Re: Normalize samples?
Re: Normalize samples?
- Subject: Re: Normalize samples?
- From: Urs Heckmann <email@hidden>
- Date: Wed, 17 Nov 2004 03:43:57 +0100
Hiya Tim,
There's no simple recipe for your job. After all, the input level of
any microphone can't be foreseen. Most time it's probably silent or
maybe some background noise, but your software doesn't know when the
maximum peak is reached.
I think what you look for is a so called "brickwall limiter" - That
would be a compressor with an infinite compression ratio, a short
attack time (say 5 - 20 milliseconds) and maybe a look ahead (latency!)
of exactly that attack time. I don't know, maybe Apple's built in
"AUPeakLimiter" Audio Unit might do the job?
On the other hand, there's an AU plugin called something like "Rider"
which slowly adjusts the audio gain to a certain level... dunno if that
is what you're after...
Cheers,
;) Urs
Am 17.11.2004 um 03:15 schrieb Tim Omernick:
Hi,
I searched through the list archives and could not find an answer to
this seemingly simple question. The application I'm working on needs
to perform some processing on samples from a microphone, but only if
the volume level of those samples exceeds some threshold.
Is there a way to normalize the samples passed to my IOProc so that
that every amplitude value lies within the range {-1.0, 1.0}? I get
different amplitude ranges for different microphones, even with
identical volume settings.
Am I missing something?
Thanks,
-Tim Omernick
Engineer, The Omni Group
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