Talk:Dolby Digital

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Dates?

What is the timeline on Dolby Digital? Where does it fit in with the other Dolby codecs?

technical details?

I'd like to see a bit more technical detail here. It should *at a very minimum* at least be mentioned that it uses a logarithmic scale for quantization rather than the more standard linear scale. As far as I know it is significantly different from standard PCM-based encoders that some in-depth discussion would be useful.

Naming

I'm pretty sure that Dolby Digital EX and Dolby Digital Surround EX (Or Dolby SEX as some projectionists have dubbed it) are different names for the same system - one that matrix decodes additional rear channels from the surround channels.

Also, the article mentions the term SR-D as referring to sources that are compatible with dolby surround technology. I do not think this is correct. Dolby SR means Dolby Spectral Recording - a new method of noise reduction introduced in the late 1980s for use on analogue film soundtracks, also backwards compatible with Dolby A. Dolby SR-D therefore means Dolby Spectral Recording - Digital, since SR-D is the replacement for SR and SR-D soundtracks on films ALWAYS have a Dolby SR track as a backup. The name has nothing to do with Dolby Surround, and soundtracks featured surround channels long before Dolby SR or SR-D came out.

"Dolby Technologies in Packaged Media Formats" question

What does the "mandatory" vs. "optional" in the status column in the "Dolby Technologies in Packaged Media Formats" table refer to? Does this refer to whether players of the particular media format (e.g. DVD) require a Dolby decoder?--GregRM 01:19, 14 August 2006 (UTC)[reply]

Mandatory means that the specifacations requires that all players MUST decode that kind of codec. Optional means that the player manufacturer can choose whether to add that decoding functionalty to their player. Example: all blu-ray players must decode Dolby Digital. But, lets say that Sony wanted to add Dolby TrueHD decoding to only their high-end players. They could still do that because the blu-ray spec gives them the option to add it. -- Sam916 02:08, 14 August 2006 (UTC)[reply]
- OK, that makes sense...thanks.--GregRM 14:14, 14 August 2006 (UTC)[reply]

Bitrates

The bit rates are unclear. It would be nice to see both the compressed data rate encoded onto the media, and the per channel PCM rate (such as 96hkz/24 bits or whatever.)