Your confusion is different than Eric’s though. I was aiming to address his previous post about "well i'm not here to talk about whether or not i can discriminate dither from music”
I agree with your comments. Subtractive dither is used in the MQA codec because Peter Craven is trying to salvage every last ounce of SNR, but it's not difficult to handle in a streamed file, and in a situation where the original file’s specs are measured during encoding. Vicki > On Jan 10, 2022, at 5:53 PM, robert bristow-johnson > <[email protected]> wrote: > >> On 01/10/2022 1:37 PM vicki melchior <[email protected]> wrote: >> >> >> Okay. In the context of subtractive dither, I understand the confusion. > > I don't. I'm just confused. > >> Yes, the purpose of subtractive dither is to reduce the total dither noise >> remaining in the output, typically after adding dither during bit reduction. >> Clearly, that will increase the SNR > > But only by 4.77 dB. But, hey, it's 4.77 dB. So if they can standardize how > the dither is generated from the LSBs of the quantized signal, and, if noise > shaping is done, what the transfer function is from dither to quantized > output, then why not do this subtractive dither thing? > > The worst that can happen is that the receiver does not decode those LSBs and > subtract the dither. Then you're no worse off than if it was just additive > dither and you don't recover those 4.77 dB SNR. > >> and allow you to hear more of the signal. > > only really makes a difference if the audio is living down by the noise floor > (which it could be if it's a CD and classical or uncompressed acoustic music > with a large dynamic range). > > but 4.77 dB is 4.77 dB. that's something. 96 dB dynamic range is better > than 91 dB. > > -- > > r b-j . _ . _ . _ . _ [email protected] > > "Imagination is more important than knowledge." > > . > . > .
