Myth II: BD's higher bitrate will NEVER improve PQ (relative to HD)

I think you are wrong on this topic.

Fact: VC-1, AVC, and MPEG-2 implementations are standards that exist even outside BD/HD-DVD. Each format has a specified maximum bit rate that can be decoded per these standards. The highest bit rate when discussing BD/HD-DVD is 36 Mbs, which is for MPEG-2. The HD-DVD standard specifies that every player is able to transmit 36.55 Mbs, which means it is capable of handling the highest possible bit rate of any of the three compression standards supported by HD-DVD or BD.

Bluray's higher 54 Mbs transfer rate only comes into play for BD games on the PS3, and as a storage medium on the PC (you would be able to read burned BD discs in less time than a burned HD-DVD disc with the same content).

But when it comes to playing movies, there is absolutely no advantage to BD;s transfer rate when compared to HD-DVD. The only myth I know of is the one that says BD's higher transfer rate equals a better picture quality. That is a total myth.

The issue is bandwidth. You may have noticed that there is something called "audio" on these discs. And you may have noticed that there often needs to be more than one audio track, especially for foreign languages. Why the hell should the lower bandwidth / lower capacity format be chosen as the next generation format? There is absolutely no rational reason to do so. It's just that simple.

Just FYI, I've watched a few VC-1 BD's that have gone over 30Mbps in spots.

wnorris, you are confusing data bit rates with video bit rates. BD has greater bandwidth with respect to playing movies:

http://www.avsforum.com/avs-vb/showt...&&#post8358387

Flame Bait.

And examples of those "rare but real scenes" are......? (Feel free to name the movie and scenes)


Not sure I understand the point here. There are titles like Click that have BD50 and MPEG2 that don't help your argument, if it's the "extra space + extra bandwidth = better PQ" argument.


Many of us have asked for the following...Take a title on HD DVD (especially one like HPGoF, which also has a TrueHD track and IME, therefore lowering the video rate, and should make it even easier for you )....throw more bits at it, with any codec you want, and show the end result having a noticeably better PQ. Should be easy enough to prove or disprove. Or take ANY title and do this! Prove that the extra bandwidth can be used for real benefits...like better PQ, instead of wasting it on kludgy pseudo-PiP.

Up to a certain point, right? Would DVD have looked better at 20 Mbps peak? Better at 30 than 20? I think we can agree there's a point of "enough" beyond which more doesn't make any difference.

The question is what that value is for particular combinations of codec, implementation, and content, and if particuar formats hit that bar for particular scenarios.

You're contending that HD DVD isn't "enough." You're going to have to define the scenario where you think this would be an issue in more detail if we're going to have a useful conversation about it.


Free codec in what sense?

Sorry, you are wrong and you are misrepresenting what was posted in the thread you linked. Or if that is what the poster believed, then they are wrong too.

BD does not have greater bandwidth with respect to video. A few posts later, the poster you are referring to backpedaled, said they would have to check the standard again, and then never reposted on the topic (at least that I could find).

BD and HD-DVD both have to comply with the standards for MPEG-2, AVC, and VC-1, which exist outside of BD and HD-DVD. Basically, the bandwidth is limited to 36 Mbs, 25 Mbs, and 20 Mbs respectively for video. HD-DVD standard says 36.55 Mbs and BD standard says 54 Mbs required.

You do have a point with audio, even though not in the way you mention it (it doesn't matter if there is one or five languages, you only play one at a time, all from the same area of the disc). Technically, a full on MPEG-2 stream (36 Mbs) with a lossless audio track might be more than HD-DVD could handle.

However, the fact that a "new" format can only claim it's "superior" in the area of using a 15 year old encoding codec isn't much to brag about in my book. A 20Mbs VC-1 transfer can look as equally as good as a 36 Mbs MPEG-2 transfer, which actually leaves plenty of room for the lossless track too.

Then where are the lossless tracks on HD DVD? To me it seems like bandwidth is a major problem for HD DVD. You know something is up when flagship titles like King Kong and Hulk gets a mere 1.5DD+ (which sounds great still) but why not True HD or PCM? Isn't this the format that claims "the look and sound of perfect"?

It's even more surprising that no one on the HD DVD forums bring this issue up.

Well, you answered your own question in large part by pointing out that 1.5 Mbps DD+ sounds great .

The biggest part is that there really isn't an audible gap between 1.5 Mbps DD+ and lossless for movie soundtracks. And from a workflow perspective, using a constant bitrate codec is easier, since you know what the bitrate is in advance, unlike with a VBR audio like TrueHD or DTS-MA.

But there are plenty of HD DVD discs with lossless audio, so it's not like it's impossible, or even hard.

Ah.

I'm not sure of the date. But the advanced codecs aren't that expensive. See:

http://www.mpegla.com/news/n_06-08-17_pr.pdf

MPEG-2 is actually more expensive per disc right now:

http://www.mpegla.com/m2/m2-agreement.cfm

And that's the per-disc fee. The actual encoders and operation of them is likely to cost a lot more per title than all the per-disc fees.

20 years from the date of filing, unless this falls under the terms of a design patent, in which case 14 years


Except the encoders were likely paid off quite awhile ago, and are multipurpose (creating broadcast/cable versions for instance), whereas you're not counting the hardware required for VC-1 encoding, nor the massive man hours that are put into doing so (reports from authors I know are "up to 6 passes at 8 hours a pass using 4 high-end PCs in parallel")

So it still is likely cheaper to them because they can do MPEG-2 in real time and only 3 passes. Maybe you've gotten a lot faster since them, but I doubt you're even close to 6 hours per movie.

Batman Begins would be the reference title for this. It has TrueHD and PiP.



Why are you blaming the format for decisions made by the studios? Superman Returns had lossless audio, the full movie, and the 90 minutes worth of extras (albeit not in HD), and did not seem to have a problem with bandwidth or space.

Why spend the time and energy to work on a lossless track when DD+ 1.5 would be more than sufficient for home use?


Sigh, this thread is another one that is based on variable information. Something that can be proven quite easily on both sides. And so therefore a wash. Almost like the OP is just looking for a little more attention.

Where did you get this stuff about the video being limited to 36, 25 and 20Mbps? MPEG-2 itself isn't limited to 36Mbps. Even VC-1 isn't. "Flight Plan" in VC-1 on Blu-ray hits 40Mbps. Not counting buffers, HD DVD has a total mux rate of about 30Mbps (about 6Mbps less than 36Mbps for overhead), which includes all audio tracks, subtitles, and PiP that can play during the movie (whether it is being played or not). Blu-ray has a total mux rate for those things of 48Mbps, but limits the video to 40Mbps. That isn't an MPEG-2, VC-1, or AVC/MPEG-4 limit. It is 40Mbps for each.
You seem to think that only the language that is getting played counts against the mux rate. If that is what you believe, then you really don't understand how this works. Those count whether currently being played or not. Same as the way DVD has worked from the beginning. Amir didn't understand this in the past (like back when he was pushing lossless audio inclusion for HD DVD), told some of us that we were wrong about it, but ended up apologizing after he learned the truth.

--Darin

Then why are we seeing the more expensive MPEG-2 being used now ?


Nope. Plenty of titles in both formats use higher peak rates than that.

Most encoders aren't multi-use in practice, for any codec. A live encoder is all about 1-pass CBR real-time "best effort." A disc encoder is all about 2-pass VBR with tweaking.

And, no, A-list encoders are replaced before they're fully amortized. They get upgraded often, especially in HD.


Increasing numbers of studios are moving to VC-1 because they feel the quality gains are worth it for them.

Maybe for "long-tail" titles, a real-time encoder might have some value, but it's not like most studios are using real-time encoders for DVD even now. They're still sweating the details with mutliple encode passes for A-list titles.

Our encoder can work in an automated hands-off, scratch speed mode if desired (still beating MPEG-2 at a given bitrate), but for A-list titles, studios are willing to put in a lot more time if it can help make a great looking title.

Umm, perhaps you missed all the banding artifacts in the water scenes. Or the pro/user reviews who had comments like "easily the softest HD title I have" etc?

HD DVD has hit the capacity wall, period.

We'd be happy to help Sony with VC-1 whenever they're ready to use it, FWIW.

Did the BD version look better?

I haven't seen that master, but it was shot digitally, and I'm told it's a pretty accurate presentation of the mater.

No, because Warner did not re-encode it from the initial VC-1 encode from the HD DVD. Some 20GB of space went unused.


I saw it twice theatrically: IMAX 3D and DLP. It wasn't soft.

Point 1 is absolutely valid. Video compression is highly program material dependent. A 24fps Peter Greenaway film (lots of static shots, some panning) will compress fine with a low bitrate, but a 60fps high octane music or concert video with strobe lights and fast, epilepsy-inducing edits will consume bitrate like crazy. Bitrate is as important to digital media as SNR is to analog. More is always better.

Point 2 is irrelevant. MPEG-2 is outdated and should be put out to pasture by the studios.

1080p60 is neither part of the BD specs, nor of HD DVD specs, so your example is not very good.

Both HD DVD and BD should have enough bitrate for 720p60 though (which is part of the specs).

Well, movies like King Kong are an exception as very few movies are rarely that long (3 hours or more). However, also consider that TrueHD is a format that only Warner seems to implement currently (and they don't implement it on BD for some reason...hmmm). The two titles you mentioned are non-Warner titles, so you will need to ask Universal why they have used TrueHD on 0 of their releases.

It's likely possible for them to do so if the demand is there. With the new TL discs, it shouldn't be a problem even for 3 hour films like Kong.