diff --git a/Changelog b/Changelog
index e26320c0ce..bc1593bfd1 100644
--- a/Changelog
+++ b/Changelog
@@ -31,6 +31,7 @@ version <next>:
 - thistogram filter
 - freezeframes filter
 - Argonaut Games ADPCM decoder
+- Argonaut Games ASF demuxer
 
 version 4.2:
 - tpad filter
diff --git a/libavformat/Makefile b/libavformat/Makefile
index 52f29b1a6d..ba6ea8c4a6 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -99,6 +99,7 @@ OBJS-$(CONFIG_APTX_MUXER)                += rawenc.o
 OBJS-$(CONFIG_APTX_HD_DEMUXER)           += aptxdec.o rawdec.o
 OBJS-$(CONFIG_APTX_HD_MUXER)             += rawenc.o
 OBJS-$(CONFIG_AQTITLE_DEMUXER)           += aqtitledec.o subtitles.o
+OBJS-$(CONFIG_ARGO_ASF_DEMUXER)          += argo_asf.o
 OBJS-$(CONFIG_ASF_DEMUXER)               += asfdec_f.o asf.o asfcrypt.o \
                                             avlanguage.o
 OBJS-$(CONFIG_ASF_O_DEMUXER)             += asfdec_o.o asf.o asfcrypt.o \
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index ff9bdb906f..fe74a32e47 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -60,6 +60,7 @@ extern AVOutputFormat ff_aptx_muxer;
 extern AVInputFormat  ff_aptx_hd_demuxer;
 extern AVOutputFormat ff_aptx_hd_muxer;
 extern AVInputFormat  ff_aqtitle_demuxer;
+extern AVInputFormat  ff_argo_asf_demuxer;
 extern AVInputFormat  ff_asf_demuxer;
 extern AVOutputFormat ff_asf_muxer;
 extern AVInputFormat  ff_asf_o_demuxer;
diff --git a/libavformat/argo_asf.c b/libavformat/argo_asf.c
new file mode 100644
index 0000000000..d8f2d71009
--- /dev/null
+++ b/libavformat/argo_asf.c
@@ -0,0 +1,260 @@
+/*
+ * Argonaut Games ASF demuxer
+ *
+ * Copyright (C) 2020 Zane van Iperen (zane@zanevaniperen.com)
+ *
+ * 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 "avformat.h"
+#include "internal.h"
+#include "libavutil/intreadwrite.h"
+
+#define ASF_TAG                 MKTAG('A', 'S', 'F', '\0')
+#define ASF_FILE_HEADER_SIZE    (24)
+#define ASF_CHUNK_HEADER_SIZE   (20)
+
+typedef struct ArgoASFFileHeader {
+    uint32_t    magic;          /*< Magic Number, {'A', 'S', 'F', '\0'} */
+    uint16_t    version_major;  /*< File Major Version. */
+    uint16_t    version_minor;  /*< File Minor Version. */
+    uint32_t    num_chunks;     /*< No. chunks in the file. */
+    uint32_t    chunk_offset;   /*< Offset to the first chunk from the start of the file. */
+    int8_t      name[8];        /*< Name. */
+} ArgoASFFileHeader;
+
+typedef struct ArgoASFChunkHeader {
+    uint32_t    num_blocks;     /*< No. blocks in the chunk. */
+    uint32_t    num_samples;    /*< No. samples per channel in a block. */
+    uint32_t    unk1;           /*< Unknown */
+    uint16_t    sample_rate;    /*< Sample rate. */
+    uint16_t    unk2;           /*< Unknown. */
+    uint32_t    flags;          /*< Stream flags. */
+} ArgoASFChunkHeader;
+
+enum {
+    ASF_CF_BITS_PER_SAMPLE  = (1 << 0), /*< 16-bit if set, 8 otherwise.      */
+    ASF_CF_STEREO           = (1 << 1), /*< Stereo if set, mono otherwise.   */
+    ASF_CF_ALWAYS1_1        = (1 << 2), /*< Unknown, always seems to be set. */
+    ASF_CF_ALWAYS1_2        = (1 << 3), /*< Unknown, always seems to be set. */
+
+    ASF_CF_ALWAYS1          = ASF_CF_ALWAYS1_1 | ASF_CF_ALWAYS1_2,
+    ASF_CF_ALWAYS0          = ~(ASF_CF_BITS_PER_SAMPLE | ASF_CF_STEREO | ASF_CF_ALWAYS1)
+};
+
+typedef struct ArgoASFDemuxContext
+{
+    ArgoASFFileHeader   fhdr;
+    ArgoASFChunkHeader  ckhdr;
+    uint32_t            blocks_read;
+} ArgoASFDemuxContext;
+
+static void argo_asf_parse_file_header(ArgoASFFileHeader *hdr, const uint8_t *buf)
+{
+    hdr->magic           = AV_RL32(buf + 0);
+    hdr->version_major   = AV_RL16(buf + 4);
+    hdr->version_minor   = AV_RL16(buf + 6);
+    hdr->num_chunks      = AV_RL32(buf + 8);
+    hdr->chunk_offset    = AV_RL32(buf + 12);
+    for(int i = 0; i < 8; ++i)
+        hdr->name[i]     = AV_RL8(buf + 16 + i);
+}
+
+static void argo_asf_parse_chunk_header(ArgoASFChunkHeader *hdr, const uint8_t *buf)
+{
+    hdr->num_blocks     = AV_RL32(buf + 0);
+    hdr->num_samples    = AV_RL32(buf + 4);
+    hdr->unk1           = AV_RL32(buf + 8);
+    hdr->sample_rate    = AV_RL16(buf + 12);
+    hdr->unk2           = AV_RL16(buf + 14);
+    hdr->flags          = AV_RL32(buf + 16);
+}
+
+/*
+ * Known versions:
+ * 1.1: The sample files in /game-formats/brender/part2.zip
+ * 1.2: Croc! Legend of the Gobbos
+ * 2.1: Croc 2
+ */
+static int argo_asf_is_known_version(const ArgoASFFileHeader *hdr)
+{
+    return (hdr->version_major == 1 && hdr->version_minor == 1) ||
+           (hdr->version_major == 1 && hdr->version_minor == 2) ||
+           (hdr->version_major == 2 && hdr->version_minor == 1);
+}
+
+static int argo_asf_probe(const AVProbeData *p)
+{
+    int score;
+    ArgoASFFileHeader hdr;
+
+    if (p->buf_size < ASF_FILE_HEADER_SIZE)
+        return AVPROBE_SCORE_RETRY;
+
+    score = 0;
+    if (av_match_ext(p->filename, "asf"))
+        score += AVPROBE_SCORE_EXTENSION;
+
+    argo_asf_parse_file_header(&hdr, p->buf);
+
+    if(hdr.magic != ASF_TAG)
+        return 0;
+
+    if (argo_asf_is_known_version(&hdr))
+        score += 25;
+
+    /* Have only ever seen these with 1 chunk. */
+    if (hdr.num_chunks == 1)
+        score += 25;
+
+    if (hdr.chunk_offset > INT_MAX)
+        score -= 50;
+
+    if (score > AVPROBE_SCORE_MAX)
+        score = AVPROBE_SCORE_MAX;
+
+    return score;
+}
+
+
+
+static int argo_asf_read_header(AVFormatContext *s)
+{
+    int64_t ret;
+    AVIOContext *pb = s->pb;
+    AVStream *st;
+    ArgoASFDemuxContext *asf = s->priv_data;
+    uint8_t buf[FFMAX(ASF_FILE_HEADER_SIZE, ASF_CHUNK_HEADER_SIZE)];
+
+    if (!(st = avformat_new_stream(s, NULL)))
+        return AVERROR(ENOMEM);
+
+    if ((ret = avio_read(pb, buf, ASF_FILE_HEADER_SIZE)) < 0)
+        return ret;
+    else if (ret != ASF_FILE_HEADER_SIZE)
+        return AVERROR(EIO);
+
+    argo_asf_parse_file_header(&asf->fhdr, buf);
+
+    if (!argo_asf_is_known_version(&asf->fhdr)) {
+        avpriv_request_sample(s, "Version %hu.%hu",
+            asf->fhdr.version_major, asf->fhdr.version_minor
+        );
+        return AVERROR_PATCHWELCOME;
+    }
+
+    if (asf->fhdr.chunk_offset < ASF_FILE_HEADER_SIZE)
+        return AVERROR_INVALIDDATA;
+
+    if ((ret = avio_skip(pb, asf->fhdr.chunk_offset - ASF_FILE_HEADER_SIZE)) < 0)
+        return ret;
+
+    if ((ret = avio_read(pb, buf, ASF_CHUNK_HEADER_SIZE)) < 0)
+        return ret;
+    else if (ret != ASF_CHUNK_HEADER_SIZE)
+        return AVERROR(EIO);
+
+    argo_asf_parse_chunk_header(&asf->ckhdr, buf);
+
+    if ((asf->ckhdr.flags & ASF_CF_ALWAYS1) != ASF_CF_ALWAYS1 || (asf->ckhdr.flags & ASF_CF_ALWAYS0) != 0) {
+        avpriv_request_sample(s, "Nonstandard flags (0x%08X)", asf->ckhdr.flags);
+        return AVERROR_PATCHWELCOME;
+    }
+
+    st->codecpar->codec_type                = AVMEDIA_TYPE_AUDIO;
+    st->codecpar->codec_id                  = AV_CODEC_ID_ADPCM_ARGO;
+    st->codecpar->format                    = AV_SAMPLE_FMT_S16;
+
+    if (asf->ckhdr.flags & ASF_CF_STEREO) {
+        st->codecpar->channel_layout        = AV_CH_LAYOUT_STEREO;
+        st->codecpar->channels              = 2;
+    } else {
+        st->codecpar->channel_layout        = AV_CH_LAYOUT_MONO;
+        st->codecpar->channels              = 1;
+    }
+
+    st->codecpar->sample_rate               = asf->ckhdr.sample_rate;
+
+    st->codecpar->bits_per_coded_sample     = 4;
+
+    if (asf->ckhdr.flags & ASF_CF_BITS_PER_SAMPLE)
+        st->codecpar->bits_per_raw_sample   = 16;
+    else
+        st->codecpar->bits_per_raw_sample   = 8;
+
+    if (st->codecpar->bits_per_raw_sample != 16) {
+        /* The header allows for these, but I've never seen any files with them. */
+        avpriv_request_sample(s, "Non 16-bit samples");
+        return AVERROR_PATCHWELCOME;
+    }
+
+    /*
+     * (nchannel control bytes) + ((bytes_per_channel) * nchannel)
+     * For mono, this is 17. For stereo, this is 34.
+     */
+    st->codecpar->frame_size            = st->codecpar->channels +
+                                          (asf->ckhdr.num_samples / 2) *
+                                          st->codecpar->channels;
+
+    st->codecpar->block_align           = st->codecpar->frame_size;
+
+    st->codecpar->bit_rate              = st->codecpar->channels *
+                                          st->codecpar->sample_rate *
+                                          st->codecpar->bits_per_coded_sample;
+
+    avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
+    st->start_time      = 0;
+    st->duration        = asf->ckhdr.num_blocks * asf->ckhdr.num_samples;
+    st->nb_frames       = asf->ckhdr.num_blocks;
+    return 0;
+}
+
+static int argo_asf_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    ArgoASFDemuxContext *asf = s->priv_data;
+
+    AVStream *st = s->streams[0];
+    AVIOContext *pb = s->pb;
+    int ret;
+
+    if (asf->blocks_read >= asf->ckhdr.num_blocks)
+        return AVERROR_EOF;
+
+    if ((ret = av_get_packet(pb, pkt, st->codecpar->frame_size)) < 0)
+        return ret;
+    else if (ret != st->codecpar->frame_size)
+        return AVERROR_INVALIDDATA;
+
+    pkt->stream_index   = st->index;
+    pkt->duration       = asf->ckhdr.num_samples;
+
+    ++asf->blocks_read;
+    return 0;
+}
+
+/*
+ * Not actually sure what ASF stands for.
+ * - Argonaut Sound File?
+ * - Audio Stream File?
+ */
+AVInputFormat ff_argo_asf_demuxer = {
+    .name           = "argo_asf",
+    .long_name      = NULL_IF_CONFIG_SMALL("Argonaut Games ASF"),
+    .priv_data_size = sizeof(ArgoASFDemuxContext),
+    .read_probe     = argo_asf_probe,
+    .read_header    = argo_asf_read_header,
+    .read_packet    = argo_asf_read_packet
+};
diff --git a/libavformat/version.h b/libavformat/version.h
index 0a79868663..f72fb9478a 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -32,8 +32,8 @@
 // Major bumping may affect Ticket5467, 5421, 5451(compatibility with Chromium)
 // Also please add any ticket numbers that you believe might be affected here
 #define LIBAVFORMAT_VERSION_MAJOR  58
-#define LIBAVFORMAT_VERSION_MINOR  35
-#define LIBAVFORMAT_VERSION_MICRO 103
+#define LIBAVFORMAT_VERSION_MINOR  36
+#define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \
