diff --git a/libs/ultrahdr/jpegencoderhelper.cpp b/libs/ultrahdr/jpegencoderhelper.cpp
index 10a7630..867ffbb 100644
--- a/libs/ultrahdr/jpegencoderhelper.cpp
+++ b/libs/ultrahdr/jpegencoderhelper.cpp
@@ -139,7 +139,7 @@
     jpeg_set_quality(cinfo, quality, TRUE);
     jpeg_set_colorspace(cinfo, isSingleChannel ? JCS_GRAYSCALE : JCS_YCbCr);
     cinfo->raw_data_in = TRUE;
-    cinfo->dct_method = JDCT_IFAST;
+    cinfo->dct_method = JDCT_ISLOW;
 
     if (!isSingleChannel) {
         // Configure sampling factors. The sampling factor is JPEG subsampling 420 because the