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Spider-Man 3. Why TrueHD AND pcm?

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#1 of 6 OFFLINE   brap


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Posted December 22 2007 - 07:48 AM

All of this is based on my knowledge of dolby TrueHD being lossless (dial norm on HD-DVD aside) and used to conserve space and bandwidth other than using the bulky PCM. Why would Spider-man 3 have both? PCM is mainly used for compatibility with players in case TrueHD and DTS Master are not supported. If there is a compatible lossless track on the disc why waste the space on another? is it for the core DD track within the TrueHD? For people who have TrueHD receivers? Then again, if you have the Bandwidth and space, then use it. Any thoughts?

#2 of 6 OFFLINE   Adam Barratt

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Posted December 22 2007 - 05:38 PM

At face value the TrueHD version's accompanying Dolby Digital soundtrack provides greater compatibility for the many users listening via an external decoder. However, Sony could simply have included a 24-bit PCM soundtrack and a Dolby Digital soundtrack for the same level of compatibility (and saved up to 2.7Mbps of bandwidth in the process). The combination of PCM and TrueHD it chose allowed the company to use a higher resolution (24-bit) soundtrack to start weaning people off PCM, which I suspect they will be phasing out entirely over the next six months in favor of one of the lossless variants (eg. Close Encounters of the Third Kind and the first two Spider-Man films). Dialog Normalization isn't restricted to HD DVD: it's used on every TrueHD/Dolby Digital soundtrack regardless of format (and has no impact on the 'losslessness' of a soundtrack). Also, unlike DTS-HD MA, there is no 'core' Dolby Digital soundtrack present in TrueHD. Adam

#3 of 6 OFFLINE   Jeff Adkins

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Posted December 23 2007 - 12:10 AM

The Immortal Beloved BD has only a TrueHD track. It does not have a legacy DD track. I'm not sure if its a true core like DTS-MA but it has to be compatible with all players.

#4 of 6 OFFLINE   Robert George

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Posted December 23 2007 - 01:59 AM

With Dolby's codecs, there is always dialnorm. The default setting for dialnorm on Dolby encoders is -27 dBfs, which attenuates the audio 4 dB at the decoder. One can change the setting on the encoder to whatever one deems appropriate. In Sony's case, to appease the Blu-ray fanboys that don't know any better, but still make a lot of noise on the Internet, TrueHD encodes on Sony BDs are using a dailnorm setting of -31 dBfs, which has no attenuation at the decoder.

What I find most interesting about this is not that Sony is somehow being more responsive to their customers, though I suppose one could look at it that way, but that Sony is willing to compromise their product to score points with Blu-ray supporters. Dialnorm serves a very specific purpose and is a tool that Dolby provides to users of its encoder to solve specific problems, that being, inconsistent audio levels on film and video material. In the past, on DVD, Sony was in fact one of the very few companies that actually used dialnorm as it was intended. Most studio/post houses simply leave the encoder on the default position without taking the time to determine what the appropriate setting should be on the material being encoded. Sony did take the time to check levels and use dailnorm to either boost low levels or attenuate soundtracks that may have been mixed too "hot".

Now, Sony is not using this otherwise useful feature of audio post production in order to promote their format among a very small, but very vocal minority that simply don't understand the technology. There's a word for that, and it is called "pandering".

#5 of 6 ONLINE   Robert Crawford

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Posted December 23 2007 - 02:34 AM

You're right there is a lot of misinformation being spread about on the internet about dialnorm and how it is suppose to work. It's no wonder, why so many on even this forum are confused about this technology. Crawdaddy

#6 of 6 OFFLINE   Adam Barratt

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Posted December 23 2007 - 06:26 AM

As with Spider-Man 1 and 2, and with Close Encounters of the Third Kind, this title has a parallel Dolby Digital soundtrack that is not listed in the disc menu. This hidden soundtrack is used if a player without TrueHD is used and the TrueHD soundtrack selected, and ensures compatibility with all hardware on the market. The other user of TrueHD on Blu-ray, Warner Brothers, allows their discs' parallel Dolby Digital soundtracks to be selected directly and always lists them in the audio menu. Adam

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