diff --git a/libav/avformat.h b/libav/avformat.h
index c0d25f1607..0f04e71989 100644
--- a/libav/avformat.h
+++ b/libav/avformat.h
@@ -1,4 +1,8 @@
 
+#define LIBAV_VERSION_INT 0x000406  
+#define LIBAV_VERSION     "0.4.6"
+#define LIBAV_BUILD       4600
+
 #include "avcodec.h"
 
 #include "avio.h"
diff --git a/libav/wav.c b/libav/wav.c
index 0023ac608a..d92b20c5e8 100644
--- a/libav/wav.c
+++ b/libav/wav.c
@@ -20,9 +20,8 @@
 #include "avi.h"
 
 CodecTag codec_wav_tags[] = {
-    { CODEC_ID_MP2, 0x55 },
-    { CODEC_ID_MP3LAME, 0x55 },
     { CODEC_ID_MP2, 0x50 },
+    { CODEC_ID_MP3LAME, 0x55 },
     { CODEC_ID_AC3, 0x2000 },
     { CODEC_ID_PCM_S16LE, 0x01 },
     { CODEC_ID_PCM_U8, 0x01 }, /* must come after s16le in this list */
@@ -39,7 +38,7 @@ int put_wav_header(ByteIOContext *pb, AVCodecContext *enc)
     tag = codec_get_tag(codec_wav_tags, enc->codec_id);
     if (tag == 0)
         return -1;
-    put_le16(pb, tag); 
+    put_le16(pb, tag);
     put_le16(pb, enc->channels);
     put_le32(pb, enc->sample_rate);
     if (enc->codec_id == CODEC_ID_PCM_U8 ||
@@ -52,9 +51,10 @@ int put_wav_header(ByteIOContext *pb, AVCodecContext *enc)
         bps = 16;
     }
     
-    if (enc->codec_id == CODEC_ID_MP2 || enc->codec_id == CODEC_ID_MP3LAME)
+    if (enc->codec_id == CODEC_ID_MP2 || enc->codec_id == CODEC_ID_MP3LAME) {
         blkalign = 1;
-    else
+        //blkalign = 144 * enc->bit_rate/enc->sample_rate;
+    } else
         blkalign = enc->channels*bps >> 3;
     if (enc->codec_id == CODEC_ID_PCM_U8 ||
         enc->codec_id == CODEC_ID_PCM_S16LE) {
@@ -65,13 +65,23 @@ int put_wav_header(ByteIOContext *pb, AVCodecContext *enc)
     put_le32(pb, bytespersec); /* bytes per second */
     put_le16(pb, blkalign); /* block align */
     put_le16(pb, bps); /* bits per sample */
-    if (enc->codec_id == CODEC_ID_MP2 || enc->codec_id == CODEC_ID_MP3LAME) {
+    if (enc->codec_id == CODEC_ID_MP3LAME) {
         put_le16(pb, 12); /* wav_extra_size */
         put_le16(pb, 1); /* wID */
         put_le32(pb, 2); /* fdwFlags */
         put_le16(pb, 1152); /* nBlockSize */
         put_le16(pb, 1); /* nFramesPerBlock */
         put_le16(pb, 1393); /* nCodecDelay */
+    } else if (enc->codec_id == CODEC_ID_MP2) {
+        put_le16(pb, 22); /* wav_extra_size */
+        put_le16(pb, 2);  /* fwHeadLayer */
+        put_le32(pb, enc->bit_rate); /* dwHeadBitrate */
+        put_le16(pb, enc->channels == 2 ? 1 : 8); /* fwHeadMode */
+        put_le16(pb, 0);  /* fwHeadModeExt */
+        put_le16(pb, 1);  /* wHeadEmphasis */
+        put_le16(pb, 16); /* fwHeadFlags */
+        put_le32(pb, 0);  /* dwPTSLow */
+        put_le32(pb, 0);  /* dwPTSHigh */
     } else
         put_le16(pb, 0); /* wav_extra_size */
 
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index c5209bdac6..07d6d5889c 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -3,6 +3,11 @@
 
 #include "common.h"
 
+#define LIBAVCODEC_VERSION_INT 0x000406
+#define LIBAVCODEC_VERSION     "0.4.6"
+#define LIBAVCODEC_BUILD       4600
+#define LIBAVCODEC_BUILD_STR   "4600"
+
 enum CodecID {
     CODEC_ID_NONE, 
     CODEC_ID_MPEG1VIDEO,
@@ -70,7 +75,7 @@ enum Motion_Est_ID {
 extern int motion_estimation_method;
 
 /* ME algos sorted by quality */
-static const int Motion_Est_QTab[] = { -4, -1, -2, 1, 0, -3 };
+static const int Motion_Est_QTab[] = { 1, 4, 3, 6, 5, 2 };
 
 /* encoding support */
 /* note not everything is supported yet */
@@ -229,6 +234,7 @@ extern AVCodec mpeg_decoder;
 extern AVCodec h263i_decoder;
 extern AVCodec rv10_decoder;
 extern AVCodec mjpeg_decoder;
+extern AVCodec mp2_decoder;
 extern AVCodec mp3_decoder;
 
 /* pcm codecs */
diff --git a/libavcodec/h263.c b/libavcodec/h263.c
index 429caf3f5a..f415e00661 100644
--- a/libavcodec/h263.c
+++ b/libavcodec/h263.c
@@ -873,7 +873,8 @@ static void put_string(PutBitContext * pbc, char *s)
 static void mpeg4_encode_vol_header(MpegEncContext * s)
 {
     int vo_ver_id=1; //must be 2 if we want GMC or q-pel
-
+    char buf[255];
+    
     if(get_bit_count(&s->pb)!=0) mpeg4_stuffing(&s->pb);
     put_bits(&s->pb, 16, 0);
     put_bits(&s->pb, 16, 0x100);        /* video obj */
@@ -926,7 +927,8 @@ static void mpeg4_encode_vol_header(MpegEncContext * s)
     mpeg4_stuffing(&s->pb);
     put_bits(&s->pb, 16, 0);
     put_bits(&s->pb, 16, 0x1B2);	/* user_data */
-    put_string(&s->pb, "ffmpeg"); //FIXME append some version ...
+    sprintf(buf, "FFmpeg v%s / libavcodec build: %s", FFMPEG_VERSION, LIBAVCODEC_BUILD_STR);
+    put_string(&s->pb, buf);
 
     s->no_rounding = 0;
 }
diff --git a/libavcodec/mpegaudiodec.c b/libavcodec/mpegaudiodec.c
index b423788ca8..f533743bda 100644
--- a/libavcodec/mpegaudiodec.c
+++ b/libavcodec/mpegaudiodec.c
@@ -2393,9 +2393,9 @@ static int decode_frame(AVCodecContext * avctx,
     return buf_ptr - buf;
 }
 
-AVCodec mp3_decoder =
+AVCodec mp2_decoder =
 {
-    "mpegaudio",
+    "mp2",
     CODEC_TYPE_AUDIO,
     CODEC_ID_MP2,
     sizeof(MPADecodeContext),
@@ -2404,3 +2404,15 @@ AVCodec mp3_decoder =
     NULL,
     decode_frame,
 };
+
+AVCodec mp3_decoder =
+{
+    "mp3",
+    CODEC_TYPE_AUDIO,
+    CODEC_ID_MP3LAME,
+    sizeof(MPADecodeContext),
+    decode_init,
+    NULL,
+    NULL,
+    decode_frame,
+};
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index e74926841a..a1df40898f 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -454,6 +454,7 @@ void avcodec_register_all(void)
     register_avcodec(&h263i_decoder);
     register_avcodec(&rv10_decoder);
     register_avcodec(&mjpeg_decoder);
+    register_avcodec(&mp2_decoder);
     register_avcodec(&mp3_decoder);
 #ifdef CONFIG_AC3
     register_avcodec(&ac3_decoder);