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1 /*
2  * Copyright (c) 2015 Kyle Swanson <k@ylo.ph>.
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public License
8  * as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg 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
14  * GNU Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public License
17  * along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include "libavutil/opt.h"
22 #include "audio.h"
23 #include "avfilter.h"
24 #include "filters.h"
25 #include "internal.h"
26 #include "libavutil/lfg.h"
27 #include "libavutil/random_seed.h"
28 
29 typedef struct ANoiseSrcContext {
30     const AVClass *class;
31     int sample_rate;
32     double amplitude;
33     int64_t duration;
34     int color;
35     int64_t seed;
36     int nb_samples;
37 
38     int64_t pts;
39     int infinite;
40     double (*filter)(double white, double *buf, double half_amplitude);
41     double buf[7];
42     AVLFG c;
43 } ANoiseSrcContext;
44 
45 enum NoiseMode {
46     NM_WHITE,
47     NM_PINK,
48     NM_BROWN,
49     NM_BLUE,
50     NM_VIOLET,
51     NM_VELVET,
52     NM_NB
53 };
54 
55 #define OFFSET(x) offsetof(ANoiseSrcContext, x)
56 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
57 
58 static const AVOption anoisesrc_options[] = {
59     { "sample_rate",  "set sample rate",  OFFSET(sample_rate),  AV_OPT_TYPE_INT,       {.i64 = 48000},     15,  INT_MAX,    FLAGS },
60     { "r",            "set sample rate",  OFFSET(sample_rate),  AV_OPT_TYPE_INT,       {.i64 = 48000},     15,  INT_MAX,    FLAGS },
61     { "amplitude",    "set amplitude",    OFFSET(amplitude),    AV_OPT_TYPE_DOUBLE,    {.dbl = 1.},        0.,  1.,         FLAGS },
62     { "a",            "set amplitude",    OFFSET(amplitude),    AV_OPT_TYPE_DOUBLE,    {.dbl = 1.},        0.,  1.,         FLAGS },
63     { "duration",     "set duration",     OFFSET(duration),     AV_OPT_TYPE_DURATION,  {.i64 =  0},         0,  INT64_MAX,  FLAGS },
64     { "d",            "set duration",     OFFSET(duration),     AV_OPT_TYPE_DURATION,  {.i64 =  0},         0,  INT64_MAX,  FLAGS },
65     { "color",        "set noise color",  OFFSET(color),        AV_OPT_TYPE_INT,       {.i64 =  0},         0,  NM_NB - 1,  FLAGS, "color" },
66     { "colour",       "set noise color",  OFFSET(color),        AV_OPT_TYPE_INT,       {.i64 =  0},         0,  NM_NB - 1,  FLAGS, "color" },
67     { "c",            "set noise color",  OFFSET(color),        AV_OPT_TYPE_INT,       {.i64 =  0},         0,  NM_NB - 1,  FLAGS, "color" },
68     {     "white",    0,                  0,                    AV_OPT_TYPE_CONST,     {.i64 = NM_WHITE},   0,  0,          FLAGS, "color" },
69     {     "pink",     0,                  0,                    AV_OPT_TYPE_CONST,     {.i64 = NM_PINK},    0,  0,          FLAGS, "color" },
70     {     "brown",    0,                  0,                    AV_OPT_TYPE_CONST,     {.i64 = NM_BROWN},   0,  0,          FLAGS, "color" },
71     {     "blue",     0,                  0,                    AV_OPT_TYPE_CONST,     {.i64 = NM_BLUE},    0,  0,          FLAGS, "color" },
72     {     "violet",   0,                  0,                    AV_OPT_TYPE_CONST,     {.i64 = NM_VIOLET},  0,  0,          FLAGS, "color" },
73     {     "velvet",   0,                  0,                    AV_OPT_TYPE_CONST,     {.i64 = NM_VELVET},  0,  0,          FLAGS, "color" },
74     { "seed",         "set random seed",  OFFSET(seed),         AV_OPT_TYPE_INT64,     {.i64 = -1},        -1,  UINT_MAX,   FLAGS },
75     { "s",            "set random seed",  OFFSET(seed),         AV_OPT_TYPE_INT64,     {.i64 = -1},        -1,  UINT_MAX,   FLAGS },
76     { "nb_samples",   "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 1, INT_MAX, FLAGS },
77     { "n",            "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 1, INT_MAX, FLAGS },
78     {NULL}
79 };
80 
81 AVFILTER_DEFINE_CLASS(anoisesrc);
82 
query_formats(AVFilterContext * ctx)83 static av_cold int query_formats(AVFilterContext *ctx)
84 {
85     ANoiseSrcContext *s = ctx->priv;
86     static const int64_t chlayouts[] = { AV_CH_LAYOUT_MONO, -1 };
87     int sample_rates[] = { s->sample_rate, -1 };
88     static const enum AVSampleFormat sample_fmts[] = {
89         AV_SAMPLE_FMT_DBL,
90         AV_SAMPLE_FMT_NONE
91     };
92 
93     AVFilterFormats *formats;
94     AVFilterChannelLayouts *layouts;
95     int ret;
96 
97     formats = ff_make_format_list(sample_fmts);
98     if (!formats)
99         return AVERROR(ENOMEM);
100     ret = ff_set_common_formats (ctx, formats);
101     if (ret < 0)
102         return ret;
103 
104     layouts = ff_make_format64_list(chlayouts);
105     if (!layouts)
106         return AVERROR(ENOMEM);
107     ret = ff_set_common_channel_layouts(ctx, layouts);
108     if (ret < 0)
109         return ret;
110 
111     formats = ff_make_format_list(sample_rates);
112     if (!formats)
113         return AVERROR(ENOMEM);
114     return ff_set_common_samplerates(ctx, formats);
115 }
116 
white_filter(double white,double * buf,double ha)117 static double white_filter(double white, double *buf, double ha)
118 {
119     return white;
120 }
121 
pink_filter(double white,double * buf,double ha)122 static double pink_filter(double white, double *buf, double ha)
123 {
124     double pink;
125 
126     /* http://www.musicdsp.org/files/pink.txt */
127     buf[0] = 0.99886 * buf[0] + white * 0.0555179;
128     buf[1] = 0.99332 * buf[1] + white * 0.0750759;
129     buf[2] = 0.96900 * buf[2] + white * 0.1538520;
130     buf[3] = 0.86650 * buf[3] + white * 0.3104856;
131     buf[4] = 0.55000 * buf[4] + white * 0.5329522;
132     buf[5] = -0.7616 * buf[5] - white * 0.0168980;
133     pink = buf[0] + buf[1] + buf[2] + buf[3] + buf[4] + buf[5] + buf[6] + white * 0.5362;
134     buf[6] = white * 0.115926;
135     return pink * 0.11;
136 }
137 
blue_filter(double white,double * buf,double ha)138 static double blue_filter(double white, double *buf, double ha)
139 {
140     double blue;
141 
142     /* Same as pink_filter but subtract the offsets rather than add */
143     buf[0] = 0.0555179 * white - 0.99886 * buf[0];
144     buf[1] = 0.0750759 * white - 0.99332 * buf[1];
145     buf[2] = 0.1538520 * white - 0.96900 * buf[2];
146     buf[3] = 0.3104856 * white - 0.86650 * buf[3];
147     buf[4] = 0.5329522 * white - 0.55000 * buf[4];
148     buf[5] = -0.016898 * white + 0.76160 * buf[5];
149     blue = buf[0] + buf[1] + buf[2] + buf[3] + buf[4] + buf[5] + buf[6] + white * 0.5362;
150     buf[6] = white * 0.115926;
151     return blue * 0.11;
152 }
153 
brown_filter(double white,double * buf,double ha)154 static double brown_filter(double white, double *buf, double ha)
155 {
156     double brown;
157 
158     brown = ((0.02 * white) + buf[0]) / 1.02;
159     buf[0] = brown;
160     return brown * 3.5;
161 }
162 
violet_filter(double white,double * buf,double ha)163 static double violet_filter(double white, double *buf, double ha)
164 {
165     double violet;
166 
167     violet = ((0.02 * white) - buf[0]) / 1.02;
168     buf[0] = violet;
169     return violet * 3.5;
170 }
171 
velvet_filter(double white,double * buf,double ha)172 static double velvet_filter(double white, double *buf, double ha)
173 {
174     return 2. * ha * ((white > ha) - (white < -ha));
175 }
176 
config_props(AVFilterLink * outlink)177 static av_cold int config_props(AVFilterLink *outlink)
178 {
179     AVFilterContext *ctx = outlink->src;
180     ANoiseSrcContext *s = ctx->priv;
181 
182     if (s->seed == -1)
183         s->seed = av_get_random_seed();
184     av_lfg_init(&s->c, s->seed);
185 
186     if (s->duration == 0)
187         s->infinite = 1;
188     s->duration = av_rescale(s->duration, s->sample_rate, AV_TIME_BASE);
189 
190     switch (s->color) {
191     case NM_WHITE:  s->filter = white_filter;  break;
192     case NM_PINK:   s->filter = pink_filter;   break;
193     case NM_BROWN:  s->filter = brown_filter;  break;
194     case NM_BLUE:   s->filter = blue_filter;   break;
195     case NM_VIOLET: s->filter = violet_filter; break;
196     case NM_VELVET: s->filter = velvet_filter; break;
197     }
198 
199     return 0;
200 }
201 
activate(AVFilterContext * ctx)202 static int activate(AVFilterContext *ctx)
203 {
204     AVFilterLink *outlink = ctx->outputs[0];
205     ANoiseSrcContext *s = ctx->priv;
206     AVFrame *frame;
207     int nb_samples, i;
208     double *dst;
209 
210     if (!ff_outlink_frame_wanted(outlink))
211         return FFERROR_NOT_READY;
212 
213     if (!s->infinite && s->duration <= 0) {
214         ff_outlink_set_status(outlink, AVERROR_EOF, s->pts);
215         return 0;
216     } else if (!s->infinite && s->duration < s->nb_samples) {
217         nb_samples = s->duration;
218     } else {
219         nb_samples = s->nb_samples;
220     }
221 
222     if (!(frame = ff_get_audio_buffer(outlink, nb_samples)))
223         return AVERROR(ENOMEM);
224 
225     dst = (double *)frame->data[0];
226     for (i = 0; i < nb_samples; i++) {
227         double white;
228         white = s->amplitude * ((2 * ((double) av_lfg_get(&s->c) / 0xffffffff)) - 1);
229         dst[i] = s->filter(white, s->buf, s->amplitude * 0.5);
230     }
231 
232     if (!s->infinite)
233         s->duration -= nb_samples;
234 
235     frame->pts = s->pts;
236     s->pts    += nb_samples;
237     return ff_filter_frame(outlink, frame);
238 }
239 
240 static const AVFilterPad anoisesrc_outputs[] = {
241     {
242         .name          = "default",
243         .type          = AVMEDIA_TYPE_AUDIO,
244         .config_props  = config_props,
245     },
246     { NULL }
247 };
248 
249 AVFilter ff_asrc_anoisesrc = {
250     .name          = "anoisesrc",
251     .description   = NULL_IF_CONFIG_SMALL("Generate a noise audio signal."),
252     .query_formats = query_formats,
253     .priv_size     = sizeof(ANoiseSrcContext),
254     .inputs        = NULL,
255     .activate      = activate,
256     .outputs       = anoisesrc_outputs,
257     .priv_class    = &anoisesrc_class,
258 };
259