Thread: DTS vs DD vs SACD vs DVD-A

Posts: 4

Post by Borchgrevink September 25, 2003 (1 of 4)
Can someone help me with the technical details for these formats? (thinking of kbps, bit etc)

Thanks

Christian

Post by Dinko September 25, 2003 (2 of 4)

Post by sound_labs September 30, 2003 (3 of 4)
Borchgrevink said:

Can someone help me with the technical details for these formats? (thinking of kbps, bit etc)

Thanks

Christian

Well, I can't give every detail here without punching up some 20,000 word "white paper" but Dolby digital and DTS should be lumped together, and SACD and DVD-A should be separate even though they aren't even remotely related, except for their actual intended purpose.

DD and DTS do the same thing in slightly different ways. The term dolby digital is a very broad one. That term on a DVD can mean anything from a mono track, all the way up to a 6.1 EX (matrixed) soundtrack, running at the 448K rate. The most popular bit rates for DD are the 348K? and the 448K, I could be wrong on the number a bit, but my memory seems to recall those numbers.

I've heard rumors that DD supports another 667K (or in that ballpark) but I've never seen a disk that uses that higher bit rate. DTS in truth really isn't that different, like DD, DTS uses similar tricks to pack all the info at high quality onto a DVD. DTS has the advantage of using two higher bit rates. One maxes out at around 754K the other runs at 1.5mb or 1500k. The 1.5mb rate is rare, but if memory serves me correctly, the Sheryl Crow Globe Sessions DVD runs at the max rate. Every other dts disc I own runs at the 700k rate.

Some claim people can't hear the dif between DD and DTS, both camps take shots at each others' weaknesses. And they both have them. I favor DTS for only one reason, I will always choose a higher bit rate, regardless of what it's called. All things being equal, a codec running at a higher bit rate will tend to throw away less essential data. So regardless of the fact that I might or might not hear it, I'm a DTS guy when that option exists.


SACD and DVD-A, now there is a whole other mess. When comparing the two, we are really comparing PCM running at a broad range of rates, maxing out at 24/192K in stereo, and 24/96K for multi-channel. MLP (Meridian lossless packing) is often used to compare to DSD, but MLP isn't really "DVD-A" but a method to pack the info onto the disc, and then retrieve it with bit for bit accuracy. DVD-A is really CD on crack, it's really the same method used for CD, but at higher bit rates, and sampling rates. The max data rate is still tied to DVD video, and that max is 9.1 Mb give or take.


When talking about SACD, we are really talking about DSD or direct stream digital. SACD has another method similar to MLP to actually pack the data, DST or Direct Stream Transfer. Like MLP, Sony and Philips claim that this is a lossless packing method for the DSD codec.

Now this is where things get a little fuzzy. While SACD uses DVD for the media, the max bit rate isn't floating around out there so far as I can tell. If Sony and Philips saved some money in the R&D, it's safe to say that the max bit rate for SACD is similar to the 9.1Mb rate. But since SACD doesn't use the 'fold down' method to hold stereo tracks and multi-channel tracks as DVD-A does, the bit rate COULD be lower than DVD-A in theory for a single layer SACD with both stereo and multi-channel tracks.

But, because the the codecs (PCM vs. DSD one bit) are so totally different, comparing raw data rates starts to lose meaning. For example, some could argue that a DSD multi-channel stream running at say 5mb per second sounds just as good or better than a DVD-A stream running at 7mb, and vice versa.

These arguements could go on and on, and until identical albums are available in both SACD, and DVD-A, and someone sets up blind tests with identical equipment, the arguements will go on. And even if a test was done, and one format came out on top without any doubt, I'm sure the debates would continue.

I chose SACD before I even purchased my first player. I liked the idea that SACD used DSD to break away from the CD's and DVD-A PCM. So now on my second SACD player, I'm happy with the sound. I've heard DVD-A and it sounds fantastic, but not having a player, I haven't sat down a long time with it. I'm no DVD-A hater, but I've chosen my format, I'm happy with it, and I'm in it for the long haul. And I almost forgot about SACD II, some people are saying some really weird things about it. It's not a new format, and everything mentioned in the SACD II statements so far were mentioned back in 1999. All are things that were in the original specs, and would come to light at some later date. Those new features are things like lyrics, video, and still pictures that DVD-A makes use of now. The only new addition was the mention of stronger encryption methods. I'm sure that includes changes to the digital water mark and such.

I hope I've shed some light on your questions. And I hope (crossing fingers) that I remembered all of my facts correctly, if I slipped somewhere, I'm sure someone will point it out!

- Tony



http://www.epinions.com/user-sslabs

Post by tony October 3, 2003 (4 of 4)
DD and DTS do the same thing in slightly different ways. The term dolby digital is a very broad one. That term on a DVD can mean anything from a mono track, all the way up to a 6.1 EX (matrixed) soundtrack, running at the 448K rate. The most popular bit rates for DD are the 348K? and the 448K, I could be wrong on the number a bit, but my memory seems to recall those numbers.

I've heard rumors that DD supports another 667K (or in that ballpark) but I've never seen a disk that uses that higher bit rate. DTS in truth really isn't that different, like DD, DTS uses similar tricks to pack all the info at high quality onto a DVD. DTS has the advantage of using two higher bit rates. One maxes out at around 754K the other runs at 1.5mb or 1500k. The 1.5mb rate is rare, but if memory serves me correctly, the Sheryl Crow Globe Sessions DVD runs at the max rate. Every other dts disc I own runs at the 700k rate.

I would STRONGLY disagree that DTS sounds the same or as good as DD. DD is pretty crap (dull, lifeless, no detail…), however DTS is much better in both movie and audio tracks, so if you have a choice between a DTS version of a movie and DD (and you have the appropriate decoder) pay the extra for DTS. In fact I have been repurchasing some DVDs to get the DTS format, which is sad because the DTS layer has always been available, the movie people are just shafting me. Although this information (my post) is relatively useless because this is an SACD site...

I have a £300 (Yamaha 630) amp DD/DTS/6.1 and £300 (Pioneer 656) DVD/SACD/DVDA player and I have found (very unscientifically) that SACD is slightly better (clearer details on a mixture of music) than DVDA, then DTS (struggles with lots of information) then poor DD (which just struggles). You also have PCM CD music which is somewhere in between and my DVD player even plays MP3 which are completely shite (even at 320kbps).

I think most people will agree that SACD does outshine DVDA in all areas? If that’s what the original poster was looking for.

Cheers
Another Tony

P.S The reason i put the prices in, was to establish that even a cheap[er] amp/dvd you can notice significant differences in deatil.

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