483 lines
12 KiB
C++
483 lines
12 KiB
C++
/*
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* Copyright (C) 2002 Steve Harris <steve@plugin.org.uk>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include "gdither_types_internal.h"
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#include "gdither.h"
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/* this monstrosity is necessary to get access to lrintf() and random().
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whoever is writing the glibc headers <cmath> and <cstdlib> should be
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hauled off to a programmer re-education camp. for the rest of
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their natural lives. or longer. <paul@linuxaudiosystems.com>
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*/
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#define _ISOC9X_SOURCE 1
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#define _ISOC99_SOURCE 1
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#ifdef __cplusplus
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#include <cmath>
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#else
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#include <math.h>
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#endif
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#undef __USE_SVID
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#define __USE_SVID 1
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#ifdef __cplusplus
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#include <cstdlib>
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#else
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#include <stdlib.h>
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#endif
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#include <assert.h>
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#include <sys/types.h>
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/* Lipshitz's minimally audible FIR, only really works for 46kHz-ish signals */
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static const float shaped_bs[] = { 2.033f, -2.165f, 1.959f, -1.590f, 0.6149f };
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/* Some useful constants */
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#define MAX_U8 255
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#define MIN_U8 0
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#define SCALE_U8 128.0f
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#define MAX_S16 32767
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#define MIN_S16 -32768
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#define SCALE_S16 32768.0f
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#define MAX_S24 8388607
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#define MIN_S24 -8388608
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#define SCALE_S24 8388608.0f
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inline static float gdither_noise ()
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{
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static uint32_t rnd = 23232323;
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rnd = (rnd * 196314165) + 907633515;
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return rnd * 2.3283064365387e-10f;
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}
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GDither gdither_new(GDitherType type, uint32_t channels,
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GDitherSize bit_depth, int dither_depth)
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{
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GDither s;
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s = (GDither)calloc(1, sizeof(struct GDither_s));
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s->type = type;
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s->channels = channels;
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s->bit_depth = (int)bit_depth;
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if (dither_depth <= 0 || dither_depth > (int)bit_depth) {
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dither_depth = (int)bit_depth;
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}
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s->dither_depth = dither_depth;
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s->scale = (float)(1LL << (dither_depth - 1));
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if (bit_depth == GDitherFloat || bit_depth == GDitherDouble) {
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s->post_scale_fp = 1.0f / s->scale;
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s->post_scale = 0;
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} else {
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s->post_scale_fp = 0.0f;
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s->post_scale = 1 << ((int)bit_depth - dither_depth);
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}
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switch (bit_depth) {
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case GDither8bit:
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/* Unsigned 8 bit */
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s->bias = 1.0f;
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s->clamp_u = 255;
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s->clamp_l = 0;
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break;
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case GDither16bit:
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/* Signed 16 bit */
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s->bias = 0.0f;
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s->clamp_u = 32767;
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s->clamp_l = -32768;
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break;
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case GDither32bit:
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/* Signed 24 bit, in upper 24 bits of 32 bit word */
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s->bias = 0.0f;
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s->clamp_u = 8388607;
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s->clamp_l = -8388608;
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break;
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case GDitherFloat:
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/* normalised float */
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s->bias = 0.0f;
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s->clamp_u = lrintf(s->scale);
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s->clamp_l = lrintf(-s->scale);
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break;
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case GDitherDouble:
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/* normalised float */
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s->bias = 0.0f;
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s->clamp_u = lrintf(s->scale);
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s->clamp_l = lrintf(-s->scale);
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break;
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case GDitherPerformanceTest:
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/* special performance test case */
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s->scale = SCALE_S24;
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s->post_scale = 256;
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s->bias = 0.0f;
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s->clamp_u = 8388607;
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s->clamp_l = -8388608;
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break;
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default:
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/* Not a bit depth we can handle */
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free(s);
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return NULL;
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break;
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}
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switch (type) {
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case GDitherNone:
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case GDitherRect:
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/* No state */
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break;
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case GDitherTri:
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/* The last whitenoise sample */
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s->tri_state = (float *) calloc(channels, sizeof(float));
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break;
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case GDitherShaped:
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/* The error from the last few samples encoded */
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s->shaped_state = (GDitherShapedState*)
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calloc(channels, sizeof(GDitherShapedState));
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break;
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}
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return s;
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}
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void gdither_free(GDither s)
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{
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if (s) {
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free(s->tri_state);
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free(s->shaped_state);
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free(s);
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}
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}
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inline static void gdither_innner_loop(const GDitherType dt,
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const uint32_t stride, const float bias, const float scale,
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const uint32_t post_scale, const int bit_depth,
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const uint32_t channel, const uint32_t length, float *ts,
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GDitherShapedState *ss, float const *x, void *y, const int clamp_u,
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const int clamp_l)
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{
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uint32_t pos, i;
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uint8_t *o8 = (uint8_t*) y;
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int16_t *o16 = (int16_t*) y;
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int32_t *o32 = (int32_t*) y;
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float tmp, r, ideal;
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int64_t clamped;
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i = channel;
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for (pos = 0; pos < length; pos++, i += stride) {
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tmp = x[i] * scale + bias;
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switch (dt) {
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case GDitherNone:
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break;
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case GDitherRect:
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tmp -= gdither_noise ();
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break;
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case GDitherTri:
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r = gdither_noise () - 0.5f;
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tmp -= r - ts[channel];
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ts[channel] = r;
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break;
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case GDitherShaped:
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/* Save raw value for error calculations */
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assert (ss);
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ideal = tmp;
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/* Run FIR and add white noise */
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ss->buffer[ss->phase] = gdither_noise () * 0.5f;
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tmp += ss->buffer[ss->phase] * shaped_bs[0]
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+ ss->buffer[(ss->phase - 1) & GDITHER_SH_BUF_MASK]
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* shaped_bs[1]
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+ ss->buffer[(ss->phase - 2) & GDITHER_SH_BUF_MASK]
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* shaped_bs[2]
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+ ss->buffer[(ss->phase - 3) & GDITHER_SH_BUF_MASK]
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* shaped_bs[3]
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+ ss->buffer[(ss->phase - 4) & GDITHER_SH_BUF_MASK]
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* shaped_bs[4];
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/* Roll buffer and store last error */
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ss->phase = (ss->phase + 1) & GDITHER_SH_BUF_MASK;
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ss->buffer[ss->phase] = (float)lrintf(tmp) - ideal;
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break;
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}
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clamped = lrintf(tmp);
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if (clamped > clamp_u) {
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clamped = clamp_u;
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} else if (clamped < clamp_l) {
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clamped = clamp_l;
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}
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switch (bit_depth) {
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case GDither8bit:
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o8[i] = (uint8_t) (clamped * post_scale);
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break;
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case GDither16bit:
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o16[i] = (int16_t) (clamped * post_scale);
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break;
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case GDither32bit:
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o32[i] = (int32_t) (clamped * post_scale);
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break;
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}
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}
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}
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/* floating pint version of the inner loop function */
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inline static void gdither_innner_loop_fp(const GDitherType dt,
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const uint32_t stride, const float bias, const float scale,
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const float post_scale, const int bit_depth,
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const uint32_t channel, const uint32_t length, float *ts,
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GDitherShapedState *ss, float const *x, void *y, const int clamp_u,
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const int clamp_l)
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{
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uint32_t pos, i;
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float *oflt = (float*) y;
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double *odbl = (double*) y;
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float tmp, r, ideal;
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double clamped;
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i = channel;
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for (pos = 0; pos < length; pos++, i += stride) {
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tmp = x[i] * scale + bias;
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switch (dt) {
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case GDitherNone:
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break;
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case GDitherRect:
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tmp -= gdither_noise ();
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break;
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case GDitherTri:
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r = gdither_noise () - 0.5f;
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tmp -= r - ts[channel];
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ts[channel] = r;
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break;
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case GDitherShaped:
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assert (ss);
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/* Save raw value for error calculations */
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ideal = tmp;
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/* Run FIR and add white noise */
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ss->buffer[ss->phase] = gdither_noise () * 0.5f;
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tmp += ss->buffer[ss->phase] * shaped_bs[0]
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+ ss->buffer[(ss->phase - 1) & GDITHER_SH_BUF_MASK]
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* shaped_bs[1]
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+ ss->buffer[(ss->phase - 2) & GDITHER_SH_BUF_MASK]
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* shaped_bs[2]
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+ ss->buffer[(ss->phase - 3) & GDITHER_SH_BUF_MASK]
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* shaped_bs[3]
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+ ss->buffer[(ss->phase - 4) & GDITHER_SH_BUF_MASK]
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* shaped_bs[4];
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/* Roll buffer and store last error */
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ss->phase = (ss->phase + 1) & GDITHER_SH_BUF_MASK;
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ss->buffer[ss->phase] = (float)lrintf(tmp) - ideal;
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break;
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}
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clamped = (double)lrintf(tmp);
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if (clamped > clamp_u) {
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clamped = clamp_u;
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} else if (clamped < clamp_l) {
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clamped = clamp_l;
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}
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switch (bit_depth) {
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case GDitherFloat:
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oflt[i] = (float) (clamped * post_scale);
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break;
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case GDitherDouble:
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odbl[i] = (double) (clamped * post_scale);
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break;
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}
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}
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}
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#define GDITHER_CONV_BLOCK 512
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void gdither_run(GDither s, uint32_t channel, uint32_t length,
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double const *x, void *y)
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{
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float conv[GDITHER_CONV_BLOCK];
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uint32_t i, pos;
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char *ycast = (char *)y;
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int step;
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switch (s->bit_depth) {
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case GDither8bit:
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step = 1;
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break;
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case GDither16bit:
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step = 2;
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break;
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case GDither32bit:
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case GDitherFloat:
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step = 4;
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break;
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case GDitherDouble:
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step = 8;
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break;
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default:
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step = 0;
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break;
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}
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pos = 0;
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while (pos < length) {
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for (i=0; (i + pos) < length && i < GDITHER_CONV_BLOCK; i++) {
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conv[i] = x[pos + i];
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}
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gdither_runf(s, channel, i, conv, ycast + s->channels * step);
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pos += i;
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}
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}
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void gdither_runf(GDither s, uint32_t channel, uint32_t length,
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float const *x, void *y)
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{
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uint32_t pos, i;
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float tmp;
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int64_t clamped;
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GDitherShapedState *ss = NULL;
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if (!s || channel >= s->channels) {
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return;
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}
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if (s->shaped_state) {
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ss = s->shaped_state + channel;
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}
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if (s->type == GDitherNone && s->bit_depth == 23) {
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int32_t *o32 = (int32_t*) y;
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for (pos = 0; pos < length; pos++) {
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i = channel + (pos * s->channels);
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tmp = x[i] * 8388608.0f;
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clamped = lrintf(tmp);
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if (clamped > 8388607) {
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clamped = 8388607;
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} else if (clamped < -8388608) {
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clamped = -8388608;
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}
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o32[i] = (int32_t) (clamped * 256);
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}
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return;
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}
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/* some common case handling code - looks a bit wierd, but it allows
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* the compiler to optimise out the branches in the inner loop */
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if (s->bit_depth == 8 && s->dither_depth == 8) {
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switch (s->type) {
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case GDitherNone:
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gdither_innner_loop(GDitherNone, s->channels, 128.0f, SCALE_U8,
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1, 8, channel, length, NULL, NULL, x, y,
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MAX_U8, MIN_U8);
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break;
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case GDitherRect:
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gdither_innner_loop(GDitherRect, s->channels, 128.0f, SCALE_U8,
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1, 8, channel, length, NULL, NULL, x, y,
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MAX_U8, MIN_U8);
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break;
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case GDitherTri:
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gdither_innner_loop(GDitherTri, s->channels, 128.0f, SCALE_U8,
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1, 8, channel, length, s->tri_state,
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NULL, x, y, MAX_U8, MIN_U8);
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break;
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case GDitherShaped:
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gdither_innner_loop(GDitherShaped, s->channels, 128.0f, SCALE_U8,
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1, 8, channel, length, NULL,
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ss, x, y, MAX_U8, MIN_U8);
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break;
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}
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} else if (s->bit_depth == 16 && s->dither_depth == 16) {
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switch (s->type) {
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case GDitherNone:
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gdither_innner_loop(GDitherNone, s->channels, 0.0f, SCALE_S16,
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1, 16, channel, length, NULL, NULL, x, y,
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MAX_S16, MIN_S16);
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break;
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case GDitherRect:
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gdither_innner_loop(GDitherRect, s->channels, 0.0f, SCALE_S16,
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1, 16, channel, length, NULL, NULL, x, y,
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MAX_S16, MIN_S16);
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break;
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case GDitherTri:
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gdither_innner_loop(GDitherTri, s->channels, 0.0f, SCALE_S16,
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1, 16, channel, length, s->tri_state,
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NULL, x, y, MAX_S16, MIN_S16);
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break;
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case GDitherShaped:
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gdither_innner_loop(GDitherShaped, s->channels, 0.0f,
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SCALE_S16, 1, 16, channel, length, NULL,
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ss, x, y, MAX_S16, MIN_S16);
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break;
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}
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} else if (s->bit_depth == 32 && s->dither_depth == 24) {
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switch (s->type) {
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case GDitherNone:
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gdither_innner_loop(GDitherNone, s->channels, 0.0f, SCALE_S24,
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256, 32, channel, length, NULL, NULL, x,
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y, MAX_S24, MIN_S24);
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break;
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case GDitherRect:
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gdither_innner_loop(GDitherRect, s->channels, 0.0f, SCALE_S24,
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256, 32, channel, length, NULL, NULL, x,
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y, MAX_S24, MIN_S24);
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break;
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case GDitherTri:
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gdither_innner_loop(GDitherTri, s->channels, 0.0f, SCALE_S24,
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256, 32, channel, length, s->tri_state,
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NULL, x, y, MAX_S24, MIN_S24);
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break;
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case GDitherShaped:
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gdither_innner_loop(GDitherShaped, s->channels, 0.0f, SCALE_S24,
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256, 32, channel, length,
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NULL, ss, x, y, MAX_S24, MIN_S24);
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break;
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}
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} else if (s->bit_depth == GDitherFloat || s->bit_depth == GDitherDouble) {
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gdither_innner_loop_fp(s->type, s->channels, s->bias, s->scale,
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s->post_scale_fp, s->bit_depth, channel, length,
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s->tri_state, ss, x, y, s->clamp_u, s->clamp_l);
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} else {
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/* no special case handling, just process it from the struct */
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gdither_innner_loop(s->type, s->channels, s->bias, s->scale,
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s->post_scale, s->bit_depth, channel,
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length, s->tri_state, ss, x, y, s->clamp_u,
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s->clamp_l);
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}
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}
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