avfilter: add anoisesrc

Signed-off-by: Kyle Swanson <k@ylo.ph>
Signed-off-by: Paul B Mahol <onemda@gmail.com>

Changelog

@@ -32,6 +32,7 @@ version <next>:
 - Interplay ACM demuxer and audio decoder
 - XMA1 & XMA2 decoder
 - realtime filter
+- anoisesrc audio filter source
 
 
 version 2.8:

doc/filters.texi

@@ -3157,6 +3157,46 @@ ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
 For more information about libflite, check:
 @url{http://www.speech.cs.cmu.edu/flite/}
 
+@section anoisesrc
+
+Generate a noise audio signal.
+
+The filter accepts the following options:
+
+@table @option
+@item sample_rate, r
+Specify the sample rate. Default value is 48000 Hz.
+
+@item amplitude, a
+Specify the amplitude (0.0 - 1.0) of the generated audio stream. Default value
+is 1.0.
+
+@item duration, d
+Specify the duration of the generated audio stream. Not specifying this option
+results in noise with an infinite length.
+
+@item color, colour, c
+Specify the color of noise. Available noise colors are white, pink, and brown.
+Default color is white.
+
+@item seed, s
+Specify a value used to seed the PRNG.
+
+@item nb_samples, n
+Set the number of samples per each output frame, default is 1024.
+@end table
+
+@subsection Examples
+
+@itemize
+
+@item
+Generate 60 seconds of pink noise, with a 44.1 kHz sampling rate and an amplitude of 0.5:
+@example
+anoisesrc=d=60:c=pink:r=44100:a=0.5
+@end example
+@end itemize
+
 @section sine
 
 Generate an audio signal made of a sine wave with amplitude 1/8.

libavfilter/Makefile

@@ -91,6 +91,7 @@ OBJS-$(CONFIG_VOLUME_FILTER)                 += af_volume.o
 OBJS-$(CONFIG_VOLUMEDETECT_FILTER)           += af_volumedetect.o
 
 OBJS-$(CONFIG_AEVALSRC_FILTER)               += aeval.o
+OBJS-$(CONFIG_ANOISESRC_FILTER)              += asrc_anoisesrc.o
 OBJS-$(CONFIG_ANULLSRC_FILTER)               += asrc_anullsrc.o
 OBJS-$(CONFIG_FLITE_FILTER)                  += asrc_flite.o
 OBJS-$(CONFIG_SINE_FILTER)                   += asrc_sine.o

libavfilter/allfilters.c

@@ -113,6 +113,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(VOLUMEDETECT,   volumedetect,   af);
 
     REGISTER_FILTER(AEVALSRC,       aevalsrc,       asrc);
+    REGISTER_FILTER(ANOISESRC,      anoisesrc,      asrc);
     REGISTER_FILTER(ANULLSRC,       anullsrc,       asrc);
     REGISTER_FILTER(FLITE,          flite,          asrc);
     REGISTER_FILTER(SINE,           sine,           asrc);

libavfilter/asrc_anoisesrc.c

+/*
+ * Copyright (c) 2015 Kyle Swanson <k@ylo.ph>.
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/opt.h"
+#include "audio.h"
+#include "avfilter.h"
+#include "internal.h"
+#include "libavutil/lfg.h"
+#include "libavutil/random_seed.h"
+
+typedef struct {
+    const AVClass *class;
+    int sample_rate;
+    double amplitude;
+    int64_t duration;
+    int64_t color;
+    int64_t seed;
+    int nb_samples;
+
+    int64_t pts;
+    int infinite;
+    double (*filter)(double white, double *buf);
+    double buf[7];
+    AVLFG c;
+} ANoiseSrcContext;
+
+#define OFFSET(x) offsetof(ANoiseSrcContext, x)
+#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption anoisesrc_options[] = {
+    { "sample_rate",  "set sample rate",  OFFSET(sample_rate),  AV_OPT_TYPE_INT,       {.i64 = 48000},  15,  INT_MAX,    FLAGS },
+    { "r",            "set sample rate",  OFFSET(sample_rate),  AV_OPT_TYPE_INT,       {.i64 = 48000},  15,  INT_MAX,    FLAGS },
+    { "amplitude",    "set amplitude",    OFFSET(amplitude),    AV_OPT_TYPE_DOUBLE,    {.dbl = 1.},     0.,  1.,         FLAGS },
+    { "a",            "set amplitude",    OFFSET(amplitude),    AV_OPT_TYPE_DOUBLE,    {.dbl = 1.},     0.,  1.,         FLAGS },
+    { "duration",     "set duration",     OFFSET(duration),     AV_OPT_TYPE_DURATION,  {.i64 =  0},      0,  INT64_MAX,  FLAGS },
+    { "d",            "set duration",     OFFSET(duration),     AV_OPT_TYPE_DURATION,  {.i64 =  0},      0,  INT64_MAX,  FLAGS },
+    { "color",        "set noise color",  OFFSET(color),        AV_OPT_TYPE_INT,       {.i64 =  1},      0,  2,          FLAGS, "color" },
+    { "colour",       "set noise color",  OFFSET(color),        AV_OPT_TYPE_INT,       {.i64 =  1},      0,  2,          FLAGS, "color" },
+    { "c",            "set noise color",  OFFSET(color),        AV_OPT_TYPE_INT,       {.i64 =  0},      0,  2,          FLAGS, "color" },
+    {     "white",    0,                  0,                    AV_OPT_TYPE_CONST,     {.i64 =  0},      0,  0,          FLAGS, "color" },
+    {     "pink",     0,                  0,                    AV_OPT_TYPE_CONST,     {.i64 =  1},      0,  0,          FLAGS, "color" },
+    {     "brown",    0,                  0,                    AV_OPT_TYPE_CONST,     {.i64 =  2},      0,  0,          FLAGS, "color" },
+    { "seed",         "set random seed",  OFFSET(seed),         AV_OPT_TYPE_INT64,     {.i64 = -1},     -1,  UINT_MAX,   FLAGS },
+    { "s",            "set random seed",  OFFSET(seed),         AV_OPT_TYPE_INT64,     {.i64 = -1},     -1,  UINT_MAX,   FLAGS },
+    { "nb_samples",   "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 1, INT_MAX, FLAGS },
+    { "n",            "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 1, INT_MAX, FLAGS },
+    {NULL}
+};
+
+AVFILTER_DEFINE_CLASS(anoisesrc);
+
+static av_cold int query_formats(AVFilterContext *ctx)
+{
+    ANoiseSrcContext *s = ctx->priv;
+    static const int64_t chlayouts[] = { AV_CH_LAYOUT_MONO, -1 };
+    int sample_rates[] = { s->sample_rate, -1 };
+    static const enum AVSampleFormat sample_fmts[] = {
+        AV_SAMPLE_FMT_DBL,
+        AV_SAMPLE_FMT_NONE
+    };
+
+    AVFilterFormats *formats;
+    AVFilterChannelLayouts *layouts;
+    int ret;
+
+    formats = ff_make_format_list(sample_fmts);
+    if (!formats)
+        return AVERROR(ENOMEM);
+    ret = ff_set_common_formats (ctx, formats);
+    if (ret < 0)
+        return ret;
+
+    layouts = avfilter_make_format64_list(chlayouts);
+    if (!layouts)
+        return AVERROR(ENOMEM);
+    ret = ff_set_common_channel_layouts(ctx, layouts);
+    if (ret < 0)
+        return ret;
+
+    formats = ff_make_format_list(sample_rates);
+    if (!formats)
+        return AVERROR(ENOMEM);
+    return ff_set_common_samplerates(ctx, formats);
+}
+
+static double white_filter(double white, double *buf)
+{
+    return white;
+};
+
+static double pink_filter(double white, double *buf)
+{
+    double pink;
+
+    /* http://www.musicdsp.org/files/pink.txt */
+    buf[0] = 0.99886 * buf[0] + white * 0.0555179;
+    buf[1] = 0.99332 * buf[1] + white * 0.0750759;
+    buf[2] = 0.96900 * buf[2] + white * 0.1538520;
+    buf[3] = 0.86650 * buf[3] + white * 0.3104856;
+    buf[4] = 0.55000 * buf[4] + white * 0.5329522;
+    buf[5] = -0.7616 * buf[5] - white * 0.0168980;
+    pink = buf[0] + buf[1] + buf[2] + buf[3] + buf[4] + buf[5] + buf[6] + white * 0.5362;
+    buf[6] = white * 0.115926;
+    return pink * 0.11;
+}
+
+static double brown_filter(double white, double *buf)
+{
+    double brown;
+
+    brown = ((0.02 * white) + buf[0]) / 1.02;
+    buf[0] = brown;
+    return brown * 3.5;
+}
+
+static av_cold int config_props(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    ANoiseSrcContext *s = ctx->priv;
+
+    if (s->seed == -1)
+        s->seed = av_get_random_seed();
+    av_lfg_init(&s->c, s->seed);
+
+    if (s->duration == 0)
+        s->infinite = 1;
+    s->duration = av_rescale(s->duration, s->sample_rate, AV_TIME_BASE);
+
+    switch (s->color) {
+    case 0: s->filter = white_filter; break;
+    case 1: s->filter = pink_filter;  break;
+    case 2: s->filter = brown_filter; break;
+    }
+
+    return 0;
+}
+
+static int request_frame(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    ANoiseSrcContext *s = ctx->priv;
+    AVFrame *frame;
+    int nb_samples, i;
+    double *dst;
+
+    if (!s->infinite && s->duration <= 0) {
+        return AVERROR_EOF;
+    } else if (!s->infinite && s->duration < s->nb_samples) {
+        nb_samples = s->duration;
+    } else {
+        nb_samples = s->nb_samples;
+    }
+
+    if (!(frame = ff_get_audio_buffer(outlink, nb_samples)))
+        return AVERROR(ENOMEM);
+
+    dst = (double *)frame->data[0];
+    for (i = 0; i < nb_samples; i++) {
+        double white;
+        white = s->amplitude * ((2 * ((double) av_lfg_get(&s->c) / 0xffffffff)) - 1);
+        dst[i] = s->filter(white, s->buf);
+    }
+
+    if (!s->infinite)
+        s->duration -= nb_samples;
+
+    frame->pts = s->pts;
+    s->pts    += nb_samples;
+    return ff_filter_frame(outlink, frame);
+}
+
+static const AVFilterPad anoisesrc_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_AUDIO,
+        .request_frame = request_frame,
+        .config_props  = config_props,
+    },
+    { NULL }
+};
+
+AVFilter ff_asrc_anoisesrc = {
+    .name          = "anoisesrc",
+    .description   = NULL_IF_CONFIG_SMALL("Generate a noise audio signal."),
+    .query_formats = query_formats,
+    .priv_size     = sizeof(ANoiseSrcContext),
+    .inputs        = NULL,
+    .outputs       = anoisesrc_outputs,
+    .priv_class    = &anoisesrc_class,
+};

libavfilter/version.h

@@ -30,8 +30,8 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   6
-#define LIBAVFILTER_VERSION_MINOR  14
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MINOR  15
+#define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \