diff --git a/Changelog b/Changelog
index 5ad2cef..5170a6a 100644
--- a/Changelog
+++ b/Changelog
@@ -4,6 +4,7 @@ releases are sorted from youngest to oldest.
 version 5.1:
 - dialogue enhance audio filter
 - dropped obsolete XvMC hwaccel
+- DFPWM audio encoder/decoder
 
 
 version 5.0:
diff --git a/MAINTAINERS b/MAINTAINERS
index f33ccbd..57b6f33 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -161,6 +161,7 @@ Codecs:
   cscd.c                                Reimar Doeffinger
   cuviddec.c                            Timo Rothenpieler
   dca*                                  foo86
+  dfpwm*                                Jack Bruienne
   dirac*                                Rostislav Pehlivanov
   dnxhd*                                Baptiste Coudurier
   dolby_e*                              foo86
diff --git a/doc/general_contents.texi b/doc/general_contents.texi
index df1692c..14aeaed 100644
--- a/doc/general_contents.texi
+++ b/doc/general_contents.texi
@@ -1194,6 +1194,7 @@ following image formats are supported:
 @item CRI HCA                @tab     @tab X
 @item Delphine Software International CIN audio  @tab     @tab  X
     @tab Codec used in Delphine Software International games.
+@item DFPWM                  @tab  X  @tab  X
 @item Digital Speech Standard - Standard Play mode (DSS SP) @tab     @tab  X
 @item Discworld II BMV Audio @tab     @tab  X
 @item COOK                   @tab     @tab  X
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 6076b4a..7474220 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -289,6 +289,8 @@ OBJS-$(CONFIG_DERF_DPCM_DECODER)       += dpcm.o
 OBJS-$(CONFIG_DIRAC_DECODER)           += diracdec.o dirac.o diracdsp.o diractab.o \
                                           dirac_arith.o dirac_dwt.o dirac_vlc.o
 OBJS-$(CONFIG_DFA_DECODER)             += dfa.o
+OBJS-$(CONFIG_DFPWM_DECODER)           += dfpwmdec.o
+OBJS-$(CONFIG_DFPWM_ENCODER)           += dfpwmenc.o
 OBJS-$(CONFIG_DNXHD_DECODER)           += dnxhddec.o dnxhddata.o
 OBJS-$(CONFIG_DNXHD_ENCODER)           += dnxhdenc.o dnxhddata.o
 OBJS-$(CONFIG_DOLBY_E_DECODER)         += dolby_e.o dolby_e_parse.o kbdwin.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index d1e1019..c3a0c26 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -437,6 +437,8 @@ extern const AVCodec ff_bmv_audio_decoder;
 extern const AVCodec ff_cook_decoder;
 extern const AVCodec ff_dca_encoder;
 extern const AVCodec ff_dca_decoder;
+extern const AVCodec ff_dfpwm_encoder;
+extern const AVCodec ff_dfpwm_decoder;
 extern const AVCodec ff_dolby_e_decoder;
 extern const AVCodec ff_dsd_lsbf_decoder;
 extern const AVCodec ff_dsd_msbf_decoder;
diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
index 725c687..81f3b3c 100644
--- a/libavcodec/codec_desc.c
+++ b/libavcodec/codec_desc.c
@@ -3237,6 +3237,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
         .long_name = NULL_IF_CONFIG_SMALL("MSN Siren"),
         .props     = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSY,
     },
+    {
+        .id        = AV_CODEC_ID_DFPWM,
+        .type      = AVMEDIA_TYPE_AUDIO,
+        .name      = "dfpwm",
+        .long_name = NULL_IF_CONFIG_SMALL("DFPWM (Dynamic Filter Pulse Width Modulation)"),
+        .props     = AV_CODEC_PROP_LOSSY,
+    },
 
     /* subtitle codecs */
     {
diff --git a/libavcodec/codec_id.h b/libavcodec/codec_id.h
index ab265ec..3ffb9bd 100644
--- a/libavcodec/codec_id.h
+++ b/libavcodec/codec_id.h
@@ -516,6 +516,7 @@ enum AVCodecID {
     AV_CODEC_ID_HCA,
     AV_CODEC_ID_FASTAUDIO,
     AV_CODEC_ID_MSNSIREN,
+    AV_CODEC_ID_DFPWM,
 
     /* subtitle codecs */
     AV_CODEC_ID_FIRST_SUBTITLE = 0x17000,          ///< A dummy ID pointing at the start of subtitle codecs.
diff --git a/libavcodec/dfpwmdec.c b/libavcodec/dfpwmdec.c
new file mode 100644
index 0000000..7946428
--- /dev/null
+++ b/libavcodec/dfpwmdec.c
@@ -0,0 +1,133 @@
+/*
+ * DFPWM decoder
+ * Copyright (c) 2022 Jack Bruienne
+ * Copyright (c) 2012, 2016 Ben "GreaseMonkey" Russell
+ *
+ * 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
+ * DFPWM1a decoder
+ */
+
+#include "libavutil/internal.h"
+#include "avcodec.h"
+#include "codec_id.h"
+#include "internal.h"
+
+typedef struct {
+    int fq, q, s, lt;
+} DFPWMState;
+
+// DFPWM codec from https://github.com/ChenThread/dfpwm/blob/master/1a/
+// Licensed in the public domain
+
+static void au_decompress(DFPWMState *state, int fs, int len, uint8_t *outbuf, uint8_t *inbuf)
+{
+    unsigned d;
+    for (int i = 0; i < len; i++) {
+        // get bits
+        d = *(inbuf++);
+        for (int j = 0; j < 8; j++) {
+            int nq, lq, st, ns, ov;
+            // set target
+            int t = ((d&1) ? 127 : -128);
+            d >>= 1;
+
+            // adjust charge
+            nq = state->q + ((state->s * (t-state->q) + 512)>>10);
+            if(nq == state->q && nq != t)
+                nq += (t == 127 ? 1 : -1);
+            lq = state->q;
+            state->q = nq;
+
+            // adjust strength
+            st = (t != state->lt ? 0 : 1023);
+            ns = state->s;
+            if(ns != st)
+                ns += (st != 0 ? 1 : -1);
+            if(ns < 8) ns = 8;
+            state->s = ns;
+
+            // FILTER: perform antijerk
+            ov = (t != state->lt ? (nq+lq+1)>>1 : nq);
+
+            // FILTER: perform LPF
+            state->fq += ((fs*(ov-state->fq) + 0x80)>>8);
+            ov = state->fq;
+
+            // output sample
+            *(outbuf++) = ov + 128;
+
+            state->lt = t;
+        }
+    }
+}
+
+static av_cold int dfpwm_dec_init(struct AVCodecContext *ctx)
+{
+    DFPWMState *state = ctx->priv_data;
+
+    state->fq = 0;
+    state->q = 0;
+    state->s = 0;
+    state->lt = -128;
+
+    ctx->sample_fmt = AV_SAMPLE_FMT_U8;
+    ctx->bits_per_raw_sample = 8;
+
+    return 0;
+}
+
+static int dfpwm_dec_frame(struct AVCodecContext *ctx, void *data,
+    int *got_frame, struct AVPacket *packet)
+{
+    DFPWMState *state = ctx->priv_data;
+    AVFrame *frame = data;
+    int ret;
+
+    if (ctx->channels <= 0) {
+        av_log(ctx, AV_LOG_ERROR, "Invalid number of channels\n");
+        *got_frame = 0;
+        return AVERROR(EINVAL);
+    }
+
+    frame->nb_samples = packet->size * 8 / ctx->channels;
+    ret = ff_get_buffer(ctx, frame, 0);
+    if (ret) {
+        *got_frame = 0;
+        return ret;
+    }
+
+    au_decompress(state, 140, packet->size, frame->data[0], packet->data);
+
+    *got_frame = 1;
+    return packet->size;
+}
+
+const AVCodec ff_dfpwm_decoder = {
+    .name           = "dfpwm",
+    .long_name      = NULL_IF_CONFIG_SMALL("DFPWM1a audio"),
+    .type           = AVMEDIA_TYPE_AUDIO,
+    .id             = AV_CODEC_ID_DFPWM,
+    .priv_data_size = sizeof(DFPWMState),
+    .init           = dfpwm_dec_init,
+    .decode         = dfpwm_dec_frame,
+    .capabilities   = AV_CODEC_CAP_DR1,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
+};
diff --git a/libavcodec/dfpwmenc.c b/libavcodec/dfpwmenc.c
new file mode 100644
index 0000000..02f2e64
--- /dev/null
+++ b/libavcodec/dfpwmenc.c
@@ -0,0 +1,121 @@
+/*
+ * DFPWM encoder
+ * Copyright (c) 2022 Jack Bruienne
+ * Copyright (c) 2012, 2016 Ben "GreaseMonkey" Russell
+ *
+ * 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
+ * DFPWM1a encoder
+ */
+
+#include "libavutil/internal.h"
+#include "avcodec.h"
+#include "codec_id.h"
+#include "encode.h"
+#include "internal.h"
+
+typedef struct {
+    int fq, q, s, lt;
+} DFPWMState;
+
+// DFPWM codec from https://github.com/ChenThread/dfpwm/blob/master/1a/
+// Licensed in the public domain
+
+// note, len denotes how many compressed bytes there are (uncompressed bytes / 8).
+static void au_compress(DFPWMState *state, int len, uint8_t *outbuf, uint8_t *inbuf)
+{
+    unsigned d = 0;
+    for (int i = 0; i < len; i++) {
+        for (int j = 0; j < 8; j++) {
+            int nq, st, ns;
+            // get sample
+            int v = *(inbuf++) - 128;
+            // set bit / target
+            int t = (v > state->q || (v == state->q && v == 127) ? 127 : -128);
+            d >>= 1;
+            if(t > 0)
+                d |= 0x80;
+
+            // adjust charge
+            nq = state->q + ((state->s * (t-state->q) + 512)>>10);
+            if(nq == state->q && nq != t)
+                nq += (t == 127 ? 1 : -1);
+            state->q = nq;
+
+            // adjust strength
+            st = (t != state->lt ? 0 : 1023);
+            ns = state->s;
+            if(ns != st)
+                ns += (st != 0 ? 1 : -1);
+            if(ns < 8) ns = 8;
+            state->s = ns;
+
+            state->lt = t;
+        }
+
+        // output bits
+        *(outbuf++) = d;
+    }
+}
+
+static av_cold int dfpwm_enc_init(struct AVCodecContext *ctx)
+{
+    DFPWMState *state = ctx->priv_data;
+
+    state->fq = 0;
+    state->q = 0;
+    state->s = 0;
+    state->lt = -128;
+
+    ctx->bits_per_coded_sample = 1;
+
+    return 0;
+}
+
+static int dfpwm_enc_frame(struct AVCodecContext *ctx, struct AVPacket *packet,
+    const struct AVFrame *frame, int *got_packet)
+{
+    DFPWMState *state = ctx->priv_data;
+    int size = frame->nb_samples * frame->channels / 8 + (frame->nb_samples % 8 > 0 ? 1 : 0);
+    int ret = ff_get_encode_buffer(ctx, packet, size, 0);
+
+    if (ret) {
+        *got_packet = 0;
+        return ret;
+    }
+
+    au_compress(state, size, packet->data, frame->data[0]);
+
+    *got_packet = 1;
+    return 0;
+}
+
+const AVCodec ff_dfpwm_encoder = {
+    .name            = "dfpwm",
+    .long_name       = NULL_IF_CONFIG_SMALL("DFPWM1a audio"),
+    .type            = AVMEDIA_TYPE_AUDIO,
+    .id              = AV_CODEC_ID_DFPWM,
+    .priv_data_size  = sizeof(DFPWMState),
+    .init            = dfpwm_enc_init,
+    .encode2         = dfpwm_enc_frame,
+    .sample_fmts     = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_U8, AV_SAMPLE_FMT_NONE},
+    .capabilities    = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_VARIABLE_FRAME_SIZE,
+    .caps_internal   = FF_CODEC_CAP_INIT_THREADSAFE,
+};
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 6f9d90a..066da76 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -577,6 +577,8 @@ enum AVCodecID av_get_pcm_codec(enum AVSampleFormat fmt, int be)
 int av_get_bits_per_sample(enum AVCodecID codec_id)
 {
     switch (codec_id) {
+    case AV_CODEC_ID_DFPWM:
+        return 1;
     case AV_CODEC_ID_ADPCM_SBPRO_2:
         return 2;
     case AV_CODEC_ID_ADPCM_SBPRO_3:
diff --git a/libavcodec/version.h b/libavcodec/version.h
index d900503..84f3979 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -28,7 +28,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVCODEC_VERSION_MAJOR  59
-#define LIBAVCODEC_VERSION_MINOR  21
+#define LIBAVCODEC_VERSION_MINOR  22
 #define LIBAVCODEC_VERSION_MICRO 100
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
