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In Reply to: Re: Usually the 48/16 is just resampled from the 44.1/16. posted by AudiophileBob on November 5, 2005 at 19:27:37:
>>why upsample to 48 ?<<Because the minimum specification for LPCM on DVD-V is 16/48.
Follow Ups:
Thanks for confirming the 16/48 content on the DVD-V side.What I meant about the upsampling was that I doubted that the master was 16/44.1, but who knows ?
But that doesn't mean it didn't go 48-44.1-48. Most post-production practices on mass-produced albums would scare you.As Racerguy said, the only reason it is 48khz is because the DVD-V minimum spec is 48khz.
Look at a post I made earlier where I analyzed both sides of a "Enhanced LPCM" DualDisc. If you want, I can do a spectrum of both, too; i'm almost positive they will both roll off at 22050, not 24000.
The 3-6dB cut that I've seen on most DVD-V sides (versus the CD side) make me believe that the DVD-V LPCM track was derived from the RBCD/CDDA track, not the other way around.
Unless the 48/16 track cut by 3-6dB *IS* the first stage, and the sound is just 'boosted' by 3-6dB on the CD side. In either case: you get 48khz that isn't really 48khz one way, or 16 bit that isn't really 16 bit, the other. (14-15 bits actualized after a 3-6dB drop.)
... and you did say the rolloff was 22.05, which is proof enough for me.The 3-6dB cut is because of a video post processing standard to avoid clipping in some broadcast equipment. I can't remember the actual standard, but i think you are never allowed to exceed -1dB, and strongly recommended to stay under -3dB.
I wish they have this rule for CDs - it would avoid 0dBFS+ mastering errors.
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