@@ -2408,6 +2408,103 @@ silenceremove=1:5:0.02

 @end example

 @end itemize

+@section stereotools

+

+This filter has some handy utilities to manage stereo signals, for converting

+M/S stereo recordings to L/R signal while having control over the parameters

+or spreading the stereo image of master track.

+

+The filter accepts the following options:

+

+@table @option

+@table level_in

+Set input level before filtering for both channels. Defaults is 1.

+Allowed range is from 0.015625 to 64.

+

+@table level_out

+Set output level after filtering for both channels. Defaults is 1.

+Allowed range is from 0.015625 to 64.

+

+@item balance_in

+Set input balance between both channels. Default is 0.

+Allowed range is from -1 to 1.

+

+@item balance_out

+Set output balance between both channels. Default is 0.

+Allowed range is from -1 to 1.

+

+@item softclip

+Enable softclipping. Results in analog distortion instead of harsh digital 0dB

+clipping. Disabled by default.

+

+@item mutel

+Mute the left channel. Disabled by default.

+

+@item muter

+Mute the right channel. Disabled by default.

+

+@item phasel

+Change the phase of the left channel. Disabled by default.

+

+@item phaser

+Change the phase of the right channel. Disabled by default.

+

+@item mode

+Set stereo mode. Available values are:

+

+@table @samp

+@item lr>lr

+Left/Right to Left/Right, this is default.

+

+@item lr>ms

+Left/Right to Mid/Side.

+

+@item ms>lr

+Mid/Side to Left/Right.

+

+@item lr>ll

+Left/Right to Left/Left.

+

+@item lr>rr

+Left/Right to Right/Right.

+

+@item lr>l+r

+Left/Right to Left + Right.

+

+@item lr>rl

+Left/Right to Right/Left.

+@end table

+

+@item slev

+Set level of side signal. Default is 1.

+Allowed range is from 0.015625 to 64.

+

+@item sbal

+Set balance of side signal. Default is 0.

+Allowed range is from -1 to 1.

+

+@item mlev

+Set level of the middle signal. Default is 1.

+Allowed range is from 0.015625 to 64.

+

+@item mpan

+Set middle signal pan. Default is 0. Allowed range is from -1 to 1.

+

+@item base

+Set stereo base between mono and inversed channels. Default is 0.

+Allowed range is from -1 to 1.

+

+@item delay

+Set delay in milliseconds how much to delay left from right channel and

+vice versa. Default is 0. Allowed range is from -20 to 20.

+

+@item sclevel

+Set S/C level. Default is 1. Allowed range is from 1 to 100.

+

+@item phase

+Set the stereo phase in degrees. Default is 0. Allowed range is from 0 to 360.

+@end table

+

 @section stereowiden

 This filter enhance the stereo effect by suppressing signal common to both

@@ -80,6 +80,7 @@ OBJS-$(CONFIG_RESAMPLE_FILTER)               += af_resample.o

 OBJS-$(CONFIG_SIDECHAINCOMPRESS_FILTER)      += af_sidechaincompress.o

 OBJS-$(CONFIG_SILENCEDETECT_FILTER)          += af_silencedetect.o

 OBJS-$(CONFIG_SILENCEREMOVE_FILTER)          += af_silenceremove.o

+OBJS-$(CONFIG_STEREOTOOLS_FILTER)            += af_stereotools.o

 OBJS-$(CONFIG_STEREOWIDEN_FILTER)            += af_stereowiden.o

 OBJS-$(CONFIG_TREBLE_FILTER)                 += af_biquads.o

 OBJS-$(CONFIG_VOLUME_FILTER)                 += af_volume.o

new file mode 100644

@@ -0,0 +1,302 @@

+/*

+ * Copyright (C) 2001-2010 Krzysztof Foltman, Markus Schmidt, Thor Harald Johansen

+ *

+ * 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 StereoToolsContext {

+    const AVClass *class;

+

+    int softclip;

+    int mute_l;

+    int mute_r;

+    int phase_l;

+    int phase_r;

+    int mode;

+    double slev;

+    double sbal;

+    double mlev;

+    double mpan;

+    double phase;

+    double base;

+    double delay;

+    double balance_in;

+    double balance_out;

+    double phase_sin_coef;

+    double phase_cos_coef;

+    double sc_level;

+    double inv_atan_shape;

+    double level_in;

+    double level_out;

+

+    double *buffer;

+    int length;

+    int pos;

+} StereoToolsContext;

+

+#define OFFSET(x) offsetof(StereoToolsContext, x)

+#define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM

+

+static const AVOption stereotools_options[] = {

+    { "level_in",    "set level in",     OFFSET(level_in),    AV_OPT_TYPE_DOUBLE, {.dbl=1},   0.015625,  64, A },

+    { "level_out",   "set level out",    OFFSET(level_out),   AV_OPT_TYPE_DOUBLE, {.dbl=1},   0.015625,  64, A },

+    { "balance_in",  "set balance in",   OFFSET(balance_in),  AV_OPT_TYPE_DOUBLE, {.dbl=0},  -1,          1, A },

+    { "balance_out", "set balance out",  OFFSET(balance_out), AV_OPT_TYPE_DOUBLE, {.dbl=0},  -1,          1, A },

+    { "softclip",    "enable softclip",  OFFSET(softclip),    AV_OPT_TYPE_BOOL,   {.i64=0},   0,          1, A },

+    { "mutel",       "mute L",           OFFSET(mute_l),      AV_OPT_TYPE_BOOL,   {.i64=0},   0,          1, A },

+    { "muter",       "mute R",           OFFSET(mute_r),      AV_OPT_TYPE_BOOL,   {.i64=0},   0,          1, A },

+    { "phasel",      "phase L",          OFFSET(phase_l),     AV_OPT_TYPE_BOOL,   {.i64=0},   0,          1, A },

+    { "phaser",      "phase R",          OFFSET(phase_r),     AV_OPT_TYPE_BOOL,   {.i64=0},   0,          1, A },

+    { "mode",        "set stereo mode",  OFFSET(mode),        AV_OPT_TYPE_INT,    {.i64=0},   0,          6, A, "mode" },

+    {     "lr>lr",   0,                  0,                   AV_OPT_TYPE_CONST,  {.i64=0},   0,          0, A, "mode" },

+    {     "lr>ms",   0,                  0,                   AV_OPT_TYPE_CONST,  {.i64=1},   0,          0, A, "mode" },

+    {     "ms>lr",   0,                  0,                   AV_OPT_TYPE_CONST,  {.i64=2},   0,          0, A, "mode" },

+    {     "lr>ll",   0,                  0,                   AV_OPT_TYPE_CONST,  {.i64=3},   0,          0, A, "mode" },

+    {     "lr>rr",   0,                  0,                   AV_OPT_TYPE_CONST,  {.i64=4},   0,          0, A, "mode" },

+    {     "lr>l+r",  0,                  0,                   AV_OPT_TYPE_CONST,  {.i64=5},   0,          0, A, "mode" },

+    {     "lr>rl",   0,                  0,                   AV_OPT_TYPE_CONST,  {.i64=6},   0,          0, A, "mode" },

+    { "slev",        "set side level",   OFFSET(slev),        AV_OPT_TYPE_DOUBLE, {.dbl=1},   0.015625,  64, A },

+    { "sbal",        "set side balance", OFFSET(sbal),        AV_OPT_TYPE_DOUBLE, {.dbl=0},  -1,          1, A },

+    { "mlev",        "set middle level", OFFSET(mlev),        AV_OPT_TYPE_DOUBLE, {.dbl=1},   0.015625,  64, A },

+    { "mpan",        "set middle pan",   OFFSET(mpan),        AV_OPT_TYPE_DOUBLE, {.dbl=0},  -1,          1, A },

+    { "base",        "set stereo base",  OFFSET(base),        AV_OPT_TYPE_DOUBLE, {.dbl=0},  -1,          1, A },

+    { "delay",       "set delay",        OFFSET(delay),       AV_OPT_TYPE_DOUBLE, {.dbl=0}, -20,         20, A },

+    { "sclevel",     "set S/C level",    OFFSET(sc_level),    AV_OPT_TYPE_DOUBLE, {.dbl=1},   1,        100, A },

+    { "phase",       "set stereo phase", OFFSET(phase),       AV_OPT_TYPE_DOUBLE, {.dbl=0},   0,        360, A },

+    { NULL }

+};

+

+AVFILTER_DEFINE_CLASS(stereotools);

+

+static int query_formats(AVFilterContext *ctx)

+{

+    AVFilterFormats *formats = NULL;

+    AVFilterChannelLayouts *layout = NULL;

+

+    ff_add_format(&formats, AV_SAMPLE_FMT_DBL);

+    ff_set_common_formats(ctx, formats);

+    ff_add_channel_layout(&layout, AV_CH_LAYOUT_STEREO);

+    ff_set_common_channel_layouts(ctx, layout);

+

+    formats = ff_all_samplerates();

+    if (!formats)

+        return AVERROR(ENOMEM);

+

+    return ff_set_common_samplerates(ctx, formats);

+}

+

+static int config_input(AVFilterLink *inlink)

+{

+    AVFilterContext *ctx = inlink->dst;

+    StereoToolsContext *s = ctx->priv;

+

+    s->length = 2 * inlink->sample_rate * 0.05;

+    s->buffer = av_calloc(s->length, sizeof(*s->buffer));

+    if (!s->buffer)

+        return AVERROR(ENOMEM);

+

+    s->inv_atan_shape = 1.0 / atan(s->sc_level);

+    s->phase_cos_coef = cos(s->phase / 180 * M_PI);

+    s->phase_sin_coef = sin(s->phase / 180 * M_PI);

+

+    return 0;

+}

+

+static int filter_frame(AVFilterLink *inlink, AVFrame *in)

+{

+    AVFilterContext *ctx = inlink->dst;

+    AVFilterLink *outlink = ctx->outputs[0];

+    StereoToolsContext *s = ctx->priv;

+    const double *src = (const double *)in->data[0];

+    const double sb = s->base < 0 ? s->base * 0.5 : s->base;

+    const double sbal = 1 + s->sbal;

+    const double mpan = 1 + s->mpan;

+    const double slev = s->slev;

+    const double mlev = s->mlev;

+    const double balance_in = s->balance_in;

+    const double balance_out = s->balance_out;

+    const double level_in = s->level_in;

+    const double level_out = s->level_out;

+    const double sc_level = s->sc_level;

+    const double delay = s->delay;

+    const int length = s->length;

+    const int mute_l = floor(s->mute_l + 0.5);

+    const int mute_r = floor(s->mute_r + 0.5);

+    const int phase_l = floor(s->phase_l + 0.5);

+    const int phase_r = floor(s->phase_r + 0.5);

+    double *buffer = s->buffer;

+    AVFrame *out = NULL;

+    double *dst;

+    int nbuf = inlink->sample_rate * (FFABS(delay) / 1000.);

+    int n;

+

+    nbuf -= nbuf % 2;

+    if (av_frame_is_writable(in)) {

+        out = in;

+    } else {

+        AVFrame *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 = (double *)out->data[0];

+

+    for (n = 0; n < in->nb_samples; n++, src += 2, dst += 2) {

+        double L = src[0], R = src[1], l, r, m, S;

+

+        L *= level_in;

+        R *= level_in;

+

+        L *= 1. - FFMAX(0., balance_in);

+        R *= 1. + FFMIN(0., balance_in);

+

+        if (s->softclip) {

+            R = s->inv_atan_shape * atan(R * sc_level);

+            L = s->inv_atan_shape * atan(L * sc_level);

+        }

+

+        switch (s->mode) {

+        case 0:

+            m = (L + R) * 0.5;

+            S = (L - R) * 0.5;

+            l = m * mlev * FFMIN(1., 2. - mpan) + S * slev * FFMIN(1., 2. - sbal);

+            r = m * mlev * FFMIN(1., mpan)      - S * slev * FFMIN(1., sbal);

+            L = l;

+            R = r;

+            break;

+        case 1:

+            l = L * FFMIN(1., 2. - sbal);

+            r = R * FFMIN(1., sbal);

+            L = 0.5 * (l + r) * mlev;

+            R = 0.5 * (l - r) * slev;

+            break;

+        case 2:

+            l = L * mlev * FFMIN(1., 2. - mpan) + R * slev * FFMIN(1., 2. - sbal);

+            r = L * mlev * FFMIN(1., mpan)      - R * slev * FFMIN(1., sbal);

+            L = l;

+            R = r;

+            break;

+        case 3:

+            R = L;

+            break;

+        case 4:

+            L = R;

+            break;

+        case 5:

+            L = (L + R) / 2;

+            R = L;

+            break;

+        case 6:

+            l = L;

+            L = R;

+            R = l;

+            m = (L + R) * 0.5;

+            S = (L - R) * 0.5;

+            l = m * mlev * FFMIN(1., 2. - mpan) + S * slev * FFMIN(1., 2. - sbal);

+            r = m * mlev * FFMIN(1., mpan)      - S * slev * FFMIN(1., sbal);

+            L = l;

+            R = r;

+            break;

+        }

+

+        L *= 1. - mute_l;

+        R *= 1. - mute_r;

+

+        L *= (2. * (1. - phase_l)) - 1.;

+        R *= (2. * (1. - phase_r)) - 1.;

+

+        buffer[s->pos  ] = L;

+        buffer[s->pos+1] = R;

+

+        if (delay > 0.) {

+            R = buffer[(s->pos - (int)nbuf + 1 + length) % length];

+        } else if (delay < 0.) {

+            L = buffer[(s->pos - (int)nbuf + length)     % length];

+        }

+

+        l = L + sb * L - sb * R;

+        r = R + sb * R - sb * L;

+

+        L = l;

+        R = r;

+

+        l = L * s->phase_cos_coef - R * s->phase_sin_coef;

+        r = L * s->phase_sin_coef + R * s->phase_cos_coef;

+

+        L = l;

+        R = r;

+

+        s->pos = (s->pos + 2) % s->length;

+

+        L *= 1. - FFMAX(0., balance_out);

+        R *= 1. + FFMIN(0., balance_out);

+

+        L *= level_out;

+        R *= level_out;

+

+        dst[0] = L;

+        dst[1] = R;

+    }

+

+    if (out != in)

+        av_frame_free(&in);

+    return ff_filter_frame(outlink, out);

+}

+

+static av_cold void uninit(AVFilterContext *ctx)

+{

+    StereoToolsContext *s = ctx->priv;

+

+    av_freep(&s->buffer);

+}

+

+static const AVFilterPad inputs[] = {

+    {

+        .name         = "default",

+        .type         = AVMEDIA_TYPE_AUDIO,

+        .filter_frame = filter_frame,

+        .config_props = config_input,

+    },

+    { NULL }

+};

+

+static const AVFilterPad outputs[] = {

+    {

+        .name = "default",

+        .type = AVMEDIA_TYPE_AUDIO,

+    },

+    { NULL }

+};

+

+AVFilter ff_af_stereotools = {

+    .name           = "stereotools",

+    .description    = NULL_IF_CONFIG_SMALL("Apply various stereo tools."),

+    .query_formats  = query_formats,

+    .priv_size      = sizeof(StereoToolsContext),

+    .priv_class     = &stereotools_class,

+    .uninit         = uninit,

+    .inputs         = inputs,

+    .outputs        = outputs,

+};

@@ -102,6 +102,7 @@ void avfilter_register_all(void)

     REGISTER_FILTER(SIDECHAINCOMPRESS, sidechaincompress, af);

     REGISTER_FILTER(SILENCEDETECT,  silencedetect,  af);

     REGISTER_FILTER(SILENCEREMOVE,  silenceremove,  af);

+    REGISTER_FILTER(STEREOTOOLS,    stereotools,    af);

     REGISTER_FILTER(STEREOWIDEN,    stereowiden,    af);

     REGISTER_FILTER(TREBLE,         treble,         af);

     REGISTER_FILTER(VOLUME,         volume,         af);

@@ -30,7 +30,7 @@

 #include "libavutil/version.h"

 #define LIBAVFILTER_VERSION_MAJOR   6

-#define LIBAVFILTER_VERSION_MINOR   4

+#define LIBAVFILTER_VERSION_MINOR   5

 #define LIBAVFILTER_VERSION_MICRO 100

 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \