diff --git a/cjpeg.c b/cjpeg.c
index a56a1ecd..94b1aecb 100644
--- a/cjpeg.c
+++ b/cjpeg.c
@@ -326,7 +326,7 @@ parse_switches (j_compress_ptr cinfo, int argc, char **argv,
       cinfo->optimize_scans = FALSE;
 
     } else if (keymatch(arg, "flat", 4)) {
-      cinfo->use_flat_quant_tbl = TRUE;
+      cinfo->quant_tbl_master_idx = 1;
       jpeg_set_quality(cinfo, 75, TRUE);
 
     } else if (keymatch(arg, "grayscale", 2) || keymatch(arg, "greyscale",2)) {
@@ -507,28 +507,28 @@ parse_switches (j_compress_ptr cinfo, int argc, char **argv,
       cinfo->trellis_quant_dc = TRUE;
       
     } else if (keymatch(arg, "tune-psnr", 6)) {
-      cinfo->use_flat_quant_tbl = TRUE;
+      cinfo->quant_tbl_master_idx = 1;
       cinfo->lambda_log_scale1 = 9.0;
       cinfo->lambda_log_scale2 = 0.0;
       cinfo->use_lambda_weight_tbl = FALSE;
       jpeg_set_quality(cinfo, 75, TRUE);
       
     } else if (keymatch(arg, "tune-ssim", 6)) {
-      cinfo->use_flat_quant_tbl = TRUE;
+      cinfo->quant_tbl_master_idx = 1;
       cinfo->lambda_log_scale1 = 12.0;
       cinfo->lambda_log_scale2 = 13.5;
       cinfo->use_lambda_weight_tbl = FALSE;
       jpeg_set_quality(cinfo, 75, TRUE);
       
     } else if (keymatch(arg, "tune-ms-ssim", 6)) {
-      cinfo->use_flat_quant_tbl = FALSE;
+      cinfo->quant_tbl_master_idx = 0;
       cinfo->lambda_log_scale1 = 14.25;
       cinfo->lambda_log_scale2 = 12.75;
       cinfo->use_lambda_weight_tbl = TRUE;
       jpeg_set_quality(cinfo, 75, TRUE);
       
     } else if (keymatch(arg, "tune-hvs-psnr", 6)) {
-      cinfo->use_flat_quant_tbl = FALSE;
+      cinfo->quant_tbl_master_idx = 0;
       cinfo->lambda_log_scale1 = 16.0;
       cinfo->lambda_log_scale2 = 15.5;
       cinfo->use_lambda_weight_tbl = TRUE;
diff --git a/jcparam.c b/jcparam.c
index d3b8ea15..ef8826a0 100644
--- a/jcparam.c
+++ b/jcparam.c
@@ -70,36 +70,49 @@ jpeg_add_quant_table (j_compress_ptr cinfo, int which_tbl,
  * The spec says that the values given produce "good" quality, and
  * when divided by 2, "very good" quality.
  */
-static const unsigned int std_luminance_quant_tbl[DCTSIZE2] = {
-  16,  11,  10,  16,  24,  40,  51,  61,
-  12,  12,  14,  19,  26,  58,  60,  55,
-  14,  13,  16,  24,  40,  57,  69,  56,
-  14,  17,  22,  29,  51,  87,  80,  62,
-  18,  22,  37,  56,  68, 109, 103,  77,
-  24,  35,  55,  64,  81, 104, 113,  92,
-  49,  64,  78,  87, 103, 121, 120, 101,
-  72,  92,  95,  98, 112, 100, 103,  99
+static const unsigned int std_luminance_quant_tbl[][DCTSIZE2] = {
+  {
+    16,  11,  10,  16,  24,  40,  51,  61,
+    12,  12,  14,  19,  26,  58,  60,  55,
+    14,  13,  16,  24,  40,  57,  69,  56,
+    14,  17,  22,  29,  51,  87,  80,  62,
+    18,  22,  37,  56,  68, 109, 103,  77,
+    24,  35,  55,  64,  81, 104, 113,  92,
+    49,  64,  78,  87, 103, 121, 120, 101,
+    72,  92,  95,  98, 112, 100, 103,  99
+  },
+  {
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16
+  }
 };
-static const unsigned int std_chrominance_quant_tbl[DCTSIZE2] = {
-  17,  18,  24,  47,  99,  99,  99,  99,
-  18,  21,  26,  66,  99,  99,  99,  99,
-  24,  26,  56,  99,  99,  99,  99,  99,
-  47,  66,  99,  99,  99,  99,  99,  99,
-  99,  99,  99,  99,  99,  99,  99,  99,
-  99,  99,  99,  99,  99,  99,  99,  99,
-  99,  99,  99,  99,  99,  99,  99,  99,
-  99,  99,  99,  99,  99,  99,  99,  99
-};
-
-static const unsigned int flat_quant_tbl[DCTSIZE2] = {
-  16,  16,  16,  16,  16,  16,  16,  16,
-  16,  16,  16,  16,  16,  16,  16,  16,
-  16,  16,  16,  16,  16,  16,  16,  16,
-  16,  16,  16,  16,  16,  16,  16,  16,
-  16,  16,  16,  16,  16,  16,  16,  16,
-  16,  16,  16,  16,  16,  16,  16,  16,
-  16,  16,  16,  16,  16,  16,  16,  16,
-  16,  16,  16,  16,  16,  16,  16,  16
+static const unsigned int std_chrominance_quant_tbl[][DCTSIZE2] = {
+  {
+    17,  18,  24,  47,  99,  99,  99,  99,
+    18,  21,  26,  66,  99,  99,  99,  99,
+    24,  26,  56,  99,  99,  99,  99,  99,
+    47,  66,  99,  99,  99,  99,  99,  99,
+    99,  99,  99,  99,  99,  99,  99,  99,
+    99,  99,  99,  99,  99,  99,  99,  99,
+    99,  99,  99,  99,  99,  99,  99,  99,
+    99,  99,  99,  99,  99,  99,  99,  99
+  },
+  {
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16
+  }
 };
 
 #if JPEG_LIB_VERSION >= 70
@@ -111,18 +124,11 @@ jpeg_default_qtables (j_compress_ptr cinfo, boolean force_baseline)
  */
 {
   /* Set up two quantization tables using the specified scaling */
-  if (cinfo->use_flat_quant_tbl) {
-    jpeg_add_quant_table(cinfo, 0, flat_quant_tbl,
-                         cinfo->q_scale_factor[0], force_baseline);
-    jpeg_add_quant_table(cinfo, 1, flat_quant_tbl,
-                         cinfo->q_scale_factor[1], force_baseline);
-  } else {
-  jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl,
+  jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl[cinfo->quant_tbl_master_idx],
                        cinfo->q_scale_factor[0], force_baseline);
-  jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl,
+  jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl[cinfo->quant_tbl_master_idx],
                        cinfo->q_scale_factor[1], force_baseline);
 }
-}
 #endif
 
 
@@ -136,18 +142,11 @@ jpeg_set_linear_quality (j_compress_ptr cinfo, int scale_factor,
  */
 {
   /* Set up two quantization tables using the specified scaling */
-  if (cinfo->use_flat_quant_tbl) {
-    jpeg_add_quant_table(cinfo, 0, flat_quant_tbl,
-                         scale_factor, force_baseline);
-    jpeg_add_quant_table(cinfo, 1, flat_quant_tbl,
-                         scale_factor, force_baseline);
-  } else {
-  jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl,
+  jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl[cinfo->quant_tbl_master_idx],
                        scale_factor, force_baseline);
-  jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl,
+  jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl[cinfo->quant_tbl_master_idx],
                        scale_factor, force_baseline);
 }
-}
 
 
 GLOBAL(int)
diff --git a/jpeglib.h b/jpeglib.h
index e5d78ebd..96df1475 100644
--- a/jpeglib.h
+++ b/jpeglib.h
@@ -381,7 +381,7 @@ struct jpeg_compress_struct {
   boolean trellis_quant; /* TRUE=use trellis quantization */
   boolean trellis_quant_dc; /* TRUE=use trellis quant for DC coefficient */
   boolean trellis_eob_opt; /* TRUE=optimize for sequences of EOB */
-  boolean use_flat_quant_tbl; /* TRUE=use flat quantization table */
+  int quant_tbl_master_idx; /* Quantization table master index */
   boolean use_lambda_weight_tbl; /* TRUE=use lambda weighting table */
   boolean use_scans_in_trellis; /* TRUE=use scans in trellis optimization */
   boolean trellis_passes; /* TRUE=currently doing trellis-related passes */
diff --git a/rdswitch.c b/rdswitch.c
index 75b2081c..f63d6ebe 100644
--- a/rdswitch.c
+++ b/rdswitch.c
@@ -279,52 +279,58 @@ bogus:
  * The spec says that the values given produce "good" quality, and
  * when divided by 2, "very good" quality.
  */
-static const unsigned int std_luminance_quant_tbl[DCTSIZE2] = {
-  16,  11,  10,  16,  24,  40,  51,  61,
-  12,  12,  14,  19,  26,  58,  60,  55,
-  14,  13,  16,  24,  40,  57,  69,  56,
-  14,  17,  22,  29,  51,  87,  80,  62,
-  18,  22,  37,  56,  68, 109, 103,  77,
-  24,  35,  55,  64,  81, 104, 113,  92,
-  49,  64,  78,  87, 103, 121, 120, 101,
-  72,  92,  95,  98, 112, 100, 103,  99
+static const unsigned int std_luminance_quant_tbl[][DCTSIZE2] = {
+  {
+    16,  11,  10,  16,  24,  40,  51,  61,
+    12,  12,  14,  19,  26,  58,  60,  55,
+    14,  13,  16,  24,  40,  57,  69,  56,
+    14,  17,  22,  29,  51,  87,  80,  62,
+    18,  22,  37,  56,  68, 109, 103,  77,
+    24,  35,  55,  64,  81, 104, 113,  92,
+    49,  64,  78,  87, 103, 121, 120, 101,
+    72,  92,  95,  98, 112, 100, 103,  99
+  },
+  {
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16
+  }
 };
-static const unsigned int std_chrominance_quant_tbl[DCTSIZE2] = {
-  17,  18,  24,  47,  99,  99,  99,  99,
-  18,  21,  26,  66,  99,  99,  99,  99,
-  24,  26,  56,  99,  99,  99,  99,  99,
-  47,  66,  99,  99,  99,  99,  99,  99,
-  99,  99,  99,  99,  99,  99,  99,  99,
-  99,  99,  99,  99,  99,  99,  99,  99,
-  99,  99,  99,  99,  99,  99,  99,  99,
-  99,  99,  99,  99,  99,  99,  99,  99
-};
-
-static const unsigned int flat_quant_tbl[DCTSIZE2] = {
-  16,  16,  16,  16,  16,  16,  16,  16,
-  16,  16,  16,  16,  16,  16,  16,  16,
-  16,  16,  16,  16,  16,  16,  16,  16,
-  16,  16,  16,  16,  16,  16,  16,  16,
-  16,  16,  16,  16,  16,  16,  16,  16,
-  16,  16,  16,  16,  16,  16,  16,  16,
-  16,  16,  16,  16,  16,  16,  16,  16,
-  16,  16,  16,  16,  16,  16,  16,  16
+static const unsigned int std_chrominance_quant_tbl[][DCTSIZE2] = {
+  {
+    17,  18,  24,  47,  99,  99,  99,  99,
+    18,  21,  26,  66,  99,  99,  99,  99,
+    24,  26,  56,  99,  99,  99,  99,  99,
+    47,  66,  99,  99,  99,  99,  99,  99,
+    99,  99,  99,  99,  99,  99,  99,  99,
+    99,  99,  99,  99,  99,  99,  99,  99,
+    99,  99,  99,  99,  99,  99,  99,  99,
+    99,  99,  99,  99,  99,  99,  99,  99
+  },
+  {
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16,
+    16,  16,  16,  16,  16,  16,  16,  16
+  }
 };
 
 LOCAL(void)
 jpeg_default_qtables (j_compress_ptr cinfo, boolean force_baseline)
 {
-  if (cinfo->use_flat_quant_tbl) {
-    jpeg_add_quant_table(cinfo, 0, flat_quant_tbl,
-                         q_scale_factor[0], force_baseline);
-    jpeg_add_quant_table(cinfo, 1, flat_quant_tbl,
-                         q_scale_factor[1], force_baseline);
-  } else {
-    jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl,
-                         q_scale_factor[0], force_baseline);
-    jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl,
-                         q_scale_factor[1], force_baseline);
-  }
+  jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl[cinfo->quant_tbl_master_idx],
+                       q_scale_factor[0], force_baseline);
+  jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl[cinfo->quant_tbl_master_idx],
+                       q_scale_factor[1], force_baseline);
 }
 #endif