avfilter: add crystalizer audio filter

Signed-off-by: Vitaly Ostrosablin <tmp6154@yandex.ru>

Changelog

@@ -13,6 +13,7 @@ version <next>:
 - OpenH264 decoder wrapper
 - MediaCodec hwaccel
 - True Audio (TTA) muxer
+- crystalizer audio filter
 
 
 version 3.1:

doc/filters.texi

@@ -2110,6 +2110,20 @@ Set temperature degree in Celsius. This is the temperature of the environment.
 Default is 20.
 @end table
 
+@section crystalizer
+Simple algorithm to expand audio dynamic range.
+
+The filter accepts the following options:
+
+@table @option
+@item i
+Sets the intensity of effect (default: 2.0). Must be in range between 0.0
+(unchanged sound) to 10.0 (maximum effect).
+
+@item c
+Enable clipping. By default is enabled.
+@end table
+
 @section dcshift
 Apply a DC shift to the audio.
 

libavfilter/Makefile

@@ -78,6 +78,7 @@ OBJS-$(CONFIG_CHANNELSPLIT_FILTER)           += af_channelsplit.o
 OBJS-$(CONFIG_CHORUS_FILTER)                 += af_chorus.o generate_wave_table.o
 OBJS-$(CONFIG_COMPAND_FILTER)                += af_compand.o
 OBJS-$(CONFIG_COMPENSATIONDELAY_FILTER)      += af_compensationdelay.o
+OBJS-$(CONFIG_CRYSTALIZER_FILTER)            += af_crystalizer.o
 OBJS-$(CONFIG_DCSHIFT_FILTER)                += af_dcshift.o
 OBJS-$(CONFIG_DYNAUDNORM_FILTER)             += af_dynaudnorm.o
 OBJS-$(CONFIG_EARWAX_FILTER)                 += af_earwax.o

libavfilter/af_crystalizer.c

@@ -0,0 +1,153 @@
+/*
+ * Copyright (c) 2016 The FFmpeg Project
+ *
+ * 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/channel_layout.h"
+#include "libavutil/opt.h"
+#include "avfilter.h"
+#include "audio.h"
+#include "formats.h"
+
+typedef struct CrystalizerContext {
+    const AVClass *class;
+    float mult;
+    int clip;
+    AVFrame *prev;
+} CrystalizerContext;
+
+#define OFFSET(x) offsetof(CrystalizerContext, x)
+#define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption crystalizer_options[] = {
+    { "i", "set intensity",    OFFSET(mult), AV_OPT_TYPE_FLOAT, {.dbl=2.0}, 0, 10, A },
+    { "c", "enable clipping",  OFFSET(clip), AV_OPT_TYPE_BOOL,  {.i64=1},   0,  1, A },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(crystalizer);
+
+static int query_formats(AVFilterContext *ctx)
+{
+    AVFilterFormats *formats = NULL;
+    AVFilterChannelLayouts *layouts = NULL;
+    int ret;
+
+    if ((ret = ff_add_format        (&formats, AV_SAMPLE_FMT_FLT )) < 0 ||
+        (ret = ff_set_common_formats(ctx     , formats           )) < 0)
+        return ret;
+
+    layouts = ff_all_channel_counts();
+    if (!layouts)
+        return AVERROR(ENOMEM);
+
+    ret = ff_set_common_channel_layouts(ctx, layouts);
+    if (ret < 0)
+        return ret;
+
+    formats = ff_all_samplerates();
+    return ff_set_common_samplerates(ctx, formats);
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    CrystalizerContext *s = ctx->priv;
+    const float *src = (const float *)in->data[0];
+    const float mult = s->mult;
+    AVFrame *out;
+    float *dst, *prv;
+    int n, c;
+
+    if (!s->prev) {
+        s->prev = ff_get_audio_buffer(inlink, 1);
+        if (!s->prev) {
+            av_frame_free(&in);
+            return AVERROR(ENOMEM);
+        }
+    }
+
+    if (av_frame_is_writable(in)) {
+        out = in;
+    } else {
+        out = ff_get_audio_buffer(inlink, in->nb_samples);
+        if (!out) {
+            av_frame_free(&in);
+            return AVERROR(ENOMEM);
+        }
+        av_frame_copy_props(out, in);
+    }
+
+    dst = (float *)out->data[0];
+    prv = (float *)s->prev->data[0];
+
+    for (n = 0; n < in->nb_samples; n++) {
+        for (c = 0; c < in->channels; c++) {
+            float current = src[c];
+
+            dst[c] = current + (current - prv[c]) * mult;
+            prv[c] = current;
+            if (s->clip) {
+                dst[c] = av_clipf(dst[c], -1, 1);
+            }
+        }
+        dst += c;
+        src += c;
+    }
+
+    if (out != in)
+        av_frame_free(&in);
+
+    return ff_filter_frame(outlink, out);
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    CrystalizerContext *s = ctx->priv;
+
+    av_frame_free(&s->prev);
+}
+
+static const AVFilterPad inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_AUDIO,
+        .filter_frame = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_AUDIO,
+    },
+    { NULL }
+};
+
+AVFilter ff_af_crystalizer = {
+    .name           = "crystalizer",
+    .description    = NULL_IF_CONFIG_SMALL("Simple expand audio dynamic range filter."),
+    .query_formats  = query_formats,
+    .priv_size      = sizeof(CrystalizerContext),
+    .priv_class     = &crystalizer_class,
+    .uninit         = uninit,
+    .inputs         = inputs,
+    .outputs        = outputs,
+};

libavfilter/allfilters.c

@@ -96,6 +96,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(CHORUS,         chorus,         af);
     REGISTER_FILTER(COMPAND,        compand,        af);
     REGISTER_FILTER(COMPENSATIONDELAY, compensationdelay, af);
+    REGISTER_FILTER(CRYSTALIZER,    crystalizer,    af);
     REGISTER_FILTER(DCSHIFT,        dcshift,        af);
     REGISTER_FILTER(DYNAUDNORM,     dynaudnorm,     af);
     REGISTER_FILTER(EARWAX,         earwax,         af);

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   6
-#define LIBAVFILTER_VERSION_MINOR  49
+#define LIBAVFILTER_VERSION_MINOR  50
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \