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Discussion Starter #1
One of the best purchases I have made in the last several years has been my AX-1. CD's sound wonderful, SD DVD's look stunning to say the least, and the HD images from HD DVD disk are absolutely grand. However I have just one problem with this new format, the reliance on lossy audio codecs.

George Lucas has stated many times that the audio was 50% of the movie experience. So if this is the case, then why has HD on every platform count audio as last. HDTV has 5.1, but at no more than 384kbps, but more than 14mbps has been devoted to the picture. Now we have HD on disc, and aside from a few Dolby TrueHD soundtracks, only 1.5mbps max has been applied to the audio side of things. Blu ray has been a huge improvement by incorporating uncompressed LPCM tracks on quite a few releases.

I am just not understanding why more emphasis is not being placed on the audio side of things.
 

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Discussion Starter #3
Would you say the audio quality is worse, the same or better than SD-DVD?
Sonnie,
It is better, but not by all that much. The comparisons I have done with regular Dolby Digital, and Dolby TrueHD(The Perfect Storm) recently gave me the impression that overall the TrueHD soundtrack sounded more open and airy, a LITTLE less hard in the mids, much more extended top end, and a little more heft at the bottom. Batman Begins was a night a day difference in many areas. Charlie and the Chocolate factory had more bass and highs in the DD+ soundtrack, but the mids sound pretty simular. U-571 DD+ sounded a little more full than the Dts SD DVD version, but the bass and highs and imaging were very simular.

Imaging and seperation is much better in DD+. However I think the uncompressed tracks of Blu Ray really trumps HD DVD offerings.
 

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However I think the uncompressed tracks of Blu Ray really trumps HD DVD offerings.
They would be great on the BD50 discs. However they, when combined with the old MPEG2 video codec, take up far to much room on a BD25 with resulting poor video encode quality.

Bob
 

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Discussion Starter #5
They would be great on the BD50 discs. However they, when combined with the old MPEG2 video codec, take up far to much room on a BD25 with resulting poor video encode quality.

Bob
I do not agree with this. How do you know the master is not of poor quality. I work in this business, and its something I see on occasion. Without access to the source for comparison, you are just repeating claims circulating around the internet.
 

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...just repeating claims circulating around the internet.
The point that I was trying to make is that to encode high definition video you need both bandwidth and space. Using uncompressed linear PCM instead of lossless encoded Dolby TrueHD or dts-HD Master audio codecs takes up more than twice the bandwidth and space. Using MPEG2 instead of more advanced video codecs like VC-1 or H.264/AVC takes up twice the bandwidth and space. When constrained to 25 GB a compressionist then has a very hard time of doing an artifact free video encode using MPEG2 and linear PCM. The problem is nowhere near as severe with 50 GB to play with. But more advanced video and audio codecs let you do a good job with only 25 GB. Like the Warner VC-1/DD encodes of titles for Blu-ray on BD25 compare very well (the same quality) to their VC-1/DD+ (640kbps) encodes of the same title for HD30 on HD DVD. Why use old technology for codecs when newer/improved/more efficient ones are available? This is not a BD versus HD DVD format issue with the exception that BD did not make any lossless or extra high bitrate audio codec mandatory.

The Universal titles with 1.5 mbps DD+ seem to offer very good soundtracks, that IMHO are quite close to a lossless codec or uncompressed linear PCM.

YMMV,
Bob
 

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Discussion Starter #7
The point that I was trying to make is that to encode high definition video you need both bandwidth and space. Using uncompressed linear PCM instead of lossless encoded Dolby TrueHD or dts-HD Master audio codecs takes up more than twice the bandwidth and space. Using MPEG2 instead of more advanced video codecs like VC-1 or H.264/AVC takes up twice the bandwidth and space.
I believe twice the amount of bandwidth and space is definately an overestimate.


When constrained to 25 GB a compressionist then has a very hard time of doing an artifact free video encode using MPEG2 and linear PCM.
Its hard, but not impossible. I know of a couple of Studio(Sony being one of them) that use highly tweaked MPEG encoders that do an incredible job in situations like this. Its these kinds of difficult tasks that seperate the good compressionist from the best, and the good equipment from the best.




The problem is nowhere near as severe with 50 GB to play with. But more advanced video and audio codecs let you do a good job with only 25 GB. Like the Warner VC-1/DD encodes of titles for Blu-ray on BD25 compare very well (the same quality) to their VC-1/DD+ (640kbps) encodes of the same title for HD30 on HD DVD. Why use old technology for codecs when newer/improved/more efficient ones are available? This is not a BD versus HD DVD format issue with the exception that BD did not make any lossless or extra high bitrate audio codec mandatory.
You use the older video codecs because they have a track record, do faster more time efficient encodes, and you work with something that you are comfortable with. I anticipate that BD-50 will probably supplant BD-25 on most releases, so this issue will most likely be moot when it is all said and done. By the way, neither format makes lossless or extra high bitrate audio codecs mandatory. However it looks like Blu Ray is dedicated to offering uncompressed audio tracks, and that is good enough for me.

The Universal titles with 1.5 mbps DD+ seem to offer very good soundtracks, that IMHO are quite close to a lossless codec or uncompressed linear PCM.

YMMV,
Bob
We have had Dts at 1.5mbps for years, and DD+ at 1.5mbps is no real improvment over that. It may be close, but its not there yet.
 
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