diff --git a/libavformat/Makefile b/libavformat/Makefile
index a671e283e2..70acbe7c39 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -106,6 +106,7 @@ OBJS-$(CONFIG_MATROSKA_DEMUXER)          += matroskadec.o matroska.o \
 OBJS-$(CONFIG_MATROSKA_MUXER)            += matroskaenc.o matroska.o \
                                             riff.o isom.o avc.o \
                                             flacenc_header.o
+OBJS-$(CONFIG_MD5_MUXER)                 += md5enc.o
 OBJS-$(CONFIG_MJPEG_DEMUXER)             += raw.o
 OBJS-$(CONFIG_MJPEG_MUXER)               += raw.o
 OBJS-$(CONFIG_MLP_DEMUXER)               += raw.o id3v2.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 27dba103d2..852cb58313 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -106,6 +106,7 @@ void av_register_all(void)
     REGISTER_DEMUXER  (IV8, iv8);
     REGISTER_DEMUXER  (LMLM4, lmlm4);
     REGISTER_MUXDEMUX (M4V, m4v);
+    REGISTER_MUXER    (MD5, md5);
     REGISTER_MUXDEMUX (MATROSKA, matroska);
     REGISTER_MUXER    (MATROSKA_AUDIO, matroska_audio);
     REGISTER_MUXDEMUX (MJPEG, mjpeg);
diff --git a/libavformat/md5enc.c b/libavformat/md5enc.c
new file mode 100644
index 0000000000..600b95d6dc
--- /dev/null
+++ b/libavformat/md5enc.c
@@ -0,0 +1,73 @@
+/*
+ * MD5 encoder (for codec/format testing)
+ * Copyright (c) 2009 Reimar Döffinger, based on crcenc (c) 2002 Fabrice Bellard
+ *
+ * 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 "libavutil/md5.h"
+#include "avformat.h"
+
+#define PRIVSIZE 512
+
+static int write_header(struct AVFormatContext *s)
+{
+    if (PRIVSIZE < av_md5_size) {
+        av_log(s, AV_LOG_ERROR, "Insuffient size for md5 context\n");
+        return -1;
+    }
+    av_md5_init(s->priv_data);
+    return 0;
+}
+
+static int write_packet(struct AVFormatContext *s, AVPacket *pkt)
+{
+    av_md5_update(s->priv_data, pkt->data, pkt->size);
+    return 0;
+}
+
+static int write_trailer(struct AVFormatContext *s)
+{
+    uint8_t md5[16];
+    char buf[64] = "MD5=";
+    int i, offset = strlen(buf);
+
+    av_md5_final(s->priv_data, md5);
+    for (i = 0; i < sizeof(md5); i++) {
+        snprintf(buf + offset, 3, "%02"PRIx8, md5[i]);
+        offset += 2;
+    }
+    buf[offset] = '\n';
+    buf[offset+1] = 0;
+
+    put_buffer(s->pb, buf, strlen(buf));
+    put_flush_packet(s->pb);
+    return 0;
+}
+
+AVOutputFormat md5_muxer = {
+    "md5",
+    NULL_IF_CONFIG_SMALL("MD5 testing format"),
+    NULL,
+    "",
+    PRIVSIZE,
+    CODEC_ID_PCM_S16LE,
+    CODEC_ID_RAWVIDEO,
+    write_header,
+    write_packet,
+    write_trailer,
+};