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Update twolame to 0.3.13.

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lllucius
2013-10-24 04:32:13 +00:00
parent 99acb56af6
commit 3effa9693f
124 changed files with 44671 additions and 44430 deletions
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104
lib-src/twolame/libtwolame/ath.c
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@@ -18,7 +18,7 @@
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* $Id: ath.c,v 1.3 2008-02-01 19:44:27 richardash1981 Exp $
* $Id$
*
*/
@@ -34,68 +34,57 @@
/* freq in hz */
FLOAT ath_db(FLOAT f, FLOAT value)
{
/* from Painter & Spanias
modified by Gabriel Bouvigne to better fit the reality
ath = 3.640 * pow(f,-0.8)
- 6.800 * exp(-0.6*pow(f-3.4,2.0))
+ 6.000 * exp(-0.15*pow(f-8.7,2.0))
+ 0.6* 0.001 * pow(f,4.0);
In the past LAME was using the Painter &Spanias formula.
But we had some recurrent problems with HF content.
We measured real ATH values, and found the older formula
to be inacurate in the higher part. So we made this new
formula and this solved most of HF problematic testcases.
The tradeoff is that in VBR mode it increases a lot the
bitrate.*/
/* from Painter & Spanias modified by Gabriel Bouvigne to better fit the reality ath = 3.640 *
pow(f,-0.8) - 6.800 * exp(-0.6*pow(f-3.4,2.0)) + 6.000 * exp(-0.15*pow(f-8.7,2.0)) + 0.6*
0.001 * pow(f,4.0);
/*this curve can be udjusted according to the VBR scale:
it adjusts from something close to Painter & Spanias
on V9 up to Bouvigne's formula for V0. This way the VBR
bitrate is more balanced according to the -V value.*/
In the past LAME was using the Painter &Spanias formula. But we had some recurrent problems
with HF content. We measured real ATH values, and found the older formula to be inacurate in
the higher part. So we made this new formula and this solved most of HF problematic
testcases. The tradeoff is that in VBR mode it increases a lot the bitrate. */
FLOAT ath;
FLOAT valueold = 0.0;
if (f < -.3)
f=3410;
f /= 1000; // convert to khz
f = MAX(0.01, f);
f = MIN(18.0, f);
ath = 3.640 * pow(f,-0.8)
- 6.800 * exp(-0.6*pow(f-3.4,2.0))
+ 6.000 * exp(-0.15*pow(f-8.7,2.0))
+ (0.6+0.04*valueold)* 0.001 * pow(f,4.0);
/* MFC Feb 2003
I've changed the fudge technique on the code.
The "-l [float]" value raises/lowers the ATH by this many dB */
return (ath + value);
/* this curve can be udjusted according to the VBR scale: it adjusts from something close to
Painter & Spanias on V9 up to Bouvigne's formula for V0. This way the VBR bitrate is more
balanced according to the -V value. */
FLOAT ath;
FLOAT valueold = 0.0;
if (f < -.3)
f = 3410;
f /= 1000; // convert to khz
f = MAX(0.01, f);
f = MIN(18.0, f);
ath = 3.640 * pow(f, -0.8)
- 6.800 * exp(-0.6 * pow(f - 3.4, 2.0))
+ 6.000 * exp(-0.15 * pow(f - 8.7, 2.0))
+ (0.6 + 0.04 * valueold) * 0.001 * pow(f, 4.0);
/* MFC Feb 2003 I've changed the fudge technique on the code. The "-l [float]" value
raises/lowers the ATH by this many dB */
return (ath + value);
}
/* Convert ATH values from dB into energy values as required by the psycho model */
FLOAT ath_energy(FLOAT freq, FLOAT value)
{
FLOAT db;
db = ath_db(freq, 0) + value; // Originally: ath_db(freq,value)
/* The values in the standard, and from the ATH formula are in dB.
In the psycho model we are working in the energy domain. Hence the values that
are in the absthr_X tables are not in dB. This function converts from dB into the energy domain.
As noted on the LAME mailing list from years ago (MFC FIX find the reference), the
absolute threhsold of hearing values in the tables in the standard are dodgy - the
ATH in the tables do not correspond to any previously known values of the ATH.
From ISO 11172 Tables D.4.x
"A value of 0dB represents a level in the absolute threshold calculation of
96dB below the energy of a sine wave of amplitude 32760."
But I still don't know why the factor of 41.837375 is the value that it is.
MFC Feb 2003
*/
return(pow(10.0, (db+41.837375)*0.1));
FLOAT db;
db = ath_db(freq, 0) + value; // Originally: ath_db(freq,value)
/* The values in the standard, and from the ATH formula are in dB. In the psycho model we are
working in the energy domain. Hence the values that are in the absthr_X tables are not in
dB. This function converts from dB into the energy domain. As noted on the LAME mailing list
from years ago (MFC FIX find the reference), the absolute threhsold of hearing values in the
tables in the standard are dodgy - the ATH in the tables do not correspond to any previously
known values of the ATH. From ISO 11172 Tables D.4.x "A value of 0dB represents a level in
the absolute threshold calculation of 96dB below the energy of a sine wave of amplitude
32760." But I still don't know why the factor of 41.837375 is the value that it is. MFC Feb
2003 */
return (pow(10.0, (db + 41.837375) * 0.1));
}
@@ -104,9 +93,10 @@ FLOAT ath_energy(FLOAT freq, FLOAT value)
see for example "Zwicker: Psychoakustik, 1982; ISBN 3-540-11401-7 */
FLOAT ath_freq2bark(FLOAT freq)
{
if (freq<0) freq=0;
freq = freq * 0.001;
return 13.0*atan(.76*freq) + 3.5*atan(freq*freq/(7.5*7.5));
if (freq < 0)
freq = 0;
freq = freq * 0.001;
return 13.0 * atan(.76 * freq) + 3.5 * atan(freq * freq / (7.5 * 7.5));
}
// vim:ts=4:sw=4:nowrap: