Author Topic: questions about dithering and noise shaping  (Read 6689 times)

amit

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I have a two questions about dithering and noise shaping:

1. What is the source resolution when dithering ? Is it always 32bit floating point or is it the same floating point resolusion of the fixed point output chosen?

2.There are two selection boxes : one for dithering and one for noise shaping. I thought noise shaping is a part of the dithering process so whats the ifluence of choosing noise shaping without dithering? is it effectively disabled when chosen alone?

Amit.

Ian @ un4seen

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Re: questions about dithering and noise shaping
« Reply #1 on: 6 Sep '06 - 17:42 »
1. What is the source resolution when dithering ? Is it always 32bit floating point or is it the same floating point resolusion of the fixed point output chosen?

All sample data in XMPlay is floating-point, before being converted to the output format at the end.

2.There are two selection boxes : one for dithering and one for noise shaping. I thought noise shaping is a part of the dithering process so whats the ifluence of choosing noise shaping without dithering? is it effectively disabled when chosen alone?

Even without dithering, you can have rounding errors (eg. 10.2 becomes 10), and so that error/noise can be shaped.

amit

  • Posts: 723
Re: questions about dithering and noise shaping
« Reply #2 on: 6 Sep '06 - 19:18 »
Thanks for the answers.
« Last Edit: 6 Sep '06 - 21:34 by amit »

amit

  • Posts: 723
Re: questions about dithering and noise shaping
« Reply #3 on: 8 Nov '06 - 19:44 »
When playing lossless formats eg cd-audio or flac , is it worth using dither or noise shaping , as the original format of the audio is already in fix point format?

Is it possible for xmplay to ignore these options internally when playing lossless formats?

Ian @ un4seen

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Re: questions about dithering and noise shaping
« Reply #4 on: 9 Nov '06 - 16:29 »
It already does :)

If the output resolution is equal to or greater than the source resolution, then XMPlay won't apply any dither. That's if no DSP is applied, including volume/balance/amp, ie. volume=100, balance=centre, amp=0.

amit

  • Posts: 723
Re: questions about dithering and noise shaping
« Reply #5 on: 9 Nov '06 - 16:42 »
so , If currently all my cda files are amplified (in the saved setting) the dither can't be ignored (if enabled) when playing them?

Edit:

A DSP plugin such as audioscrobbler would be considered as a regular dsp plugin for that matter?
« Last Edit: 9 Nov '06 - 16:59 by amit »

amit

  • Posts: 723
Re: questions about dithering and noise shaping
« Reply #6 on: 16 Nov '06 - 13:57 »
sorry for these petty questions :)

will enabling autoamp prevent the dither from being disabled or as long as amp is on 0 it ok?

(as I didn't get response for my last two questions i am guessing the answers are :1.yes 2.no)

Thanks

Ian @ un4seen

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  • Posts: 20400
Re: questions about dithering and noise shaping
« Reply #7 on: 16 Nov '06 - 15:35 »
so , If currently all my cda files are amplified (in the saved setting) the dither can't be ignored (if enabled) when playing them?

If the sample data changes then dither can't be ignored, as the data probably isn't nice whole numbers anymore.

A DSP plugin such as audioscrobbler would be considered as a regular dsp plugin for that matter?

Yep, looking at the audioscrobbler code, it would currently be assumed to be modifying the data. That would be changed by its "DSP_Process" function returning 0 :)

will enabling autoamp prevent the dither from being disabled or as long as amp is on 0 it ok?

It's the amp slider that affects the sample data. If that's at 0, then the data isn't affected.

(as I didn't get response for my last two questions i am guessing the answers are :1.yes 2.no)

Sorry about that, I only just noticed them :)