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Discussion Starter · #1 ·
I have a question regarding uncompressed audio on the new HD formats (HD-DVD and Blu-Ray). Both formats seem to be using different formats of audio, BR - PCM / HD-DVD - TrueHD. I was wondering if there is any difference between the two types used?


Would a movie released in both formats sound the same or better on either format using the different delivery methods?


Thanks for helping me wrap my brain around this
 

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There are a couple of new lossless HD audio codecs you'll start seeing more of: Dolby TrueHD and DTS-HD MA (Master Audio). Both these codecs take uncompressed PCM and pack it more efficiently to take up less space on the disc. Think of it as zipping a computer file to shrink its size.


When you decode these tracks, you end up with an identical (bit-for-bit) copy of the original uncompressed PCM soundtrack. Since the data is identical, an uncompressed PCM soundtrack will sound the same as its TrueHD and DTS-HD MA versions.


Note that lossless packing codecs are different from lossy compression codecs (DD, DD+, DTS, DTS-HD), which discard data during compression. Those work along the same lines as MP3 compression.


Sanjay
 

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Discussion Starter · #3 ·
Thanks for the info, it really helped to me to understand these new audio schemes.


So a soundtrack recorded in uncompressed PCM (BR) and TrueHD (HD-DVD) are identical (sound wise) except when it comes to file size. Is there a reason then why all BR releases do not use TrueHD/DTS-HD MA?
 

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I would guess licensing fees for using the codec, support for the codec in the players (most current BD players don't support DTS-HD MA or TrueHD), and also because Sony isn't too concerned about saving space on the BD media (yet), as they have more room to work with.
 

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Quote:
Originally Posted by Meat2783 /forum/post/0


So a soundtrack recorded in uncompressed PCM (BR) and TrueHD (HD-DVD) are identical (sound wise) except when it comes to file size.

Exactly. Bit-for-bit identical data. Just like zipping a file.
Quote:
Is there a reason then why all BR releases do not use TrueHD/DTS-HD MA?

Most BD players don't have decoders for the new HD audio codecs. But that will probably change in time. Meanwhile, I think there are a few BD releases in Europe that have DTS-HD MA soundtracks and one US release ('Legends of Jazz' maybe?) that has a TrueHD soundtrack. More will probably show up eventually. For titles where there is plenty of room available on the disc, the soundtrack can be left as uncompressed PCM.


Sanjay
 

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Quote:
Originally Posted by Yates /forum/post/0


Here's a thread I started on this issue.


If the producer I quote is for real, it gives a reason why an uncompressed track could sound potentially better.

http://www.avsforum.com/avs-vb/showthread.php?t=790018

That has nothing to do with the compression -- it has to do with processing applied before the track was compressed.
 
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