diff --git a/common/rfb/tightEncode.h b/common/rfb/tightEncode.h
index 0c6b364..2e6d0d8 100644
--- a/common/rfb/tightEncode.h
+++ b/common/rfb/tightEncode.h
@@ -574,6 +574,8 @@
 
   jpeg_set_defaults(&cinfo);
   jpeg_set_quality(&cinfo, s_pjconf->jpegQuality, TRUE);
+  if(s_pjconf->jpegQuality >= 96) cinfo.dct_method = JDCT_ISLOW;
+  else cinfo.dct_method = JDCT_FASTEST;
 
   switch (s_pjconf->jpegSubSample) {
   case SUBSAMP_420: