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Old 2007-08-10, 05:38 PM
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paddington paddington is offline
crumpet-stuffer
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Join Date: Jan 2005
Location: UK
Re: Is decompressed AC3 lossy?

yes. Take the LPCM audio file you suspect is dual-mono (exact same left and right channels) and open in Cool Edit Pro 2.0 (or Adobe Audition - whichever you have).

Highlight the whole thing and open the "channel mixer". Invert ONE of the channels and play. If the audio is exactly the same left-right, it will be completly silent since you are subtracting the inverse from one side to the other. Get audio, and you do not have a true dual-mono source.


Now, if that is the case and you have isloated a mono source, the only remaining question is whether you can include an LPCM mono track on a DVD and still be compliant with the standard. I know with a CD, that would NOT be compliant - you have to double to 2 channels - back where you started.

Maybe a video mod can chime in about whether a DVD can contain a 1 channel mono LPCM stream - or you can visit www.videohelp.com and look up the DVD-Video standards. I'll try to have a look later if I have a chance.
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