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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 
swri_get_dither(SwrContext * s,void * dst,int len,unsigned seed,enum AVSampleFormat noise_fmt)26 int 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     if (!tmp)
33         return AVERROR(ENOMEM);
34 
35     for(i=0; i<len + TMP_EXTRA; i++){
36         double v;
37         seed = seed* 1664525 + 1013904223;
38 
39         switch(s->dither.method){
40             case SWR_DITHER_RECTANGULAR: v= ((double)seed) / UINT_MAX - 0.5; break;
41             default:
42                 av_assert0(s->dither.method < SWR_DITHER_NB);
43                 v = ((double)seed) / UINT_MAX;
44                 seed = seed*1664525 + 1013904223;
45                 v-= ((double)seed) / UINT_MAX;
46                 break;
47         }
48         tmp[i] = v;
49     }
50 
51     for(i=0; i<len; i++){
52         double v;
53 
54         switch(s->dither.method){
55             default:
56                 av_assert0(s->dither.method < SWR_DITHER_NB);
57                 v = tmp[i];
58                 break;
59             case SWR_DITHER_TRIANGULAR_HIGHPASS :
60                 v = (- tmp[i] + 2*tmp[i+1] - tmp[i+2]) / sqrt(6);
61                 break;
62         }
63 
64         v*= scale;
65 
66         switch(noise_fmt){
67             case AV_SAMPLE_FMT_S16P: ((int16_t*)dst)[i] = v; break;
68             case AV_SAMPLE_FMT_S32P: ((int32_t*)dst)[i] = v; break;
69             case AV_SAMPLE_FMT_FLTP: ((float  *)dst)[i] = v; break;
70             case AV_SAMPLE_FMT_DBLP: ((double *)dst)[i] = v; break;
71             default: av_assert0(0);
72         }
73     }
74 
75     av_free(tmp);
76     return 0;
77 }
78 
swri_dither_init(SwrContext * s,enum AVSampleFormat out_fmt,enum AVSampleFormat in_fmt)79 av_cold int swri_dither_init(SwrContext *s, enum AVSampleFormat out_fmt, enum AVSampleFormat in_fmt)
80 {
81     int i;
82     double scale = 0;
83 
84     if (s->dither.method > SWR_DITHER_TRIANGULAR_HIGHPASS && s->dither.method <= SWR_DITHER_NS)
85         return AVERROR(EINVAL);
86 
87     out_fmt = av_get_packed_sample_fmt(out_fmt);
88     in_fmt  = av_get_packed_sample_fmt( in_fmt);
89 
90     if(in_fmt == AV_SAMPLE_FMT_FLT || in_fmt == AV_SAMPLE_FMT_DBL){
91         if(out_fmt == AV_SAMPLE_FMT_S32) scale = 1.0/(1LL<<31);
92         if(out_fmt == AV_SAMPLE_FMT_S16) scale = 1.0/(1LL<<15);
93         if(out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1.0/(1LL<< 7);
94     }
95     if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S32 && (s->dither.output_sample_bits&31)) scale = 1;
96     if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S16) scale = 1<<16;
97     if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1<<24;
98     if(in_fmt == AV_SAMPLE_FMT_S16 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1<<8;
99 
100     scale *= s->dither.scale;
101 
102     if (out_fmt == AV_SAMPLE_FMT_S32 && s->dither.output_sample_bits)
103         scale *= 1<<(32-s->dither.output_sample_bits);
104 
105     if (scale == 0) {
106         s->dither.method = 0;
107         return 0;
108     }
109 
110     s->dither.ns_pos = 0;
111     s->dither.noise_scale=   scale;
112     s->dither.ns_scale   =   scale;
113     s->dither.ns_scale_1 = scale ? 1/scale : 0;
114     memset(s->dither.ns_errors, 0, sizeof(s->dither.ns_errors));
115     for (i=0; filters[i].coefs; i++) {
116         const filter_t *f = &filters[i];
117         if (llabs(s->out_sample_rate - f->rate)*20 <= f->rate && f->name == s->dither.method) {
118             int j;
119             s->dither.ns_taps = f->len;
120             for (j=0; j<f->len; j++)
121                 s->dither.ns_coeffs[j] = f->coefs[j];
122             s->dither.ns_scale_1 *= 1 - exp(f->gain_cB * M_LN10 * 0.005) * 2 / (1<<(8*av_get_bytes_per_sample(out_fmt)));
123             break;
124         }
125     }
126     if (!filters[i].coefs && s->dither.method > SWR_DITHER_NS) {
127         av_log(s, AV_LOG_WARNING, "Requested noise shaping dither not available at this sampling rate, using triangular hp dither\n");
128         s->dither.method = SWR_DITHER_TRIANGULAR_HIGHPASS;
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