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Question about upmixing and systems that do not have decoders Effects Pedals, Units & Accessories
Old 17th September 2011
  #1
Gear Head
 

Question about upmixing and systems that do not have decoders

So how does the phantom image of a stereo movie get up-mixed to a 5.1 system (Dolby Digital/DTS)? (I'm sure there are texts on this but my searches aren't yielding anything)

and

What happens to an .ac3 file when it is played out of a system that doesn't have a dolby digital decoder or when the file is played through a DTS decoder? Simply disc not read?

If anyone could clear that up it would patch a lot of holes in my knowledge about authoring.
Old 18th September 2011
  #2
I send a stereo signal to a Dolby seu4 encoder to create an LtRt then send that to the Sdu4 decoder to spilt it back to an LCRS. Matrix automatically converts phantom center to a discrete center. Then I patch the LCR to my DAW and record it then bus each to the appropriate speaker.

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Old 18th September 2011
  #3
Regarding the ac3 question, all dvd players have a built in decoder that decodes and folds down to an LtRt for output to analog stereo outs. Same with cable set top boxes.

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Old 18th September 2011
  #4
Quote:
Originally Posted by bbell View Post
So how does the phantom image of a stereo movie get up-mixed to a 5.1 system (Dolby Digital/DTS)? (I'm sure there are texts on this but my searches aren't yielding anything)
It doesn't, unless you are using DSP processing within the receiver.
Remember that Dolby Digital is from mono to 5.1 on DVD, and mandatory onall players - even if the AC3 file is a 5.1 file, it wil still have downmix parameters included (albeit highly unsatisfactory to my mind).

Quote:
Originally Posted by bbell View Post
What happens to an .ac3 file when it is played out of a system that doesn't have a dolby digital decoder or when the file is played through a DTS decoder? Simply disc not read?
All DVD players must be capable of decoding .ac3 (Dolby Digital) as it is a mandatory codec for DVD along with LPCM at 16/48 resolution (higher sample rates and bit depths are not mandatory for LPCM).
It's impossible to output AC3 through a DTS decoder as it would not understand the file format - although this is not going to be an issue unless you are trying to output through some hardware unit like the CAD units from DTS - all receivers with DTS decoding capability also have Dolby Digital decoding capability so this is just not a problem.

Hope this helps.
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