DD+ vs Truehd - High-Def Digest Forums
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Old 11-03-2007, 12:56 PM
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Default DD+ vs Truehd

I came across this hdf dvd review and noticed the audio part compared the dd+ track to the Truehd track. Funny how he states the truehd track sounded much better. I tought dd+ sounded identical, guess not.

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So it wasn't too hard to find a few scenes in which to put the Dolby TrueHD track through its paces. And the results were pretty much what I expected -- the differences are not necessarily night and day, but they are considerable, and became more pronounced the more in-depth I got in my A/B comparisons. Which is all a good thing. Quite frankly, I don't think anyone expected that Dolby TrueHD would necessarily sound like a completely new experience, but instead be more akin to the upgrades we've have heard in the past between Dolby Digital and DTS, or Dolby Digital and Dolby Digital-Plus. But based just on 'Training Day,' I would go a little farther and say that at times, Dolby TrueHD delivered such a significant upgrade that I can't imagine choosing any other option if a Dolby TrueHD track was included on a disc.
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Low bass is also more powerful in TrueHD -- during this scene as well as all throughout the film's extended climax, I heard occasional rumblings and felt vibrations that went by unnoticed in Dolby Digital-Plus. Tightness with the .1 LFE is also improved -- for example, the sound of a helicopter landing in the first scene didn't feel as "wobbly" on the TrueHD, meaning it was less distorted and artificial.

http://hddvd.highdefdigest.com/trainingday.html
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Old 11-03-2007, 01:15 PM
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No, it has been said that DD+ at 1.5Mbps is true to the original. It has been stated many times that Warner uses 640Kbps which is simply not good enough. Paramount and Universal both use 1.5Mbps DD+ - more than twice the bitrate used by Warner.
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Old 11-03-2007, 01:43 PM
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Default 1.5

Tought this disc was 1.5 for dd+, my bad if its not.

Anyway the debate between lossless and lossy still bugs me. Ask yourself a question. If you had a movie theater and one room was showing the movie with the original master audio and another with a DD+ compressed track, which door would you go in?? Its the same thing with hd media. The lossless track is supposed to be bit for bit identical to the master. So, a DD+ track will never sound better then the master, but the master can and should sound better then a compressed version of itself.

There is no benefit to lossy except for disc space, which is why its used. I don't care if some people think dd+ is transparent to lossless, I want to know I am listening to the exact master, maybe just for piece of mind. I will never believe that you can't make a lpcm track sound at least a bit better then a DD+ track.
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Old 11-03-2007, 02:03 PM
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As far as I know, all Warner titles are 640Kbps (in fact, it has been said that the Warner track is not "true" DD+, but simply the same DD track used on the Blu-ray release simply tagged as DD+, so they only need to encode it once). I think they made that decisions since they were the first studio to more regularly provide TrueHD, so the DD+ track is purely auxiliary. In fact, now that Universal is mostly providing TrueHD, it would not surprise me if they switched to a lower bitrate DD+ channel as well - after all, it is redundant to include 2 hi-rez audio tracks.

I don't think anyone disagrees that all else being equal, one would choose the lossless over lossy - why wouldn't we (though actually, there are cases where DD+ could be potentially superior such as when the PCM track has the bit-depth truncated, which is unfortunately pretty common )? But at the same time, it does not bother me in the slightest bit if only the high-bitrate lossy encode is available because I realize I will enjoy it just as much.

For reference purposes, I encode my music for my iPod at 192Kbps (using AAC). I have a very hard time distinguishing it from the uncompressed source. Heck, I have a hard time distinguishing it even at 128Kbps. The 1.5Mbps tracks use 10 times the bitrate than those encodes, and this for sources which are inherently much easier to encode than music.
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Old 11-03-2007, 04:31 PM
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Originally Posted by Micker View Post
Anyway the debate between lossless and lossy still bugs me. Ask yourself a question. If you had a movie theater and one room was showing the movie with the original master audio and another with a DD+ compressed track, which door would you go in??
Now ask yourself this question. If you went into the theater room labelled lossless audio and came out of it saying, "Wow that sounded amazing!", only to have someone tell you that they switched the signs by mistake and you actually heard the DD+ track, what would happen then? Would the sound you just described as "amazing" suddenly not sound so good anymore?
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Old 11-03-2007, 04:35 PM
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Default ipod

With your ipod, you don't take into account for things like: seamless panning, accuracy of sound placement, fullness of the soundstage, lfe bass(nothing like a dedicated sub with headphones) etc., also doesn't 2 channels take less bandwidth then 5.1?? Not sure if that 192kbps would need to be split up between all the channels. I know with stereo, you can get away with a lot less, espically listening with headphones.
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Old 11-03-2007, 04:39 PM
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Default lossless

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Originally Posted by Josh Z View Post
Now ask yourself this question. If you went into the theater room labelled lossless audio and came out of it saying, "Wow that sounded amazing!", only to have someone tell you that they switched the signs by mistake and you actually heard the DD+ track, what would happen then? Would the sound you just described as "amazing" suddenly not sound so good anymore?
I would say, wow I wonder how much better it would have sounded with a lossless track. I am not saying DD+ doesn't sound awesome, I am saying I think lossless could sound even better. When I hear a lpcm track on a BR disc, I know that is the best i'm gonna hear that movie sound, if the lpcm is indeed a bit for bit copy of the master. With DD+, I am left wondering if it could have sounded better, even if it was fantastic.

You tell me that the 1.5mbs core of the DTS-HD MA track sounds exactly like the full lossless version?? I have not been able to hear the difference yet, but if they sound exactly the same why all the excitement over dts-hd ma decoding and alll the reports of how much better it sounds?? Is all the extra data that is compressed out completely worthless??
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Old 11-03-2007, 04:51 PM
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Originally Posted by Micker View Post
With your ipod, you don't take into account for things like: seamless panning, accuracy of sound placement, fullness of the soundstage, lfe bass(nothing like a dedicated sub with headphones) etc., also doesn't 2 channels take less bandwidth then 5.1?? Not sure if that 192kbps would need to be split up between all the channels. I know with stereo, you can get away with a lot less, espically listening with headphones.
I actually also play them back on my Elite Pioneer channel for evaluation - but the point is replication of the individual channels. In any case, I was just giving some reference for comparison sake, to put things in perspective. You are correct that it is stereo vs. 5.1, so the ratio is not as high as the numbers might suggest, however the ratio is still very high due to a number of factors - a movie soundtrack primarily uses the center, left and right. The surrounds only typically use a fraction of the bandwidth for movie soundtracks, as does the LFE . Also, all of the channels share compression data which also significantly increases efficiency. And finally, movie soundtracks are typically much easier to compress than complex music. So while it is not effectively 10 times more bitrate per channel, it is still extremely high.

The final point here though, is that high bitrate DD+ is going to give you awesome quality. You can quibble about this and that, but at the end of the day what matters is that they are virtually the same and while some people are going to get caught up in the fact that they are missing a check-box that makes them happy, for the vast majority of people what matters is that it sounds great. I personally like it that Warner and Universal are pretty much standard with TrueHD (at this point) - but at the same time I don't really have a problem with Paramount's approach either using DD+ because frankly, it is plenty good enough.
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Old 11-03-2007, 04:58 PM
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Default DD+

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I don't really have a problem with Paramount's approach either using DD+ because frankly, it is plenty good enough
But why settle for good enough, when we should be getting perfect at this point?? Why is paramount refusing to add lossless tracks?? Its not disc space, I don't believe, because they did it with BR. They pissed me off when they were making BR discs. 50gb and they have a 640k DD+ track!!!! Come on, thats almost an insult. Lossless should be included on all HDM movies, unless there is no space, which on BR I can't imagine.
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Old 11-03-2007, 05:04 PM
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Originally Posted by Micker View Post
But why settle for good enough, when we should be getting perfect at this point?? Why is paramount refusing to add lossless tracks?? Its not disc space, I don't believe, because they did it with BR. They pissed me off when they were making BR discs. 50gb and they have a 640k DD+ track!!!! Come on, thats almost an insult. Lossless should be included on all HDM movies, unless there is no space, which on BR I can't imagine.
Really, I wouldn't work yourself up too much over it. I understand that for you this is an important feature, and I am not going to gainsay you on that. But if possible I would try to just enjoy the sound without worrying about the specs on paper too much. I wouldn't be surprised if at some point Paramount comes around to doing that if only to please the people who just get caught up specs, but in the meantime the titles still sounds excellent so there is no reason not to enjoy them.
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