Dolby TrueHD and DTS-HD Master Audio - What are the real-life bitrates?

[BuGsArEtAsTy]

I've searched and searched, but I can't find it...

What are the Dolby TrueHD and DTS-HD Master Audio bitrates on shipping discs?

[William]

Most have said that so far HD-DVD has only used 48/16 masters for DD+ and TrueHD. It seams that I remember reading that Fox was going to use 96 or 48/24 masters for DTS-HD Master. Sony has also used 48/24 LPCM on a few titles.

[BuGsArEtAsTy]

Re: 48/16: So are we talking around 3 Mbps for 7.1 audio with lossless compression? Is the .1 channel the only one that isn't full range? If my guesstimate of 3 Mbps for 7.1 48/16 is close, then 48/24 would be about 4.5 Mbps.

So, that would mean the HD DVD bandwidth of 29+ Mbps would be more than sufficient for VC-1 video, plus two full range 48/24 7.1 tracks, plus a few DD tracks, etc. I have zero interest in 96/24. I wonder if the studios truly think it's important for movies. My guess is no, but then again you tell me Fox has considered it. It might be a useful marketing tool for music discs, but for those having multiple tracks isn't that important.

Thus, it seems to me that bandwidth isn't really an issue for HD DVD. It seems to me a reasonable expectation for a "deluxe" HD DVD is that a studio might use two non-lossy 48/24 tracks, plus three compressed DD tracks, for a total audio bitrate of about 10 Mbps. Together with a 16 Mbps video stream, that's 26 Mbps, or 195 MB per minute, with within HD DVD bandwidth constraints.

For a two hour movie, that's about 23 GB, leaving quite a bit of room left over for more extras. Thus, in practical terms, with HD DVD dual-layer I don't see either disk space or bandwidth as a limitation with the vast majority of movies. It could be an issue with super long movies however. Bandwidth still isn't an issue, but storage space in this context becomes more important. You're looking at maybe 2.5 hours for a movie with this plethora of audio tracks, and no extras, which means that extras would have to go onto a second disk.

If you wanted a longer movie, you'd probably drop down to 48/16 and/or scrap one of the non-lossy tracks. The bitrate would then drop to around 20 Mbps, or 150 MB/min, which means that an HD DVD could easily hold a movie longer than 3 hours (without extras) with pristine video and several audio tracks, including one with non-lossy audio compression at 7.1 channels.

[bfdtv]

Most have said that so far HD-DVD has only used 48/16 masters for DD+ and TrueHD. It seams that I remember reading that Fox was going to use 96 or 48/24 masters for DTS-HD Master. Sony has also used 48/24 LPCM on a few titles.Warner has used 16/48 TrueHD. Universal has apparently done some 20/48.

Several of the announced 24/48 titles from FOX are derived from 20/48 sources. The DTS-HD MA encoder only supports 16/48 and 24/48 at this time, so any source with higher fidelity than 16/48 must be upsampled to 24/48.

All but one or two Sony titles are 16/48.

[BuGsArEtAsTy]

Warner has used 16/48 TrueHD. Universal has apparently done some 20/48.

Several of the announced 24/48 titles from FOX are derived from 20/48 sources. The DTS-HD MA encoder only supports 16/48 and 24/48 at this time, so any source with higher fidelity than 16/48 must be upsampled to 24/48.

All but one or two Sony titles are 16/48.
Strange. I would have expected they'd be all over 20/48, especially if the sources are 20/48. 20/48 is quite a big jump over 16/48, yet doesn't use that much bandwidth/space. I guess we can hope to see it later for DTS-HD MA.

In any case, as suspected, it seems like 24/96 is indeed irrelevant for movies from the studios' standpoint.

[HPforMe]

I have zero interest in 96/24.

My Yamaha receiver can do DTS 96 kHz /24 and with a 1.5 Mbits/sec data rate this can sound very good but how much is there out there? Very little. I'm very satisfied with the bit rate of current titles with lossless TrueHD. Batman Begins is an example with TrueHD and tremendous video that blows anything away.

[bfdtv]

Strange. I would have expected they'd be all over 20/48, especially if the sources are 20/48. 20/48 is quite a big jump over 16/48, yet doesn't use that much bandwidth/space.Most modern films are available with either 20/48 or 24/48 masters.

The use of 16/48 (over 20/48, which TrueHD supports) is really a bandwidth / encoder issue. On HD-DVD, you have about 30Mbps for the video + audio + IME (interactive) stream content. On a typical title, this might consist of:

21 Mbps peak for VC-1 feature (12Mbps ABR)
3.0 Mbps peak for TrueHD (1.5Mbps ABR)
640Kbps x 3 for Dolby Digital Plus soundtracks in English, Spanish, French
256Kbps for director commentary
3.5 Mbps peak for IME (interactive video) in MPEG-2

Add those together and you're at about the max mux rate for HD-DVD. A number of changes are coming to improve the quality of HD-DVD disks.

In the near future, we'll start to see the IME (interactive video) content delivered using VC-1 instead of MPEG-2, which will cut the required bit rates of that content by 60-75%.

Another upcoming area of improvement is dynamic muxing.

Currently, the VC-1 video feature may average 12Mbps, but during a handful of action-packed scenes in the movie, the bit rate may spike to 19, 21, or 23 Mbps (depending on the encode). For a 2-hour movie that averages 12Mbps, only 60 seconds of the film may need >20Mbps peak bit rate. However, with the way films are encoded and muxed now -- which assumes the worst case scenario at all times -- you are wasting all that extra bandwidth for the 98% of the movie where it isn't needed.

The same goes for audio. A TrueHD track may run <1.8Mbps for 95% of the film, but spike to 3.0Mbps for 5% of the film. With the way films are encoded and muxed now -- which assumes the worst case scenario at all times -- you are wasting that extra bandwidth for the 95% of the movie that doesn't need it.

Currently, audio, video, and IME are encoded separately, with separate tools, and muxed together at the very end. Because everything is done separately, none of the parts know what the others need (in terms of bandwidth) at a given point in the film. So each must assume the worst from the other for muxing purposes. Significant ineffeciency results from this. Does that make sense?

Microsoft is now working on encoder improvements and increased levels of integration / workflow that will significantly improve the situation. In upcoming versions of these encoders, the VC-1 encode of the main feature will know that the 24/48 TrueHD audio spikes at 1:42:06 into the movie, and be able to compensate for that. In the future, lossless audio encoders will know that the video spikes at 1:15:06 for three seconds, so it can adjust audio fidelity from 24/48 to 16/48 for those three seconds if needed. There are several levels of dynamic muxing in the works; above is a generalized description of high-level muxing improvements, but low-level dynamic muxing to deal with instantaneous peaks is also under development.

Any studio not on board with Microsoft and its VC-1 encoder are really going to struggle to produce competitive disks in the next two years, imo. No other encoder vendor has the experience Microsoft does with software, and few are likely to match the integration and workflow that they have in the works. Many vendors are so singularly focused on video bits that they lose sight of the big picture -- which is making the best possible use of the full disk mux rate with all integrated video, audio, and interactive features, while also maintaining the best possible feature efficiency (audio + video + interactive) for future Internet-based delivery.

[BuGsArEtAsTy]

Thanks. That explanation makes a lot of sense, and it's nice to see dynamic muxing is something that is in the works.

BTW, I had thought the average 12 Mbps reported for newer VC-1 encodes was a bit optimistic, but you seem to suggest it is not. Sweet.

MS seems to have done quite a bit of work to move all of this along with VC-1. I had been hoping to see as much effort put into this from other companies on the H.264 side, but that doesn't seem to be the case. That is definitely not the case with Sony.

[draggoon01]

Most modern films are available with either 20/48 or 24/48 masters.

The use of 16/48 (over 20/48, which TrueHD supports) is really a bandwidth / encoder issue. On HD-DVD, you have about 30Mbps for the video + audio + IME (interactive) stream content. On a typical title, this might consist of:

21 Mbps peak for VC-1 feature (12Mbps ABR)
3.0 Mbps peak for TrueHD (1.5Mbps ABR)
640Kbps x 3 for Dolby Digital Plus soundtracks in English, Spanish, French
256Kbps for director commentary
3.5 Mbps peak for IME (interactive video) in MPEG-2

Add those together and you're at about the max mux rate for HD-DVD. A number of changes are coming to improve the quality of HD-DVD disks.

In the near future, we'll start to see the IME (interactive video) content delivered using VC-1 instead of MPEG-2, which will cut the required bit rates of that content by 60-75%.

Another upcoming area of improvement is dynamic muxing.

Currently, the VC-1 video feature may average 12Mbps, but during a handful of action-packed scenes in the movie, the bit rate may spike to 19, 21, or 23 Mbps (depending on the encode). For a 2-hour movie that averages 12Mbps, only 60 seconds of the film may need >20Mbps peak bit rate. However, with the way films are encoded and muxed now -- which assumes the worst case scenario at all times -- you are wasting all that extra bandwidth for the 98% of the movie where it isn't needed.

The same goes for audio. A TrueHD track may run <1.8Mbps for 95% of the film, but spike to 3.0Mbps for 5% of the film. With the way films are encoded and muxed now -- which assumes the worst case scenario at all times -- you are wasting that extra bandwidth for the 95% of the movie that doesn't need it.

Currently, audio, video, and IME are encoded separately, with separate tools, and muxed together at the very end. Because everything is done separately, none of the parts know what the others need (in terms of bandwidth) at a given point in the film. So each must assume the worst from the other for muxing purposes. Significant ineffeciency results from this. Does that make sense?

Microsoft is now working on encoder improvements and increased levels of integration / workflow that will significantly improve the situation. In upcoming versions of these encoders, the VC-1 encode of the main feature will know that the 24/48 TrueHD audio spikes at 1:42:06 into the movie, and be able to compensate for that. In the future, lossless audio encoders will know that the video spikes at 1:15:06 for three seconds, so it can adjust audio fidelity from 24/48 to 16/48 for those three seconds if needed. There are several levels of dynamic muxing in the works; above is a generalized description of high-level muxing improvements, but low-level dynamic muxing to deal with instantaneous peaks is also under development.

Any studio not on board with Microsoft and its VC-1 encoder are really going to struggle to produce competitive disks in the next two years, imo. No other encoder vendor has the experience Microsoft does with software, and few are likely to match the integration and workflow that they have in the works. Many vendors are so singularly focused on video bits that they lose sight of the big picture -- which is making the best possible use of the full disk mux rate with all integrated video, audio, and interactive features, while also maintaining the best possible feature efficiency (audio + video + interactive) for future Internet-based delivery.


wouldn't peak video bitrate usually happen at the same time as peak audio bitrate? specifically action sequences

[BuGsArEtAsTy]

BTW, amirm has stated in another thread they are considering adding a feature in the Xbox 360 (with add-on) which will allow it to decode high bitrate multi-channel tracks and convert them on-the-fly to 1.5 Mbps DTS.

Apparently, the Toshiba HD-A1 and HD-XA1 already have this feature.

[aaronwt]

They have a DTS encoder. Ideally they would also have had a DD encoder so the user could choose which encoding process they want.
Does the 360 currently encode DD in hardware or software? Would any update to allow DTS encoding would be done in software?

[JMicke]

From where do you get the "3 Mbps for 7.1 audio with lossless compression" number?
Wikipedia (http://en.wikipedia.org/wiki/Dolby_TrueHD) says TrueHD supports 24 bit, 96 kHz audio channels at up to 18 Mbit/s over 8 channels (HD DVD and Blu-ray Disc standards currently limit their maximum number of audio channels to eight. Of couse, 18Mbit/s is the max limit at 8 channel audio...

I'm curious since I am considering buying an HD DVD player for christmas, but I'm not sure if it can handle 8-channel Dolby TrueHD audio and still output a quality picture movie...

[BuGsArEtAsTy]

That's why I asked the question - I wanted to know the real-life bitrates.

Even if it supports up to 18 Mbps, few would ever use that for movies because it's not necessary and it's far too much bandwidth. The fact is even the original audio masters aren't 96 KHz to begin with, and many are not 24-bit either, according to the previous posts.

[JMicke]

Ok, I can see that. I was just wondering if you had found some info. I haven't found any other number than the 18Mbit/s on the wikipedia page.

[BuGsArEtAsTy]

96000 Hz * 24 bits * 8 channels = 18432000 bits

96/24, full-range 8 channel = 18 Mbps
48/24, full-range 8 channel = 9 Mbps
48/16, full-range 8 channel = 6 Mbps
48/16, full-range 7.1 channel with lossless compression = my guess of 3 Mbps
48/16, 7.1 channel with reduced surround ranges and lossless compression = my guess of somewhere < 3 Mbps.

I seem to be in the right ballpark as bfdtv says real-life it's around 3 Mbps peak, 1.5 Mbps average.

[bfdtv]

That's why I asked the question - I wanted to know the real-life bitrates.Here's the table of real-life TrueHD bitrates from Dolby.

Right now, for muxing purposes, tools assume the worst (the peak rate) at all times. With upcoming versions of Microsoft's encoder, the average bit rate will be the column that matters most.

http://fioswatch.com/downloads/TrueHD.png

[Gary Murrell]

Gone in 60 seconds on BR is 48/24 ;)

what I have heard so far on HD-DVD in regards to True-Hd is to be honest not much :(, no tracks I have listened to so far have been any improvement over DD+, maybe a 5% increase if that, not even noticeable to those but the pickiest of AV freaks and at that it is mighty slim, my audio setup is:

Boston Acoustics AVP7
Atlantic Technology A-2000
Atlantic Technology System 370 THX with dual subs
Velodyne SMS-1
Zektor HDS4.1 for switching between BR, HD, SACD and DVD-Audio
Toshiba connected via Analog

EQ, tweaked and calibrated to perfection with treated room and TrueHD is nothing all that special, as a audio freak that is sad, I have a feeling it is the 48/16 masters being used, we need some real HD audio ;)

I mean I am glad for the TrueHD we have, but those who haven't heard it and are expecting worlds of improvement are gonna be dissapointed

-Gary

[PRO-630HD]

For a Dolby True HD example, Phantom of the Opera is 1.6 mbps average and 3 mbps max or peak bit rate.

[bfdtv]

Keep in mind several of the announced DTS-HD MA 48/24 tracks are actually sourced from 48/20 audio masters. The current version of the DTS-HD encoder doesn't support anything between 48/16 and 48/24, so any source higher than 48/16 must be upsampled to 48/24.

The Dolby Digital Plus 1.5Mbps tracks on a number of Universal titles are 48/24 as well.

[FilmMixer]

Keep in mind several of the announced DTS-HD MA 48/24 tracks are actually sourced from 48/20 audio masters. The current version of the DTS-HD encoder doesn't support anything between 48/16 and 48/24, so any source higher than 48/16 must be upsampled to 48/24.

The Dolby Digital Plus 1.5Mbps tracks on a number of Universal titles are 48/24 as well.

How do you know that the masters are 20 bit? I have mixed over 85 films... every one has a 24 bit/48kHz master... every other mix stage in our company runs at 24/48.. and every stage in town runs at 24/48..

When we send masters to DTS for theatrical release masters, they get clones of our 6 track 24/48 masters... and a lot of times they are used for the home video masters..

[BuGsArEtAsTy]

Most modern films are available with either 20/48 or 24/48 masters.

The use of 16/48 (over 20/48, which TrueHD supports) is really a bandwidth / encoder issue. On HD-DVD, you have about 30Mbps for the video + audio + IME (interactive) stream content. On a typical title, this might consist of:

21 Mbps peak for VC-1 feature (12Mbps ABR)
3.0 Mbps peak for TrueHD (1.5Mbps ABR)
640Kbps x 3 for Dolby Digital Plus soundtracks in English, Spanish, French
256Kbps for director commentary
3.5 Mbps peak for IME (interactive video) in MPEG-2Here's the table of real-life TrueHD bitrates from Dolby.

Right now, for muxing purposes, tools assume the worst (the peak rate) at all times. With upcoming versions of Microsoft's encoder, the average bit rate will be the column that matters most.

http://fioswatch.com/downloads/TrueHD.png
Thanks. OK then:

21 Mbps peak VC1 (12 Mbps avg)
3.0 Mbps peak TrueHD English (1.5 Mbps avg)
1.92 Mbps peak DD+ Spanish, French, Inuktitut <-- We don't need another English track do we?
0.256 Kbps commentary <-- Why that high? Just cuz you can?
3.5 Mbps IME
----------------
Total 29.7 Mbps (19.2 mbps avg)

Maximum total bitrate is 30.24 Mbps so that's OK.

Let's give the average bitrate a bit of leeway and call it 20 Mbps. That's 2.5 MB/s, or 150 MB per minute, or 30000 MB for 200 minutes.

Thus, I predict the 3 hour and 8 minute long King Kong (2005) is going to be reference video quality.

It doesn't have a TrueHD track, but 3 Dolby Digital Plus 5.1 tracks is pretty good. I don't think it has much in the way of extras, but I think they might have been able to put on some 480p ones on it if they had really wanted. However, that will come with a re-release later, to make us open our pockets yet again.

[bfdtv]

How do you know that the masters are 20 bit? I have mixed over 85 films... every one has a 24 bit/48kHz master... every other mix stage in our company runs at 24/48.. and every stage in town runs at 24/48..Most of the 24/48 DTS-HD MA releases may be sourced from actual 24/48 masters. There was a discussion earlier -- unfortunately I no longer have the link -- where an insider noted that one of the first announced movies with 24/48 DTS-HD didn't have a master with that fidelity.

[JMicke]

So, if CD sound is sampled at 44,1 kHz, and the Dolby TrueHD sound usually is sampled at 24kHz, or lower. Or is it 24 bit sound at 48kHz?

[bfdtv]

Or is it 24 bit sound at 48kHz?24-bit @ 48khz

Most current TrueHD tracks are 16-bit @ 48khz, due to the way films are muxed now. With improvements coming to the encoder and mux tools, all TrueHD titles should be 24/48 in the not-too-distant future.

[FilmMixer]

Most of the 24/48 DTS-HD MA releases may be sourced from actual 24/48 masters. There was a discussion earlier -- unfortunately I no longer have the link -- where an insider noted that one of the first announced movies with 24/48 DTS-HD didn't have a master with that fidelity.

You have to be very careful, then, in saying that "several announced titles..." You don't really have any concrete information to back that up, and it is frankly worng.. As I said, I don't know one mixer, or one mix stage in town that is mixing in 20bit... it doesn't happen... I personally know the mixers of almost all of the Fox films that are coming out in the initial wave, so I do know of what I speak... if you can't point out exactly where you are getting this information, you shouldn't be stating this as fact ;)

Most current TrueHD tracks are 16-bit @ 48khz, due to the way films are muxed now. With improvements coming to the encoder and mux tools, all TrueHD titles should be 24/48 in the not-too-distant future.

Source? I don't do encoding or work with the tools, but common sense says that the 50% data savings in using 16 rather than 24 bit would be the reason... but as I said, I am no expert on this part of the process. It takes effort to make a 24 bit master 16 bit properly, and if this were true it would surprise me.. all of Dolby's encoding tools in the past have done an amazing job of bit scaling... just curious.

[bfdtv]

Film,

I'm sure you don't bookmark every little piece of information you read However, the fact remains that any title with content >16/48 must be upsampled to 24/48 for the current DTS-HD encoder. I am confident in my statement that at least one of the upcoming Fox 24/48 releases is upsampled from something less; I would not have mentioned it otherwise. I am not going to spend my time searching for a link, however, so you can choose to believe what you want.

Source?Source is Dolby and discussions in the Insiders thread. See references to dynamic muxing. Amir has posted several times on the issue. Here's his latest post:Well, actually, that brings up a question. Does TrueHD, DTS MA, and PCM all share the same bandwidth requirements?They do but they are not supposed to . Today, the authoring work flow involves allocating bandwidth in advance for absolute worst case scenario for the entire length of the movie. As such, the slot allocated [to audio] is for the pathological cases, rather than actual bandwidth needed (which can be as low as 4 times less than PCM per Dolby documentation for 5.1 content). As you climb up from 48Khz sampling rate, such allocation becomes even more wasteful as there is little audible data above human hearing range.

We hope to get around this in the future as we better integrate our tools with that of other companies.For muxing purposes, the current tools assume that a 16/48 TrueHD track requires ~3.0 Mbps at all times, even though the ABR is less than half that. A 24/48 TrueHD track requires ~3.4 Mbps ABR.

In the Insiders thread, it's also been said that Microsoft's VC-1 tools will soon support secondary video streams (IME), which will reduce peak bandwidth on that MPEG-2 content by 60-75%. That will create another 1.5-2.5Mbps, depending on the title.

Nothing has been said about when we can expect these tools, or when we will see disks authored with these tools. Predictions and expectations from insiders are still predictions and expectations, and until studios have these tools and are using them, I doubt we will see 24/48 TrueHD releases on HD-DVD.

[FilmMixer]

Film,

I'm sure you don't bookmark every little piece of information you read However, the fact remains that any title with content >16/48 must be upsampled to 24/48 for the current DTS-HD encoder. I am confident in my statement that at least one of the upcoming Fox 24/48 releases is upsampled from something less; I would not have mentioned it otherwise. I am not going to spend my time searching for a link, however, so you can choose to believe what you want.

I understand that... but I want to point out again that "something you read somewhere on an AVS thread that is true to your recollection" is not fact... it is your recollection, and not authoritative information...

Your other quote from the insiders threat has nothing to do with bit depth... it has to do with sample rate... two completely different things.. Upping the sample rate is seen to some as wasteful... and while it is ture that there is nothing audible in these upper frequencies, many proponents of higher sampling rate feel that the greater resolution reduces sideband harmonics induced when sampling...

That being said, I think if I am understanding you correctly, that becuase all of the processes are unaware of the other bandwidth requirements for other areas (audio, video, secondary streams, etc) it is very difficult to allocate so much data to the audio streams with the current state of encoding tools.... so I think we are both correct in our statements.... 24/48 will come later when bandwidth can be better, more wisely allocated to a project...

I think I misunderstood your oriignal comment to say that the Dolby encoders didn't support the higher bith depth at the current time

I hope you don't feel that I am picking on you.. I just think it is dangerous when you state something as fact without first hand knowledge or experience.... I am enjoying the conversation with you :)

[HiFiGuy1]

My take on this thread is that I am very excited about the future of HD DVD. When these new dynamic allocation tools are brought to bear on real movies, can you imagine the audio and video quality that we will be experiencing? It is fantastic to contemplate. Already there are reportedly gains from the initial VC-1 encoder used, for example, on Serenity, and the re-release that is coming out in Europe. I almost want to buy the new disc just to see the improvements. Frankly, I was pretty impressed with the first iteration. Word is that the second one is significantly improved. Unbelievable! Combine that with lossless TrueHD or DTS-HD Master Audio sourced from 24 bit masters. Yowza!!

[BuGsArEtAsTy]

I note that disc releases generally continue to be DD+ on HD DVD, and DD5.1 on Blu-ray (if lossless codecs are not used).

We're told that DD+ is usually 640 Kbps on HD DVD. I see from the Dolby Digital wiki (http://en.wikipedia.org/wiki/Dolby_Digital#Dolby_Technologies_in_packaged_media_formats) that max DD5.1 output is 640 Kbps on Blu-ray as well (compared to 448 on HD DVD). However, it was my understanding that many DD5.1 receivers cannot deal with 640 Kbps DD5.1. Is that correct?

Are most Blu-ray DD5.1 tracks 448 Kbps or 640?

I also see from the wiki that max DD+ bitrates are 3 Mbps on HD DVD (mandatory) and 1.7 Mbps on Blu-ray (optional). However, that bitrate difference seems irrelevant to me.

Also, the Xbox 360 will compress TrueHD to DD5.1 (http://www.avsforum.com/avs-vb/showthread.php?p=8733314&&#post8733314). This site says 640 Kbps (http://experts.about.com/e/d/do/dolby_digital.htm). Kinda surprised me, since some older DD receivers IIRC cannot process DD at bitrates that high. I guess it's not a major issue though, since we haven't heard many complaints about it.

[FilmMixer]

I note that disc releases generally continue to be DD+ on HD DVD, and DD5.1 on Blu-ray (if lossless codecs are not used).

We're told that DD+ is usually 640 Kbps on HD DVD. I see from the Dolby Digital wiki (http://en.wikipedia.org/wiki/Dolby_Digital#Dolby_Technologies_in_packaged_media_formats) that max DD5.1 output is 640 Kbps on Blu-ray as well (compared to 448 on HD DVD). However, it was my understanding that many DD5.1 receivers cannot deal with 640 Kbps DD5.1. Is that correct?

Are most Blu-ray DD5.1 tracks 448 Kbps or 640?

I also see from the wiki that max DD+ bitrates are 3 Mbps on HD DVD (mandatory) and 1.7 Mbps on Blu-ray (optional). However, that bitrate difference seems irrelevant to me.

Also, the Xbox 360 will compress TrueHD to DD5.1 (http://www.avsforum.com/avs-vb/showthread.php?p=8733314&&#post8733314). This site says 640 Kbps (http://experts.about.com/e/d/do/dolby_digital.htm). Kinda surprised me, since some older DD receivers IIRC cannot process DD at bitrates that high.

Most of the Paramount and Universal titles have been at 1.5....

All DD decoders must be able to process 640kpbs.. it was the DVD players that were not always passing out that signal, as the max "official" spec for regular DVD DD was 448.

[BuGsArEtAsTy]

Most of the Paramount titles have been at 1.5..
For DD Plus or average bitrate of TrueHD?

All DD decoders must be able to process 640kpbs.. it was the DVD players that were not always passing out that signal, as the max "official" spec for regular DVD DD was 448.
Yes, but I just remember when the first 640 Kbps test tracks were released for testing in the early days of DD, all sorts of receivers weren't working properly with them, including expensive ones.

I don't know if it was something wonky with the test tracks, or bugs in the receivers, but I guess everything got sorted out quickly. I'm showing my home theatre age... ;)

[BuGsArEtAsTy]

Thanks. OK then:

21 Mbps peak VC1 (12 Mbps avg)
3.0 Mbps peak TrueHD English (1.5 Mbps avg)
1.92 Mbps peak DD+ Spanish, French, Inuktitut <-- We don't need another English track do we?
0.256 Kbps commentary <-- Why that high? Just cuz you can?
3.5 Mbps IME
----------------
Total 29.7 Mbps (19.2 mbps avg)

Maximum total bitrate is 30.24 Mbps so that's OK.

Let's give the average bitrate a bit of leeway and call it 20 Mbps. That's 2.5 MB/s, or 150 MB per minute, or 30000 MB for 200 minutes.

Thus, I predict the 3 hour and 8 minute long King Kong (2005) is going to be reference video quality.

It doesn't have a TrueHD track, but 3 Dolby Digital Plus 5.1 tracks is pretty good. I don't think it has much in the way of extras, but I think they might have been able to put on some 480p ones on it if they had really wanted. However, that will come with a re-release later, to make us open our pockets yet again.
I am so looking forward to looking at King Kong. It is now shipping (with the 360 HD DVD drive.) I hope to receive it within the week.

If indeed it is reference level video, then that should silence most of the critics. It would have been nice to have one DD+ track as the primary, but that's OK.

[BuGsArEtAsTy]

So far so good. (http://www.avsforum.com/avs-vb/showthread.php?p=8852143&&#post8852143)

"some scenes in King Kong are the best I have ever seen, but overall MI:3 is probably the one of the best pq HD DVD's I have watched so far."

[jayselle]

Gone in 60 seconds on BR is 48/24 ;)

what I have heard so far on HD-DVD in regards to True-Hd is to be honest not much :(, no tracks I have listened to so far have been any improvement over DD+, maybe a 5% increase if that, not even noticeable to those but the pickiest of AV freaks and at that it is mighty slim, my audio setup is:

Boston Acoustics AVP7
Atlantic Technology A-2000
Atlantic Technology System 370 THX with dual subs
Velodyne SMS-1
Zektor HDS4.1 for switching between BR, HD, SACD and DVD-Audio
Toshiba connected via Analog

EQ, tweaked and calibrated to perfection with treated room and TrueHD is nothing all that special, as a audio freak that is sad, I have a feeling it is the 48/16 masters being used, we need some real HD audio ;)

I mean I am glad for the TrueHD we have, but those who haven't heard it and are expecting worlds of improvement are gonna be dissapointed

-Gary

If you can't hear the difference between DD+ and TrueHD with V for Vendetta or Batman Begins then you must have hearing problems.

I can tell a noticeable difference especially in V. Judging from other responses in this forum I am not alone. Might want to check that you have the audio setup properly on the receiver and that the receiver is outputting it correctly.

But it's obvious you are making a BD plug here.

[BuGsArEtAsTy]

Thanks. OK then:

21 Mbps peak VC1 (12 Mbps avg)
3.0 Mbps peak TrueHD English (1.5 Mbps avg)
1.92 Mbps peak DD+ Spanish, French, Inuktitut <-- We don't need another English track do we?
0.256 Kbps commentary <-- Why that high? Just cuz you can?
3.5 Mbps IME
----------------
Total 29.7 Mbps (19.2 mbps avg)

Maximum total bitrate is 30.24 Mbps so that's OK.

Let's give the average bitrate a bit of leeway and call it 20 Mbps. That's 2.5 MB/s, or 150 MB per minute, or 30000 MB for 200 minutes.

Thus, I predict the 3 hour and 8 minute long King Kong (2005) is going to be reference video quality.

It doesn't have a TrueHD track, but 3 Dolby Digital Plus 5.1 tracks is pretty good. I don't think it has much in the way of extras, but I think they might have been able to put on some 480p ones on it if they had really wanted. However, that will come with a re-release later, to make us open our pockets yet again.
OK, what about the extended version of Lord of the Rings: The Return of the King?

21 Mbps peak VC1 (12 Mbps avg)
No TrueHD
1.92 Mbps peak DD+ Spanish, French, English
0.256 Kbps commentary
3.5 Mbps IME
----------------
Total 26.7 Mbps (17.7 mbps avg)

Let's give the average bitrate a bit of leeway and call it 18 Mbps. That's 2.25 MB/s, or 135 MB per minute, or 33750 MB for 250 minutes.

No good, unless they used DL34. :( Let's try again:

21 Mbps peak VC1 (12 Mbps avg)
No TrueHD
1.92 Mbps peak DD+ Spanish, French, English
0.256 Kbps commentary
1.8 Mbps VC-1 IME
----------------
Total 25 Mbps (16.0 mbps avg)

That's 2 MB/s, or 120 MB per minute, or 30000 MB for 250 minutes. So, to make the above really fit considering overhead, etc, one would need to drop the video bitrate even further, drop an audio track, or drop the PiP IME feature.

To put it another way, LOTR: TROTK would fit on HD30 only if the total average bitrate were less than 16 Mbps, with minimal extras. HD34 would be an advantage, since one could bump up the bitrate to 18 Mbps total. (BTW, other extras would go on a second disc.) TL51 remains unnecessary, unless you want to include multiple TrueHD tracks and more extras on the same disc. The other option of course is TL45, which requires no increase in data density, but needs the 3rd layer.

[BuGsArEtAsTy]

If we bump the videobitrate up by 3 Mbps:

24 Mbps peak VC1 (15 Mbps avg)
No TrueHD
1.92 peak DD+ Spanish, French, English
0.256 Kbps commentary
1.8 Mbps VC-1 IME
----------------
Total 28 Mbps (19.0 mbps avg)

19 Mbps = 2.375 MB/s = 142.5 MB/min

Divide that into 30000 MB and add in a little overhead, and one gets somewhere between 3 to 3.5 hours worth of video on HD30.

So, movies like Kong are no problem, as we've seen by its reference-level video quality on its official release.

23 Mbps peak VC1 (14 Mbps avg)
No TrueHD
1.92 peak DD+ Spanish, French, English
0.256 Kbps commentary
1.8 Mbps VC-1 IME
----------------
Total 27 Mbps (18.0 mbps avg)

18 Mbps = 2.25 MB/s = 135 MB/min = 222 minutes. Just to reiterate, it seems LOTR:ROTK can reasonably be achieved on HD34 (17 GB per layer) even with U-control and an average 14 Mbps bitrate. However, all of the above calculations require the elimination of TrueHD.

EDIT:

benes says DD+ audio tracks are often 1536 Kbps and 768 Kbps. And it's 32 Kbps for the subs. So:

23 Mbps peak VC1 (14 Mbps avg)
No TrueHD
3.072 DD+ Spanish, French, English
0.256 Kbps commentary
0.96 subtitles x 3
1.8 Mbps VC-1 IME
-----------------------

29.1 Mbps peak, 20.1 Mbps average. (I note that the audio tracks could be VBR and less than 3 Mbps average, but I'm not factoring that in right now.)

Thus, one might guess that for an average movie, 20 Mbps (150 MB/min) for everything (except TrueHD) gives lots of headroom, which means that anything under 200 minutes should be OK.