Re: AudioConverter gives non normalized samples?!
Re: AudioConverter gives non normalized samples?!
- Subject: Re: AudioConverter gives non normalized samples?!
- From: "Mike Kluev" <email@hidden>
- Date: Thu, 29 Jan 2009 11:42:38 +0300
On Wed, 28 Jan 2009 12:07:29 -0800
Brian Willoughby <email@hidden> wrote:
On Jan 28, 2009, at 08:42, Doug Wyatt wrote:
You don't know how close to 1 you can get on the positive side
because you don't know whether the eventual integer has 12, 16, 20
or 64 bits.
Very good point.
That is incorrectly; it should always be multiplying and dividing
by 32768. I've submitted feedback to that effect.
Yes. I deleted Mike's asymmetrical conversion range,
that was not mine but Apple's :)
but I wanted
to reinforce the fact that the mul/div factor should always be the
same for both positive and negative, and it should be a nice power
of 2. Anything else creates distortion, especially in pass-through
situations. Many programmers obsess about reaching that last sample
value for certain waveforms, but the truth is that twos-complement
integers are asymmetrical by design, and you cannot fix this by
using an asymmetrical conversion - it just turns out worse.
I think the same. But still, do you guys know of any papers or
references
to internet pages, etc. that detail why the factor should be (1) the
same
and (2) a power of two -- to not cause distortions? I want to present
this information to our audio guys from a separate team that for some
reason use 0x7FFF instead of 0x8000 as the scaling factor in another
project.
Mike
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Coreaudio-api mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden