diff --git a/configure b/configure
index 46f2038627..da5bd9a485 100755
--- a/configure
+++ b/configure
@@ -207,6 +207,7 @@ External library support:
   --disable-bzlib          disable bzlib [autodetect]
   --disable-coreimage      disable Apple CoreImage framework [autodetect]
   --enable-chromaprint     enable audio fingerprinting with chromaprint [no]
+  --enable-csound          enable Csound audio filtering [no]
   --enable-frei0r          enable frei0r video filtering [no]
   --enable-gcrypt          enable gcrypt, needed for rtmp(t)e support
                            if openssl, librtmp or gmp is not used [no]
@@ -1752,6 +1753,7 @@ EXTERNAL_LIBRARY_LIST="
     $EXTERNAL_LIBRARY_VERSION3_LIST
     $EXTERNAL_LIBRARY_GPLV3_LIST
     chromaprint
+    csound
     gcrypt
     gnutls
     jni
@@ -3474,6 +3476,7 @@ coreimagesrc_filter_deps="coreimage appkit"
 coreimagesrc_filter_extralibs="-framework OpenGL"
 cover_rect_filter_deps="avcodec avformat gpl"
 cropdetect_filter_deps="gpl"
+csound_filter_deps="csound"
 deconvolve_filter_deps="avcodec"
 deconvolve_filter_select="fft"
 deinterlace_qsv_filter_deps="libmfx"
@@ -6222,6 +6225,7 @@ done
 # these are off by default, so fail if requested and not available
 enabled cuda_nvcc         && { check_nvcc cuda_nvcc || die "ERROR: failed checking for nvcc."; }
 enabled chromaprint       && require chromaprint chromaprint.h chromaprint_get_version -lchromaprint
+enabled csound            && require csound csound/csound.h csoundCreate -lcsound64
 enabled decklink          && { require_headers DeckLinkAPI.h &&
                                { test_cpp_condition DeckLinkAPIVersion.h "BLACKMAGIC_DECKLINK_API_VERSION >= 0x0a090500" || die "ERROR: Decklink API version must be >= 10.9.5."; } }
 enabled frei0r            && require_headers "frei0r.h dlfcn.h"
diff --git a/doc/filters.texi b/doc/filters.texi
index 6fb660b05a..41c90e6819 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -3230,6 +3230,22 @@ Enable clipping. By default is enabled.
 
 This filter supports the all above options as @ref{commands}.
 
+@section csound
+
+Load a Csound plugin.
+
+Csound is a unit generator-based, user-programmable computer music system.
+
+To enable compilation of this filter you need to configure FFmpeg with
+@code{--enable-csound}.
+
+@table @option
+@item csd
+Give name or full path to CSD script file.
+CSD file holds unified orchestra and score file.
+This option must always be set.
+@end table
+
 @section dcshift
 Apply a DC shift to the audio.
 
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 8b8a5bd535..18885950ec 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -102,6 +102,7 @@ OBJS-$(CONFIG_COMPAND_FILTER)                += af_compand.o
 OBJS-$(CONFIG_COMPENSATIONDELAY_FILTER)      += af_compensationdelay.o
 OBJS-$(CONFIG_CROSSFEED_FILTER)              += af_crossfeed.o
 OBJS-$(CONFIG_CRYSTALIZER_FILTER)            += af_crystalizer.o
+OBJS-$(CONFIG_CSOUND_FILTER)                 += af_csound.o
 OBJS-$(CONFIG_DCSHIFT_FILTER)                += af_dcshift.o
 OBJS-$(CONFIG_DEESSER_FILTER)                += af_deesser.o
 OBJS-$(CONFIG_DRMETER_FILTER)                += af_drmeter.o
diff --git a/libavfilter/af_csound.c b/libavfilter/af_csound.c
new file mode 100644
index 0000000000..9404a42f58
--- /dev/null
+++ b/libavfilter/af_csound.c
@@ -0,0 +1,267 @@
+/*
+ * Copyright (c) 2020 Paul B Mahol
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * Csound wrapper
+ */
+
+#include <csound/csound.h>
+#include "libavutil/avassert.h"
+#include "libavutil/avstring.h"
+#include "libavutil/channel_layout.h"
+#include "libavutil/opt.h"
+#include "audio.h"
+#include "avfilter.h"
+#include "filters.h"
+#include "internal.h"
+
+typedef struct CsoundContext {
+    const AVClass *class;
+    int sample_rate;
+    int nchnls, nchnls_input;
+    char *csd_filename;
+
+    uint32_t ksmps;
+    int format;
+    int64_t pts;
+    CSOUND *csound;
+    controlChannelInfo_t *devs;
+} CsoundContext;
+
+#define OFFSET(x) offsetof(CsoundContext, x)
+#define FLAGS AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption csound_options[] = {
+    { "csd", "set CSD name or full path", OFFSET(csd_filename), AV_OPT_TYPE_STRING, .flags = FLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(csound);
+
+static int activate(AVFilterContext *ctx)
+{
+    CsoundContext *s = ctx->priv;
+    AVFilterLink *inlink = ctx->inputs[0];
+    AVFilterLink *outlink = ctx->outputs[0];
+    int ret, nb_samples, nb_in_samples;
+    MYFLT *buffer;
+    AVFrame *out, *in;
+
+    FF_FILTER_FORWARD_STATUS_BACK_ALL(outlink, ctx);
+
+    nb_in_samples = csoundGetInputBufferSize(s->csound) / s->nchnls;
+
+    if (nb_in_samples > 0) {
+        ret = ff_inlink_consume_samples(inlink, nb_in_samples, nb_in_samples, &in);
+        if (ret > 0) {
+            buffer = csoundGetInputBuffer(s->csound);
+            if (buffer) {
+                const int nch = s->nchnls;
+                MYFLT *dst = buffer;
+                MYFLT *src = (MYFLT *)in->data[0];
+
+                for (int f = 0; f < nb_in_samples / s->ksmps; f++) {
+                    for (int ch = 0; ch < nch; ch++) {
+                        for (int n = 0; n < s->ksmps; n++) {
+                            dst[n] = *src++;
+                        }
+                        dst += s->ksmps;
+                    }
+                }
+            }
+            av_frame_free(&in);
+        } else if (!ret) {
+            FF_FILTER_FORWARD_WANTED(outlink, inlink);
+            return 0;
+        } else {
+            return ret;
+        }
+    }
+    ret = csoundPerformBuffer(s->csound);
+    nb_samples = csoundGetOutputBufferSize(s->csound) / s->nchnls;
+    if (ret || !nb_samples) {
+        ff_outlink_set_status(outlink, AVERROR_EOF, 0);
+        return 0;
+    }
+
+    buffer = csoundGetOutputBuffer(s->csound);
+    if (buffer) {
+        const int nch = s->nchnls;
+        MYFLT *src = buffer;
+        MYFLT *dst;
+
+        out = ff_get_audio_buffer(outlink, nb_samples);
+        if (!out)
+            return AVERROR(ENOMEM);
+        dst = (MYFLT *)out->data[0];
+        out->pts = s->pts;
+        s->pts += nb_samples;
+        for (int f = 0; f < nb_samples / s->ksmps; f++) {
+            for (int ch = 0; ch < nch; ch++) {
+                for (int n = 0; n < s->ksmps; n++) {
+                    *dst++ = src[n];
+                }
+                src += s->ksmps;
+            }
+        }
+
+        return ff_filter_frame(outlink, out);
+    }
+
+    FF_FILTER_FORWARD_STATUS(inlink, outlink);
+
+    return 0;
+}
+
+static void callback(CSOUND *csound, int attr, const char *format, va_list valist)
+{
+    int level;
+
+    switch (attr & CSOUNDMSG_TYPE_MASK) {
+    case CSOUNDMSG_ERROR:   level = AV_LOG_ERROR; break;
+    case CSOUNDMSG_WARNING: level = AV_LOG_WARNING; break;
+    default: level = AV_LOG_VERBOSE; break;
+    }
+
+    av_vlog(csoundGetHostData(csound), level, format, valist);
+}
+
+static av_cold int init(AVFilterContext *ctx)
+{
+    CsoundContext *s = ctx->priv;
+    int ret, size;
+
+    csoundSetDefaultMessageCallback(callback);
+    s->csound = csoundCreate(NULL);
+    if (!s->csound)
+        return AVERROR(ENOMEM);
+
+    if (!s->csd_filename)
+        return AVERROR(EINVAL);
+
+    csoundSetHostData(s->csound, s);
+    csoundSetHostImplementedAudioIO(s->csound, 1, 1024);
+    csoundSetMessageCallback(s->csound, callback);
+    ret = csoundCompileCsd(s->csound, s->csd_filename);
+    if (ret != 0)
+        return AVERROR_EXTERNAL;
+    csoundStart(s->csound);
+    s->sample_rate = csoundGetSr(s->csound);
+    s->ksmps = csoundGetKsmps(s->csound);
+    s->nchnls = csoundGetNchnls(s->csound);
+    s->nchnls_input = csoundGetNchnlsInput(s->csound);
+
+    size = csoundGetSizeOfMYFLT();
+    switch (size) {
+    case 4: s->format = AV_SAMPLE_FMT_FLT; break;
+    case 8: s->format = AV_SAMPLE_FMT_DBL; break;
+    default: return AVERROR_BUG;
+    }
+
+    return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    CsoundContext *s = ctx->priv;
+    AVFilterFormats *formats;
+    AVFilterChannelLayouts *layouts;
+    int sample_rates[] = { s->sample_rate, -1 };
+    enum AVSampleFormat sample_fmts[] = {
+        s->format, AV_SAMPLE_FMT_NONE };
+    uint64_t inlayout = FF_COUNT2LAYOUT(s->nchnls_input);
+    uint64_t outlayout = FF_COUNT2LAYOUT(s->nchnls);
+    AVFilterLink *outlink = ctx->outputs[0];
+    AVFilterLink *inlink = ctx->inputs[0];
+    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;
+
+    formats = ff_make_format_list(sample_rates);
+    if (!formats)
+        return AVERROR(ENOMEM);
+
+    ret = ff_set_common_samplerates(ctx, formats);
+    if (ret < 0)
+        return ret;
+
+
+    layouts = NULL;
+    ret = ff_add_channel_layout(&layouts, inlayout);
+    if (ret < 0)
+        return ret;
+    ret = ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts);
+    if (ret < 0)
+        return ret;
+
+    layouts = NULL;
+    ret = ff_add_channel_layout(&layouts, outlayout);
+    if (ret < 0)
+        return ret;
+    ret = ff_channel_layouts_ref(layouts, &outlink->in_channel_layouts);
+    if (ret < 0)
+        return ret;
+
+    return 0;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    CsoundContext *s = ctx->priv;
+
+    csoundReset(s->csound);
+    csoundDestroy(s->csound);
+}
+
+static const AVFilterPad inputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_AUDIO,
+    },
+    { NULL }
+};
+
+static const AVFilterPad outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_AUDIO,
+    },
+    { NULL }
+};
+
+AVFilter ff_af_csound = {
+    .name          = "csound",
+    .description   = NULL_IF_CONFIG_SMALL("Apply Csound script."),
+    .priv_size     = sizeof(CsoundContext),
+    .priv_class    = &csound_class,
+    .init          = init,
+    .activate      = activate,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .inputs        = inputs,
+    .outputs       = outputs,
+};
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 9f2080f857..12a591ff5d 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -95,6 +95,7 @@ extern AVFilter ff_af_compand;
 extern AVFilter ff_af_compensationdelay;
 extern AVFilter ff_af_crossfeed;
 extern AVFilter ff_af_crystalizer;
+extern AVFilter ff_af_csound;
 extern AVFilter ff_af_dcshift;
 extern AVFilter ff_af_deesser;
 extern AVFilter ff_af_drmeter;
