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Difference DTS-HD versus AC3

post #1 of 24
Thread Starter 
For an average home theater system, whatever 'average' is - but not super high-end speakers/amp, is there much of a difference you can hear between True-HD and DTS-HD soundtracks versus AC3 at 640kbit?

I know the audiophiles will say so, but for your average person, with middle-of-the line audio equipment, is there much difference?
post #2 of 24
Read the following article thoroughly:

http://www.hemagazine.com/node/Dolby...compressed_PCM

They originally set out to compare the new lossless packing codecs (TrueHD, DTS-HD MA) to the uncompressed PCM original. As you can guess, there was no difference.

While at the Dolby and DTS facilities, the authors decided to compare the new hi-rez lossy codecs (DD+, DTS-HD HRA) and legacy lossy codecs (DD, DTS) to the uncompressed originals.

You might be surprised how close the legacy codecs sounded to the uncompressed original, especially on Blu-ray where they run at their highest bitrate (DD @ 640kbps, DTS @ 1.5Mbps).
post #3 of 24
Thread Starter 
That doesn't surprise me. Just confirms my original hunch.

The reason I ask is because I'm streaming movies to a PS3. I greatly prefer the Tversity media server but its doesn't easily play MKV files without a bunch of messing with it. Playes m2ts just fine. I've found that I can take a PCM or HD soundtrack and compress it to FLAC lossless without losing anything but you can't mux it into an m2ts, only MKV. So I have to convert to DD 640kbit to use an m2ts container. Bottom line, if I want to watch something like Polar Express once a year at Xmas, I'll get out my Blu-Ray and pop it in. But other times I want the kids (and I) to play movies without risking scratches in the disc. They've destroyed too many already. It's like the though if we have 50GB of storage, we might as well use it.


I've been surprised how small you can compress 1080P movies with virtually no loss in picture quality. It has made me wonder why is a 25 or 50GB media disc necessary if in most cases everything will fit on two DVD9's (one for the main movie, the other for special features). It seems these new HD audio formats are simply trying to increase the perceived value of the Blu-Ray format with its increased storage capacity. Whether they make a difference and are necessary is debatable in my opinion.
post #4 of 24
The higher bitrates may not be necessary for you, but not everyone is looking to do exactly the same things with their media. For instance, if you were watching that picture while sitting pretty close to a 120" projection screen, then you might be surprised at what you could notice without even trying very hard.

Having a high bitrate source doesn't prevent you from ripping to a smaller format if you so desire. But for someone who wants as much quality as possible, scaling up from a small source file is problematic.
post #5 of 24
Quote:
Originally Posted by Consultant View Post

That doesn't surprise me. Just confirms my original hunch.

The reason I ask is because I'm streaming movies to a PS3. I greatly prefer the Tversity media server but its doesn't easily play MKV files without a bunch of messing with it. Playes m2ts just fine. I've found that I can take a PCM or HD soundtrack and compress it to FLAC lossless without losing anything but you can't mux it into an m2ts, only MKV. So I have to convert to DD 640kbit to use an m2ts container. Bottom line, if I want to watch something like Polar Express once a year at Xmas, I'll get out my Blu-Ray and pop it in. But other times I want the kids (and I) to play movies without risking scratches in the disc. They've destroyed too many already. It's like the though if we have 50GB of storage, we might as well use it.


I've been surprised how small you can compress 1080P movies with virtually no loss in picture quality. It has made me wonder why is a 25 or 50GB media disc necessary if in most cases everything will fit on two DVD9's (one for the main movie, the other for special features). It seems these new HD audio formats are simply trying to increase the perceived value of the Blu-Ray format with its increased storage capacity. Whether they make a difference and are necessary is debatable in my opinion.

FWIW, if you use MKV2VOB, you can get DTS tracks thru PS3mediaserver which should be a bump up in quality from AC3
post #6 of 24
Dolby Digital AC3 can't take any original material with a sampling rate above 48kHz. It will retain all 24bits, but that's it.

The new codecs allow for higher rates, as much as 192kHz in some cases.
post #7 of 24
Quote:
Originally Posted by Eric Seaberg View Post

Dolby Digital AC3 can't take any original material with a sampling rate above 48kHz. It will retain all 24bits, but that's it.

The new codecs allow for higher rates, as much as 192kHz in some cases.

Yes, but 192kHz is very much overkill, too!

And that won't stop them from promoting even higher rates in the future, either. Just watch what they will try to tell you that you need in the coming years
post #8 of 24
Quote:
Originally Posted by Consultant View Post

For an average home theater system, whatever 'average' is - but not super high-end speakers/amp, is there much of a difference you can hear between True-HD and DTS-HD soundtracks versus AC3 at 640kbit?

I know the audiophiles will say so, but for your average person, with middle-of-the line audio equipment, is there much difference?

I have Pink Floyd's "Pulse" DVD and it has both the 448 and 640kHz Dolby Digital tracks available. The 640 track definitely sounds better but I seriously doubt that anyone can hear the difference between it and the PCM track.

The so-called lossless tracks are not going to offer audibly better sound to any more than about .0001% of the population. And even then, I think listening that hard to the soundtrack is just going to rob you of the enjoyment of the performance anyway
post #9 of 24
Quote:
Originally Posted by Sitting Bull View Post

Yes, but 192kHz is very much overkill, too!

And that won't stop them from promoting even higher rates in the future, either. Just watch what they will try to tell you that you need in the coming years

SA-CD (DSD) is 2.822MHz and it's been available for years.

Quote:
Originally Posted by Sitting Bull View Post

I have Pink Floyd's "Pulse" DVD and it has both the 448 and 640kHz Dolby Digital tracks available. The 640 track definitely sounds better but I seriously doubt that anyone can hear the difference between it and the PCM track.

The so-called lossless tracks are not going to offer audibly better sound to any more than about .0001% of the population. And even then, I think listening that hard to the soundtrack is just going to rob you of the enjoyment of the performance anyway

So you can hear the difference between lossy 448Kbps and 640Kbps (which many consider indistinguishable) but only 0.001% of the population can hear the difference between lossy 640Kbps and lossless 13Mbps?

Also what is your source for the 0.001% figure or did you just make that up?
post #10 of 24
Quote:
Originally Posted by William View Post

Also what is your source for the 0.001% figure or did you just make that up?

72.4% of all statistics are made up
post #11 of 24
Quote:
Originally Posted by William View Post

So you can hear the difference between lossy 448Kbps and 640Kbps (which many consider indistinguishable)

Many? I don't know anyone who can't hear a difference between DD at 448 and 640, or DTS at 784 and 1.5M. Far fewer people can hear a difference between DD at 640 and DTHD, or DTS at 1.5M and DTS-MA. The science certainly backs up those results. In fact, the only independent double blind testing I've read indicates that perhaps the above is the case and high bit rate lossy cannot be distinguished from lossless most of the time. Audio quality can be great or garbage with any of the above, so it's dependent on comparison of identical audio, level-matched.
post #12 of 24
Quote:
Originally Posted by William View Post

So you can hear the difference between lossy 448Kbps and 640Kbps (which many consider indistinguishable) but only 0.001% of the population can hear the difference between lossy 640Kbps and lossless 13Mbps?

Also what is your source for the 0.001% figure or did you just make that up?

Yeah, anyone can hear the dif between 448 and 640, but maybe you can't. Thus I leave room for people with your ear type in my .001% estimation. Hey, you should feel flattered--you're only one in a thousand!
post #13 of 24
Quote:
Originally Posted by SiriuslyCold View Post

72.4% of all statistics are made up

100% of all statistics are statistically inaccurate.
post #14 of 24
Quote:
Originally Posted by Sitting Bull View Post

Yeah, anyone can hear the dif between 448 and 640, but maybe you can't...

So since "anyone" (100%) can hear the difference how did I get left out? Also why do you assume I can't hear the difference (or do you have a statistical model to cover it?) since I made no declaration?
post #15 of 24
Quote:
Originally Posted by William View Post

So since "anyone" (100%) can hear the difference how did I get left out? Also why do you assume I can't hear the difference (or do you have a statistical model to cover it?) since I made no declaration?

Well, William, like a politician you seem to do a lot of talking without saying anything. So I spoke up for you

Don't worry, we understand that you're one of those debatable types that fit into the .0001%
post #16 of 24
hi there....i have a dillema between dts and ac3...i have tested the same movie, jurassic park the lost world, in both dts 1.500kb and ac3 640kb...the channels were 5.1 in both...the sound effects were exactly the same, meaning f.e. when someone was calling ''Dr Malcolm...Dr Malcolm'' a few times from a speaker in the movie which used to come from the left, in both sound formats it came from the left...when a dino was roaring it had the exact same balance and depth... i tried it many times...

i have a 5.1 ET-5015 wombat speaker system...not bad...i managed to find a logitech z550 system...5.1...i tested both movies...same results...no quality difference...so i wonder, because i read all the above...am i deaf??? really can someone recognize when a sound is in dts 1509kb or ac3 640kb??? the dillema occurs cause i found out that ac3 could save me much space per bluray rip...

correct me if i am wrong but a human being cannot adjust the quality as an amplifier can...unless u have speakers in the size of a door and ears 100 times more capable...
post #17 of 24
Quote:
Originally Posted by rdgrimes View Post

100% of all statistics are statistically inaccurate.

That is likely inaccurate.

But is beyond way too cute.

But then I majored in math.
post #18 of 24
Quote:
Originally Posted by Alexboom View Post

...am i deaf??? really can someone recognize when a sound is in dts 1509kb or ac3 640kb???

You aren't deaf and no, they can't recognize the difference.
post #19 of 24
Quote:
Originally Posted by OtherSongs View Post


That is likely inaccurate.

But is beyond way too cute.

But then I majored in math.

Your post is leet!
post #20 of 24
Quote:
Originally Posted by BIslander View Post

You aren't deaf and no, they can't recognize the difference.

thnxx...i hope i'm not...

anyway as for a final test i will take the movie ''300'' tested to a friend's home cinema with an YAMAHA amp and klipsch speakers...and this is why the ''300'' movie had a slightly different sound, not worse or better, with a DTS than an AC3 format..i figured it out wearing headphones...in 5.1 output they sounded the same..and generally even with headphones they are similar..

but AC3 has the advantage of saving disk space and playing on my TV which won't support DTS sound
post #21 of 24
Quote:
Originally Posted by Alexboom View Post

...i tested both movies...same results...no quality difference......really can someone recognize when a sound is in dts 1509kb or ac3 640kb???...

Looks like you can.

Quote:
Originally Posted by Alexboom View Post

...and this is why the ''300'' movie had a slightly different sound, not worse or better, with a DTS than an AC3 format..i figured it out wearing headphones...

Since you heard a difference then by definition one was objectively "worse" than the other since the one that sounded closer to the master was objectively "better".
post #22 of 24
So when these blu rays with "dubbed ac3" tracks are on sale their audio tracks are inferior to the regularly priced versions...?
post #23 of 24
Quote:
Originally Posted by William View Post

...Since you heard a difference then by definition one was objectively "worse" than the other since the one that sounded closer to the master was objectively "better".

I'm with William... so we're 2 in a thousand
I've tested over years many *MUSIC* DVD's and BD's... and with a "medium-high" class equipement (Oppo/NuForce + Rotel + Dynaudio) the sound quality differences between lossy formats (AC3 and DTS) and "hi def" sources are (to me *and* my wife...) quite noticeable.
I've even tried some DVD and DVD-Audio in similar class auto amplifiers (Bang & Olufsen on Audi and Mark Levinson on Lexus) and there's a strong difference between AC3 640 and DTS 1.5, and both of them inferior to stereo 192KHz (DVD Audio).

In my humble opinion if you're going to listen at MUSIC (not movies), DTS is my minimum acceptable option: in some cases I've heard it playing really well.
Obviously the new lossless format are better, if available.
With classical or jazz music you can easily feel the differences, while with movies... you need some good (and big) speakers to hear a difference between DTS and DTS MA. Always in my humble opinion.
post #24 of 24
^^
While we all have own personal experiences, the only tests that come close to being scientifically rigorous suggest that the higher bitrate lossy codecs on Blu-ray are indistinguishable from lossless.
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