How come I see lots of HD-DVD's with DD+ audio tracks but no DD+ on Blu-Ray? Don't get me wrong, I'm happy everytime I see a Blu-Ray title with a LPCM, True HD or DTS-MA audio track. But I'd at least like to see DD+ audio in lieu of the titles that only put a DD audio track on the BRD. DD+ doesn't take that much more space of DD, right.

Josh Z just had a very in-depth article posted at HDD on next-gen audio:

http://www.highdefdigest.com/news/sh...Explained/1064

Quoting relevant part:

So if a WB HD DVD has a 640Kbps DD+ track, the Blu-Ray with a 640Kbps DD track *should* be near identical.

Obviously if the HD DVD has a 1.5Mbps DD+, that should be better than a 640Kbps DD track on the Blu-Ray.

I guess I was assuming that DD meant 640 kbps and DD+ meant 1.5 mbps.

It does usually, except for any WB title.

Anyway I think it's because DD+ decoding isn't a requirement for BR players, so there's no guarantee that a player can handle it.

It depends on the title.

Many of HDD's reviews list the rate on the DD+ track. For instance, I just looked at the reviews for Alexander: Final Cut and Wyatt Earp on HD DVD, and both say 640.

I'm not sure how they know unless it comes from press release. To my knowledge they don't put this info on the back of the case.

Interesting... Excuse my extreme lack of knowledge in this matter, but what is the difference in a 640kbps DD+ track and 640kbps DD track then?

There are some technical differences in how they're encoded, but audibly the two should be identical at that rate.

DD+, however, can go up to 1509 kb/s, while standard Dolby Digital can't.

DD+ doesn't seem to be much different than DD, and I'm not sure what they do to "improve" the audio before making it +. But I doubt it's much, since even the extras show up as DD+ on my Toshiba players display. And I mean deleted scenes with bad audio (stereo or mono) & video are still in DD+. So it doesn't seem like it has to meet any quality standard, they just boost the bitrate. DTS tracks sound better than DD+ (Riddick comes to mind). And it seems like most HD-DVDs use a lower bitrate on the TrueHD tracks as well (probably because of space). Where PCM tracks are 4.6Mbps or 6.9Mbps (24-bit), most TrueHD tracks peak around 3.5mbps. And Blurays with both (Ghost Rider & 300), the PCM has more volume & just sounds better. But the Sony exclusive TrueHD tracks actually are as high as the PCM- Surf's Up goes up to 4.6Mbps at least. And the NIN concert goes into the 5s. So while they say the 20 extra GBs on Bluray are unnecessary, they're really not. They allow for higher bitrates on the audio & video (28 Weeks Later's video is a whopping 37Mbps). That's why a movie as long as Transformers can't have lossless sound on HD-DVD.

That is a trick, don't be fooled. You need to compare on relevant issues.

The reason is because DD+ is an optional codec on BD players but mandatory on HD DVD.

Just because it "has more volume" does not make it sound any better. Look at why a lot of people like DTS over DD. It is mastered at a higher volume level and thus "sounds better" to some. Don't get me wrong, DTS most of the time sounds better than DD, but it is not because it is louder, it's because of how it is encoded and mastered.

I'd like to know this as well. Reviewers - how do you know what the DD+ bit rate is?

Not to derail the thread but I'm actually more curious why Dolby TrueHD and DD+ tracks are usually both featured on the same HD DVD. Aren't both codecs mandatory on HD DVD? If so, why not only feature a TrueHD tracks of the film's main audio and omit a DD+ track of the same?

I mean, I understood the DD and DTS issue oon DVD given that PCM and DD were mandatory whereas DTS was not. That's why a DVD with DTS also had to have a DD or PCM track. But in the case of HD DVD, it's pointless to have a DD+ track if you're already going include a TrueHD track.

The HD DVD spec only requires TrueHD decoding at a minimum of 2 channels. That's how the HD-A1 and HD-XA1 started out, until they were later upgraded to 5.1 decoding. The LG combi player still only has 2.0 decoding of TrueHD.

Because of this, most studios include a DD+ track as well just to be sure that all viewers can listen to the soundtrack in 5.1.

Warner discs use a 640 kb/s bit rate for DD+. Paramount and Universal (usually) use 1509 kb/s.

Warner has always been conservative in their audio specs. For many years, their DD 5.1 tracks on DVD were encoded at 384 kb/s even though everyone else in the industry used 448 kb/s. They didn't switch to 448 until The Matrix Reloaded. The studio has also rarely offered DTS on their discs.

Didn't Warner only do about 6 or 7 titles with DTS?

4 WB titles I remember: Twister, Interview With a Vampire, Lethal Weapon (Dir Cut), Lethal Weapon 2 (Dir Cut)

2 WB/Morgan Creek titles: Robin Hood: Prince of Thieves, True Romance

I don't cont New Line, they work on their own pretty much...

fitprod

That's about all I could think of too, except Lethal Weapon 3 was also given the Director's Cut/DTS treatment.

I knew I missed one... I just couldn't remember it. It's not like it's part of a series...


fitprod

Ah, I see. Thanks for clearing that up for me, Josh Z.

So to the 2 that said just volume isn't better, you're saying that PCM tracks aren't the best out there right now? Do you have a Bluray player & HDMI receiver? It's the highest bitrate uncompressed audio on either HD formats. And the 24-bit 6,9 Mbps tracks are double the bitrate of almost any TrueHD. Hell, Purple Rain fluctuates from 1.7-2.4, and they call that TrueHD? And pretty much every review prefers the PCM tracks over any other. To say that PCM is just louder is ignorant. IF a TrueHd track is mastered at the same bitrate (Surf's Up, 5th Elemant- notice both Sony), they do sound practically identical & the same volume level. But since most only use about 1/2 to 2/3 the bitrate, they do not sound as loud or as good. The main reason I prefer Bluray is the PCM audio.

And who was saying that TrueHD is mandatory on HD-DVDs? I wish. It's more like 1/10 & that's better than before. And the thing is they usually pick strange movies to give them to. Hot Fuzz & Bourne-no, Notting Hill & Darkman- yes?

True HD decoding is required on all HD DVD hardware up to 2.0. Anything beyond 2.0 is optional. That's what people meant about True HD being obligatory.

As for the rest of your post, you are correct that sample rates and such do make a difference with the audio, but you kind of defeated your own argument when you mentioned that similarly sampled tracks sound the same. What you're really complaining about is the use of lower bitrate audio, regardless of the name. And even then I'd say a well mastered track with a good mix and no audible distortion is a good mix regardless of the bitrate or what they call it.

It's the only uncompressed audio format on either HD disc format.

Yes, that's kinda the point of TrueHD: to have the same audio quality of uncompressed audio, but losslessly compressed to a lower bitrate. Therefore, bitrate doesn't matter: what's important is that the TrueHD track has the same sample rate and sample-depth as the PCM track it's compared to.

Neither Spiky nor steebo777 claimed that PCM tracks are "just louder." They were countering your claim that PCM tracks are better because they're louder, which isn't true. A PCM track could still be better than TrueHD, but only if you're looking at what Spiky called the "relevant issues," the mixing of the track and the sample rate and depth.

Neither of those TrueHD tracks have the same bitrate.

From:
http://bluray.highdefdigest.com/fift...emastered.html
"This new edition [has a] PCM 5.1 surround track (48kHz/16-bit/4.6mbps) [and] a new Dolby TrueHD option, which enjoys a slightly boosted encode of 48kHz/20-bit (note that TrueHD is a variable bitrate format, so there is no set bitrate to report)."

http://bluray.highdefdigest.com/1025/surfsup.html
"Sony provides both an uncompressed PCM (48kHz/16-bit) and a Dolby TrueHD 5.1 (48kHz/24-bit) surround track for 'Surf's Up.'"

So the bitrates aren't the same, and the sample depths aren't the same. The TrueHD tracks on these discs deliver lossless audio at a superior sample depth and lower bitrate.

The whole point of using compression is to reduce the bit rate. Here is a very simplified example of how lossless compression works:

If the original studio master reads:

0110011100001

An uncompressed PCM track will read:

0110011100001

Meanwhile, a lossless TrueHD or DTS-HD MA track will be encoded with:

_11__111____1

The blank spaces contain flags that tell the decoder to populate them with 0s. Hence, once decoded, the final output looks like:

0110011100001

You get the exact same end results at a fraction of the disc space.

Suppose a movie had 1 hour of audio and 1 hour of complete dead silence. A PCM track would have to encode bits for every second of that silence, but a TrueHD track would conserve the space by only encoding the bits that actually create audio.

To say that PCM is "better" than TrueHD for no other reason that that it has a higher bit rate is purely ignorant.

Thank you.

Kabong,
Try to keep straight what YOU write vs what OTHERS write.