warn the user if we had to clip some dct coefficient due to a crappy format...

warn the user if we had to clip some dct coefficient due to a crappy format which doenst support the whole needed range (msmpeg4/wmv mostly but mpeg1 too to a lesser extend)

Originally committed as revision 2661 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mpegvideo.c

@@ -3140,6 +3140,7 @@ static inline void clip_coeffs(MpegEncContext *s, DCTELEM *block, int last_index
     int i;
     const int maxlevel= s->max_qcoeff;
     const int minlevel= s->min_qcoeff;
+    int overflow=0;
     
     if(s->mb_intra){
         i=1; //skip clipping of intra dc
@@ -3150,11 +3151,19 @@ static inline void clip_coeffs(MpegEncContext *s, DCTELEM *block, int last_index
         const int j= s->intra_scantable.permutated[i];
         int level = block[j];
        
-        if     (level>maxlevel) level=maxlevel;
-        else if(level<minlevel) level=minlevel;
-
+        if     (level>maxlevel){
+            level=maxlevel;
+            overflow++;
+        }else if(level<minlevel){
+            level=minlevel;
+            overflow++;
+        }
+        
         block[j]= level;
     }
+    
+    if(overflow && s->avctx->mb_decision == FF_MB_DECISION_SIMPLE)
+        av_log(s->avctx, AV_LOG_INFO, "warning, cliping %d dct coefficents to %d..%d\n", overflow, minlevel, maxlevel);
 }
 
 #if 0