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Consolidate gdither noise code

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This commit is contained in:
Robin Gareus 2019-02-28 20:40:45 +01:00
parent 2a8d3ff4f0
commit 9131cd17a0
Signed by: rgareus
GPG Key ID: A090BCE02CF57F04
2 changed files with 14 additions and 45 deletions
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38
libs/ardour/ardour/noise.h
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@ -1,38 +0,0 @@
/*
Copyright (C) 2000-2007 Paul Davis
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef NOISE_H
#define NOISE_H
/* Can be overrriden with any code that produces whitenoise between 0.0f and
* 1.0f, eg (random() / (float)RAND_MAX) should be a good source of noise, but
* its expensive */
#ifndef GDITHER_NOISE
#define GDITHER_NOISE gdither_noise()
#endif
inline static float gdither_noise()
{
static uint32_t rnd = 23232323;
rnd = (rnd * 196314165) + 907633515;
return rnd * 2.3283064365387e-10f;
}
#endif

21
libs/audiographer/private/gdither/gdither.cc
View File

@ -19,7 +19,6 @@
#include "gdither_types_internal.h"
#include "gdither.h"
#include "noise.h"
/* this monstrosity is necessary to get access to lrintf() and random().
whoever is writing the glibc headers <cmath> and <cstdlib> should be
@ -62,6 +61,14 @@ static const float shaped_bs[] = { 2.033f, -2.165f, 1.959f, -1.590f, 0.6149f };
#define MIN_S24 -8388608
#define SCALE_S24 8388608.0f
inline static float gdither_noise ()
{
static uint32_t rnd = 23232323;
rnd = (rnd * 196314165) + 907633515;
return rnd * 2.3283064365387e-10f;
}
GDither gdither_new(GDitherType type, uint32_t channels,
GDitherSize bit_depth, int dither_depth)
@ -189,10 +196,10 @@ inline static void gdither_innner_loop(const GDitherType dt,
case GDitherNone:
break;
case GDitherRect:
tmp -= GDITHER_NOISE;
tmp -= gdither_noise ();
break;
case GDitherTri:
r = GDITHER_NOISE - 0.5f;
r = gdither_noise () - 0.5f;
tmp -= r - ts[channel];
ts[channel] = r;
break;
@ -202,7 +209,7 @@ inline static void gdither_innner_loop(const GDitherType dt,
ideal = tmp;
/* Run FIR and add white noise */
ss->buffer[ss->phase] = GDITHER_NOISE * 0.5f;
ss->buffer[ss->phase] = gdither_noise () * 0.5f;
tmp += ss->buffer[ss->phase] * shaped_bs[0]
+ ss->buffer[(ss->phase - 1) & GDITHER_SH_BUF_MASK]
* shaped_bs[1]
@ -265,10 +272,10 @@ inline static void gdither_innner_loop_fp(const GDitherType dt,
case GDitherNone:
break;
case GDitherRect:
tmp -= GDITHER_NOISE;
tmp -= gdither_noise ();
break;
case GDitherTri:
r = GDITHER_NOISE - 0.5f;
r = gdither_noise () - 0.5f;
tmp -= r - ts[channel];
ts[channel] = r;
break;
@ -278,7 +285,7 @@ inline static void gdither_innner_loop_fp(const GDitherType dt,
ideal = tmp;
/* Run FIR and add white noise */
ss->buffer[ss->phase] = GDITHER_NOISE * 0.5f;
ss->buffer[ss->phase] = gdither_noise () * 0.5f;
tmp += ss->buffer[ss->phase] * shaped_bs[0]
+ ss->buffer[(ss->phase - 1) & GDITHER_SH_BUF_MASK]
* shaped_bs[1]