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Bit-perfect playback questions
monkey
post Dec 16 2011, 01:26
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I believe Jim is implying WASAPI exclusive when talking about WASAPI.

While Media Center supports WASAPI shared (ie. not exclusive), it uses exclusive mode by default. Shared mode isn't widely used or recommended.
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andy o
post Dec 16 2011, 06:52
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QUOTE (googlebot @ Dec 15 2011, 15:06) *
You can get bitperfect output with any plain old media player over DirectSound if you leave your device's sample rate at the same setting as your files (e. g. 44.1 kHz) and set the volume to 100% since Vista.

This thread is hysterical and BS marketing driven.

16 bit INT -> 32 bit FLOAT -> 16 bit INT conversion, et ceteris paribus, is lossless, before you start the "but, but, but ... float pipeline"-whining.

I thought it was the reverse? XP did it, but not Vista/7? Isn't everything dithered since Vista, like Roseval said?
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saratoga
post Dec 16 2011, 08:15
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QUOTE (JimH @ Dec 15 2011, 19:46) *
I would like to be able to discuss this without fightin' language. My post addressed the user's question. There was no "BS marketing". I admit I can be guilty of "BS".


I don't know if I'd call it "BS", but if you're getting dramatic differences between DirectSound and ASIO/WASAPI you're probably doing something very, very wrong.
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Roseval
post Dec 16 2011, 11:18
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16 int > 32 float > 16 int is a lossless conversion, Don't think anybody will deny
16 int > 32 float > 16 int > dither is not lossless by design.
It will affect the LSB so there is a small effect.

As far as I know, every media player applies dither on 16 bits material the moment any kind of DSP is applied. Looks like each and everybody thinks it is a necessary step to improve sound quality.

This post has been edited by Roseval: Dec 16 2011, 11:18


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saratoga
post Dec 16 2011, 21:08
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QUOTE (Roseval @ Dec 16 2011, 05:18) *
16 int > 32 float > 16 int > dither is not lossless by design.


Its :

"16 int > 32 float > dither > 16 int "

The dither is applied to the FP data, not the integer.

QUOTE (Roseval @ Dec 16 2011, 05:18) *
Looks like each and everybody thinks it is a necessary step to improve sound quality.


If you're going to convert from high precision to lower precision then you should apply dither. The only time not to is the trivial case where you have 16 > 32 > 16 with no actual processing at the higher precision. I have no idea idea what software is smart enough to handle this. I don't think it really matters unless you're trying to stream a compressed audio format through a digital interface.
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Roseval
post Dec 16 2011, 21:17
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QUOTE (saratoga @ Dec 16 2011, 21:08) *
"16 int > 32 float > dither > 16 int "



Thanks, is more precise

But is does affect the LSB of the 16 bit result anyway


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DVDdoug
post Dec 16 2011, 21:44
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QUOTE
As far as I know, every media player applies dither on 16 bits material the moment any kind of DSP is applied. Looks like each and everybody thinks it is a necessary step to improve sound quality.
Of course, once you've applied DSP your stream is no longer bit-perfect.
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Roseval
post Dec 16 2011, 21:56
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But if you configure your media player not to apply any DSP and the Win mixer applies dither I expect it to alter the sound.
Likewise if you bypass the mixer using ASIO or WASAPI so no dither is applied, it should sound different.


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saratoga
post Dec 16 2011, 23:14
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QUOTE (Roseval @ Dec 16 2011, 15:17) *
QUOTE (saratoga @ Dec 16 2011, 21:08) *
"16 int > 32 float > dither > 16 int "



Thanks, is more precise

But is does affect the LSB of the 16 bit result anyway


Yes, sorry didn't mean to criticize. You were correct in the end.
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Roseval
post Dec 16 2011, 23:42
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QUOTE (saratoga @ Dec 16 2011, 23:14) *
Yes, sorry didn't mean to criticize. You were correct in the end.

You were correct before the end smile.gif
Thanks


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Joe Bloggs
post Dec 4 2012, 16:29
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Is there a way to disable dithering in the windows 7 mixer?
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Arnold B. Kruege...
post Dec 4 2012, 16:40
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QUOTE (DVDdoug @ Dec 16 2011, 15:44) *
QUOTE
As far as I know, every media player applies dither on 16 bits material the moment any kind of DSP is applied. Looks like each and everybody thinks it is a necessary step to improve sound quality.
Of course, once you've applied DSP your stream is no longer bit-perfect.


Once you put it through a volume control or an equalizer...

The idea of bit-perfect playback is not exactly sane.
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nu774
post Dec 4 2012, 17:43
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QUOTE (Joe Bloggs @ Dec 5 2012, 00:29) *
Is there a way to disable dithering in the windows 7 mixer?

As far as I know, if you set 24bit output mode on sound control panel, dither will not be applied on WASAPI shared mode.
However, CAudioLimiter APO will prevent from "bit perfect playback" anyway.

This post has been edited by nu774: Dec 4 2012, 17:53
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