----- Original Message -----
From: Roel VdB <[EMAIL PROTECTED]>
To: Gabriel Bouvigne <[EMAIL PROTECTED]>
Sent: Sunday, May 28, 2000 4:06 AM
Subject: Re[2]: [MP3 ENCODER] Normalize audio input
> Hello Gabriel,
>
> Saturday, May 27, 2000, 2:44:36 PM, you wrote:
>
> GB> Good point here. If I'm not too wrong, a kind of normalization can be
done
> GB> by just changing the scalefactor value. In this case, such an option
would not change the
> GB> encoding process. Lame could encode each frame as usual, but could
change
> GB> this value during the frame packaging. I think this should not
interfere
> GB> much with the main goal of Lame, wich is mp3 encoding.
>
> This "scalefactor", would this touch the "non uniform quantization" as
> described in the Davis Yen Pan doc?
> free quote: LIII raises input to 3/4th power to get more consistent SN
ratio
> over the range of quant values.
>
> I don't understand why you would raise a input level by 3/4th, encode
> and raise to 4/3th whilst decoding, but I take there was a reason for
> this, and maybe this is not something to tinker with?
>
I don't really understand the real utility of this 3/4 power. If someone
knows about it, please drop us a line.
About this normalization thing, here is a quote from Mark some times ago:
"One easy thing would be to change the value of global_gain.
it's an 8bit int stored for each channel of each granule.
Changing this +/-1 changes the volume by .75db."
It's the thing that I think could be used, without affecting the encoding
process.
Regards,
--
Gabriel Bouvigne - France
[EMAIL PROTECTED]
icq: 12138873
MP3' Tech: www.mp3-tech.org
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