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Superbit DVDs, Why Not use the highest DTS bitrate?


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#1 of 44 ChrisA

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Posted August 24 2001 - 01:09 AM

I was just wondering that if the GOAL of superbit DVDs is to take maximum advantage of audio/Video, why not use DTS in the higher bitrate? It would be great if the only thing on a superbit was the higher bitrate DTS track and the rest going to superbit video. Nothing else should take bandwidth. Dolby Digital 5.1 is not a problem to include as long as it is not available on the fly. In other words, bandwidth is the weakest link. Whenever you have more than one track available on the fly, you are eating up bandwidth. That is why one can select either DD or DTS in the beginning and not be able to switch between the two while the movie is playing. I guess the problem could be storage space in the sense of providing full rate DTS 5.1, DD 5.1, and superbit video. I don't see a bandwidth prooblem with being able to do high quality video along with a full rate DTS track. In other words, since superbit tracks are only going to have one soundtrack available on the fly, why not make it DTS full rate? It should not be a bandwidth issue as far as I can tell. The superbit video should be able to be maxed out even with a full bitrate DTS track. So is storage space the weakest link in providing full rate DTS onn superbit DVDs? I thought since these DVDs were not stuffed full of crappy extras Posted Image that there should be plenty of room for full rate DTS and superbit video. If storage space is the issue, then I vote for a DD 2.0 track with Full rate DTS. The target market is audio/videophiles, so full rate DTS should be implemented.

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#2 of 44 YANG

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Posted August 24 2001 - 01:13 AM

I am surprise about the bitrate they are using for DTS too,if the releases will not have those extra features which will give way to more disc space...?

#3 of 44 Neil Joseph

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Posted August 24 2001 - 02:06 AM

The original Fifth Element was done on a single layer using less than half the total bitrate of the new release and yet it looks so good (try stepping frame by frame). I don't understand why they could not use full bitrate dts if they are using a dual layer. It makes sense.

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#4 of 44 Kevin P

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Posted August 24 2001 - 03:06 AM

It could be related to the fact that the maximum TOTAL bitrate (bandwidth) on a DVD is 10 Mbps, regardless of disc capacity. A full rate DTS track will rob roughly 14% of that bandwidth. Additional soundtracks, subtitles, alternate angles, yadda yadda also use part of that 10 Mbps, if they exist, even if you're not actively using them.

So if you have a DVD with a 1.4Mbps DTS soundtrack (the maximum bitrate), a 384kbps DD 5.1 soundtrack and a 192kbps DD 2.0 soundtrack, the maximum bandwidth for video is about 8 Mbps, taking overhead into account. Go to a 768kbps DTS track, and you get that much more for video (almost 9 Mbps).

So, it's basically a compromise. Getting the absolute highest video bitrate means making some compromises in the audio bitrate, and vice versa.

KJP


#5 of 44 PatrickM

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Posted August 24 2001 - 03:33 AM

I think a better question, at least for the Fifth Element in Superbit, is why it hasn't been announced with a DTS-ES soundtrack since the German R2 version contains such a soundtrack.

If its supposed to be the best sound and picture it should contain a DTS-ES track

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#6 of 44 William Ward

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Posted August 24 2001 - 04:31 AM

They should just make it Full-rate DTS with a dolby 2.0 track. Use the rest for video rate.

These titles would sell better if they had full-rate DTS.

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#7 of 44 JeremyErwin

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Posted August 24 2001 - 04:54 AM

What's the rationale for including a 192 kbs Dolby Surround 2.0 track? Won't downmixing from DD5.1/DD4.0 suffice?

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#8 of 44 ChrisA

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Posted August 24 2001 - 05:10 AM

Additional soundtracks, subtitles, alternate angles, yadda yadda also use part of that 10 Mbps, if they exist, even if you're not actively using them.

That is exactly what superbit DVDs should not do: waste bandwidth on extra languages, commentary, etc...

Remember, it makes a difference if the track is available 'on the fly' vs. not 'on the fly'. Having more soundtracks, but not having them switchable on the fly, doesn't eat up bandwidth. One simply has to give up the luxury of being able to switch audio tracks while the DVD is playing. I think it is important to expand upon "not actively using them". Sure there are many tracks available on the fly which are not all used at the same time, but are eating up bandwidth. Nontheless, it can be arranged in the DVD setup so that ONE AUDIO TRACK ONLY is taking up bandwidth. Not all tracks present on the DVD have to play simultaneously. This is mearly up to the DVD 'engineer'.

Remember "SEVEN" Included a 2.0 24/96 PCM track!!! This was iin conjunction to DTS, DD! Certainly, one chose in the setup which of those they would like to hear. Not all of them are running simultaneosly even though we are listening to just one.

The goal of a supperbit DVD is to maximize audio and video quality. ONE audio track and ONE video track should be playing at any one time.

So if you have a DVD with a 1.4Mbps DTS soundtrack (the maximum bitrate), a 384kbps DD 5.1 soundtrack and a 192kbps DD 2.0 soundtrack, the maximum bandwidth for video is about 8 Mbps, taking overhead into account. Go to a 768kbps DTS track, and you get that much more for video (almost 9 Mbps).

Asuperbit DVD should have 8.6 Mbps for video and 1.4 for DTS Audio. The extra 768 Kbps for audio should in no way impact the video. A superbit DVD is designed for max audio and picture quality, and in my opinion, this is really a farce to say they are improving the audio. 'half-rate DTS' is already on stadard DVD's. There is nothing special about 'half-rate' DTS.

They should just make it Full-rate DTS with a dolby 2.0 track. Use the rest for video rate. These titles would sell better if they had full-rate DTS.

I wholeheartedly concur. 8.6 Mbps Video and 1.4 DTS audio.
Only one audio and one video track taking up bandwidth is the way to go. The truth is that a DD 5.1 and other tracks can be included, but they can't just be made available 'on-the-fly'. It would be just a matter of storage space.

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#9 of 44 ChrisA

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Posted August 24 2001 - 05:27 AM

Duplicate post.

[Edited last by ChrisA on August 24, 2001 at 04:36 PM]
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#10 of 44 Rod Martin

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Posted August 24 2001 - 09:13 AM

There are times where I'm away from the forum for a couple weeks or more at a time. I missed all this "SuperBit DVD" stuff. With the search engine mostly on the fritz, can someone point me to a link explaining what Superbit is and what it's for?

Thanks!
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#11 of 44 Scott_MacD

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Posted August 24 2001 - 09:53 AM


Quote:
Remember "SEVEN" Included a 2.0 24/96 PCM track!!! This was iin conjunction to DTS, DD!

This was only in the exploration of the opening title sequence on Disc 2 of Se7en. Disc 1, the main movie, had a choice of DD5.1EX, DTS-ES Discrete 6.1, DD2.0 (to avoid compromising the DD5.1EX mix for downmixing to 2.0) and 4 commentaries.

Quote:
Whenever you have more than one track available on the fly, you are eating up bandwidth.

Also, I didn't know this was the case. I was convinced that all audio tracks available were muxed into the main .VOB files and the DVD player was merely grabbing 10Mbps of this in sequence and demuxing it into the relavent MPEG2 video and all different audio streams. Hence, EVERY track on a DVD-Video program eats up the bandwidth for that specific program, not just those that are disabled from on-the-fly listening.

Apologies if I appear confused, but this does throw me for a loop. But in essence, I do agree that the full DTS bitrate should be used. The SuperBit series of releases are a speciality product, and most (not all, I hasten to add) users who have true 5.1 playback equipment also have DTS decoding available too, and so using the full bitrate DTS and minimal DD support sounds right.

Cheers,

Scott

#12 of 44 Antonio_M

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Posted August 24 2001 - 10:00 AM

Please look at it this way..you cannot complain, be aware that Desperado and Fifth Element are encoded in 384kbps Dolby Digital and the Superbits are DTS 754kbps each!!!

C'mon man!

To what extent are we going to be FULLY satisfied?

I mean Jesus, look at Saving Private Ryan, it's grossly LOUD! I don't want it at 1509kbps! I am not nuts!

Besides, it's all about the job that was done on specific titles, not about the more kbps the better.

#13 of 44 Nick_Gray

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Posted August 24 2001 - 10:06 AM

Quote:
Sure there are many tracks available on the fly which are not all used at the same time, but are eating up bandwidth. Nontheless, it can be arranged in the DVD setup so that ONE AUDIO TRACK ONLY is taking up bandwidth.

Is this possible? I thought that 1x DVD only allows 10Mb/s transfer rate. This is the rate at which the laser pickup physically reads the data stream. I can't think of any way to physically lay out a disc that one could circumvent this: 10Mb/s is 100% efficiency, i.e. no seeks, just starting at the beginning of the stream and reading it as fast as possible. If only 10Mb/s is possible, that is all that can be read in real time by a single pickup, regardless of discarded data streams (they have to be mixed in the stream, or it won't be accessible in real-time without seeking = lower efficiency = lower effective bandwidth)

It's not necessarily a limitation of the data bus, or the decoding processors, it is the limitation of the physical medium; there is no means of circumventing this.

On the other hand, my argument could be full of water...

#14 of 44 ChrisA

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Posted August 24 2001 - 11:52 AM

It is my understanding that one can have many different soundtracks that do not have to be used on-the-fly. If a soundtrack is not made switchable on-the-fly, it does not have to eat up bandwidth. It is perfectly fine to design DVD playback so that there is only one soundtrack eating up bandwidth at a time. This simply means that one selects the soundtrack they desire in the beginning, and that soundtrack is used throughout the film. This is not a problem. How many of us actually switch audio tracks on the fly anyway? Some people, I hear, actually like to listen to the commentary tracks on the fly. I don't watch many commentaries anyway, let alone worry about switching between commentary and other soundtracks while watching a movie. While certainly there are many discs designed with many soundtracks all playing at the same time (even though we only listen to one at a time), the DVD 'engineer' can design the DVD so that only one track plays at a time.

Superbit DVDs could contain various soundtracks, if for some reason they actually wanted to, and be designed so that only one is being used at a time. That is how superbits should be designed since they are about achieveing the highest quality audio and video. Again, saying superbit DVDs have the best audio quality is not true unless they are using 'full-rate' DTS. Providing 'half-rate' DTS is something that standard DVDs have. In fact, as was shown here before, there are quite a few standard DVDs with 'full-rate' DTS.

A superbit DVD can use full-rate DTS and the maximum useful video rate. There is no reason not to use high rate DTS for a SUPERBIT DVD.

Does anyone know where to write email or letters to?

Sincerely,

Chris

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#15 of 44 Pete Calderwood

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Posted August 24 2001 - 01:44 PM

The primary problem with "Superbit" DVDs is that due to DVD's peak bitrate limitations, a sacrifice will have to be made in video or audio. If full bitrate DTS is used, the peak level video bitrate drops by another 768kbps, making artifacts more likely to occur on certain hard to compress scenes like explosions. For this reason, Sony chose to go with the already excellent half-bitrate DTS and save the extra bits for hard to compress scenes. FYI, the major difference between DTS half and full is simply that DTS half starts rolling off frequencies at 15khz, eventually steeply dropping off at 19khz, while full bitrate DTS has full response up to 22khz. If anyone wants to hear what kind of effect such a rolloff would have on music, email me at ruinedx@hotmail.com and I can send you a clip of something with and without the rolloff applied, so you can decide for yourself if it is worth getting concerned over half bitrate DTS.

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#16 of 44 Jeff

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Posted August 24 2001 - 01:49 PM


I agree with Pete. Using full bit rate would be a mistake. The video would really suffer. In fact, I think Dolby Digital 5.1 should have been dropped. Having both DD and DTS is pretty much going to insure that the original Fifth Element will look better, although I hope I'm wrong.

BTW, can anyone here really tell a difference between full and half bit rate DTS? Look at Saving Private Ryan. It's the best sounding DTS disc and it's half bit rate. Dances with Wolves DTS is MARGINALLY better sounding than the DD version and it's full bit rate.

Jeff

#17 of 44 Pete Calderwood

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Posted August 24 2001 - 02:17 PM

Actually will have to disagree with you there on DWW Posted Image

Dances With Wolves DTS uses (on my scale) a far superior audio master to the DD version, with higher fidelity and much better bass, reguardless of compression codec differences. Thedigitalbits.com has a good overview of the quite obvious audible differences between the two. This is due to DTS personally doing the transfer for the DWW since it was the first big-studio DTS DVD and they wanted it to be excellent - they went to London and did an excellent transfer using Studer 20bit converters off a pristine 70mm magnetic film element of DWW.

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#18 of 44 Pete Calderwood

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Posted August 24 2001 - 02:19 PM

BTW, I made an error in my previous post, I meant full response up to 24khz.

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#19 of 44 JeremyErwin

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Posted August 24 2001 - 06:37 PM

There's something some of you are forgetting-- Assuming a constant 10 Mbs bitrate (rather unrealistic) and 8.5 GB total disc capacity (dual layer, single sided)...

Or, to use rather more precise values:

4169920 sectors* 2048 bytes/sector= 8144.125 MB

8144.125 MB*8 bits per byte=65153 Megabits

65153/10.08 Mb per sec= 6464 sec
6464/60 = ~107 minutes.

Length of Fifth Element: 126 Minutes...

BTW: The absolute maximum capacity of a DVD9 is 8539996160 bytes. Thus, if one assumes that a GB is a thousand million bytes (rather than 2^30) one gets the more conventional 8.5 GB... I am not sure if the 10.08 value refers to 10.08 * 2^20 bytes or 10.8 million bytes...

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#20 of 44 David-alexander

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Posted August 24 2001 - 07:00 PM

see it the other way around:

it can be done (DTS full rate, dolby 5.1 and 2.0): THIN RED LINE, while having a stunning picture ( no extras, just 2 subtitles).

or DVD 14 could have been used.

the other way around is this: maybe DTS asked them to stick with the 1/2 DTS version since this the once that other studios use for their dual releases or single releases, in order to not cause a doubt in the mind of the public as far as the quality and justification of a 1/2 dts is concerned.

See my points ? The controversy of the 1/2 dts vs dolby is already high enough and thus dts wants to stick to its policy (a compromised policy to be able to be more and more featured on dvd releases) of the 1/2 dts....

just an idea....





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