Why not Dolby Digital Plus standard on BDs?

[HD-Greek]

I was wondering why Warner and other studios don't put Dolby Digital Plus instead of Dolby Digital in blu-ray movies.....for example.....all Warner's hd-dvds have Dolby Digital Plus but their blu-rays only Dolby Digital......

[sega_smasher]

[darkedgex]

Because Dolby Digital Plus isn't mandatory on BD hardware, and because of this, a Dolby Digital track will always be needed in addition to the Dolby Digital Plus track. Since the classic DD track would likely be 640kbps, and the DD Plus track would likely be > 1mbps, it makes more sense to include a lossless track (Dolby TrueHD or, better still, DTS HD Master Audio).

[Crackbone]

Because the spec for Dolby Digital is different in the BD standard. BD can handle up to 640kbps DD. If HD DVD were to ramp up to that bitrate on a release, it would have to be DD+. HD DVD can't handle that high of a bitrate under DD.

[foots]

Because it isn't needed (at least for 5.1):

Originally Posted by From Roger Dressler of Dolby Labs:

Due to the way HD DVD structures audio data in packets, the only way to offer advanced capabilities--higher quality sound and option for more channels--was to adopt a different codec than DD, which was locked at 5.1 and 448 kbps, same as DVD. DD+ was specifically designed to address HD DVD's structure--the DD+ coding frames become progressively shorter (from 6 to 3 or 2) to allow more of them to pass thru the framing structure in a given time, thereby raising the data thruput.

Blu-ray, on the other hand, has no such packet constraint. That allows DD to be used in its full 6-block frame for maximum coding efficiency (efficiency drops slightly as the frame size is reduced), and to use its full 640 kbps capability for the very first time on optical media, thereby bringing higher quality.

If you look at the DD+ structure when delivering a 7.1 program (someday), you will see a 2-frame pairing. The first frame is the usual complete 5.1 mix. The second frame has the new channels for the 7.1 mix. The second frame also has all the new metadata and channel management DD+ info needed to control the overall reconstruction process. This explanation is identical for HD DVD and BD. The only difference is that both frames in HD DVD are DD+ because they must have a shorter frame duration, whereas in BD the first frame is standard DD because it does not have to be shorter. Both frames in the BD pair are full 6-blocks, highest efficiency mode.

Furthermore, while HD DVD discs generally do not let you stream the DD+ to an output without going thru the mixer (and yes, the Toshiba player has the DD+ to DD640 converter, FWIW), BD does allow that option. So you have a chance to get the 640 DD stream right off the disc and into your AVR via S/PDIF. One might prefer that option to DD+ transcoded to DTS.

Given distinctly different circumstances, Dolby was able to adapt its coding technologies to bring improved quality and more channels to both formats. The goal was not to make the end results different, but the same in spite of the situation.

[Luis_A51]

Originally Posted by darkedgex

Because Dolby Digital Plus isn't mandatory on BD hardware, and because of this, a Dolby Digital track will always be needed in addition to the Dolby Digital Plus track. Since the classic DD track would likely be 640kbps, and the DD Plus track would likely be > 1mbps, it makes more sense to include a lossless track (Dolby TrueHD or, better still, DTS HD Master Audio).

There is no "better still" between Dolby TrueHD and DTS-MA, They're supposed to be identical.

People should stop assuming that the differences between DD and DTS carry over to TrueHD vs DTS-MA.

[ryoohki]

Originally Posted by Luis_A51

There is no "better still" between Dolby TrueHD and DTS-MA, They're supposed to be identical.

People should stop assuming that the differences between DD and DTS carry over to TrueHD vs DTS-MA.

Well there is in a sense that with TrueHD you can a DD5.1 640kbps in 16bits core and DTS HD MA you get a DTS 1.5mbits in 24bits.. but that's it.

[darkedgex]

Originally Posted by Luis_A51

There is no "better still" between Dolby TrueHD and DTS-MA, They're supposed to be identical.

People should stop assuming that the differences between DD and DTS carry over to TrueHD vs DTS-MA.

I'm not assuming anything. Maybe you should stop assuming there is no difference.

• DTS HD Master Audio contains a backwards compatible DTS core of up to 1.5 mbps (better compatibility with older hardware).
• DTS HD Master Audio uses less space than Dolby TrueHD, leaving more room for longer video content, extras, or additional subtitles/audio tracks.
• DTS HD Master Audio does not have dialog normalization or any other potentially audio modifying meta-data.

Really, the first two issues are the ones that matter most to me personally (with space usage being the biggest concern I have), but yes, there are indeed differences even if the end result (what comes out of our speakers) is largely the same.

[Rob Zuber]

Read the comments above from Roger Dressler. FYI, Dolby Digital on Blu-ray generally has a higher bitrate than on DVD. It's not the "old DVD DD".

[Alan Gordon]

Originally Posted by HD-Greek

I was wondering why Warner and other studios don't put Dolby Digital Plus instead of Dolby Digital in blu-ray movies.....for example.....all Warner's hd-dvds have Dolby Digital Plus but their blu-rays only Dolby Digital......

First of all... Warner Bros. Blu-rays with Dolby Digital on them have a bit-rate of 640k, and though Warner Bros. HD DVDs have Dolby Digital Plus on them, the bit-rate is 640k... so there really isn't a difference.

NOW, Paramount Blu-ray movies with Dolby Digital have a 640k bit-rate on them, but their HD DVDs with Dolby Digital Plus have a bit-rate of 1.5 mbps, so Paramount's Blu-ray are inferior to their HD DVD version, but they were going to change that right before they went HD DVD exclusive.

Universal's HD DVD titles with Dolby Digital Plus also have 1.5 mbps bit-rate.

~Alan

[MatrixS2000]

Originally Posted by HD-Greek

I was wondering why Warner and other studios don't put Dolby Digital Plus instead of Dolby Digital in blu-ray movies.....for example.....all Warner's hd-dvds have Dolby Digital Plus but their blu-rays only Dolby Digital......

I would be more concerned about why a lossless codec is not the standard....

[jcs913]

Originally Posted by darkedgex

I'm not assuming anything. Maybe you should stop assuming there is no difference.

• DTS HD Master Audio contains a backwards compatible DTS core of up to 1.5 mbps (better compatibility with older hardware).
• DTS HD Master Audio uses less space than Dolby TrueHD, leaving more room for longer video content, extras, or additional subtitles/audio tracks.
• DTS HD Master Audio does not have dialog normalization or any other potentially audio modifying meta-data.

Really, the first two issues are the ones that matter most to me personally (with space usage being the biggest concern I have), but yes, there are indeed differences even if the end result (what comes out of our speakers) is largely the same.

Actually, dial norm is applied to DTS-HDMA tracks and TrueHD tracks. Typical DTS-HDMA tracks have a much higher bitrate, some to 13mbps, so they actually take up more space than most TrueHD tracks. There is a space issue, but Fox still uses it very effectively. I wish more studios would use DTS more. Its soundstage is much more prominent than TrueHD, I think.

[krazeyeyez]

ok so i know you need a player capable of output and a receiver that can decode for the true hd/ ma tracks but...... what do you need for just pcm lossless? im looking to cover all my bases on my new stereo so in the future i can play the "lossless" formats. all 3 if i understand this stuff correctly.

[Lord_Phan]

Originally Posted by krazeyeyez

ok so i know you need a player capable of output and a receiver that can decode for the true hd/ ma tracks but...... what do you need for just pcm lossless? im looking to cover all my bases on my new stereo so in the future i can play the "lossless" formats. all 3 if i understand this stuff correctly.

PCM is what they get decoded into. If it's a 5.1 LPCM track, it just means it hasn't been compressed into TrueHD or DTS-HD, ie: it dosn't need to be decoded. You can send it straight through to your receiver with either an HDMI cable(that the receiver uses for audio) or Multichannel Analog.