diff --git a/bin/crunch_x64.exe b/bin/crunch_x64.exe
index 0700a25..e20efa9 100644
Binary files a/bin/crunch_x64.exe and b/bin/crunch_x64.exe differ
diff --git a/crnlib/crn_dxt_image.cpp b/crnlib/crn_dxt_image.cpp
index bbb7aee..6291cbd 100644
--- a/crnlib/crn_dxt_image.cpp
+++ b/crnlib/crn_dxt_image.cpp
@@ -1040,6 +1040,30 @@ void dxt_image::set_block_pixels(
         rg_etc1::pack_etc1_block(pElement, (uint32*)pPixels, pack_params);
       }
     }
+
+  } else if (m_format == cETC1S) {
+    crn_etc1_pack_params pack_params;
+    pack_params.m_perceptual = p.m_perceptual;
+    pack_params.m_dithering = p.m_dithering;
+    pack_params.m_quality = p.m_quality <= cCRNDXTQualityFast ? cCRNETCQualityFast : p.m_quality <= cCRNDXTQualityNormal ? cCRNETCQualityMedium : cCRNETCQualitySlow;
+    pack_etc1s_block(*(etc1_block*)pElement, pPixels, pack_params);
+
+  } else if (m_format == cETC2AS) {
+    for (uint element_index = 0; element_index < m_num_elements_per_block; element_index++, pElement++) {
+      if (m_element_type[element_index] == cAlphaETC2) {
+        rg_etc1::etc2a_pack_params pack_params;
+        pack_params.m_quality = p.m_quality <= cCRNDXTQualityFast ? rg_etc1::cLowQuality : p.m_quality <= cCRNDXTQualityNormal ? rg_etc1::cMediumQuality : rg_etc1::cHighQuality;
+        pack_params.comp_index = m_element_component_index[element_index];
+        rg_etc1::pack_etc2_alpha(pElement, (uint32*)pPixels, pack_params);
+      } else {
+        crn_etc1_pack_params pack_params;
+        pack_params.m_perceptual = p.m_perceptual;
+        pack_params.m_dithering = p.m_dithering;
+        pack_params.m_quality = p.m_quality <= cCRNDXTQualityFast ? cCRNETCQualityFast : p.m_quality <= cCRNDXTQualityNormal ? cCRNETCQualityMedium : cCRNETCQualitySlow;
+        pack_etc1s_block(*(etc1_block*)pElement, pPixels, pack_params);
+      }
+    }
+
   } else
 #if CRNLIB_SUPPORT_SQUISH
       if ((p.m_compressor == cCRNDXTCompressorSquish) && ((m_format == cDXT1) || (m_format == cDXT1A) || (m_format == cDXT3) || (m_format == cDXT5) || (m_format == cDXT5A))) {
diff --git a/crnlib/crn_etc.cpp b/crnlib/crn_etc.cpp
index 53d6c73..1861afa 100644
--- a/crnlib/crn_etc.cpp
+++ b/crnlib/crn_etc.cpp
@@ -1580,4 +1580,47 @@ uint64 pack_etc1_block(etc1_block& dst_block, const color_quad_u8* pSrc_pixels,
   return best_error;
 }
 
+uint64 pack_etc1s_block(etc1_block& dst_block, const color_quad_u8* pSrc_pixels, crn_etc1_pack_params& pack_params) {
+  uint8 selectors[16];
+  etc1_optimizer optimizer;
+  etc1_optimizer::params params;
+  params.m_pSrc_pixels = pSrc_pixels;
+  params.m_num_src_pixels = 16;
+  params.m_use_color4 = false;
+  params.m_constrain_against_base_color5 = false;
+  etc1_optimizer::results results;
+  results.m_pSelectors = selectors;
+  results.m_n = 16;
+  optimizer.init(params, results);
+
+  const int scan[] = {-4, -3, -2, -1, 0, 1, 2, 3, 4};
+  params.m_scan_delta_size = pack_params.m_quality == cCRNETCQualitySlow ? CRNLIB_ARRAY_SIZE(scan) : pack_params.m_quality == cCRNETCQualityMedium ? 3 : 1;
+  params.m_pScan_deltas = scan + ((CRNLIB_ARRAY_SIZE(scan) - params.m_scan_delta_size) >> 1);
+  optimizer.compute();
+
+  if (params.m_quality >= cCRNETCQualityMedium && results.m_error > 6000) {
+    const int refine_medium[] = {-3, -2, 2, 3};
+    const int refine_high[] = {-8, -7, -6, -5, 5, 6, 7, 8};
+    if (params.m_quality == cCRNETCQualityMedium) {
+      params.m_scan_delta_size = CRNLIB_ARRAY_SIZE(refine_medium);
+      params.m_pScan_deltas = refine_medium;
+    } else {
+      params.m_scan_delta_size = results.m_error > 12000 ? CRNLIB_ARRAY_SIZE(refine_high) : 2;
+      params.m_pScan_deltas = refine_high + ((CRNLIB_ARRAY_SIZE(refine_high) - params.m_scan_delta_size) >> 1);
+    }
+    optimizer.compute();
+  }
+
+  uint32 selector = 0;
+  for (uint32 i = 0, t = 8, h = 0; h < 4; h++, t -= 15) {
+    for (uint32 w = 0; w < 4; w++, t += 4, i++) {
+      uint32 s = g_selector_index_to_etc1[selectors[i]];
+      selector |= (s >> 1 | (s & 1) << 16) << (t & 15);
+    }
+  }
+
+  dst_block.m_uint64 = (uint64)selector << 32 | results.m_block_inten_table << 29 | results.m_block_inten_table << 26 | 1 << 25 | (results.m_block_color_unscaled.m_u32 & 0xFFFFFF) << 3;
+  return results.m_error;
+}
+
 }  // namespace crnlib
diff --git a/crnlib/crn_etc.h b/crnlib/crn_etc.h
index 7109960..31b487d 100644
--- a/crnlib/crn_etc.h
+++ b/crnlib/crn_etc.h
@@ -538,5 +538,6 @@ struct pack_etc1_block_context {
 void pack_etc1_block_init();
 
 uint64 pack_etc1_block(etc1_block& block, const color_quad_u8* pSrc_pixels, crn_etc1_pack_params& pack_params, pack_etc1_block_context& context);
+uint64 pack_etc1s_block(etc1_block& block, const color_quad_u8* pSrc_pixels, crn_etc1_pack_params& pack_params);
 
 }  // namespace crnlib