diff --git a/Changelog b/Changelog
index 2f71a6f083..04082a9b96 100644
--- a/Changelog
+++ b/Changelog
@@ -20,7 +20,7 @@ version <next>:
 - selectivecolor filter
 - extensive native AAC encoder improvements
 - ADPCM PSX decoder
-- genh, vag, xvag, ads, msf & svag demuxer
+- 3dostr, genh, vag, xvag, ads, msf & svag demuxer
 - zscale filter
 - wve demuxer
 - zero-copy Intel QSV transcoding in ffmpeg
diff --git a/doc/general.texi b/doc/general.texi
index 942ae63d5e..37929c99f2 100644
--- a/doc/general.texi
+++ b/doc/general.texi
@@ -223,6 +223,7 @@ library:
 
 @multitable @columnfractions .4 .1 .1 .4
 @item Name @tab Encoding @tab Decoding @tab Comments
+@item 3dostr                    @tab   @tab X
 @item 4xm                       @tab   @tab X
     @tab 4X Technologies format, used in some games.
 @item 8088flex TMV              @tab   @tab X
diff --git a/libavformat/3dostr.c b/libavformat/3dostr.c
new file mode 100644
index 0000000000..ac58a6cd80
--- /dev/null
+++ b/libavformat/3dostr.c
@@ -0,0 +1,168 @@
+/*
+ * 3DO STR demuxer
+ * Copyright (c) 2015 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 "avformat.h"
+#include "internal.h"
+
+static int threedostr_probe(AVProbeData *p)
+{
+    if (memcmp(p->buf, "CTRL", 4) &&
+        memcmp(p->buf, "SHDR", 4) &&
+        memcmp(p->buf, "SNDS", 4))
+        return 0;
+
+    return AVPROBE_SCORE_MAX / 3 * 2;
+}
+
+static int threedostr_read_header(AVFormatContext *s)
+{
+    unsigned chunk, codec = 0, size, ctrl_size = -1, found_shdr = 0;
+    AVStream *st;
+
+    while (!avio_feof(s->pb) && !found_shdr) {
+        chunk = avio_rl32(s->pb);
+        size  = avio_rb32(s->pb);
+
+        if (size < 8)
+            return AVERROR_INVALIDDATA;
+        size -= 8;
+
+        switch (chunk) {
+        case MKTAG('C','T','R','L'):
+            ctrl_size = size;
+            break;
+        case MKTAG('S','N','D','S'):
+            if (size < 56)
+                return AVERROR_INVALIDDATA;
+            avio_skip(s->pb, 8);
+            if (avio_rl32(s->pb) != MKTAG('S','H','D','R'))
+                return AVERROR_INVALIDDATA;
+            avio_skip(s->pb, 24);
+
+            st = avformat_new_stream(s, NULL);
+            if (!st)
+                return AVERROR(ENOMEM);
+
+            st->codec->codec_type  = AVMEDIA_TYPE_AUDIO;
+            st->codec->sample_rate = avio_rb32(s->pb);
+            st->codec->channels    = avio_rb32(s->pb);
+            if (st->codec->channels <= 0)
+                return AVERROR_INVALIDDATA;
+            codec                  = avio_rl32(s->pb);
+            avio_skip(s->pb, 4);
+            if (ctrl_size == 20 || ctrl_size == 3 || ctrl_size == -1)
+                st->duration       = (avio_rb32(s->pb) - 1) / st->codec->channels;
+            else
+                st->duration       = avio_rb32(s->pb) * 16 / st->codec->channels;
+            size -= 56;
+            found_shdr = 1;
+            break;
+        case MKTAG('S','H','D','R'):
+            if (size >  0x78) {
+                avio_skip(s->pb, 0x74);
+                size -= 0x78;
+                if (avio_rl32(s->pb) == MKTAG('C','T','R','L') && size > 4) {
+                    ctrl_size = avio_rb32(s->pb);
+                    size -= 4;;
+                }
+            }
+            break;
+        default:
+            av_log(s, AV_LOG_DEBUG, "skipping unknown chunk: %X\n", chunk);
+            break;
+        }
+
+        avio_skip(s->pb, size);
+    }
+
+    switch (codec) {
+    case MKTAG('S','D','X','2'):
+        st->codec->codec_id    = AV_CODEC_ID_SDX2_DPCM;
+        st->codec->block_align = 1 * st->codec->channels;
+        break;
+    default:
+        avpriv_request_sample(s, "codec %X", codec);
+        return AVERROR_PATCHWELCOME;
+    }
+
+    avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
+
+    return 0;
+}
+
+static int threedostr_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    unsigned chunk, size, found_ssmp = 0;
+    AVStream *st = s->streams[0];
+    int64_t pos;
+    int ret = 0;
+
+    while (!found_ssmp) {
+        if (avio_feof(s->pb))
+            return AVERROR_EOF;
+
+        pos   = avio_tell(s->pb);
+        chunk = avio_rl32(s->pb);
+        size  = avio_rb32(s->pb);
+
+        if (!size)
+            continue;
+
+        if (size < 8)
+            return AVERROR_INVALIDDATA;
+        size -= 8;
+
+        switch (chunk) {
+        case MKTAG('S','N','D','S'):
+            if (size <= 16)
+                return AVERROR_INVALIDDATA;
+            avio_skip(s->pb, 8);
+            if (avio_rl32(s->pb) != MKTAG('S','S','M','P'))
+                return AVERROR_INVALIDDATA;
+            avio_skip(s->pb, 4);
+            size -= 16;
+            ret = av_get_packet(s->pb, pkt, size);
+            pkt->pos = pos;
+            pkt->stream_index = 0;
+            pkt->duration = size / st->codec->channels;
+            size = 0;
+            found_ssmp = 1;
+            break;
+        default:
+            av_log(s, AV_LOG_DEBUG, "skipping unknown chunk: %X\n", chunk);
+            break;
+        }
+
+        avio_skip(s->pb, size);
+    }
+
+    return ret;
+}
+
+AVInputFormat ff_threedostr_demuxer = {
+    .name           = "3dostr",
+    .long_name      = NULL_IF_CONFIG_SMALL("3DO STR"),
+    .read_probe     = threedostr_probe,
+    .read_header    = threedostr_read_header,
+    .read_packet    = threedostr_read_packet,
+    .extensions     = "str",
+    .flags          = AVFMT_GENERIC_INDEX,
+};
diff --git a/libavformat/Makefile b/libavformat/Makefile
index 5ca2843d37..c3d9e18bf1 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -435,6 +435,7 @@ OBJS-$(CONFIG_TAK_DEMUXER)               += takdec.o apetag.o img2.o rawdec.o
 OBJS-$(CONFIG_TEDCAPTIONS_DEMUXER)       += tedcaptionsdec.o subtitles.o
 OBJS-$(CONFIG_TEE_MUXER)                 += tee.o
 OBJS-$(CONFIG_THP_DEMUXER)               += thp.o
+OBJS-$(CONFIG_THREEDOSTR_DEMUXER)        += 3dostr.o
 OBJS-$(CONFIG_TIERTEXSEQ_DEMUXER)        += tiertexseq.o
 OBJS-$(CONFIG_MKVTIMESTAMP_V2_MUXER)     += mkvtimestamp_v2.o
 OBJS-$(CONFIG_TMV_DEMUXER)               += tmv.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 69c02b1060..a67a226890 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -303,6 +303,7 @@ void av_register_all(void)
     REGISTER_MUXER   (TG2,              tg2);
     REGISTER_MUXER   (TGP,              tgp);
     REGISTER_DEMUXER (THP,              thp);
+    REGISTER_DEMUXER (THREEDOSTR,       threedostr);
     REGISTER_DEMUXER (TIERTEXSEQ,       tiertexseq);
     REGISTER_MUXER   (MKVTIMESTAMP_V2,  mkvtimestamp_v2);
     REGISTER_DEMUXER (TMV,              tmv);
diff --git a/libavformat/version.h b/libavformat/version.h
index c48e3b8239..d4ba0cef78 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFORMAT_VERSION_MAJOR  57
-#define LIBAVFORMAT_VERSION_MINOR  11
+#define LIBAVFORMAT_VERSION_MINOR  12
 #define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \