diff --git a/configure b/configure
index 9fa1665496..17e46c5daa 100755
--- a/configure
+++ b/configure
@@ -265,6 +265,7 @@ External library support:
                            if openssl or gnutls is not used [no]
   --enable-libtwolame      enable MP2 encoding via libtwolame [no]
   --enable-libv4l2         enable libv4l2/v4l-utils [no]
+  --enable-libvapoursynth  enable VapourSynth demuxer [no]
   --enable-libvidstab      enable video stabilization using vid.stab [no]
   --enable-libvmaf         enable vmaf filter via libvmaf [no]
   --enable-libvo-amrwbenc  enable AMR-WB encoding via libvo-amrwbenc [no]
@@ -1712,6 +1713,7 @@ EXTERNAL_LIBRARY_LIST="
     libtheora
     libtwolame
     libv4l2
+    libvapoursynth
     libvorbis
     libvpx
     libwavpack
@@ -3068,6 +3070,7 @@ libspeex_encoder_deps="libspeex"
 libspeex_encoder_select="audio_frame_queue"
 libtheora_encoder_deps="libtheora"
 libtwolame_encoder_deps="libtwolame"
+libvapoursynth_demuxer_deps="libvapoursynth"
 libvo_amrwbenc_encoder_deps="libvo_amrwbenc"
 libvorbis_decoder_deps="libvorbis"
 libvorbis_encoder_deps="libvorbis libvorbisenc"
@@ -6041,6 +6044,7 @@ enabled libtwolame        && require libtwolame twolame.h twolame_init -ltwolame
                              { check_lib libtwolame twolame.h twolame_encode_buffer_float32_interleaved -ltwolame ||
                                die "ERROR: libtwolame must be installed and version must be >= 0.3.10"; }
 enabled libv4l2           && require_pkg_config libv4l2 libv4l2 libv4l2.h v4l2_ioctl
+enabled libvapoursynth    && require_pkg_config libvapoursynth "vapoursynth >= 42" VapourSynth.h getVapourSynthAPI && require_pkg_config libvapoursynth "vapoursynth-script >= 42" VSScript.h vsscript_init || die "ERROR: vapoursynth or vsscript not found";
 enabled libvidstab        && require_pkg_config libvidstab "vidstab >= 0.98" vid.stab/libvidstab.h vsMotionDetectInit
 enabled libvmaf           && require_pkg_config libvmaf "libvmaf >= 0.6.2" libvmaf.h compute_vmaf
 enabled libvo_amrwbenc    && require libvo_amrwbenc vo-amrwbenc/enc_if.h E_IF_init -lvo-amrwbenc
diff --git a/libavformat/Makefile b/libavformat/Makefile
index 3eeca5091d..731b7ac714 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -570,6 +570,7 @@ OBJS-$(CONFIG_LIBRTMPTE_PROTOCOL)        += librtmp.o
 OBJS-$(CONFIG_LIBSRT_PROTOCOL)           += libsrt.o
 OBJS-$(CONFIG_LIBSSH_PROTOCOL)           += libssh.o
 OBJS-$(CONFIG_LIBSMBCLIENT_PROTOCOL)     += libsmbclient.o
+OBJS-$(CONFIG_LIBVAPOURSYNTH_DEMUXER)    += libvapoursynth.o
 
 # protocols I/O
 OBJS-$(CONFIG_ASYNC_PROTOCOL)            += async.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index d582778b3b..67f6c4339c 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -482,6 +482,7 @@ extern AVOutputFormat ff_chromaprint_muxer;
 extern AVInputFormat  ff_libgme_demuxer;
 extern AVInputFormat  ff_libmodplug_demuxer;
 extern AVInputFormat  ff_libopenmpt_demuxer;
+extern AVInputFormat  ff_libvapoursynth_demuxer;
 
 #include "libavformat/muxer_list.c"
 #include "libavformat/demuxer_list.c"
diff --git a/libavformat/libvapoursynth.c b/libavformat/libvapoursynth.c
new file mode 100644
index 0000000000..95699e81d2
--- /dev/null
+++ b/libavformat/libvapoursynth.c
@@ -0,0 +1,379 @@
+/*
+ * 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
+* VapourSynth demuxer
+*
+* Synthesizes vapour (?)
+*/
+
+#include <VapourSynth.h>
+#include <VSScript.h>
+
+#include "libavutil/avassert.h"
+#include "libavutil/avstring.h"
+#include "libavutil/eval.h"
+#include "libavutil/imgutils.h"
+#include "libavutil/opt.h"
+#include "libavutil/pixdesc.h"
+#include "avformat.h"
+#include "internal.h"
+
+typedef struct VSContext {
+    const AVClass *class;
+
+    const VSAPI *vsapi;
+    VSCore *vscore;
+    VSScript *vss;
+
+    VSNodeRef *outnode;
+    int is_cfr;
+    int current_frame;
+
+    int c_order[4];
+
+    /* options */
+    int64_t max_size;
+} VSContext;
+
+#define OFFSET(x) offsetof(VSContext, x)
+#define A AV_OPT_FLAG_AUDIO_PARAM
+#define D AV_OPT_FLAG_DECODING_PARAM
+static const AVOption options[] = {
+    {"max_size",    "set max file size supported (in bytes)", OFFSET(max_size),    AV_OPT_TYPE_INT64, {.i64 = 1 * 1024 * 1024}, 0,    SIZE_MAX - 1, A|D},
+    {NULL}
+};
+
+static int read_close_vs(AVFormatContext *s)
+{
+    VSContext *vs = s->priv_data;
+
+    if (vs->outnode)
+        vs->vsapi->freeNode(vs->outnode);
+
+    vsscript_freeScript(vs->vss);
+    vs->vss = NULL;
+    vs->vsapi = NULL;
+    vs->vscore = NULL;
+    vs->outnode = NULL;
+
+    vsscript_finalize();
+
+    return 0;
+}
+
+static int is_native_endian(enum AVPixelFormat pixfmt)
+{
+    enum AVPixelFormat other = av_pix_fmt_swap_endianness(pixfmt);
+    const AVPixFmtDescriptor *pd;
+    if (other == AV_PIX_FMT_NONE || other == pixfmt)
+        return 1; // not affected by byte order
+    pd = av_pix_fmt_desc_get(pixfmt);
+    return pd && (!!HAVE_BIGENDIAN == !!(pd->flags & AV_PIX_FMT_FLAG_BE));
+}
+
+static enum AVPixelFormat match_pixfmt(const VSFormat *vsf, int c_order[4])
+{
+    static const int yuv_order[4] = {0, 1, 2, 0};
+    static const int rgb_order[4] = {1, 2, 0, 0};
+    const AVPixFmtDescriptor *pd;
+
+    for (pd = av_pix_fmt_desc_next(NULL); pd; pd = av_pix_fmt_desc_next(pd)) {
+        int is_rgb, is_yuv, i, *order;
+        enum AVPixelFormat pixfmt;
+
+        pixfmt = av_pix_fmt_desc_get_id(pd);
+
+        if (pd->flags & (AV_PIX_FMT_FLAG_BAYER | AV_PIX_FMT_FLAG_ALPHA |
+                         AV_PIX_FMT_FLAG_HWACCEL | AV_PIX_FMT_FLAG_BITSTREAM))
+            continue;
+
+        if (pd->log2_chroma_w != vsf->subSamplingW ||
+            pd->log2_chroma_h != vsf->subSamplingH)
+            continue;
+
+        is_rgb = vsf->colorFamily == cmRGB;
+        if (is_rgb != !!(pd->flags & AV_PIX_FMT_FLAG_RGB))
+            continue;
+
+        is_yuv = vsf->colorFamily == cmYUV ||
+                 vsf->colorFamily == cmYCoCg ||
+                 vsf->colorFamily == cmGray;
+        if (!is_rgb && !is_yuv)
+            continue;
+
+        if (vsf->sampleType != ((pd->flags & AV_PIX_FMT_FLAG_FLOAT) ? stFloat : stInteger))
+            continue;
+
+        if (av_pix_fmt_count_planes(pixfmt) != vsf->numPlanes)
+            continue;
+
+        if (strncmp(pd->name, "xyz", 3) == 0)
+            continue;
+
+        if (!is_native_endian(pixfmt))
+            continue;
+
+        order = is_yuv ? yuv_order : rgb_order;
+
+        for (i = 0; i < pd->nb_components; i++) {
+            const AVComponentDescriptor *c = &pd->comp[i];
+            if (order[c->plane] != i ||
+                c->offset != 0 || c->shift != 0 ||
+                c->step != vsf->bytesPerSample ||
+                c->depth != vsf->bitsPerSample)
+                goto cont;
+        }
+
+        // Use it.
+        memcpy(c_order, order, sizeof(int[4]));
+        return pixfmt;
+
+    cont: ;
+    }
+
+    return AV_PIX_FMT_NONE;
+}
+
+static int read_header_vs(AVFormatContext *s)
+{
+    AVStream *st;
+    AVIOContext *pb = s->pb;
+    VSContext *vs = s->priv_data;
+    int64_t sz = avio_size(pb);
+    char *buf = NULL;
+    char dummy;
+    const VSVideoInfo *info;
+    int err;
+
+    vsscript_init();
+
+    if (sz < 0 || sz > vs->max_size) {
+        if (sz < 0)
+            av_log(s, AV_LOG_WARNING, "Could not determine file size\n");
+        sz = vs->max_size;
+    }
+
+    buf = av_malloc(sz + 1);
+    if (!buf) {
+        err = AVERROR(ENOMEM);
+        goto done;
+    }
+    sz = avio_read(pb, buf, sz);
+
+    if (sz < 0) {
+        av_log(s, AV_LOG_ERROR, "Could not read script.\n");
+        err = sz;
+        goto done;
+    }
+
+    // Data left means our buffer (the max_size option) is too small
+    if (avio_read(pb, &dummy, 1) == 1) {
+        av_log(s, AV_LOG_ERROR, "File size is larger than max_size option "
+               "value %"PRIi64", consider increasing the max_size option\n",
+               vs->max_size);
+        err = AVERROR_BUFFER_TOO_SMALL;
+        goto done;
+    }
+
+    if (vsscript_createScript(&vs->vss)) {
+        av_log(s, AV_LOG_ERROR, "Failed to create script instance.\n");
+        err = AVERROR_EXTERNAL;
+        goto done;
+    }
+
+    buf[sz] = '\0';
+    if (vsscript_evaluateScript(&vs->vss, buf, s->url, 0)) {
+        const char *msg = vsscript_getError(vs->vss);
+        av_log(s, AV_LOG_ERROR, "Failed to parse script: %s\n", msg ? msg : "(unknown)");
+        err = AVERROR_EXTERNAL;
+        goto done;
+    }
+
+    vs->vsapi = vsscript_getVSApi();
+    vs->vscore = vsscript_getCore(vs->vss);
+
+    vs->outnode = vsscript_getOutput(vs->vss, 0);
+    if (!vs->outnode) {
+        av_log(s, AV_LOG_ERROR, "Could not get script output node.\n");
+        err = AVERROR_EXTERNAL;
+        goto done;
+    }
+
+    st = avformat_new_stream(s, NULL);
+    if (!st) {
+        err = AVERROR(ENOMEM);
+        goto done;
+    }
+
+    info = vs->vsapi->getVideoInfo(vs->outnode);
+
+    if (info->fpsDen) {
+        vs->is_cfr = 1;
+        avpriv_set_pts_info(st, 64, info->fpsDen, info->fpsNum);
+        st->duration = info->numFrames;
+    } else {
+        // VFR. Just set "something".
+        avpriv_set_pts_info(st, 64, 1, AV_TIME_BASE);
+        s->ctx_flags |= AVFMTCTX_UNSEEKABLE;
+    }
+
+    st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
+    st->codecpar->codec_id = AV_CODEC_ID_WRAPPED_AVFRAME;
+    st->codecpar->width = info->width;
+    st->codecpar->height = info->height;
+    st->codecpar->format = match_pixfmt(info->format, vs->c_order);
+
+    if (st->codecpar->format == AV_PIX_FMT_NONE) {
+        av_log(s, AV_LOG_ERROR, "Unsupported VS pixel format %s\n", info->format->name);
+        err = AVERROR_EXTERNAL;
+        goto done;
+    }
+    av_log(s, AV_LOG_VERBOSE, "VS format %s -> pixfmt %s\n", info->format->name,
+           av_get_pix_fmt_name(st->codecpar->format));
+
+    if (info->format->colorFamily == cmYCoCg)
+        st->codecpar->color_space = AVCOL_SPC_YCGCO;
+
+done:
+    av_free(buf);
+    if (err < 0)
+        read_close_vs(s);
+    return err;
+}
+
+static void free_frame(void *opaque, uint8_t *data)
+{
+    AVFrame *frame = (AVFrame *)data;
+
+    av_frame_free(&frame);
+}
+
+static int read_packet_vs(AVFormatContext *s, AVPacket *pkt)
+{
+    VSContext *vs = s->priv_data;
+    AVStream *st = s->streams[0];
+    AVFrame *frame = NULL;
+    char vserr[80];
+    const VSFrameRef *vsframe = NULL;
+    const VSVideoInfo *info = vs->vsapi->getVideoInfo(vs->outnode);
+    int err = 0;
+    const uint8_t *src_data[4];
+    int src_linesizes[4];
+    int i;
+
+    if (vs->current_frame >= info->numFrames)
+        return AVERROR_EOF;
+
+    vsframe = vs->vsapi->getFrame(vs->current_frame, vs->outnode, vserr, sizeof(vserr));
+    if (!vsframe) {
+        av_log(s, AV_LOG_ERROR, "Error getting frame: %s\n", vserr);
+        err = AVERROR_EXTERNAL;
+        goto end;
+    }
+
+    frame = av_frame_alloc();
+    if (!frame) {
+        err = AVERROR(ENOMEM);
+        goto end;
+    }
+
+    frame->format       = st->codecpar->format;
+    frame->width        = st->codecpar->width;
+    frame->height       = st->codecpar->height;
+    frame->colorspace   = st->codecpar->color_space;
+
+    av_assert0(vs->vsapi->getFrameWidth(vsframe, 0) == frame->width);
+    av_assert0(vs->vsapi->getFrameHeight(vsframe, 0) == frame->height);
+
+    err = av_frame_get_buffer(frame, 0);
+    if (err < 0)
+        goto end;
+
+    for (i = 0; i < info->format->numPlanes; i++) {
+        int p = vs->c_order[i];
+        src_data[i] = vs->vsapi->getReadPtr(vsframe, p);
+        src_linesizes[i] = vs->vsapi->getStride(vsframe, p);
+    }
+
+    av_image_copy(frame->data, frame->linesize, src_data, src_linesizes,
+                  frame->format, frame->width, frame->height);
+
+    pkt->buf = av_buffer_create((uint8_t*)frame, sizeof(*frame),
+                                free_frame, NULL, 0);
+    if (!pkt->buf) {
+        err = AVERROR(ENOMEM);
+        goto end;
+    }
+
+    frame = NULL; // pkt owns it now
+
+    pkt->data   = pkt->buf->data;
+    pkt->size   = pkt->buf->size;
+    pkt->flags |= AV_PKT_FLAG_TRUSTED;
+
+    if (vs->is_cfr)
+        pkt->pts = vs->current_frame;
+
+    vs->current_frame++;
+
+end:
+    if (err < 0)
+        av_packet_unref(pkt);
+    av_frame_free(&frame);
+    vs->vsapi->freeFrame(vsframe);
+    return err;
+}
+
+static int read_seek_vs(AVFormatContext *s, int stream_idx, int64_t ts, int flags)
+{
+    VSContext *vs = s->priv_data;
+
+    if (!vs->is_cfr)
+        return AVERROR(ENOSYS);
+
+    vs->current_frame = FFMIN(FFMAX(0, ts), s->streams[0]->duration);
+    return 0;
+}
+
+static int probe_vs(AVProbeData *p)
+{
+    // Explicitly do not support this. VS scripts are written in Python, and
+    // can run arbitrary code on the user's system.
+    return 0;
+}
+
+static const AVClass class_vs = {
+    .class_name = "VapourSynth demuxer",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+AVInputFormat ff_libvapoursynth_demuxer = {
+    .name           = "libvapoursynth",
+    .long_name      = NULL_IF_CONFIG_SMALL("VapourSynth demuxer"),
+    .priv_data_size = sizeof(VSContext),
+    .read_probe     = probe_vs,
+    .read_header    = read_header_vs,
+    .read_packet    = read_packet_vs,
+    .read_close     = read_close_vs,
+    .read_seek      = read_seek_vs,
+    .priv_class     = &class_vs,
+};
