From 89678280d2f3c527a9ffffb3b7a55414891a7453 Mon Sep 17 00:00:00 2001
From: Jonathan Brown <jonathanbr30@gmail.com>
Date: Fri, 18 Apr 2025 08:13:07 +0100
Subject: [PATCH 01/26] New Fork

---
 lib/extras/enc/jpegli.cc | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/lib/extras/enc/jpegli.cc b/lib/extras/enc/jpegli.cc
index 14a7a398..48c75951 100644
--- a/lib/extras/enc/jpegli.cc
+++ b/lib/extras/enc/jpegli.cc
@@ -434,6 +434,7 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
     }
     jpegli_set_cicp_transfer_function(&cinfo, cicp_tf);
     jpegli_set_defaults(&cinfo);
+    float distance = jpegli_quality_to_distance(jpeg_settings.quality);
     if (!jpeg_settings.chroma_subsampling.empty()) {
       if (jpeg_settings.chroma_subsampling == "444") {
         cinfo.comp_info[0].h_samp_factor = 1;
@@ -454,11 +455,15 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
         cinfo.comp_info[i].h_samp_factor = 1;
         cinfo.comp_info[i].v_samp_factor = 1;
       }
-    } else if (!jpeg_settings.xyb) {
-      // Default is no chroma subsampling.
-      cinfo.comp_info[0].h_samp_factor = 1;
-      cinfo.comp_info[0].v_samp_factor = 1;
-    }
+    } if ((jpeg_settings.distance >= 6.4 && !jpeg_settings.xyb) || 
+	      (jpeg_settings.quality > 0.0 && jpegli_quality_to_distance(jpeg_settings.quality) >= 6.4)) {
+        // At lower qualities 420 subsampling begins to outperform 444
+        cinfo.comp_info[0].h_samp_factor = 2;
+        cinfo.comp_info[0].v_samp_factor = 2;
+      } else {
+        cinfo.comp_info[0].h_samp_factor = 1;
+        cinfo.comp_info[0].v_samp_factor = 1;
+      }
     jpegli_enable_adaptive_quantization(
         &cinfo, TO_JXL_BOOL(jpeg_settings.use_adaptive_quantization));
     if (jpeg_settings.psnr_target > 0.0) {

From 8a90d97684cb65e67e03e9f93bccf32d68d1a4da Mon Sep 17 00:00:00 2001
From: Jonathan Brown <jonathanbr30@gmail.com>
Date: Fri, 18 Apr 2025 08:14:57 +0100
Subject: [PATCH 02/26] New Fork

---
 lib/jpegli/encode.cc | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/lib/jpegli/encode.cc b/lib/jpegli/encode.cc
index ac4917d2..178822f7 100644
--- a/lib/jpegli/encode.cc
+++ b/lib/jpegli/encode.cc
@@ -783,8 +783,8 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     default:
       JPEGLI_ERROR("Unsupported jpeg colorspace %d", colorspace);
   }
-  // Adobe marker is only needed to distinguish CMYK and YCCK JPEGs.
-  cinfo->write_Adobe_marker = TO_JXL_BOOL(cinfo->jpeg_color_space == JCS_YCCK);
+ // Adobe marker is needed to distinguish CMYK, YCCK and RGB(XYB) JPEGs.
+  cinfo->write_Adobe_marker = TO_JXL_BOOL((cinfo->jpeg_color_space == JCS_YCCK || cinfo->master->xyb_mode));
   if (cinfo->comp_info == nullptr) {
     cinfo->comp_info =
         jpegli::Allocate<jpeg_component_info>(cinfo, MAX_COMPONENTS);
@@ -807,9 +807,9 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     cinfo->comp_info[2].component_id = 'B';
     if (cinfo->master->xyb_mode) {
       // Subsample blue channel.
-      cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
-      cinfo->comp_info[1].h_samp_factor = cinfo->comp_info[1].v_samp_factor = 2;
-      cinfo->comp_info[2].h_samp_factor = cinfo->comp_info[2].v_samp_factor = 1;
+      //cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
+      //cinfo->comp_info[1].h_samp_factor = cinfo->comp_info[1].v_samp_factor = 2;
+      //cinfo->comp_info[2].h_samp_factor = cinfo->comp_info[2].v_samp_factor = 1;
       // Use separate quantization tables for each component
       cinfo->comp_info[1].quant_tbl_no = 1;
       cinfo->comp_info[2].quant_tbl_no = 2;
@@ -826,7 +826,7 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     cinfo->comp_info[1].dc_tbl_no = cinfo->comp_info[1].ac_tbl_no = 1;
     cinfo->comp_info[2].dc_tbl_no = cinfo->comp_info[2].ac_tbl_no = 1;
     // Use chroma subsampling by default
-    cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
+    //cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
     if (colorspace == JCS_YCCK) {
       cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
     }

From 92355bad38f471f1a9ca36988971518483a5ba4f Mon Sep 17 00:00:00 2001
From: Jonathan Brown <jonathanbr30@gmail.com>
Date: Fri, 18 Apr 2025 09:20:06 +0100
Subject: [PATCH 03/26] Comments

---
 lib/jpegli/encode.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/jpegli/encode.cc b/lib/jpegli/encode.cc
index 178822f7..e361d695 100644
--- a/lib/jpegli/encode.cc
+++ b/lib/jpegli/encode.cc
@@ -806,6 +806,7 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     cinfo->comp_info[1].component_id = 'G';
     cinfo->comp_info[2].component_id = 'B';
     if (cinfo->master->xyb_mode) {
+      // Subsampling RGB JPEG is incompatible with JPEG XL transcoding.
       // Subsample blue channel.
       //cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
       //cinfo->comp_info[1].h_samp_factor = cinfo->comp_info[1].v_samp_factor = 2;
@@ -825,6 +826,7 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     cinfo->comp_info[2].quant_tbl_no = 1;
     cinfo->comp_info[1].dc_tbl_no = cinfo->comp_info[1].ac_tbl_no = 1;
     cinfo->comp_info[2].dc_tbl_no = cinfo->comp_info[2].ac_tbl_no = 1;
+    // Subsampling is only useful at low qualities. Check added elsewhere.
     // Use chroma subsampling by default
     //cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
     if (colorspace == JCS_YCCK) {

From c5757c3ea25feab1861479d4c3bd7af499da8656 Mon Sep 17 00:00:00 2001
From: Jonathan Brown <jonathanbr30@gmail.com>
Date: Sun, 20 Apr 2025 15:10:50 +0100
Subject: [PATCH 04/26] Subsampling default fix

---
 lib/extras/enc/jpegli.cc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/extras/enc/jpegli.cc b/lib/extras/enc/jpegli.cc
index 48c75951..f6a9e8e9 100644
--- a/lib/extras/enc/jpegli.cc
+++ b/lib/extras/enc/jpegli.cc
@@ -455,12 +455,12 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
         cinfo.comp_info[i].h_samp_factor = 1;
         cinfo.comp_info[i].v_samp_factor = 1;
       }
-    } if ((jpeg_settings.distance >= 6.4 && !jpeg_settings.xyb) || 
-	      (jpeg_settings.quality > 0.0 && jpegli_quality_to_distance(jpeg_settings.quality) >= 6.4)) {
+    } else if ((jpeg_settings.distance >= 6.4 && !jpeg_settings.xyb) {
         // At lower qualities 420 subsampling begins to outperform 444
         cinfo.comp_info[0].h_samp_factor = 2;
         cinfo.comp_info[0].v_samp_factor = 2;
       } else {
+	// Default to 444 for XYB or medium to high quality
         cinfo.comp_info[0].h_samp_factor = 1;
         cinfo.comp_info[0].v_samp_factor = 1;
       }

From c7f58cbd3480ffa9de31fc35d0abef0ebe35ac06 Mon Sep 17 00:00:00 2001
From: Jonathan Brown <jonathanbr30@gmail.com>
Date: Sun, 20 Apr 2025 15:45:54 +0100
Subject: [PATCH 05/26] XYB subsampling spaghetti

---
 lib/extras/enc/jpegli.cc | 43 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 40 insertions(+), 3 deletions(-)

diff --git a/lib/extras/enc/jpegli.cc b/lib/extras/enc/jpegli.cc
index f6a9e8e9..c2a96dc4 100644
--- a/lib/extras/enc/jpegli.cc
+++ b/lib/extras/enc/jpegli.cc
@@ -435,23 +435,60 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
     jpegli_set_cicp_transfer_function(&cinfo, cicp_tf);
     jpegli_set_defaults(&cinfo);
     float distance = jpegli_quality_to_distance(jpeg_settings.quality);
+    // TODO(Jonnyawsom3): Clean up redundant variables later.
+    // Ideally use YBX instead of XYB, and try subsampling X too
+    // to avoid any of this. Subsampling doesn't help XYB much anyway
+    // but forcing it shouldn't ruin quality, hence spaghetti.
     if (!jpeg_settings.chroma_subsampling.empty()) {
       if (jpeg_settings.chroma_subsampling == "444") {
+	// Set all in case of 444 XYB
         cinfo.comp_info[0].h_samp_factor = 1;
-        cinfo.comp_info[0].v_samp_factor = 1;
+	cinfo.comp_info[0].v_samp_factor = 1;
+	cinfo.comp_info[1].h_samp_factor = 1;
+	cinfo.comp_info[1].v_samp_factor = 1;
+	cinfo.comp_info[2].h_samp_factor = 1;
+	cinfo.comp_info[2].v_samp_factor = 1;
       } else if (jpeg_settings.chroma_subsampling == "440") {
         cinfo.comp_info[0].h_samp_factor = 1;
         cinfo.comp_info[0].v_samp_factor = 2;
+	if (cinfo->master->xyb_mode) {
+	// Subsample blue channel for XYB.
+	cinfo.comp_info[0].h_samp_factor = 1;
+	cinfo.comp_info[0].v_samp_factor = 2;
+	cinfo.comp_info[1].h_samp_factor = 1;
+	cinfo.comp_info[1].v_samp_factor = 2;
+	cinfo.comp_info[2].h_samp_factor = 1;
+	cinfo.comp_info[2].v_samp_factor = 1;
+	}
       } else if (jpeg_settings.chroma_subsampling == "422") {
         cinfo.comp_info[0].h_samp_factor = 2;
         cinfo.comp_info[0].v_samp_factor = 1;
+	if (cinfo->master->xyb_mode) {
+	// Subsample blue channel for XYB.
+	cinfo.comp_info[0].h_samp_factor = 2;
+	cinfo.comp_info[0].v_samp_factor = 1;
+	cinfo.comp_info[1].h_samp_factor = 2;
+	cinfo.comp_info[1].v_samp_factor = 1;
+	cinfo.comp_info[2].h_samp_factor = 1;
+	cinfo.comp_info[2].v_samp_factor = 1;
+	}
       } else if (jpeg_settings.chroma_subsampling == "420") {
         cinfo.comp_info[0].h_samp_factor = 2;
-        cinfo.comp_info[0].v_samp_factor = 2;
+	cinfo.comp_info[0].h_samp_factor = 2;
+	if (cinfo->master->xyb_mode) {
+	// Subsample blue channel for XYB.
+	cinfo.comp_info[0].h_samp_factor = 2;
+	cinfo.comp_info[0].v_samp_factor = 2;
+	cinfo.comp_info[1].h_samp_factor = 2;
+	cinfo.comp_info[1].v_samp_factor = 2;
+	cinfo.comp_info[2].h_samp_factor = 1;
+	cinfo.comp_info[2].v_samp_factor = 1;
+	}
       } else {
         return false;
       }
-      for (int i = 1; i < cinfo.num_components; ++i) {
+      if (!cinfo->master->xyb_mode) {
+	for (int i = 1; i < cinfo.num_components; ++i) {
         cinfo.comp_info[i].h_samp_factor = 1;
         cinfo.comp_info[i].v_samp_factor = 1;
       }

From 3ba68e42b1fd6d06484208fc6df2f9536e473fbb Mon Sep 17 00:00:00 2001
From: Jonathan Brown <jonathanbr30@gmail.com>
Date: Sun, 20 Apr 2025 15:51:43 +0100
Subject: [PATCH 06/26] Remove redundant subsampling code

---
 lib/jpegli/encode.cc | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/lib/jpegli/encode.cc b/lib/jpegli/encode.cc
index e361d695..fcb374d7 100644
--- a/lib/jpegli/encode.cc
+++ b/lib/jpegli/encode.cc
@@ -801,16 +801,12 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     comp->dc_tbl_no = 0;
     comp->ac_tbl_no = 0;
   }
+  // Subsampling is handled in lib/extras/enc/jpegli.cc#L438
   if (colorspace == JCS_RGB) {
     cinfo->comp_info[0].component_id = 'R';
     cinfo->comp_info[1].component_id = 'G';
     cinfo->comp_info[2].component_id = 'B';
     if (cinfo->master->xyb_mode) {
-      // Subsampling RGB JPEG is incompatible with JPEG XL transcoding.
-      // Subsample blue channel.
-      //cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
-      //cinfo->comp_info[1].h_samp_factor = cinfo->comp_info[1].v_samp_factor = 2;
-      //cinfo->comp_info[2].h_samp_factor = cinfo->comp_info[2].v_samp_factor = 1;
       // Use separate quantization tables for each component
       cinfo->comp_info[1].quant_tbl_no = 1;
       cinfo->comp_info[2].quant_tbl_no = 2;
@@ -826,9 +822,6 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     cinfo->comp_info[2].quant_tbl_no = 1;
     cinfo->comp_info[1].dc_tbl_no = cinfo->comp_info[1].ac_tbl_no = 1;
     cinfo->comp_info[2].dc_tbl_no = cinfo->comp_info[2].ac_tbl_no = 1;
-    // Subsampling is only useful at low qualities. Check added elsewhere.
-    // Use chroma subsampling by default
-    //cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
     if (colorspace == JCS_YCCK) {
       cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
     }

From 8183a2a20967ab5794d7d6abdc0d7759987b4d4f Mon Sep 17 00:00:00 2001
From: Jonathan Brown <jonathanbr30@gmail.com>
Date: Sun, 20 Apr 2025 18:16:22 +0100
Subject: [PATCH 07/26] Typo

---
 lib/extras/enc/jpegli.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/extras/enc/jpegli.cc b/lib/extras/enc/jpegli.cc
index c2a96dc4..3f6ff502 100644
--- a/lib/extras/enc/jpegli.cc
+++ b/lib/extras/enc/jpegli.cc
@@ -474,7 +474,7 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
 	}
       } else if (jpeg_settings.chroma_subsampling == "420") {
         cinfo.comp_info[0].h_samp_factor = 2;
-	cinfo.comp_info[0].h_samp_factor = 2;
+	cinfo.comp_info[0].v_samp_factor = 2;
 	if (cinfo->master->xyb_mode) {
 	// Subsample blue channel for XYB.
 	cinfo.comp_info[0].h_samp_factor = 2;

From bd739b894d937c9c9c2b55061b322b1dc141b4af Mon Sep 17 00:00:00 2001
From: Galaxy4594 <164440799+Galaxy4594@users.noreply.github.com>
Date: Mon, 21 Apr 2025 16:35:14 -0700
Subject: [PATCH 08/26] Compilation fixes

---
 lib/extras/enc/jpegli.cc | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/lib/extras/enc/jpegli.cc b/lib/extras/enc/jpegli.cc
index 3f6ff502..157d188f 100644
--- a/lib/extras/enc/jpegli.cc
+++ b/lib/extras/enc/jpegli.cc
@@ -451,7 +451,7 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
       } else if (jpeg_settings.chroma_subsampling == "440") {
         cinfo.comp_info[0].h_samp_factor = 1;
         cinfo.comp_info[0].v_samp_factor = 2;
-	if (cinfo->master->xyb_mode) {
+	if (jpeg_settings.xyb) {
 	// Subsample blue channel for XYB.
 	cinfo.comp_info[0].h_samp_factor = 1;
 	cinfo.comp_info[0].v_samp_factor = 2;
@@ -463,7 +463,7 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
       } else if (jpeg_settings.chroma_subsampling == "422") {
         cinfo.comp_info[0].h_samp_factor = 2;
         cinfo.comp_info[0].v_samp_factor = 1;
-	if (cinfo->master->xyb_mode) {
+	if (jpeg_settings.xyb) {
 	// Subsample blue channel for XYB.
 	cinfo.comp_info[0].h_samp_factor = 2;
 	cinfo.comp_info[0].v_samp_factor = 1;
@@ -475,7 +475,7 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
       } else if (jpeg_settings.chroma_subsampling == "420") {
         cinfo.comp_info[0].h_samp_factor = 2;
 	cinfo.comp_info[0].v_samp_factor = 2;
-	if (cinfo->master->xyb_mode) {
+	if (jpeg_settings.xyb) {
 	// Subsample blue channel for XYB.
 	cinfo.comp_info[0].h_samp_factor = 2;
 	cinfo.comp_info[0].v_samp_factor = 2;
@@ -487,12 +487,13 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
       } else {
         return false;
       }
-      if (!cinfo->master->xyb_mode) {
+      if (!jpeg_settings.xyb) {
 	for (int i = 1; i < cinfo.num_components; ++i) {
         cinfo.comp_info[i].h_samp_factor = 1;
         cinfo.comp_info[i].v_samp_factor = 1;
       }
-    } else if ((jpeg_settings.distance >= 6.4 && !jpeg_settings.xyb) {
+    } else if ((jpeg_settings.distance >= 6.4 && !jpeg_settings.xyb) ||
+	       (jpeg_settings.quality > 0.0 && distance >= 6.4)) {
         // At lower qualities 420 subsampling begins to outperform 444
         cinfo.comp_info[0].h_samp_factor = 2;
         cinfo.comp_info[0].v_samp_factor = 2;

From c629732d400625f7a6f63c1fed7df931c522f831 Mon Sep 17 00:00:00 2001
From: Galaxy4594 <164440799+Galaxy4594@users.noreply.github.com>
Date: Sun, 27 Apr 2025 01:37:09 -0700
Subject: [PATCH 09/26] Correct 440 and 422 XYB subsampling

---
 lib/extras/enc/jpegli.cc | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/lib/extras/enc/jpegli.cc b/lib/extras/enc/jpegli.cc
index 157d188f..7eeb52d6 100644
--- a/lib/extras/enc/jpegli.cc
+++ b/lib/extras/enc/jpegli.cc
@@ -453,11 +453,11 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
         cinfo.comp_info[0].v_samp_factor = 2;
 	if (jpeg_settings.xyb) {
 	// Subsample blue channel for XYB.
-	cinfo.comp_info[0].h_samp_factor = 1;
-	cinfo.comp_info[0].v_samp_factor = 2;
-	cinfo.comp_info[1].h_samp_factor = 1;
+	cinfo.comp_info[0].h_samp_factor = 2;
+	cinfo.comp_info[0].v_samp_factor = 1;
+	cinfo.comp_info[1].h_samp_factor = 2;
 	cinfo.comp_info[1].v_samp_factor = 2;
-	cinfo.comp_info[2].h_samp_factor = 1;
+	cinfo.comp_info[2].h_samp_factor = 2;
 	cinfo.comp_info[2].v_samp_factor = 1;
 	}
       } else if (jpeg_settings.chroma_subsampling == "422") {
@@ -466,11 +466,11 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
 	if (jpeg_settings.xyb) {
 	// Subsample blue channel for XYB.
 	cinfo.comp_info[0].h_samp_factor = 2;
-	cinfo.comp_info[0].v_samp_factor = 1;
+	cinfo.comp_info[0].v_samp_factor = 2;
 	cinfo.comp_info[1].h_samp_factor = 2;
-	cinfo.comp_info[1].v_samp_factor = 1;
+	cinfo.comp_info[1].v_samp_factor = 2;
 	cinfo.comp_info[2].h_samp_factor = 1;
-	cinfo.comp_info[2].v_samp_factor = 1;
+	cinfo.comp_info[2].v_samp_factor = 2;
 	}
       } else if (jpeg_settings.chroma_subsampling == "420") {
         cinfo.comp_info[0].h_samp_factor = 2;

From 8d6a57974452b5469755310ecabd1e30230d44b9 Mon Sep 17 00:00:00 2001
From: Jonathan Brown <jonathanbr30@gmail.com>
Date: Sun, 27 Apr 2025 10:30:16 +0100
Subject: [PATCH 10/26] Add APP14 marker to all RGB JPEGs

---
 lib/jpegli/encode.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/jpegli/encode.cc b/lib/jpegli/encode.cc
index fcb374d7..e7877456 100644
--- a/lib/jpegli/encode.cc
+++ b/lib/jpegli/encode.cc
@@ -784,7 +784,7 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
       JPEGLI_ERROR("Unsupported jpeg colorspace %d", colorspace);
   }
  // Adobe marker is needed to distinguish CMYK, YCCK and RGB(XYB) JPEGs.
-  cinfo->write_Adobe_marker = TO_JXL_BOOL((cinfo->jpeg_color_space == JCS_YCCK || cinfo->master->xyb_mode));
+  cinfo->write_Adobe_marker = TO_JXL_BOOL((cinfo->jpeg_color_space == JCS_YCCK || cinfo->jpeg_color_space == JCS_RGB));
   if (cinfo->comp_info == nullptr) {
     cinfo->comp_info =
         jpegli::Allocate<jpeg_component_info>(cinfo, MAX_COMPONENTS);

From 68a85424553796cf1db8fa366ac639791f3edabf Mon Sep 17 00:00:00 2001
From: Jonathan Brown <jonathanbr30@gmail.com>
Date: Sun, 27 Apr 2025 10:31:58 +0100
Subject: [PATCH 11/26] Comment update

---
 lib/extras/enc/jpegli.cc | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/lib/extras/enc/jpegli.cc b/lib/extras/enc/jpegli.cc
index 7eeb52d6..cc2d16f9 100644
--- a/lib/extras/enc/jpegli.cc
+++ b/lib/extras/enc/jpegli.cc
@@ -436,9 +436,7 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
     jpegli_set_defaults(&cinfo);
     float distance = jpegli_quality_to_distance(jpeg_settings.quality);
     // TODO(Jonnyawsom3): Clean up redundant variables later.
-    // Ideally use YBX instead of XYB, and try subsampling X too
-    // to avoid any of this. Subsampling doesn't help XYB much anyway
-    // but forcing it shouldn't ruin quality, hence spaghetti.
+    // Figure out why H and V are swapped in some cases.
     if (!jpeg_settings.chroma_subsampling.empty()) {
       if (jpeg_settings.chroma_subsampling == "444") {
 	// Set all in case of 444 XYB

From 41b32c47a56cf259cd1d8928ab645022736467bd Mon Sep 17 00:00:00 2001
From: Jonathan Brown <jonathanbr30@gmail.com>
Date: Sun, 27 Apr 2025 23:36:08 +0100
Subject: [PATCH 12/26] Fixes and comment updates

---
 lib/extras/enc/jpegli.cc | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/lib/extras/enc/jpegli.cc b/lib/extras/enc/jpegli.cc
index cc2d16f9..e3d370a4 100644
--- a/lib/extras/enc/jpegli.cc
+++ b/lib/extras/enc/jpegli.cc
@@ -435,11 +435,10 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
     jpegli_set_cicp_transfer_function(&cinfo, cicp_tf);
     jpegli_set_defaults(&cinfo);
     float distance = jpegli_quality_to_distance(jpeg_settings.quality);
-    // TODO(Jonnyawsom3): Clean up redundant variables later.
-    // Figure out why H and V are swapped in some cases.
+    // All factors need to be specified to subsample the blue channel
+    // for XYB. H and V are swapped between YCbCr and XYB.
     if (!jpeg_settings.chroma_subsampling.empty()) {
       if (jpeg_settings.chroma_subsampling == "444") {
-	// Set all in case of 444 XYB
         cinfo.comp_info[0].h_samp_factor = 1;
 	cinfo.comp_info[0].v_samp_factor = 1;
 	cinfo.comp_info[1].h_samp_factor = 1;
@@ -450,7 +449,6 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
         cinfo.comp_info[0].h_samp_factor = 1;
         cinfo.comp_info[0].v_samp_factor = 2;
 	if (jpeg_settings.xyb) {
-	// Subsample blue channel for XYB.
 	cinfo.comp_info[0].h_samp_factor = 2;
 	cinfo.comp_info[0].v_samp_factor = 1;
 	cinfo.comp_info[1].h_samp_factor = 2;
@@ -462,7 +460,6 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
         cinfo.comp_info[0].h_samp_factor = 2;
         cinfo.comp_info[0].v_samp_factor = 1;
 	if (jpeg_settings.xyb) {
-	// Subsample blue channel for XYB.
 	cinfo.comp_info[0].h_samp_factor = 2;
 	cinfo.comp_info[0].v_samp_factor = 2;
 	cinfo.comp_info[1].h_samp_factor = 2;
@@ -474,7 +471,6 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
         cinfo.comp_info[0].h_samp_factor = 2;
 	cinfo.comp_info[0].v_samp_factor = 2;
 	if (jpeg_settings.xyb) {
-	// Subsample blue channel for XYB.
 	cinfo.comp_info[0].h_samp_factor = 2;
 	cinfo.comp_info[0].v_samp_factor = 2;
 	cinfo.comp_info[1].h_samp_factor = 2;
@@ -489,14 +485,15 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
 	for (int i = 1; i < cinfo.num_components; ++i) {
         cinfo.comp_info[i].h_samp_factor = 1;
         cinfo.comp_info[i].v_samp_factor = 1;
+	}
       }
-    } else if ((jpeg_settings.distance >= 6.4 && !jpeg_settings.xyb) ||
+    } else if ((jpeg_settings.distance >= 6.4 && colorspace == JCS_YCbCr) ||
 	       (jpeg_settings.quality > 0.0 && distance >= 6.4)) {
-        // At lower qualities 420 subsampling begins to outperform 444
+        // At low quality, 420 subsampling begins to outperform 444.
         cinfo.comp_info[0].h_samp_factor = 2;
         cinfo.comp_info[0].v_samp_factor = 2;
       } else {
-	// Default to 444 for XYB or medium to high quality
+	// Default to 444 for RGB(XYB) JPEG or medium to high quality.
         cinfo.comp_info[0].h_samp_factor = 1;
         cinfo.comp_info[0].v_samp_factor = 1;
       }

From 42982712d7d78f47a03bf4e8993d7e3449852c69 Mon Sep 17 00:00:00 2001
From: Galaxy4594 <164440799+Galaxy4594@users.noreply.github.com>
Date: Sun, 27 Apr 2025 15:53:11 -0700
Subject: [PATCH 13/26] Fixed wrong chroma values + redefined used variable

---
 lib/extras/enc/jpegli.cc | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/extras/enc/jpegli.cc b/lib/extras/enc/jpegli.cc
index e3d370a4..7806dc45 100644
--- a/lib/extras/enc/jpegli.cc
+++ b/lib/extras/enc/jpegli.cc
@@ -434,7 +434,7 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
     }
     jpegli_set_cicp_transfer_function(&cinfo, cicp_tf);
     jpegli_set_defaults(&cinfo);
-    float distance = jpegli_quality_to_distance(jpeg_settings.quality);
+    float qDistance = jpegli_quality_to_distance(jpeg_settings.quality);
     // All factors need to be specified to subsample the blue channel
     // for XYB. H and V are swapped between YCbCr and XYB.
     if (!jpeg_settings.chroma_subsampling.empty()) {
@@ -450,7 +450,7 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
         cinfo.comp_info[0].v_samp_factor = 2;
 	if (jpeg_settings.xyb) {
 	cinfo.comp_info[0].h_samp_factor = 2;
-	cinfo.comp_info[0].v_samp_factor = 1;
+	cinfo.comp_info[0].v_samp_factor = 2;
 	cinfo.comp_info[1].h_samp_factor = 2;
 	cinfo.comp_info[1].v_samp_factor = 2;
 	cinfo.comp_info[2].h_samp_factor = 2;
@@ -488,7 +488,7 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
 	}
       }
     } else if ((jpeg_settings.distance >= 6.4 && colorspace == JCS_YCbCr) ||
-	       (jpeg_settings.quality > 0.0 && distance >= 6.4)) {
+	       (jpeg_settings.quality > 0.0 && qDistance >= 6.4)) {
         // At low quality, 420 subsampling begins to outperform 444.
         cinfo.comp_info[0].h_samp_factor = 2;
         cinfo.comp_info[0].v_samp_factor = 2;

From d20292ca01008ab7e5553363ff65418cc224d92f Mon Sep 17 00:00:00 2001
From: Jonathan Brown <jonathanbr30@gmail.com>
Date: Mon, 28 Apr 2025 01:29:30 +0100
Subject: [PATCH 14/26] Move 420 check to encode.cc

---
 lib/extras/enc/jpegli.cc | 23 ++---------------------
 1 file changed, 2 insertions(+), 21 deletions(-)

diff --git a/lib/extras/enc/jpegli.cc b/lib/extras/enc/jpegli.cc
index 7806dc45..a5ef3021 100644
--- a/lib/extras/enc/jpegli.cc
+++ b/lib/extras/enc/jpegli.cc
@@ -434,17 +434,13 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
     }
     jpegli_set_cicp_transfer_function(&cinfo, cicp_tf);
     jpegli_set_defaults(&cinfo);
-    float qDistance = jpegli_quality_to_distance(jpeg_settings.quality);
+    // Defaults are set in lib/jpegli/encode.cc#L799
     // All factors need to be specified to subsample the blue channel
     // for XYB. H and V are swapped between YCbCr and XYB.
     if (!jpeg_settings.chroma_subsampling.empty()) {
       if (jpeg_settings.chroma_subsampling == "444") {
         cinfo.comp_info[0].h_samp_factor = 1;
 	cinfo.comp_info[0].v_samp_factor = 1;
-	cinfo.comp_info[1].h_samp_factor = 1;
-	cinfo.comp_info[1].v_samp_factor = 1;
-	cinfo.comp_info[2].h_samp_factor = 1;
-	cinfo.comp_info[2].v_samp_factor = 1;
       } else if (jpeg_settings.chroma_subsampling == "440") {
         cinfo.comp_info[0].h_samp_factor = 1;
         cinfo.comp_info[0].v_samp_factor = 2;
@@ -481,22 +477,7 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
       } else {
         return false;
       }
-      if (!jpeg_settings.xyb) {
-	for (int i = 1; i < cinfo.num_components; ++i) {
-        cinfo.comp_info[i].h_samp_factor = 1;
-        cinfo.comp_info[i].v_samp_factor = 1;
-	}
-      }
-    } else if ((jpeg_settings.distance >= 6.4 && colorspace == JCS_YCbCr) ||
-	       (jpeg_settings.quality > 0.0 && qDistance >= 6.4)) {
-        // At low quality, 420 subsampling begins to outperform 444.
-        cinfo.comp_info[0].h_samp_factor = 2;
-        cinfo.comp_info[0].v_samp_factor = 2;
-      } else {
-	// Default to 444 for RGB(XYB) JPEG or medium to high quality.
-        cinfo.comp_info[0].h_samp_factor = 1;
-        cinfo.comp_info[0].v_samp_factor = 1;
-      }
+    }
     jpegli_enable_adaptive_quantization(
         &cinfo, TO_JXL_BOOL(jpeg_settings.use_adaptive_quantization));
     if (jpeg_settings.psnr_target > 0.0) {

From ace997f733ea08c382d53cf990e427348f1e52d6 Mon Sep 17 00:00:00 2001
From: Jonathan Brown <jonathanbr30@gmail.com>
Date: Mon, 28 Apr 2025 01:30:06 +0100
Subject: [PATCH 15/26] Move 420 check from jpegli.cc and fix APP14 CMYK

---
 lib/jpegli/encode.cc | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/lib/jpegli/encode.cc b/lib/jpegli/encode.cc
index e7877456..f79be80b 100644
--- a/lib/jpegli/encode.cc
+++ b/lib/jpegli/encode.cc
@@ -784,7 +784,8 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
       JPEGLI_ERROR("Unsupported jpeg colorspace %d", colorspace);
   }
  // Adobe marker is needed to distinguish CMYK, YCCK and RGB(XYB) JPEGs.
-  cinfo->write_Adobe_marker = TO_JXL_BOOL((cinfo->jpeg_color_space == JCS_YCCK || cinfo->jpeg_color_space == JCS_RGB));
+  cinfo->write_Adobe_marker = TO_JXL_BOOL((cinfo->jpeg_color_space == JCS_CMYK ||
+    cinfo->jpeg_color_space == JCS_YCCK || cinfo->jpeg_color_space == JCS_RGB));
   if (cinfo->comp_info == nullptr) {
     cinfo->comp_info =
         jpegli::Allocate<jpeg_component_info>(cinfo, MAX_COMPONENTS);
@@ -795,21 +796,21 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     jpeg_component_info* comp = &cinfo->comp_info[c];
     comp->component_index = c;
     comp->component_id = c + 1;
+    // Default is no chroma subsampling.
     comp->h_samp_factor = 1;
     comp->v_samp_factor = 1;
     comp->quant_tbl_no = 0;
     comp->dc_tbl_no = 0;
     comp->ac_tbl_no = 0;
   }
-  // Subsampling is handled in lib/extras/enc/jpegli.cc#L438
   if (colorspace == JCS_RGB) {
     cinfo->comp_info[0].component_id = 'R';
     cinfo->comp_info[1].component_id = 'G';
     cinfo->comp_info[2].component_id = 'B';
     if (cinfo->master->xyb_mode) {
-      // Use separate quantization tables for each component
-      cinfo->comp_info[1].quant_tbl_no = 1;
-      cinfo->comp_info[2].quant_tbl_no = 2;
+    // Use separate quantization tables for each component
+    cinfo->comp_info[1].quant_tbl_no = 1;
+    cinfo->comp_info[2].quant_tbl_no = 2;
     }
   } else if (colorspace == JCS_CMYK) {
     cinfo->comp_info[0].component_id = 'C';
@@ -822,8 +823,14 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     cinfo->comp_info[2].quant_tbl_no = 1;
     cinfo->comp_info[1].dc_tbl_no = cinfo->comp_info[1].ac_tbl_no = 1;
     cinfo->comp_info[2].dc_tbl_no = cinfo->comp_info[2].ac_tbl_no = 1;
+    // At low quality, 420 subsampling begins to outperform 444.
+    float qDistance = jpegli_quality_to_distance(jpeg_settings.quality);
+    if (jpeg_settings.distance >= 6.4 ||
+    (jpeg_settings.quality > 0.0 && qDistance >= 6.4)) {
+    cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
     if (colorspace == JCS_YCCK) {
-      cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
+    cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
+    }
     }
   }
 }

From 5419b9b2f96d593dafc58cd3125baed031850170 Mon Sep 17 00:00:00 2001
From: Galaxy4594 <164440799+Galaxy4594@users.noreply.github.com>
Date: Mon, 28 Apr 2025 18:40:03 -0700
Subject: [PATCH 16/26] Compile Fixes

---
 lib/jpegli/encode.cc | 114 ++++++++++++++++++++++++-------------------
 1 file changed, 65 insertions(+), 49 deletions(-)

diff --git a/lib/jpegli/encode.cc b/lib/jpegli/encode.cc
index f79be80b..a4e2527e 100644
--- a/lib/jpegli/encode.cc
+++ b/lib/jpegli/encode.cc
@@ -717,6 +717,65 @@ void jpegli_set_defaults(j_compress_ptr cinfo) {
                                    /*is_dc=*/true);
 }
 
+bool auto420 = false;
+bool q100RGB = false;
+
+void jpegli_set_distance(j_compress_ptr cinfo, float distance,
+                         boolean force_baseline) {
+  CheckState(cinfo, jpegli::kEncStart);
+  cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
+  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
+  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/true);
+  if (distance >= 6.4) {
+	  auto420 = true;
+  }
+  // At quality 100 (distance 0) auto select RGB colorspace.
+  if (distance == 0) {
+	  q100RGB = true;
+  }
+}
+
+float jpegli_quality_to_distance(int quality) {
+  return (quality >= 100  ? 0.01f
+          : quality >= 30 ? 0.1f + (100 - quality) * 0.09f
+                          : 53.0f / 3000.0f * quality * quality -
+                                23.0f / 20.0f * quality + 25.0f);
+}
+
+void jpegli_set_psnr(j_compress_ptr cinfo, float psnr, float tolerance,
+                     float min_distance, float max_distance) {
+  CheckState(cinfo, jpegli::kEncStart);
+  cinfo->master->psnr_target = psnr;
+  cinfo->master->psnr_tolerance = tolerance;
+  cinfo->master->min_distance = min_distance;
+  cinfo->master->max_distance = max_distance;
+}
+
+void jpegli_set_quality(j_compress_ptr cinfo, int quality,
+                        boolean force_baseline) {
+  CheckState(cinfo, jpegli::kEncStart);
+  cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
+  float distance = jpegli_quality_to_distance(quality);
+  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
+  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/false);
+  if (distance >= 6.4) {
+	  auto420 = true;
+  }
+  // At quality 100 (distance 0) auto select RGB colorspace.
+  if (distance == 0) {
+	  q100RGB = true;
+  }
+}
+
+void jpegli_set_linear_quality(j_compress_ptr cinfo, int scale_factor,
+                               boolean force_baseline) {
+  CheckState(cinfo, jpegli::kEncStart);
+  cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
+  float distance = jpegli::LinearQualityToDistance(scale_factor);
+  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
+  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/false);
+}
+
 void jpegli_default_colorspace(j_compress_ptr cinfo) {
   CheckState(cinfo, jpegli::kEncStart);
   if (cinfo->in_color_space == JCS_RGB && cinfo->master->xyb_mode) {
@@ -823,60 +882,17 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     cinfo->comp_info[2].quant_tbl_no = 1;
     cinfo->comp_info[1].dc_tbl_no = cinfo->comp_info[1].ac_tbl_no = 1;
     cinfo->comp_info[2].dc_tbl_no = cinfo->comp_info[2].ac_tbl_no = 1;
-    // At low quality, 420 subsampling begins to outperform 444.
-    float qDistance = jpegli_quality_to_distance(jpeg_settings.quality);
-    if (jpeg_settings.distance >= 6.4 ||
-    (jpeg_settings.quality > 0.0 && qDistance >= 6.4)) {
+    // At low qualities, 420 subsampling begins to outperform 444.
+    // Therefore it's enabled by default.
+    if (auto420) {
     cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
-    if (colorspace == JCS_YCCK) {
-    cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
-    }
+      if (colorspace == JCS_YCCK) {
+      cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
+      }
     }
   }
 }
 
-void jpegli_set_distance(j_compress_ptr cinfo, float distance,
-                         boolean force_baseline) {
-  CheckState(cinfo, jpegli::kEncStart);
-  cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
-  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
-  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/true);
-}
-
-float jpegli_quality_to_distance(int quality) {
-  return (quality >= 100  ? 0.01f
-          : quality >= 30 ? 0.1f + (100 - quality) * 0.09f
-                          : 53.0f / 3000.0f * quality * quality -
-                                23.0f / 20.0f * quality + 25.0f);
-}
-
-void jpegli_set_psnr(j_compress_ptr cinfo, float psnr, float tolerance,
-                     float min_distance, float max_distance) {
-  CheckState(cinfo, jpegli::kEncStart);
-  cinfo->master->psnr_target = psnr;
-  cinfo->master->psnr_tolerance = tolerance;
-  cinfo->master->min_distance = min_distance;
-  cinfo->master->max_distance = max_distance;
-}
-
-void jpegli_set_quality(j_compress_ptr cinfo, int quality,
-                        boolean force_baseline) {
-  CheckState(cinfo, jpegli::kEncStart);
-  cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
-  float distance = jpegli_quality_to_distance(quality);
-  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
-  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/false);
-}
-
-void jpegli_set_linear_quality(j_compress_ptr cinfo, int scale_factor,
-                               boolean force_baseline) {
-  CheckState(cinfo, jpegli::kEncStart);
-  cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
-  float distance = jpegli::LinearQualityToDistance(scale_factor);
-  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
-  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/false);
-}
-
 #if JPEG_LIB_VERSION >= 70
 void jpegli_default_qtables(j_compress_ptr cinfo, boolean force_baseline) {
   CheckState(cinfo, jpegli::kEncStart);

From 0dc619f00ea8a8ed96cd0172a61bbb71006c2fab Mon Sep 17 00:00:00 2001
From: Galaxy4594 <164440799+Galaxy4594@users.noreply.github.com>
Date: Wed, 30 Apr 2025 18:57:19 -0700
Subject: [PATCH 17/26] Rebase

---
 lib/jpegli/encode.cc | 142 ++++++++++++++++++++++---------------------
 1 file changed, 72 insertions(+), 70 deletions(-)

diff --git a/lib/jpegli/encode.cc b/lib/jpegli/encode.cc
index a4e2527e..334b1688 100644
--- a/lib/jpegli/encode.cc
+++ b/lib/jpegli/encode.cc
@@ -717,65 +717,6 @@ void jpegli_set_defaults(j_compress_ptr cinfo) {
                                    /*is_dc=*/true);
 }
 
-bool auto420 = false;
-bool q100RGB = false;
-
-void jpegli_set_distance(j_compress_ptr cinfo, float distance,
-                         boolean force_baseline) {
-  CheckState(cinfo, jpegli::kEncStart);
-  cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
-  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
-  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/true);
-  if (distance >= 6.4) {
-	  auto420 = true;
-  }
-  // At quality 100 (distance 0) auto select RGB colorspace.
-  if (distance == 0) {
-	  q100RGB = true;
-  }
-}
-
-float jpegli_quality_to_distance(int quality) {
-  return (quality >= 100  ? 0.01f
-          : quality >= 30 ? 0.1f + (100 - quality) * 0.09f
-                          : 53.0f / 3000.0f * quality * quality -
-                                23.0f / 20.0f * quality + 25.0f);
-}
-
-void jpegli_set_psnr(j_compress_ptr cinfo, float psnr, float tolerance,
-                     float min_distance, float max_distance) {
-  CheckState(cinfo, jpegli::kEncStart);
-  cinfo->master->psnr_target = psnr;
-  cinfo->master->psnr_tolerance = tolerance;
-  cinfo->master->min_distance = min_distance;
-  cinfo->master->max_distance = max_distance;
-}
-
-void jpegli_set_quality(j_compress_ptr cinfo, int quality,
-                        boolean force_baseline) {
-  CheckState(cinfo, jpegli::kEncStart);
-  cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
-  float distance = jpegli_quality_to_distance(quality);
-  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
-  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/false);
-  if (distance >= 6.4) {
-	  auto420 = true;
-  }
-  // At quality 100 (distance 0) auto select RGB colorspace.
-  if (distance == 0) {
-	  q100RGB = true;
-  }
-}
-
-void jpegli_set_linear_quality(j_compress_ptr cinfo, int scale_factor,
-                               boolean force_baseline) {
-  CheckState(cinfo, jpegli::kEncStart);
-  cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
-  float distance = jpegli::LinearQualityToDistance(scale_factor);
-  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
-  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/false);
-}
-
 void jpegli_default_colorspace(j_compress_ptr cinfo) {
   CheckState(cinfo, jpegli::kEncStart);
   if (cinfo->in_color_space == JCS_RGB && cinfo->master->xyb_mode) {
@@ -842,9 +783,9 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     default:
       JPEGLI_ERROR("Unsupported jpeg colorspace %d", colorspace);
   }
- // Adobe marker is needed to distinguish CMYK, YCCK and RGB(XYB) JPEGs.
+  // Adobe marker is needed to distinguish CMYK, YCCK and RGB(XYB) JPEGs.
   cinfo->write_Adobe_marker = TO_JXL_BOOL((cinfo->jpeg_color_space == JCS_CMYK ||
-    cinfo->jpeg_color_space == JCS_YCCK || cinfo->jpeg_color_space == JCS_RGB));
+  cinfo->jpeg_color_space == JCS_YCCK || cinfo->jpeg_color_space == JCS_RGB));
   if (cinfo->comp_info == nullptr) {
     cinfo->comp_info =
         jpegli::Allocate<jpeg_component_info>(cinfo, MAX_COMPONENTS);
@@ -855,7 +796,7 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     jpeg_component_info* comp = &cinfo->comp_info[c];
     comp->component_index = c;
     comp->component_id = c + 1;
-    // Default is no chroma subsampling.
+	// Default is no chroma subsampling.
     comp->h_samp_factor = 1;
     comp->v_samp_factor = 1;
     comp->quant_tbl_no = 0;
@@ -867,9 +808,9 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     cinfo->comp_info[1].component_id = 'G';
     cinfo->comp_info[2].component_id = 'B';
     if (cinfo->master->xyb_mode) {
-    // Use separate quantization tables for each component
-    cinfo->comp_info[1].quant_tbl_no = 1;
-    cinfo->comp_info[2].quant_tbl_no = 2;
+      // Use separate quantization tables for each component
+      cinfo->comp_info[1].quant_tbl_no = 1;
+      cinfo->comp_info[2].quant_tbl_no = 2;
     }
   } else if (colorspace == JCS_CMYK) {
     cinfo->comp_info[0].component_id = 'C';
@@ -882,17 +823,78 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     cinfo->comp_info[2].quant_tbl_no = 1;
     cinfo->comp_info[1].dc_tbl_no = cinfo->comp_info[1].ac_tbl_no = 1;
     cinfo->comp_info[2].dc_tbl_no = cinfo->comp_info[2].ac_tbl_no = 1;
-    // At low qualities, 420 subsampling begins to outperform 444.
-    // Therefore it's enabled by default.
-    if (auto420) {
+    // Use chroma subsampling by default
     cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
-      if (colorspace == JCS_YCCK) {
+    if (colorspace == JCS_YCCK) {
       cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
-      }
     }
   }
 }
 
+void jpegli_set_distance(j_compress_ptr cinfo, float distance,
+                         boolean force_baseline) {
+  CheckState(cinfo, jpegli::kEncStart);
+  cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
+  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
+  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/true);
+  if (distance >= 6.4 && !(cinfo->master->xyb_mode)) {
+	// At low qualities, 420 subsampling begins to outperform 444.
+    // Therefore it's enabled by default.
+    cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
+    }
+  // At quality 100 (distance 0) auto select RGB colorspace.
+  // Disable adaptive quantization since it's unnecessary.
+  if (distance < 0.02f) {
+	  jpegli_set_colorspace(cinfo, JCS_RGB);
+	  cinfo->master->use_adaptive_quantization = false;
+  }
+}
+
+float jpegli_quality_to_distance(int quality) {
+  return (quality >= 100  ? 0.00f
+          : quality >= 30 ? 0.1f + (100 - quality) * 0.09f
+                          : 53.0f / 3000.0f * quality * quality -
+                                23.0f / 20.0f * quality + 25.0f);
+}
+
+void jpegli_set_psnr(j_compress_ptr cinfo, float psnr, float tolerance,
+                     float min_distance, float max_distance) {
+  CheckState(cinfo, jpegli::kEncStart);
+  cinfo->master->psnr_target = psnr;
+  cinfo->master->psnr_tolerance = tolerance;
+  cinfo->master->min_distance = min_distance;
+  cinfo->master->max_distance = max_distance;
+}
+
+void jpegli_set_quality(j_compress_ptr cinfo, int quality,
+                        boolean force_baseline) {
+  CheckState(cinfo, jpegli::kEncStart);
+  cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
+  float distance = jpegli_quality_to_distance(quality);
+  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
+  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/false);
+  if (distance >= 6.4 && !(cinfo->master->xyb_mode)) {
+	// At low qualities, 420 subsampling begins to outperform 444.
+    // Therefore it's enabled by default.
+    cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
+    }
+  // At quality 100 (distance 0) auto select RGB colorspace.
+  // Disable adaptive quantization since it's unnecessary.
+  if (distance < 0.02f) {
+	  jpegli_set_colorspace(cinfo, JCS_RGB);
+	  cinfo->master->use_adaptive_quantization = false;
+  }
+}
+
+void jpegli_set_linear_quality(j_compress_ptr cinfo, int scale_factor,
+                               boolean force_baseline) {
+  CheckState(cinfo, jpegli::kEncStart);
+  cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
+  float distance = jpegli::LinearQualityToDistance(scale_factor);
+  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
+  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/false);
+}
+
 #if JPEG_LIB_VERSION >= 70
 void jpegli_default_qtables(j_compress_ptr cinfo, boolean force_baseline) {
   CheckState(cinfo, jpegli::kEncStart);

From 49f340eb3fe857175cb0b0269fbcdaed746b23a3 Mon Sep 17 00:00:00 2001
From: Galaxy4594 <164440799+Galaxy4594@users.noreply.github.com>
Date: Wed, 30 Apr 2025 19:17:07 -0700
Subject: [PATCH 18/26] Add checks

---
 lib/jpegli/encode.cc | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/jpegli/encode.cc b/lib/jpegli/encode.cc
index 334b1688..99812734 100644
--- a/lib/jpegli/encode.cc
+++ b/lib/jpegli/encode.cc
@@ -796,7 +796,7 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     jpeg_component_info* comp = &cinfo->comp_info[c];
     comp->component_index = c;
     comp->component_id = c + 1;
-	// Default is no chroma subsampling.
+    // Default is no chroma subsampling.
     comp->h_samp_factor = 1;
     comp->v_samp_factor = 1;
     comp->quant_tbl_no = 0;
@@ -838,13 +838,13 @@ void jpegli_set_distance(j_compress_ptr cinfo, float distance,
   float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
   jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/true);
   if (distance >= 6.4 && !(cinfo->master->xyb_mode)) {
-	// At low qualities, 420 subsampling begins to outperform 444.
+    // At low qualities, 420 subsampling begins to outperform 444.
     // Therefore it's enabled by default.
     cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
     }
   // At quality 100 (distance 0) auto select RGB colorspace.
   // Disable adaptive quantization since it's unnecessary.
-  if (distance < 0.02f) {
+  if (distance < 0.01f && cinfo->in_color_space == JCS_RGB) {
 	  jpegli_set_colorspace(cinfo, JCS_RGB);
 	  cinfo->master->use_adaptive_quantization = false;
   }
@@ -874,13 +874,13 @@ void jpegli_set_quality(j_compress_ptr cinfo, int quality,
   float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
   jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/false);
   if (distance >= 6.4 && !(cinfo->master->xyb_mode)) {
-	// At low qualities, 420 subsampling begins to outperform 444.
+    // At low qualities, 420 subsampling begins to outperform 444.
     // Therefore it's enabled by default.
     cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
     }
   // At quality 100 (distance 0) auto select RGB colorspace.
   // Disable adaptive quantization since it's unnecessary.
-  if (distance < 0.02f) {
+  if (distance < 0.01f && cinfo->in_color_space == JCS_RGB) {
 	  jpegli_set_colorspace(cinfo, JCS_RGB);
 	  cinfo->master->use_adaptive_quantization = false;
   }

From 3c35af44c6373960eccd0e2ab440df62eeb05bee Mon Sep 17 00:00:00 2001
From: Galaxy4594 <164440799+Galaxy4594@users.noreply.github.com>
Date: Thu, 1 May 2025 23:40:44 -0700
Subject: [PATCH 19/26] Update encode_internal.h

---
 lib/jpegli/encode_internal.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/jpegli/encode_internal.h b/lib/jpegli/encode_internal.h
index 3f5d1a76..b0236a6a 100644
--- a/lib/jpegli/encode_internal.h
+++ b/lib/jpegli/encode_internal.h
@@ -75,6 +75,7 @@ struct jpeg_comp_master {
   uint8_t cicp_transfer_function;
   bool use_std_tables;
   bool use_adaptive_quantization;
+  bool chroma_subsampling_set_by_cli = false;
   int progressive_level;
   size_t xsize_blocks;
   size_t ysize_blocks;

From d02e24516302c48249d9f6810c0688f852299466 Mon Sep 17 00:00:00 2001
From: Galaxy4594 <164440799+Galaxy4594@users.noreply.github.com>
Date: Thu, 1 May 2025 23:41:48 -0700
Subject: [PATCH 20/26] Update jpegli.cc

---
 lib/extras/enc/jpegli.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/extras/enc/jpegli.cc b/lib/extras/enc/jpegli.cc
index a5ef3021..c428fe49 100644
--- a/lib/extras/enc/jpegli.cc
+++ b/lib/extras/enc/jpegli.cc
@@ -34,6 +34,7 @@
 #include "lib/extras/xyb_transform.h"
 #include "lib/jpegli/common.h"
 #include "lib/jpegli/encode.h"
+#include "lib/jpegli/encode_internal.h"
 #include "lib/jpegli/types.h"
 
 namespace jxl {
@@ -438,9 +439,10 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
     // All factors need to be specified to subsample the blue channel
     // for XYB. H and V are swapped between YCbCr and XYB.
     if (!jpeg_settings.chroma_subsampling.empty()) {
+//	  cinfo.master->chroma_subsampling_set_by_cli = true;
       if (jpeg_settings.chroma_subsampling == "444") {
         cinfo.comp_info[0].h_samp_factor = 1;
-	cinfo.comp_info[0].v_samp_factor = 1;
+		cinfo.comp_info[0].v_samp_factor = 1;
       } else if (jpeg_settings.chroma_subsampling == "440") {
         cinfo.comp_info[0].h_samp_factor = 1;
         cinfo.comp_info[0].v_samp_factor = 2;

From dce05322f656154de3aef6cb2665554ee19523ca Mon Sep 17 00:00:00 2001
From: Galaxy4594 <164440799+Galaxy4594@users.noreply.github.com>
Date: Thu, 1 May 2025 23:42:10 -0700
Subject: [PATCH 21/26] update encode.cc

---
 lib/jpegli/encode.cc | 45 ++++++++++++++++++++++----------------------
 1 file changed, 22 insertions(+), 23 deletions(-)

diff --git a/lib/jpegli/encode.cc b/lib/jpegli/encode.cc
index 99812734..6a3247bd 100644
--- a/lib/jpegli/encode.cc
+++ b/lib/jpegli/encode.cc
@@ -823,11 +823,6 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
     cinfo->comp_info[2].quant_tbl_no = 1;
     cinfo->comp_info[1].dc_tbl_no = cinfo->comp_info[1].ac_tbl_no = 1;
     cinfo->comp_info[2].dc_tbl_no = cinfo->comp_info[2].ac_tbl_no = 1;
-    // Use chroma subsampling by default
-    cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
-    if (colorspace == JCS_YCCK) {
-      cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
-    }
   }
 }
 
@@ -835,19 +830,21 @@ void jpegli_set_distance(j_compress_ptr cinfo, float distance,
                          boolean force_baseline) {
   CheckState(cinfo, jpegli::kEncStart);
   cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
-  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
-  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/true);
-  if (distance >= 6.4 && !(cinfo->master->xyb_mode)) {
-    // At low qualities, 420 subsampling begins to outperform 444.
-    // Therefore it's enabled by default.
+  if (distance >= 1.9f && !(cinfo->master->xyb_mode) &&
+    !cinfo->master->chroma_subsampling_set_by_cli) {
+    // At medium qualities, 420 subsampling begins to outperform 444.
     cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
     }
+  // Disable adaptive quantization at high qualities.
+  if (distance <= 1.0f) {
+      cinfo->master->use_adaptive_quantization = false;
+  }
   // At quality 100 (distance 0) auto select RGB colorspace.
-  // Disable adaptive quantization since it's unnecessary.
-  if (distance < 0.01f && cinfo->in_color_space == JCS_RGB) {
-	  jpegli_set_colorspace(cinfo, JCS_RGB);
-	  cinfo->master->use_adaptive_quantization = false;
+  if (distance <= 0.01f && cinfo->in_color_space == JCS_RGB) {
+      jpegli_set_colorspace(cinfo, JCS_RGB);
   }
+  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
+  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/true);
 }
 
 float jpegli_quality_to_distance(int quality) {
@@ -871,19 +868,21 @@ void jpegli_set_quality(j_compress_ptr cinfo, int quality,
   CheckState(cinfo, jpegli::kEncStart);
   cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
   float distance = jpegli_quality_to_distance(quality);
-  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
-  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/false);
-  if (distance >= 6.4 && !(cinfo->master->xyb_mode)) {
-    // At low qualities, 420 subsampling begins to outperform 444.
-    // Therefore it's enabled by default.
+  if (distance >= 1.9f && !(cinfo->master->xyb_mode) &&
+    !cinfo->master->chroma_subsampling_set_by_cli) {
+    // At medium qualities, 420 subsampling begins to outperform 444.
     cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
     }
+  // Disable adaptive quantization at high qualities.
+  if (distance <= 1.0f) {
+      cinfo->master->use_adaptive_quantization = false;
+  }
   // At quality 100 (distance 0) auto select RGB colorspace.
-  // Disable adaptive quantization since it's unnecessary.
-  if (distance < 0.01f && cinfo->in_color_space == JCS_RGB) {
-	  jpegli_set_colorspace(cinfo, JCS_RGB);
-	  cinfo->master->use_adaptive_quantization = false;
+  if (distance <= 0.01f && cinfo->in_color_space == JCS_RGB) {
+      jpegli_set_colorspace(cinfo, JCS_RGB);
   }
+  float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
+  jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/false);
 }
 
 void jpegli_set_linear_quality(j_compress_ptr cinfo, int scale_factor,

From 3cce60bf52794d20014c28a24444a36b43e3143b Mon Sep 17 00:00:00 2001
From: Galaxy4594 <164440799+Galaxy4594@users.noreply.github.com>
Date: Thu, 1 May 2025 23:47:29 -0700
Subject: [PATCH 22/26] oops small fix :P

---
 lib/extras/enc/jpegli.cc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/extras/enc/jpegli.cc b/lib/extras/enc/jpegli.cc
index c428fe49..7cac2936 100644
--- a/lib/extras/enc/jpegli.cc
+++ b/lib/extras/enc/jpegli.cc
@@ -439,10 +439,10 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
     // All factors need to be specified to subsample the blue channel
     // for XYB. H and V are swapped between YCbCr and XYB.
     if (!jpeg_settings.chroma_subsampling.empty()) {
-//	  cinfo.master->chroma_subsampling_set_by_cli = true;
+    cinfo.master->chroma_subsampling_set_by_cli = true;
       if (jpeg_settings.chroma_subsampling == "444") {
         cinfo.comp_info[0].h_samp_factor = 1;
-		cinfo.comp_info[0].v_samp_factor = 1;
+	cinfo.comp_info[0].v_samp_factor = 1;
       } else if (jpeg_settings.chroma_subsampling == "440") {
         cinfo.comp_info[0].h_samp_factor = 1;
         cinfo.comp_info[0].v_samp_factor = 2;

From 46569f86dbe9321b314e15d9861e5ea8664948f3 Mon Sep 17 00:00:00 2001
From: Galaxy4594 <164440799+Galaxy4594@users.noreply.github.com>
Date: Fri, 2 May 2025 00:02:42 -0700
Subject: [PATCH 23/26] oops! another small fix :P

---
 lib/jpegli/encode.cc | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/lib/jpegli/encode.cc b/lib/jpegli/encode.cc
index 6a3247bd..fb3aaced 100644
--- a/lib/jpegli/encode.cc
+++ b/lib/jpegli/encode.cc
@@ -833,8 +833,11 @@ void jpegli_set_distance(j_compress_ptr cinfo, float distance,
   if (distance >= 1.9f && !(cinfo->master->xyb_mode) &&
     !cinfo->master->chroma_subsampling_set_by_cli) {
     // At medium qualities, 420 subsampling begins to outperform 444.
-    cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
+	cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
+    if (cinfo->jpeg_color_space == JCS_YCCK || cinfo->jpeg_color_space == JCS_CMYK) {
+    cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
     }
+  }
   // Disable adaptive quantization at high qualities.
   if (distance <= 1.0f) {
       cinfo->master->use_adaptive_quantization = false;
@@ -871,8 +874,11 @@ void jpegli_set_quality(j_compress_ptr cinfo, int quality,
   if (distance >= 1.9f && !(cinfo->master->xyb_mode) &&
     !cinfo->master->chroma_subsampling_set_by_cli) {
     // At medium qualities, 420 subsampling begins to outperform 444.
-    cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
+	cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
+    if (cinfo->jpeg_color_space == JCS_YCCK || cinfo->jpeg_color_space == JCS_CMYK) {
+    cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
     }
+  }
   // Disable adaptive quantization at high qualities.
   if (distance <= 1.0f) {
       cinfo->master->use_adaptive_quantization = false;

From 0fb8fe8b1b52bd253cb33214f0e907a0024c5e85 Mon Sep 17 00:00:00 2001
From: Galaxy4594 <164440799+Galaxy4594@users.noreply.github.com>
Date: Fri, 2 May 2025 00:13:59 -0700
Subject: [PATCH 24/26] Remove CMYK subsampling

---
 lib/jpegli/encode.cc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/jpegli/encode.cc b/lib/jpegli/encode.cc
index fb3aaced..f0d328a3 100644
--- a/lib/jpegli/encode.cc
+++ b/lib/jpegli/encode.cc
@@ -834,7 +834,7 @@ void jpegli_set_distance(j_compress_ptr cinfo, float distance,
     !cinfo->master->chroma_subsampling_set_by_cli) {
     // At medium qualities, 420 subsampling begins to outperform 444.
 	cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
-    if (cinfo->jpeg_color_space == JCS_YCCK || cinfo->jpeg_color_space == JCS_CMYK) {
+    if (cinfo->jpeg_color_space == JCS_YCCK) {
     cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
     }
   }
@@ -875,7 +875,7 @@ void jpegli_set_quality(j_compress_ptr cinfo, int quality,
     !cinfo->master->chroma_subsampling_set_by_cli) {
     // At medium qualities, 420 subsampling begins to outperform 444.
 	cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
-    if (cinfo->jpeg_color_space == JCS_YCCK || cinfo->jpeg_color_space == JCS_CMYK) {
+    if (cinfo->jpeg_color_space == JCS_YCCK) {
     cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
     }
   }

From d167eb19d56ac99aa0a43c4c45e8659432cd7421 Mon Sep 17 00:00:00 2001
From: Jonathan Brown <jonathanbr30@gmail.com>
Date: Fri, 2 May 2025 19:34:36 +0100
Subject: [PATCH 25/26] Keep Adaptive Quantization for XYB

---
 lib/jpegli/encode.cc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/jpegli/encode.cc b/lib/jpegli/encode.cc
index f0d328a3..67f0a7bf 100644
--- a/lib/jpegli/encode.cc
+++ b/lib/jpegli/encode.cc
@@ -839,7 +839,7 @@ void jpegli_set_distance(j_compress_ptr cinfo, float distance,
     }
   }
   // Disable adaptive quantization at high qualities.
-  if (distance <= 1.0f) {
+  if (distance <= 1.0f && !(cinfo->master->xyb_mode)) {
       cinfo->master->use_adaptive_quantization = false;
   }
   // At quality 100 (distance 0) auto select RGB colorspace.
@@ -880,7 +880,7 @@ void jpegli_set_quality(j_compress_ptr cinfo, int quality,
     }
   }
   // Disable adaptive quantization at high qualities.
-  if (distance <= 1.0f) {
+  if (distance <= 1.0f && !(cinfo->master->xyb_mode)) {
       cinfo->master->use_adaptive_quantization = false;
   }
   // At quality 100 (distance 0) auto select RGB colorspace.

From bb7e2fe1e4cb523370aff0fca1a1072dd50d3ae8 Mon Sep 17 00:00:00 2001
From: Damon Townsend <damon.j.townsend@gmail.com>
Date: Tue, 6 May 2025 10:49:20 -0700
Subject: [PATCH 26/26] lint

---
 lib/extras/enc/jpegli.cc | 55 ++++++++++++++++++++--------------------
 lib/jpegli/encode.cc     | 26 ++++++++++---------
 2 files changed, 41 insertions(+), 40 deletions(-)

diff --git a/lib/extras/enc/jpegli.cc b/lib/extras/enc/jpegli.cc
index 7cac2936..461cfbe3 100644
--- a/lib/extras/enc/jpegli.cc
+++ b/lib/extras/enc/jpegli.cc
@@ -435,47 +435,46 @@ Status EncodeJpeg(const PackedPixelFile& ppf, const JpegSettings& jpeg_settings,
     }
     jpegli_set_cicp_transfer_function(&cinfo, cicp_tf);
     jpegli_set_defaults(&cinfo);
-    // Defaults are set in lib/jpegli/encode.cc#L799
     // All factors need to be specified to subsample the blue channel
     // for XYB. H and V are swapped between YCbCr and XYB.
     if (!jpeg_settings.chroma_subsampling.empty()) {
-    cinfo.master->chroma_subsampling_set_by_cli = true;
+      cinfo.master->chroma_subsampling_set_by_cli = true;
       if (jpeg_settings.chroma_subsampling == "444") {
         cinfo.comp_info[0].h_samp_factor = 1;
-	cinfo.comp_info[0].v_samp_factor = 1;
+        cinfo.comp_info[0].v_samp_factor = 1;
       } else if (jpeg_settings.chroma_subsampling == "440") {
         cinfo.comp_info[0].h_samp_factor = 1;
         cinfo.comp_info[0].v_samp_factor = 2;
-	if (jpeg_settings.xyb) {
-	cinfo.comp_info[0].h_samp_factor = 2;
-	cinfo.comp_info[0].v_samp_factor = 2;
-	cinfo.comp_info[1].h_samp_factor = 2;
-	cinfo.comp_info[1].v_samp_factor = 2;
-	cinfo.comp_info[2].h_samp_factor = 2;
-	cinfo.comp_info[2].v_samp_factor = 1;
-	}
+        if (jpeg_settings.xyb) {
+          cinfo.comp_info[0].h_samp_factor = 2;
+          cinfo.comp_info[0].v_samp_factor = 2;
+          cinfo.comp_info[1].h_samp_factor = 2;
+          cinfo.comp_info[1].v_samp_factor = 2;
+          cinfo.comp_info[2].h_samp_factor = 2;
+          cinfo.comp_info[2].v_samp_factor = 1;
+        }
       } else if (jpeg_settings.chroma_subsampling == "422") {
         cinfo.comp_info[0].h_samp_factor = 2;
         cinfo.comp_info[0].v_samp_factor = 1;
-	if (jpeg_settings.xyb) {
-	cinfo.comp_info[0].h_samp_factor = 2;
-	cinfo.comp_info[0].v_samp_factor = 2;
-	cinfo.comp_info[1].h_samp_factor = 2;
-	cinfo.comp_info[1].v_samp_factor = 2;
-	cinfo.comp_info[2].h_samp_factor = 1;
-	cinfo.comp_info[2].v_samp_factor = 2;
-	}
+        if (jpeg_settings.xyb) {
+          cinfo.comp_info[0].h_samp_factor = 2;
+          cinfo.comp_info[0].v_samp_factor = 2;
+          cinfo.comp_info[1].h_samp_factor = 2;
+          cinfo.comp_info[1].v_samp_factor = 2;
+          cinfo.comp_info[2].h_samp_factor = 1;
+          cinfo.comp_info[2].v_samp_factor = 2;
+        }
       } else if (jpeg_settings.chroma_subsampling == "420") {
         cinfo.comp_info[0].h_samp_factor = 2;
-	cinfo.comp_info[0].v_samp_factor = 2;
-	if (jpeg_settings.xyb) {
-	cinfo.comp_info[0].h_samp_factor = 2;
-	cinfo.comp_info[0].v_samp_factor = 2;
-	cinfo.comp_info[1].h_samp_factor = 2;
-	cinfo.comp_info[1].v_samp_factor = 2;
-	cinfo.comp_info[2].h_samp_factor = 1;
-	cinfo.comp_info[2].v_samp_factor = 1;
-	}
+        cinfo.comp_info[0].v_samp_factor = 2;
+        if (jpeg_settings.xyb) {
+          cinfo.comp_info[0].h_samp_factor = 2;
+          cinfo.comp_info[0].v_samp_factor = 2;
+          cinfo.comp_info[1].h_samp_factor = 2;
+          cinfo.comp_info[1].v_samp_factor = 2;
+          cinfo.comp_info[2].h_samp_factor = 1;
+          cinfo.comp_info[2].v_samp_factor = 1;
+        }
       } else {
         return false;
       }
diff --git a/lib/jpegli/encode.cc b/lib/jpegli/encode.cc
index 67f0a7bf..af3c8cbf 100644
--- a/lib/jpegli/encode.cc
+++ b/lib/jpegli/encode.cc
@@ -784,8 +784,10 @@ void jpegli_set_colorspace(j_compress_ptr cinfo, J_COLOR_SPACE colorspace) {
       JPEGLI_ERROR("Unsupported jpeg colorspace %d", colorspace);
   }
   // Adobe marker is needed to distinguish CMYK, YCCK and RGB(XYB) JPEGs.
-  cinfo->write_Adobe_marker = TO_JXL_BOOL((cinfo->jpeg_color_space == JCS_CMYK ||
-  cinfo->jpeg_color_space == JCS_YCCK || cinfo->jpeg_color_space == JCS_RGB));
+  cinfo->write_Adobe_marker =
+      TO_JXL_BOOL((cinfo->jpeg_color_space == JCS_CMYK ||
+                   cinfo->jpeg_color_space == JCS_YCCK ||
+                   cinfo->jpeg_color_space == JCS_RGB));
   if (cinfo->comp_info == nullptr) {
     cinfo->comp_info =
         jpegli::Allocate<jpeg_component_info>(cinfo, MAX_COMPONENTS);
@@ -831,20 +833,20 @@ void jpegli_set_distance(j_compress_ptr cinfo, float distance,
   CheckState(cinfo, jpegli::kEncStart);
   cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
   if (distance >= 1.9f && !(cinfo->master->xyb_mode) &&
-    !cinfo->master->chroma_subsampling_set_by_cli) {
+      !cinfo->master->chroma_subsampling_set_by_cli) {
     // At medium qualities, 420 subsampling begins to outperform 444.
-	cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
+    cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
     if (cinfo->jpeg_color_space == JCS_YCCK) {
-    cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
+      cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
     }
   }
   // Disable adaptive quantization at high qualities.
   if (distance <= 1.0f && !(cinfo->master->xyb_mode)) {
-      cinfo->master->use_adaptive_quantization = false;
+    cinfo->master->use_adaptive_quantization = false;
   }
   // At quality 100 (distance 0) auto select RGB colorspace.
   if (distance <= 0.01f && cinfo->in_color_space == JCS_RGB) {
-      jpegli_set_colorspace(cinfo, JCS_RGB);
+    jpegli_set_colorspace(cinfo, JCS_RGB);
   }
   float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
   jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/true);
@@ -872,20 +874,20 @@ void jpegli_set_quality(j_compress_ptr cinfo, int quality,
   cinfo->master->force_baseline = FROM_JXL_BOOL(force_baseline);
   float distance = jpegli_quality_to_distance(quality);
   if (distance >= 1.9f && !(cinfo->master->xyb_mode) &&
-    !cinfo->master->chroma_subsampling_set_by_cli) {
+      !cinfo->master->chroma_subsampling_set_by_cli) {
     // At medium qualities, 420 subsampling begins to outperform 444.
-	cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
+    cinfo->comp_info[0].h_samp_factor = cinfo->comp_info[0].v_samp_factor = 2;
     if (cinfo->jpeg_color_space == JCS_YCCK) {
-    cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
+      cinfo->comp_info[3].h_samp_factor = cinfo->comp_info[3].v_samp_factor = 2;
     }
   }
   // Disable adaptive quantization at high qualities.
   if (distance <= 1.0f && !(cinfo->master->xyb_mode)) {
-      cinfo->master->use_adaptive_quantization = false;
+    cinfo->master->use_adaptive_quantization = false;
   }
   // At quality 100 (distance 0) auto select RGB colorspace.
   if (distance <= 0.01f && cinfo->in_color_space == JCS_RGB) {
-      jpegli_set_colorspace(cinfo, JCS_RGB);
+    jpegli_set_colorspace(cinfo, JCS_RGB);
   }
   float distances[NUM_QUANT_TBLS] = {distance, distance, distance};
   jpegli::SetQuantMatrices(cinfo, distances, /*add_two_chroma_tables=*/false);