etc. I think most poor blu-rays are poor because they use low quality scans of low quality film (which often goes hand in hand with overzealous digital processing). But there are certainly releases that compromise a great master with shoddy compression work.

I too believe it all starts off with the original source they are using and the mastering process that follows. If either of these areas are neglected or improperly handled that I believe, regardless of bit-rate, affects the overall image far greater.

If the same rules apply here as with audio discs, then there's several points in the process where an ignorant or uncaring processor can muck up the quality.

Certainly it begins with the original film elements used and the quality of the transfer.

2nd is the mastering where egregious acts can be undertaken like DNR or noise scrubbing.

3rd is the disc mastering/authoring where decisions like compression levels are made. (make room for bonus content, extra audio tracks, etc)

Lastly is the duplication mastering stage where stupid people might decide to throw out what the mastering/authoring people decided and compress needlessly or otherwise run the video through additional un-needed processing. How many time have we seen discs that are not full?

In order for quality to come out at the end phase, the filmmakers have to have control and input in all the preceding phases.

BD is limited inherently by colour sub sampling for colour material. Mostly you would not see a problem without the master for comparison, but sometimes it's obvious that colour definition is somewhere between black and white (which is full 1080p) and fully saturated primary colours (where it's closer to 540p than 1080p).
Apart from that given a top notch uncompressed 8 bit 4:2:0 master only compression can limit quality on the disc (assuming the master is just compressed and nothing else is done).

I think it's pretty ignorant to say that bitrate is the single most important aspect of a BD transfer, in terms of affecting the image quality.

Based on what I've seen, the condition of the original master seems to be greatest contributor to good/bad quality. Note I said "greatest" contributor and not "only" contributor.. Like Grimes said, there are a number of factors all coming together to make the final product. While bitrate does contribute, it's my belief that it contributes less than the other factors; source material and processing.

Put it this way, I would rather have a 10mbs encode of Gladiator with the new master then a 40mbs encode with the old master. The primary concern should be that the master is in good shape.

Now 10mbs would of course push it. And it would benefit to increase the bitrate with some numbers, but 40 is an overkill once you take into account that the encode is locked to 8bit 4:2:0.

But I have an intresting idea that I would need some help with since I dont have the numbers.

How many disc needs to be sold, so that the savings of using a BD25 over a BD50 covers the expense of creating a new 4K master for a 2 hour movie?

First of all, BD is the best format we've ever had in the home, so I wouldn't agree that it's not "top notch" - depending on your definition.

Of course, the discs are only as good as the video transfer that they were made from.

Art, I'm sure you're playing devil's advocate here and trying to get opinions, but the encoding side is almost never the issue for me. There's enough bandwidth on BD to allow even crappy AVC encoders to usually produce a pretty good result in terms of encoding. If I'm ever unsatisfied with a BD title, it's usually because an old video transfer has been re-heated and served up.

I'm finding no problems whatsoever with Blu-ray as a home theater system. As I've suggested in the past, Blu-ray is merely a bucket into which data is placed for dissemination. As long as the film or data elements are of sufficient quality, and are not digitally damaged on their way to the final HD master, there are no problems, inclusive of bit rate. Long films can be pressed to multiple discs.

RAH

Each step in the production process factors into the final result. Compartmentalizing just one or two variables as the determining issues is oversimplifying and unhelpful.

As others have mentioned the quality of the master is the primary originator of the possible ultimate product. Additional foolhardy tinkering will defeat the point of a pristine master and loss of quality will be further exacerbated by unoptimized compression/encoding decisions. To mitigate loss in visual fidelity in the final delivery medium increasing the average bitrate will provide greater transparency and accuracy within the capabilities of the codec.

I do not completely understand why some feel 20-25mbs is the magic number for good enough for overall transparency, this seems more of a philosophical premise than one based in facts.

Frankly even if every film was maxed out at 40mbs it would not be completely transparent, it does not fully realize BR color space either, but when the standards were established it was determined that 40mbs was a good enough cap for hardware and software that was economically feasible at the time.

Yes they (BDA) certainly could have aimed higher but the cost to benefit ratio was determined not sufficient to justify the expense and the expectations that the targeted average consumer market would not have capable systems to take advantage of the increased quality.

With all that said assuming all is being equal expectations for what film should look like in HD varies and is a bit skewed in many observers eyes. Just read the disparity in reviews proves this. Those that expect ultra sharp, low to no visible grain, consistently over saturated colors and contrast, will frequently rate accurate near flawless transfers that do not match those preconceptions unfairly lower.

Back to the main point of debate, increased average bitrate benefits the film in greater accuracy and transparency, but not the sole factor in creating a quality product of excellent caliber.

Best Regards
KvE

I seriously doubt many of us could pick out a 40mbps AVC encode from a, say, 60mbps one, except maybe for some especially problematic scenes. From experience, with that sort of bit rate, the results merely look DIFFERENT rather than being obviously better. 40mbps with a good AVC encoder can produce a ridiculously good quality result.

A max video bit rate of 40mbps doesn't bother me... but I would have liked to see chroma sampling higher than 4:2:0 in BD.

Thanks Robert for posting your comments. For those that do not know Robert, click here and here or Google for Robert A Harris.


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From several years ago:

I agree with most of what you've said, except for:


Compression artefacts aren't hard to spot if you know what to look for.

I am very happy with the PQ and AQ Blu-ray is capable of.

Believe it or not, but even the master can have compression artifacts.

Yes, I am well aware. My point was: some video aberrations were/are blamed on the encodes when the problem was actually in the source material.

They theoretically can, but given that most BD titles right now are being made from HDCAM SR, I'd be amazed if there were visible compression artefacts in the source... unless they were somehow introduced further upstream...

Warner Bros and Universal thinking that remastering means either Teal and orange or DNR, all it needs is a decent print or OCN scanned at at least 2k and put on a BD50

bitrate and encoding settings and skill certainly count no doubt but that said those issues, although they should be the major ones, are minor compared to the issues of DNR, poor filtering when resize to blu-ray resolution (which can cause, among other things, flicker of fine details) and some still using white halo ringing EE and too much at that.

The ridiculously bad DNR is the single worst culprit currently.

You can't make gold out of lead. You can take excellent source material and ruin it, but you can't take an old distribution print and turn it into a great HD master. I think the availability of pristine source material is the single greatest determinant of the potential greatness of a BD release. Whether that material survives unscathed all the way to the disc is another set of issues.

With few exceptions, the great transfers of old films come from restored elements, be generationally closer to what came out of the cameras. That's why I think the lack of such elements is the single biggest limiting factor in the visual quality of BD releases.

Idiocy runs a close second, of course.

Striking a new film transfer from the original camera negative and then using the most current scanning technology is by far the number one factor in determining the image quality. But that process costs much more money for a studio than reusing an old HD master created several years ago for DVD and running it through heavy DNR.

That sums up my feelings as well except I would put it this way:
I would rather have a 20mbs encode of Patton with a new master then any-mbs encode with the current master.

There's no need to create new elements just for the transfer though, as most of the recent high-profile remasterings (Gladiator, Alien, Bond movies, Taxi Driver, Godfather etc) have gone straight from the negatives.

Anyhoo, I'm also of the opinion that's it's all about the source, and how much properly-directed care and attention a studio is willing to expend on it. The whole thing revolves around cash money, so we can't expect 4K scans off of negatives for every single catalogue title, granted.

But it puzzles me how some studios are really stepping up when it comes to preparing catalogue titles for Blu-ray, while others are still content to wheel out ancient masters and then slather them with DNR and EE. Perhaps it's because the end result is still the same, as far as units sold is concerned? In other words, they're not exactly selling like hot-cakes no matter how much or how little money/care/attention is spent on preparing them.

I'm sure most people don't bother reading reviews.
You'd think it'd be a matter of professionalism to at least TRY to not put out something half-assed though. It's not like the technology is standing still either, I know Sony's Colorworks facility has a new scanner that scans 4K at like 15fps, which is like 12 times faster than the Northlight scanner used for many 4K restorations.

With my VERY limited knowledge of the processes involved, I'm very pleased with Blu Ray.
Yes, some releases aren't much better than DVD (or VHS for that matter), but I'm rarely disappointed with Blu Ray.
My sense of it is that it's the source(s) used that probably have the biggest impact on the final outcome.
Of course, the people actually doing the work can ruin that final outcome in a heartbeat.

This question is raised over and over....I don't think any of the people wanting 30+mbps would say they'd rather have a blu-ray which used an old crap master with 40mbps encode versus a 15mbps encode with a new proper transfer.

They are just saying "there's 20 GB left on the disc, why didnt you use it?" Will it make a huge difference -- probably not.. but it would reduce artifacts that are seen more often with lower bit-rate encodes. Yeah, we're glad it was a new transfer, but now you're going to cripple it?

I've seen cases where higher bit-rate hasn't helped... I've seen cases where it has... but I dont remember seeing many cases where the added bit-rate took away... (not counting when the studio decides to add EE and DNR ...Universal...)

I think it's largely source material issue stemming from an economic problem. Lack of good catalog sales, poor economy since the format war ended, lack of resources/money so studios aren't going to necessarily do what's optimal on many titles since the return is evidently minimal to them except on certain titles.

once again I still have to go back to DNR being the number one culprit

mystic pizza uses some filthy elements but so what compared to being a mess of DNR meddling

i'll take whatever-condition elements scanned in at 1080p with no muddled DNR and EE over a 4k scan then poorly filtered down to 1080p and with nsty DNR applied!!

Kundun has perfectly fine source elements and the euro blu-ray literally looks like computer cel shader gaming! insanely bad!

Honestly, I don't care all that much about bitrate and I'd much rather see more half-assed releases than fewer excellent releases if forced to choose, because I'm not thrilled with having to watch DVDs and I consume a lot of movies. As others have mentioned, I agree that bitrate is perhaps the least important component to a quality release.

However, those not uncommon ~26-30GB BD releases always make me scratch my head. Couldn't be bothered to very slightly shrink the encode to fit onto a BD25, so just leave nearly half the disc empty? It offends my sense of efficiency and economy.