1/*
2 * Copyright (C) 2012-2013 Michael Niedermayer (michaelni@gmx.at)
3 *
4 * This file is part of libswresample
5 *
6 * libswresample is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * libswresample is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with libswresample; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#include "libavutil/avassert.h"
22#include "swresample_internal.h"
23
24#include "noise_shaping_data.c"
25
26void swri_get_dither(SwrContext *s, void *dst, int len, unsigned seed, enum AVSampleFormat noise_fmt) {
27    double scale = s->dither.noise_scale;
28#define TMP_EXTRA 2
29    double *tmp = av_malloc_array(len + TMP_EXTRA, sizeof(double));
30    int i;
31
32    for(i=0; i<len + TMP_EXTRA; i++){
33        double v;
34        seed = seed* 1664525 + 1013904223;
35
36        switch(s->dither.method){
37            case SWR_DITHER_RECTANGULAR: v= ((double)seed) / UINT_MAX - 0.5; break;
38            default:
39                av_assert0(s->dither.method < SWR_DITHER_NB);
40                v = ((double)seed) / UINT_MAX;
41                seed = seed*1664525 + 1013904223;
42                v-= ((double)seed) / UINT_MAX;
43                break;
44        }
45        tmp[i] = v;
46    }
47
48    for(i=0; i<len; i++){
49        double v;
50
51        switch(s->dither.method){
52            default:
53                av_assert0(s->dither.method < SWR_DITHER_NB);
54                v = tmp[i];
55                break;
56            case SWR_DITHER_TRIANGULAR_HIGHPASS :
57                v = (- tmp[i] + 2*tmp[i+1] - tmp[i+2]) / sqrt(6);
58                break;
59        }
60
61        v*= scale;
62
63        switch(noise_fmt){
64            case AV_SAMPLE_FMT_S16P: ((int16_t*)dst)[i] = v; break;
65            case AV_SAMPLE_FMT_S32P: ((int32_t*)dst)[i] = v; break;
66            case AV_SAMPLE_FMT_FLTP: ((float  *)dst)[i] = v; break;
67            case AV_SAMPLE_FMT_DBLP: ((double *)dst)[i] = v; break;
68            default: av_assert0(0);
69        }
70    }
71
72    av_free(tmp);
73}
74
75int swri_dither_init(SwrContext *s, enum AVSampleFormat out_fmt, enum AVSampleFormat in_fmt)
76{
77    int i;
78    double scale = 0;
79
80    if (s->dither.method > SWR_DITHER_TRIANGULAR_HIGHPASS && s->dither.method <= SWR_DITHER_NS)
81        return AVERROR(EINVAL);
82
83    out_fmt = av_get_packed_sample_fmt(out_fmt);
84    in_fmt  = av_get_packed_sample_fmt( in_fmt);
85
86    if(in_fmt == AV_SAMPLE_FMT_FLT || in_fmt == AV_SAMPLE_FMT_DBL){
87        if(out_fmt == AV_SAMPLE_FMT_S32) scale = 1.0/(1L<<31);
88        if(out_fmt == AV_SAMPLE_FMT_S16) scale = 1.0/(1L<<15);
89        if(out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1.0/(1L<< 7);
90    }
91    if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S32 && (s->dither.output_sample_bits&31)) scale = 1;
92    if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S16) scale = 1L<<16;
93    if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<24;
94    if(in_fmt == AV_SAMPLE_FMT_S16 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<8;
95
96    scale *= s->dither.scale;
97
98    if (out_fmt == AV_SAMPLE_FMT_S32 && s->dither.output_sample_bits)
99        scale *= 1<<(32-s->dither.output_sample_bits);
100
101    s->dither.ns_pos = 0;
102    s->dither.noise_scale=   scale;
103    s->dither.ns_scale   =   scale;
104    s->dither.ns_scale_1 = scale ? 1/scale : 0;
105    memset(s->dither.ns_errors, 0, sizeof(s->dither.ns_errors));
106    for (i=0; filters[i].coefs; i++) {
107        const filter_t *f = &filters[i];
108        if (fabs(s->out_sample_rate - f->rate) / f->rate <= .05 && f->name == s->dither.method) {
109            int j;
110            s->dither.ns_taps = f->len;
111            for (j=0; j<f->len; j++)
112                s->dither.ns_coeffs[j] = f->coefs[j];
113            s->dither.ns_scale_1 *= 1 - exp(f->gain_cB * M_LN10 * 0.005) * 2 / (1<<(8*av_get_bytes_per_sample(out_fmt)));
114            break;
115        }
116    }
117    if (!filters[i].coefs && s->dither.method > SWR_DITHER_NS) {
118        av_log(s, AV_LOG_WARNING, "Requested noise shaping dither not available at this sampling rate, using triangular hp dither\n");
119        s->dither.method = SWR_DITHER_TRIANGULAR_HIGHPASS;
120    }
121
122    av_assert0(!s->preout.count);
123    s->dither.noise = s->preout;
124    s->dither.temp  = s->preout;
125    if (s->dither.method > SWR_DITHER_NS) {
126        s->dither.noise.bps = 4;
127        s->dither.noise.fmt = AV_SAMPLE_FMT_FLTP;
128        s->dither.noise_scale = 1;
129    }
130
131    return 0;
132}
133
134#define TEMPLATE_DITHER_S16
135#include "dither_template.c"
136#undef TEMPLATE_DITHER_S16
137
138#define TEMPLATE_DITHER_S32
139#include "dither_template.c"
140#undef TEMPLATE_DITHER_S32
141
142#define TEMPLATE_DITHER_FLT
143#include "dither_template.c"
144#undef TEMPLATE_DITHER_FLT
145
146#define TEMPLATE_DITHER_DBL
147#include "dither_template.c"
148#undef TEMPLATE_DITHER_DBL
149