diff --git a/libavcodec/h263.c b/libavcodec/h263.c
index 98b29ad0b4fa4a9f52dad104160d42bd01abb7b8..80c9a3adc84a73391bae3f5f9521cde1adf07aca 100644
--- a/libavcodec/h263.c
+++ b/libavcodec/h263.c
@@ -3624,7 +3624,7 @@ static inline int mpeg4_decode_block(MpegEncContext * s, DCTELEM * block,
 #if 1 
                     {
                         const int abs_level= ABS(level);
-                        if(abs_level<=MAX_LEVEL && run<=MAX_RUN){
+                        if(abs_level<=MAX_LEVEL && run<=MAX_RUN && !(s->workaround_bugs&FF_BUG_AC_VLC)){
                             const int run1= run - rl->max_run[last][abs_level] - 1;
                             if(abs_level <= rl->max_level[last][run]){
                                 fprintf(stderr, "illegal 3. esc, vlc encoding possible\n");
diff --git a/libavcodec/h263dec.c b/libavcodec/h263dec.c
index 1f8fb44a886271594e0acd363f02e92df68f3fdf..2ac68060f9631f798792d0be6f97c36f250f55f4 100644
--- a/libavcodec/h263dec.c
+++ b/libavcodec/h263dec.c
@@ -442,13 +442,13 @@ retry:
     if(s->workaround_bugs&FF_BUG_AUTODETECT){
         if(s->avctx->fourcc == ff_get_fourcc("XVIX")) 
             s->workaround_bugs|= FF_BUG_XVID_ILACE;
-
+#if 0
         if(s->avctx->fourcc == ff_get_fourcc("MP4S")) 
             s->workaround_bugs|= FF_BUG_AC_VLC;
         
         if(s->avctx->fourcc == ff_get_fourcc("M4S2")) 
             s->workaround_bugs|= FF_BUG_AC_VLC;
-                
+#endif
         if(s->avctx->fourcc == ff_get_fourcc("UMP4")){
             s->workaround_bugs|= FF_BUG_UMP4;
             s->workaround_bugs|= FF_BUG_AC_VLC;