Make ff_print_debug_info() a no-op when using HW acceleration.

Patch by Gwenolé Beauchesne.

Originally committed as revision 17646 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mpegvideo.c

@@ -1096,6 +1096,7 @@ static void draw_arrow(uint8_t *buf, int sx, int sy, int ex, int ey, int w, int
  */
 void ff_print_debug_info(MpegEncContext *s, AVFrame *pict){
 
+    if(s->avctx->hwaccel) return;
     if(!pict || !pict->mb_type) return;
 
     if(s->avctx->debug&(FF_DEBUG_SKIP | FF_DEBUG_QP | FF_DEBUG_MB_TYPE)){