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gst/audioconvert/: Implement a linear congruential generator as pseudo random number generator for the dither noise. ...

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Original commit message from CVS:
* gst/audioconvert/audioconvert.h:
* gst/audioconvert/gstaudioquantize.c:
(gst_audio_quantize_setup_dither),
(gst_audio_quantize_free_dither):
* gst/audioconvert/gstfastrandom.h:
Implement a linear congruential generator as pseudo random number
generator for the dither noise. This is about 2 times faster than
using GLib's mersenne twister. Also this uses only integer math for
generating integers while GLib internally uses floating point math.
This commit is contained in:
Sebastian Dröge 2008-07-23 18:34:19 +00:00
parent 6ae4a9ccb0
commit ef5004e56e
4 changed files with 116 additions and 23 deletions
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12
ChangeLog
View file

@ -1,3 +1,15 @@
2008-07-23 Sebastian Dröge <sebastian.droege@collabora.co.uk>
* gst/audioconvert/audioconvert.h:
* gst/audioconvert/gstaudioquantize.c:
(gst_audio_quantize_setup_dither),
(gst_audio_quantize_free_dither):
* gst/audioconvert/gstfastrandom.h:
Implement a linear congruential generator as pseudo random number
generator for the dither noise. This is about 2 times faster than
using GLib's mersenne twister. Also this uses only integer math for
generating integers while GLib internally uses floating point math.
2008-07-23 Michael Smith <msmith@songbirdnest.com>
* configure.ac:

2
gst/audioconvert/audioconvert.h
View file

@ -121,8 +121,6 @@ struct _AudioConvertCtx
GstAudioConvertDithering dither;
GstAudioConvertNoiseShaping ns;
/* random number generate for dither noise */
GRand *dither_random;
/* last random number generated per channel for hifreq TPDF dither */
gpointer last_random;
/* contains the past quantization errors, error[out_channels][count] */

35
gst/audioconvert/gstaudioquantize.c
View file

@ -37,6 +37,8 @@
#include "audioconvert.h"
#include "gstaudioquantize.h"
#include "gstfastrandom.h"
#define MAKE_QUANTIZE_FUNC_NAME(name) \
gst_audio_quantize_quantize_##name
@ -144,8 +146,8 @@ MAKE_QUANTIZE_FUNC_NAME (name) (AudioConvertCtx *ctx, gdouble *src, \
gint32 dither = (1<<(scale));
#define ADD_DITHER_RPDF_I() \
rand = g_rand_int_range (ctx->dither_random, bias - dither, \
bias + dither); \
rand = gst_fast_random_int32_range (bias - dither, \
bias + dither); \
if (rand > 0 && tmp > 0 && G_MAXINT32 - tmp <= rand) \
tmp = G_MAXINT32; \
else if (rand < 0 && tmp < 0 && G_MININT32 - tmp >= rand) \
@ -157,8 +159,7 @@ MAKE_QUANTIZE_FUNC_NAME (name) (AudioConvertCtx *ctx, gdouble *src, \
gdouble dither = 1.0/(1U<<(32 - scale - 1));
#define ADD_DITHER_RPDF_F() \
tmp += g_rand_double_range (ctx->dither_random, - dither, \
dither);
tmp += gst_fast_random_double_range (- dither, dither);
#define INIT_DITHER_TPDF_I() \
gint32 rand; \
@ -166,10 +167,10 @@ MAKE_QUANTIZE_FUNC_NAME (name) (AudioConvertCtx *ctx, gdouble *src, \
bias = bias >> 1;
#define ADD_DITHER_TPDF_I() \
rand = g_rand_int_range (ctx->dither_random, bias - dither, \
bias + dither - 1) \
+ g_rand_int_range (ctx->dither_random, bias - dither, \
bias + dither - 1); \
rand = gst_fast_random_int32_range (bias - dither, \
bias + dither - 1) \
+ gst_fast_random_int32_range (bias - dither, \
bias + dither - 1); \
if (rand > 0 && tmp > 0 && G_MAXINT32 - tmp <= rand) \
tmp = G_MAXINT32; \
else if (rand < 0 && tmp < 0 && G_MININT32 - tmp >= rand) \
@ -181,10 +182,8 @@ MAKE_QUANTIZE_FUNC_NAME (name) (AudioConvertCtx *ctx, gdouble *src, \
gdouble dither = 1.0/(1U<<(32 - scale));
#define ADD_DITHER_TPDF_F() \
tmp += g_rand_double_range (ctx->dither_random, - dither, \
dither) \
+ g_rand_double_range (ctx->dither_random, - dither, \
dither);
tmp += gst_fast_random_double_range (- dither, dither) \
+ gst_fast_random_double_range (- dither, dither);
#define INIT_DITHER_TPDF_HF_I() \
gint32 rand; \
@ -193,8 +192,8 @@ MAKE_QUANTIZE_FUNC_NAME (name) (AudioConvertCtx *ctx, gdouble *src, \
bias = bias >> 1;
#define ADD_DITHER_TPDF_HF_I() \
tmp_rand = g_rand_int_range (ctx->dither_random, bias - dither, \
bias + dither); \
tmp_rand = gst_fast_random_int32_range (bias - dither, \
bias + dither); \
rand = tmp_rand - last_random[chan_pos]; \
last_random[chan_pos] = tmp_rand; \
if (rand > 0 && tmp > 0 && G_MAXINT32 - tmp <= rand) \
@ -213,8 +212,7 @@ MAKE_QUANTIZE_FUNC_NAME (name) (AudioConvertCtx *ctx, gdouble *src, \
gdouble *last_random = (gdouble *) ctx->last_random, tmp_rand;
#define ADD_DITHER_TPDF_HF_F() \
tmp_rand = g_rand_double_range (ctx->dither_random, - dither, \
dither); \
tmp_rand = gst_fast_random_double_range (- dither, dither); \
rand = tmp_rand - last_random[chan_pos]; \
last_random[chan_pos] = tmp_rand; \
tmp += rand;
@ -445,16 +443,13 @@ gst_audio_quantize_setup_dither (AudioConvertCtx * ctx)
ctx->last_random = g_new0 (gint32, ctx->out.channels);
else
ctx->last_random = g_new0 (gdouble, ctx->out.channels);
ctx->dither_random = g_rand_new ();
break;
case DITHER_RPDF:
case DITHER_TPDF:
ctx->dither_random = g_rand_new ();
ctx->last_random = NULL;
break;
case DITHER_NONE:
default:
ctx->dither_random = NULL;
ctx->last_random = NULL;
break;
}
@ -465,8 +460,6 @@ static void
gst_audio_quantize_free_dither (AudioConvertCtx * ctx)
{
g_free (ctx->last_random);
if (ctx->dither_random)
g_rand_free (ctx->dither_random);
return;
}

90
gst/audioconvert/gstfastrandom.h Normal file
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@ -0,0 +1,90 @@
/* GStreamer
* Copyright (C) 2008 Sebastian Dröge <sebastian.droege@collabora.co.uk>
*
* gstfastrandom.h: Fast, bad PNRG
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include <glib.h>
#ifndef __GST_FAST_RANDOM__
#define __GST_FAST_RANDOM__
/* transform [0..2^32] -> [0..1] */
#define GST_RAND_DOUBLE_TRANSFORM 2.3283064365386962890625e-10
/* This is the base function, implementing a linear congruential generator
* and returning a pseudo random number between 0 and 2^32 - 1.
*/
static inline guint32
gst_fast_random_uint32 ()
{
static guint32 state = 0xdeadbeef;
return (state = state * 1103515245 + 12345);
}
static inline guint32
gst_fast_random_uint32_range (gint32 start, gint32 end)
{
guint64 tmp = gst_fast_random_uint32 ();
tmp = (tmp * (end - start)) / G_MAXUINT32 + start;
return (guint32) tmp;
}
static inline gint32
gst_fast_random_int32 (void)
{
return (gint32) gst_fast_random_uint32 ();
}
static inline gint32
gst_fast_random_int32_range (gint32 start, gint32 end)
{
gint64 tmp = gst_fast_random_uint32 ();
tmp = (tmp * (end - start)) / G_MAXUINT32 + start;
return (gint32) tmp;
}
static inline gdouble
gst_fast_random_double (void)
{
gdouble ret;
ret = gst_fast_random_uint32 () * GST_RAND_DOUBLE_TRANSFORM;
ret = (ret + gst_fast_random_uint32 ()) * GST_RAND_DOUBLE_TRANSFORM;
if (ret >= 1.0)
return gst_fast_random_double ();
return ret;
}
static inline gdouble
gst_fast_random_double_range (gdouble start, gdouble end)
{
return gst_fast_random_double () * (end - start) + start;
}
#undef GST_RAND_DOUBLE_TRANSFORM
#endif /* __GST_FAST_RANDOM__ */