diff --git a/libavformat/Makefile b/libavformat/Makefile
index cbb33fe37c..1e0ac317e5 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -319,6 +319,7 @@ OBJS-$(CONFIG_MLV_DEMUXER)               += mlvdec.o riffdec.o
 OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
 OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o
 OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o rawenc.o
+OBJS-$(CONFIG_MOFLEX_DEMUXER)            += moflex.o
 OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o mov_chan.o mov_esds.o replaygain.o
 OBJS-$(CONFIG_MOV_MUXER)                 += movenc.o av1.o avc.o hevc.o vpcc.o \
                                             movenchint.o mov_chan.o rtp.o \
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 0aa9dd7198..28331facb9 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -249,6 +249,7 @@ extern AVInputFormat  ff_mlv_demuxer;
 extern AVInputFormat  ff_mm_demuxer;
 extern AVInputFormat  ff_mmf_demuxer;
 extern AVOutputFormat ff_mmf_muxer;
+extern AVInputFormat  ff_moflex_demuxer;
 extern AVInputFormat  ff_mov_demuxer;
 extern AVOutputFormat ff_mov_muxer;
 extern AVOutputFormat ff_mp2_muxer;
diff --git a/libavformat/moflex.c b/libavformat/moflex.c
new file mode 100644
index 0000000000..3761837895
--- /dev/null
+++ b/libavformat/moflex.c
@@ -0,0 +1,358 @@
+/*
+ * MOFLEX demuxer
+ * 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
+ */
+
+#include "libavcodec/bytestream.h"
+
+#include "avformat.h"
+#include "internal.h"
+
+typedef struct BitReader {
+    unsigned last;
+    unsigned pos;
+} BitReader;
+
+typedef struct MOFLEXDemuxContext {
+    unsigned size;
+    int64_t pos;
+    int64_t ts;
+    int flags;
+    int in_block;
+
+    BitReader br;
+} MOFLEXDemuxContext;
+
+static int pop(BitReader *br, AVIOContext *pb)
+{
+    if (avio_feof(pb))
+        return AVERROR_EOF;
+
+    if ((br->pos & 7) == 0)
+        br->last = (unsigned)avio_r8(pb) << 24U;
+    else
+        br->last <<= 1;
+
+    br->pos++;
+    return !!(br->last & 0x80000000);
+}
+
+static int pop_int(BitReader *br, AVIOContext *pb, int n)
+{
+    int value = 0;
+
+    for (int i = 0; i < n; i++) {
+        int ret = pop(br, pb);
+
+        if (ret < 0)
+            return ret;
+        value = 2 * value + ret;
+    }
+
+    return value;
+}
+
+static int pop_length(BitReader *br, AVIOContext *pb)
+{
+    int ret, n = 1;
+
+    while ((ret = pop(br, pb)) == 0)
+        n++;
+
+    if (ret < 0)
+        return ret;
+    return n;
+}
+
+static int read_var_byte(AVFormatContext *s, unsigned *out)
+{
+    AVIOContext *pb = s->pb;
+    unsigned value = 0, data;
+
+    data = avio_r8(pb);
+    if (!(data & 0x80)) {
+        *out = data;
+        return 0;
+    }
+
+    value = (data & 0x7F) << 7;
+    data = avio_r8(pb);
+    if (!(data & 0x80)) {
+        value |= data;
+        *out = value;
+        return 0;
+    }
+
+    value = ((data & 0x7F) | value) << 7;
+    data = avio_r8(pb);
+    if (!(data & 0x80)) {
+        value |= data;
+        *out = value;
+        return 0;
+    }
+
+    value = (((data & 0x7F) | value) << 7) | avio_r8(pb);
+    *out = value;
+
+    return 0;
+}
+
+static int moflex_probe(const AVProbeData *p)
+{
+    GetByteContext gb;
+    int score = 0;
+
+    bytestream2_init(&gb, p->buf, p->buf_size);
+
+    if (bytestream2_get_be16(&gb) != 0x4C32)
+        return 0;
+    score += 10;
+
+    bytestream2_skip(&gb, 10);
+    if (bytestream2_get_be16(&gb) == 0)
+        return 0;
+    score += 5;
+
+    while (bytestream2_get_bytes_left(&gb) > 0) {
+        int type = bytestream2_get_byte(&gb);
+        int size = bytestream2_get_byte(&gb);
+
+        if (type == 0) {
+            score += 5 * (size == 0);
+            break;
+        }
+        if ((type == 1 && size == 12) ||
+            (type == 2 && size ==  6) ||
+            (type == 3 && size == 13) ||
+            (type == 4 && size ==  2))
+            score += 20;
+        bytestream2_skip(&gb, size);
+    }
+
+    return FFMIN(AVPROBE_SCORE_MAX, score);
+}
+
+static int moflex_read_sync(AVFormatContext *s)
+{
+    MOFLEXDemuxContext *m = s->priv_data;
+    AVIOContext *pb = s->pb;
+
+    if (avio_rb16(pb) != 0x4C32) {
+        avio_seek(pb, -2, SEEK_CUR);
+        return 1;
+    }
+
+    avio_skip(pb, 2);
+    m->ts = avio_rb64(pb);
+    m->size = avio_rb16(pb) + 1;
+
+    while (!avio_feof(pb)) {
+        unsigned type, ssize, codec_id = 0;
+        unsigned codec_type, width = 0, height = 0, sample_rate = 0, channels = 0;
+        int stream_index = -1;
+        int format;
+        AVRational fps;
+
+        read_var_byte(s, &type);
+        read_var_byte(s, &ssize);
+
+        switch (type) {
+        case 0:
+            if (ssize > 0)
+                avio_skip(pb, ssize);
+            return 0;
+        case 2:
+            codec_type = AVMEDIA_TYPE_AUDIO;
+            stream_index = avio_r8(pb);
+            codec_id = avio_r8(pb);
+            switch (codec_id) {
+            case 0: codec_id = AV_CODEC_ID_FASTAUDIO; break;
+            case 1: codec_id = AV_CODEC_ID_ADPCM_IMA_MOFLEX; break;
+            case 2: codec_id = AV_CODEC_ID_PCM_S16LE; break;
+            default:
+                av_log(s, AV_LOG_ERROR, "Unsupported audio codec: %d\n", codec_id);
+                return AVERROR_PATCHWELCOME;
+            }
+            sample_rate = avio_rb24(pb) + 1;
+            channels = avio_r8(pb) + 1;
+            break;
+        case 1:
+        case 3:
+            codec_type = AVMEDIA_TYPE_VIDEO;
+            stream_index = avio_r8(pb);
+            codec_id = avio_r8(pb);
+            switch (codec_id) {
+            case 0: codec_id = AV_CODEC_ID_MOBICLIP; break;
+            default:
+                av_log(s, AV_LOG_ERROR, "Unsupported video codec: %d\n", codec_id);
+                return AVERROR_PATCHWELCOME;
+            }
+            fps.num = avio_rb16(pb);
+            fps.den = avio_rb16(pb);
+            width = avio_rb16(pb);
+            height = avio_rb16(pb);
+            format = AV_PIX_FMT_YUV420P;
+            avio_skip(pb, type == 3 ? 3 : 2);
+            break;
+        case 4:
+            codec_type = AVMEDIA_TYPE_DATA;
+            stream_index = avio_r8(pb);
+            avio_skip(pb, 1);
+            break;
+        }
+
+        if (stream_index == s->nb_streams) {
+            AVStream *st = avformat_new_stream(s, NULL);
+
+            if (!st)
+                return AVERROR(ENOMEM);
+
+            st->codecpar->codec_type = codec_type;
+            st->codecpar->codec_id   = codec_id;
+            st->codecpar->width      = width;
+            st->codecpar->height     = height;
+            st->codecpar->sample_rate= sample_rate;
+            st->codecpar->channels   = channels;
+            st->codecpar->format     = format;
+            st->priv_data            = av_packet_alloc();
+            if (!st->priv_data)
+                return AVERROR(ENOMEM);
+
+            if (sample_rate)
+                avpriv_set_pts_info(st, 63, 1, sample_rate);
+            else
+                avpriv_set_pts_info(st, 63, fps.den, fps.num);
+        }
+    }
+
+    return 0;
+}
+
+static int moflex_read_header(AVFormatContext *s)
+{
+    int ret;
+
+    ret = moflex_read_sync(s);
+    if (ret < 0)
+        return ret;
+
+    s->ctx_flags |= AVFMTCTX_NOHEADER;
+    avio_seek(s->pb, 0, SEEK_SET);
+
+    return 0;
+}
+
+static int moflex_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    MOFLEXDemuxContext *m = s->priv_data;
+    AVIOContext *pb = s->pb;
+    BitReader *br = &m->br;
+    int ret;
+
+    while (!avio_feof(pb)) {
+        if (!m->in_block) {
+            m->pos = avio_tell(pb);
+
+            ret = moflex_read_sync(s);
+            if (ret < 0)
+                return ret;
+
+            m->flags = avio_r8(pb);
+            if (m->flags & 2)
+                avio_skip(pb, 2);
+        }
+
+        while ((avio_tell(pb) < m->pos + m->size) && !avio_feof(pb) && avio_r8(pb)) {
+            int stream_index, bits, pkt_size, endframe;
+            AVPacket *packet;
+
+            m->in_block = 1;
+
+            avio_seek(pb, -1, SEEK_CUR);
+            br->pos = br->last = 0;
+
+            bits = pop_length(br, pb);
+            if (bits < 0)
+                return bits;
+            stream_index = pop_int(br, pb, bits);
+            if (stream_index < 0)
+                return stream_index;
+            if (stream_index >= s->nb_streams)
+                return AVERROR_INVALIDDATA;
+
+            endframe = pop(br, pb);
+            if (endframe < 0)
+                return endframe;
+            if (endframe) {
+                bits = pop_length(br, pb);
+                if (bits < 0)
+                    return bits;
+                pop_int(br, pb, bits);
+                pop(br, pb);
+                bits = pop_length(br, pb);
+                if (bits < 0)
+                    return bits;
+                pop_int(br, pb, bits * 2 + 26);
+            }
+
+            pkt_size = pop_int(br, pb, 13) + 1;
+            packet   = s->streams[stream_index]->priv_data;
+
+            ret = av_append_packet(pb, packet, pkt_size);
+            if (endframe) {
+                av_packet_move_ref(pkt, packet);
+                pkt->pos = m->pos;
+                pkt->stream_index = stream_index;
+                pkt->flags |= AV_PKT_FLAG_KEY;
+                return ret;
+            }
+        }
+
+        m->in_block = 0;
+
+        if (m->flags % 2 == 0)
+            avio_seek(pb, m->pos + m->size, SEEK_SET);
+    }
+
+    return AVERROR_EOF;
+}
+
+static int moflex_read_close(AVFormatContext *s)
+{
+    for (int i = 0; i < s->nb_streams; i++) {
+        AVPacket *packet = s->streams[i]->priv_data;
+
+        av_packet_free(&packet);
+        s->streams[i]->priv_data = 0;
+    }
+
+    return 0;
+}
+
+AVInputFormat ff_moflex_demuxer = {
+    .name           = "moflex",
+    .long_name      = NULL_IF_CONFIG_SMALL("MobiClip MOFLEX"),
+    .priv_data_size = sizeof(MOFLEXDemuxContext),
+    .read_probe     = moflex_probe,
+    .read_header    = moflex_read_header,
+    .read_packet    = moflex_read_packet,
+    .read_close     = moflex_read_close,
+    .extensions     = "moflex",
+    .flags          = AVFMT_GENERIC_INDEX,
+};
