Frank Klemm schrieb am Sam, 05 Aug 2000:
<snip>
> :: This seems to be an ATH problem. But isn't the ATH adjusted according to
> :: the VBR scale?
> ::
> That is VBR scale?
look out in LAME's sources for a line like:
gfc->ATH_lower = (4-gfp->VBR_q)*4.0;
here you can see that the ATH is lowered by 16 dB with -V0,
-V4 is the default and there you will get the usual ATH as
in constant bitrate coding.
>
> :: It's right that a switch to manually adjust the ATH would be good, as I also
> :: think that some low level pieces of classic music are encoded with too few
> :: bits.
> :: A rough solution is to completely disable use of the ATH with --noath
> ::
> Average Bitrate (fictitious example)
>
> Level SPL for FS
> below FS 70 dB 80 dB 90 dB 100 dB 110 dB 120 dB
> 0 180 185 180 175 165 150
> -10 175 180 185 180 175 165
> -20 165 175 180 185 180 175
> -30 150 165 175 180 185 180
> -40 130 150 165 175 180 185
> -50 105 130 150 165 175 180
> -60 80 105 130 150 165 175
> -70 50 80 105 130 150 165
> -80 20 50 80 105 130 150
> -90 0 20 50 80 105 130
>
> So if you calculate the bitrate for SPL/FS = 90 dB, you
> have the following deficiencies:
>
> Level SPL for FS
> below FS 70 dB 80 dB 90 dB 100 dB 110 dB 120 dB
> 0 - 5 - - - -
> -10 - - - - - -
> -20 - - - 5 - -
> -30 - - - 5 10 5
> -40 - - - 10 15 20
> -50 - - - 15 25 30
> -60 - - - 20 35 45
> -70 - - - 25 45 60
> -80 - - - 25 50 70
> -90 - - - 30 55 80
>
>
> So if you calculate the bitrate for SPL/FS = 90 dB and set B_min=100, you
> have the following deficiencies:
>
> Level SPL for FS
> below FS 70 dB 80 dB 90 dB 100 dB 110 dB 120 dB
> 0 - 5 - - - -
> -10 - - - - - -
> -20 - - - 5 - -
> -30 - - - 5 10 5
> -40 - - - 10 15 20
> -50 - - - 15 25 30
> -60 - - - 20 35 45
> -70 - - - 25 45 60
> -80 - - - 5 30 50
> -90 - - - - 5 30
>
> Using a bitrate of
> max (SPL/FS80, SPL/FS90, SPL/FS100, SPL/FS110)
> you can hear at any volume without audible noise.
Sorry, I don't get your point here, what is FS?
>
> --
> Mit freundlichen Gr��en
> Frank Klemm
>
> eMail | [EMAIL PROTECTED] home: [EMAIL PROTECTED]
> phone | +49 (3641) 64-2721 home: +49 (3641) 390545
> sMail | R.-Breitscheid-Str. 43, 07747 Jena, Germany
Frank, what LAME version are you using? And have you tried to disable
that scalefac_scale feature?
(If I remember right you are using -q1, leave it out and listen again)
Ciao Robert
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