diff --git a/app/src/main/rs/decoder.rs b/app/src/main/rs/decoder.rs
index 50c8621..7648a3a 100644
--- a/app/src/main/rs/decoder.rs
+++ b/app/src/main/rs/decoder.rs
@@ -247,9 +247,11 @@ void decode(int samples) {
             sync_pos = buffer_pos - sync_buildup_length;
         }
 
+        static int reset_on_first_sync;
         if (automatic_mode_detection) {
             int detected_mode = calibration_detector(dat_value, dat_amp, cnt_amp, cnt_quantized);
             if (detected_mode >= 0) {
+                reset_on_first_sync = 1;
                 free_running = 0;
                 reset_buffer();
                 switch_mode(detected_mode);
@@ -261,13 +263,23 @@ void decode(int samples) {
                 switch_mode(estimated_mode);
             }
         }
+        if (sync_pulse && reset_on_first_sync) {
+            reset_on_first_sync = 0;
+            hpos = buffer_pos - sync_pos;
+            seperator_counter = 0;
+            continue;
+        }
 
         int u_sep = u_sep_begin <= hpos && hpos < u_sep_end;
         int v_sep = v_sep_begin <= hpos && hpos < v_sep_end;
         seperator_counter += (u_sep || v_sep) ? dat_quantized : 0;
 
         if (++hpos >= maximum_length || sync_pulse) {
+            static int too_early_sync_counter;
             if (hpos < minimum_length) {
+                if (++too_early_sync_counter <= 5)
+                    continue;
+                too_early_sync_counter = 0;
                 hpos = buffer_pos - sync_pos;
                 seperator_counter = 0;
                 continue;
@@ -280,6 +292,7 @@ void decode(int samples) {
                 sync_pos += scanline_length;
             } else {
                 sync_timeout = 0;
+                too_early_sync_counter = 0;
                 hpos = buffer_pos - sync_pos;
             }
             switch (current_decoder) {
diff --git a/app/src/main/rs/initialization.rsh b/app/src/main/rs/initialization.rsh
index 8378152..77653db 100644
--- a/app/src/main/rs/initialization.rsh
+++ b/app/src/main/rs/initialization.rsh
@@ -45,7 +45,6 @@ void initialize(float rate, int length, int iw, int ih, int sw, int sh, int sgw,
     seperator_counter = 0;
     buffer_cleared = 0;
     free_running = 1;
-    minimum_length = 0.05f * sample_rate;
     minimum_sync_length = 0.002f * sample_rate;
     sync_buildup_length = round((sync_buildup_ms * sample_rate) / 1000.0f);
 
diff --git a/app/src/main/rs/modes.rsh b/app/src/main/rs/modes.rsh
index 44fe8f1..5dbae32 100644
--- a/app/src/main/rs/modes.rsh
+++ b/app/src/main/rs/modes.rsh
@@ -37,6 +37,7 @@ void raw_mode()
     bitmap_width = maximum_width;
     bitmap_height = maximum_height;
     sync_length = minimum_sync_length;
+    minimum_length = 0.05f * sample_rate;
     maximum_length = buffer_length;
     scanline_length = maximum_length;
 }
@@ -72,7 +73,8 @@ void robot36_mode()
     u_end = v_end = round((uv_end_ms * sample_rate) / 1000.0f);
 
     scanline_length = robot36_scanline_length;
-    maximum_length = scanline_length + (sync_porch_ms * sample_rate) / 1000.0f;
+    minimum_length = scanline_length - 0.001f * sample_rate;
+    maximum_length = scanline_length + 0.001f * sample_rate;
 }
 void robot72_mode()
 {
@@ -114,7 +116,8 @@ void robot72_mode()
     u_end = round((u_end_ms * sample_rate) / 1000.0f);
 
     scanline_length = robot72_scanline_length;
-    maximum_length = scanline_length + (sync_porch_ms * sample_rate) / 1000.0f;
+    minimum_length = scanline_length - 0.001f * sample_rate;
+    maximum_length = scanline_length + 0.001f * sample_rate;
 }
 void martin1_mode()
 {
@@ -146,7 +149,8 @@ void martin1_mode()
     b_begin = round((b_begin_ms * sample_rate) / 1000.0f);
 
     scanline_length = martin1_scanline_length;
-    maximum_length = scanline_length + (sync_porch_ms * sample_rate) / 1000.0f;
+    minimum_length = scanline_length - 0.001f * sample_rate;
+    maximum_length = scanline_length + 0.001f * sample_rate;
 }
 void martin2_mode()
 {
@@ -178,7 +182,8 @@ void martin2_mode()
     b_begin = round((b_begin_ms * sample_rate) / 1000.0f);
 
     scanline_length = martin2_scanline_length;
-    maximum_length = scanline_length + (sync_porch_ms * sample_rate) / 1000.0f;
+    minimum_length = scanline_length - 0.001f * sample_rate;
+    maximum_length = scanline_length + 0.001f * sample_rate;
 }
 void scottie1_mode()
 {
@@ -210,7 +215,8 @@ void scottie1_mode()
     b_begin = round((b_begin_ms * sample_rate) / 1000.0f);
 
     scanline_length = scottie1_scanline_length;
-    maximum_length = scanline_length + (sync_porch_ms * sample_rate) / 1000.0f;
+    minimum_length = scanline_length - 0.001f * sample_rate;
+    maximum_length = scanline_length + 0.001f * sample_rate;
 }
 void scottie2_mode()
 {
@@ -242,7 +248,8 @@ void scottie2_mode()
     b_begin = round((b_begin_ms * sample_rate) / 1000.0f);
 
     scanline_length = scottie2_scanline_length;
-    maximum_length = scanline_length + (sync_porch_ms * sample_rate) / 1000.0f;
+    minimum_length = scanline_length - 0.001f * sample_rate;
+    maximum_length = scanline_length + 0.001f * sample_rate;
 }
 void scottieDX_mode()
 {
@@ -274,7 +281,8 @@ void scottieDX_mode()
     b_begin = round((b_begin_ms * sample_rate) / 1000.0f);
 
     scanline_length = scottieDX_scanline_length;
-    maximum_length = scanline_length + (sync_porch_ms * sample_rate) / 1000.0f;
+    minimum_length = scanline_length - 0.001f * sample_rate;
+    maximum_length = scanline_length + 0.001f * sample_rate;
 }
 void wrasseSC2_180_mode()
 {
@@ -304,7 +312,8 @@ void wrasseSC2_180_mode()
     b_begin = round((b_begin_ms * sample_rate) / 1000.0f);
 
     scanline_length = wrasseSC2_180_scanline_length;
-    maximum_length = scanline_length + (sync_porch_ms * sample_rate) / 1000.0f;
+    minimum_length = scanline_length - 0.001f * sample_rate;
+    maximum_length = scanline_length + 0.001f * sample_rate;
 }
 
 static void switch_mode(int new_mode)