diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 0b62582a65c0ef0ff2aa1b153d58830b28d746d0..85b94425f98403ddc8281c7f9ce6708dbc4178ae 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -17,7 +17,7 @@ extern "C" {
 
 #define FFMPEG_VERSION_INT     0x000409
 #define FFMPEG_VERSION         "0.4.9-pre1"
-#define LIBAVCODEC_BUILD       4739
+#define LIBAVCODEC_BUILD       4740
 
 #define LIBAVCODEC_VERSION_INT FFMPEG_VERSION_INT
 #define LIBAVCODEC_VERSION     FFMPEG_VERSION
@@ -859,8 +859,10 @@ typedef struct AVCodecContext {
     /* The RTP callcack: This function is called  */
     /* every time the encoder as a packet to send */
     /* Depends on the encoder if the data starts  */
-    /* with a Start Code (it should) H.263 does   */
-    void (*rtp_callback)(struct AVCodecContext *avctx, void *data, int size, int packet_number); 
+    /* with a Start Code (it should) H.263 does.  */
+    /* mb_nb contains the number of macroblocks   */
+    /* encoded in the RTP payload                 */
+    void (*rtp_callback)(struct AVCodecContext *avctx, void *data, int size, int mb_nb); 
 
     /* statistics, used for 2-pass encoding */
     int mv_bits;
diff --git a/libavcodec/mpegvideo.c b/libavcodec/mpegvideo.c
index 45c9e566a081e385cf950a39cc42527da1b1bedd..bca63a19136ba2b022cff418d7a1da4c4615a212 100644
--- a/libavcodec/mpegvideo.c
+++ b/libavcodec/mpegvideo.c
@@ -4724,9 +4724,11 @@ static int encode_thread(AVCodecContext *c, void *arg){
                             assert(pbBufPtr(&s->pb) == s->ptr_lastgob);
                         }
                     }
-        
-                    if (s->avctx->rtp_callback)
-                        s->avctx->rtp_callback(s->avctx, s->ptr_lastgob, current_packet_size, 0);
+
+                    if (s->avctx->rtp_callback){
+                        int number_mb = (mb_y - s->resync_mb_y)*s->mb_width + mb_x - s->resync_mb_x;
+                        s->avctx->rtp_callback(s->avctx, s->ptr_lastgob, current_packet_size, number_mb);
+                    }
                     
                     switch(s->codec_id){
                     case CODEC_ID_MPEG4:
@@ -5166,10 +5168,11 @@ static int encode_thread(AVCodecContext *c, void *arg){
 
     /* Send the last GOB if RTP */    
     if (s->avctx->rtp_callback) {
+        int number_mb = (mb_y - s->resync_mb_y)*s->mb_width - s->resync_mb_x;
         pdif = pbBufPtr(&s->pb) - s->ptr_lastgob;
         /* Call the RTP callback to send the last GOB */
         emms_c();
-        s->avctx->rtp_callback(s->avctx, s->ptr_lastgob, pdif, 0);
+        s->avctx->rtp_callback(s->avctx, s->ptr_lastgob, pdif, number_mb);
     }
 
     return 0;