diff --git a/wled00/e131.cpp b/wled00/e131.cpp
index 6f7f193b..4ac2081c 100644
--- a/wled00/e131.cpp
+++ b/wled00/e131.cpp
@@ -105,6 +105,13 @@ void handleE131Packet(e131_packet_t* p, IPAddress clientIP, byte protocol){
   realtimeIP = clientIP;
   byte wChannel = 0;
   uint16_t totalLen = strip.getLengthTotal();
+  uint16_t availDMXLen = dmxChannels - DMXAddress + 1;
+  uint16_t dataOffset = DMXAddress;
+
+  // DMX data in Art-Net packet starts at index 0, for E1.31 at index 1
+  if (protocol == P_ARTNET && dataOffset > 0) {
+    dataOffset--;
+  }
 
   switch (DMXMode) {
     case DMX_MODE_DISABLED:
@@ -113,55 +120,55 @@ void handleE131Packet(e131_packet_t* p, IPAddress clientIP, byte protocol){
 
     case DMX_MODE_SINGLE_RGB: // RGB only
       if (uni != e131Universe) return;
-      if (dmxChannels-DMXAddress+1 < 3) return;
+      if (availDMXLen < 3) return;
       realtimeLock(realtimeTimeoutMs, mde);
       if (realtimeOverride) return;
-      wChannel = (dmxChannels-DMXAddress+1 > 3) ? e131_data[DMXAddress+3] : 0;
+      wChannel = (availDMXLen > 3) ? e131_data[dataOffset+3] : 0;
       for (uint16_t i = 0; i < totalLen; i++)
-        setRealtimePixel(i, e131_data[DMXAddress+0], e131_data[DMXAddress+1], e131_data[DMXAddress+2], wChannel);
+        setRealtimePixel(i, e131_data[dataOffset+0], e131_data[dataOffset+1], e131_data[dataOffset+2], wChannel);
       break;
 
     case DMX_MODE_SINGLE_DRGB: // Dimmer + RGB
       if (uni != e131Universe) return;
-      if (dmxChannels-DMXAddress+1 < 4) return;
+      if (availDMXLen < 4) return;
       realtimeLock(realtimeTimeoutMs, mde);
       if (realtimeOverride) return;
-      wChannel = (dmxChannels-DMXAddress+1 > 4) ? e131_data[DMXAddress+4] : 0;
-      if (DMXOldDimmer != e131_data[DMXAddress+0]) {
-        DMXOldDimmer = e131_data[DMXAddress+0];
-        bri = e131_data[DMXAddress+0];
+      wChannel = (availDMXLen > 4) ? e131_data[dataOffset+4] : 0;
+      if (DMXOldDimmer != e131_data[dataOffset+0]) {
+        DMXOldDimmer = e131_data[dataOffset+0];
+        bri = e131_data[dataOffset+0];
         strip.setBrightness(bri, true);
       }
       for (uint16_t i = 0; i < totalLen; i++)
-        setRealtimePixel(i, e131_data[DMXAddress+1], e131_data[DMXAddress+2], e131_data[DMXAddress+3], wChannel);
+        setRealtimePixel(i, e131_data[dataOffset+1], e131_data[dataOffset+2], e131_data[dataOffset+3], wChannel);
       break;
 
     case DMX_MODE_EFFECT: // Length 1: Apply Preset ID, length 11-13: apply effect config
       if (uni != e131Universe) return;
-      if (dmxChannels-DMXAddress+1 < 11) {
-        if (dmxChannels-DMXAddress+1 > 1) return;
-        applyPreset(e131_data[DMXAddress+0], CALL_MODE_NOTIFICATION);
+      if (availDMXLen < 11) {
+        if (availDMXLen > 1) return;
+        applyPreset(e131_data[dataOffset+0], CALL_MODE_NOTIFICATION);
         return;
       }
-      if (DMXOldDimmer != e131_data[DMXAddress+0]) {
-        DMXOldDimmer = e131_data[DMXAddress+0];
-        bri = e131_data[DMXAddress+0];
+      if (DMXOldDimmer != e131_data[dataOffset+0]) {
+        DMXOldDimmer = e131_data[dataOffset+0];
+        bri = e131_data[dataOffset+0];
       }
-      if (e131_data[DMXAddress+1] < MODE_COUNT)
-        effectCurrent = e131_data[DMXAddress+ 1];
-      effectSpeed     = e131_data[DMXAddress+ 2];  // flickers
-      effectIntensity = e131_data[DMXAddress+ 3];
-      effectPalette   = e131_data[DMXAddress+ 4];
-      col[0]          = e131_data[DMXAddress+ 5];
-      col[1]          = e131_data[DMXAddress+ 6];
-      col[2]          = e131_data[DMXAddress+ 7];
-      colSec[0]       = e131_data[DMXAddress+ 8];
-      colSec[1]       = e131_data[DMXAddress+ 9];
-      colSec[2]       = e131_data[DMXAddress+10];
-      if (dmxChannels-DMXAddress+1 > 11)
+      if (e131_data[dataOffset+1] < MODE_COUNT)
+        effectCurrent = e131_data[dataOffset+ 1];
+      effectSpeed     = e131_data[dataOffset+ 2];  // flickers
+      effectIntensity = e131_data[dataOffset+ 3];
+      effectPalette   = e131_data[dataOffset+ 4];
+      col[0]          = e131_data[dataOffset+ 5];
+      col[1]          = e131_data[dataOffset+ 6];
+      col[2]          = e131_data[dataOffset+ 7];
+      colSec[0]       = e131_data[dataOffset+ 8];
+      colSec[1]       = e131_data[dataOffset+ 9];
+      colSec[2]       = e131_data[dataOffset+10];
+      if (availDMXLen > 11)
       {
-        col[3]        = e131_data[DMXAddress+11]; //white
-        colSec[3]     = e131_data[DMXAddress+12];
+        col[3]        = e131_data[dataOffset+11]; //white
+        colSec[3]     = e131_data[dataOffset+12];
       }
       transitionDelayTemp = 0;               // act fast
       colorUpdated(CALL_MODE_NOTIFICATION);  // don't send UDP
@@ -177,22 +184,26 @@ void handleE131Packet(e131_packet_t* p, IPAddress clientIP, byte protocol){
         const uint16_t dmxChannelsPerLed = is4Chan ? 4 : 3;
         const uint16_t ledsPerUniverse = is4Chan ? MAX_4_CH_LEDS_PER_UNIVERSE : MAX_3_CH_LEDS_PER_UNIVERSE;
         if (realtimeOverride) return;
-        uint16_t previousLeds, dmxOffset;
+        uint16_t previousLeds, dmxOffset, ledsTotal;
         if (previousUniverses == 0) {
-          if (dmxChannels-DMXAddress < 1) return;
-          dmxOffset = DMXAddress;
+          if (availDMXLen < 1) return;
+          dmxOffset = dataOffset;
           previousLeds = 0;
           // First DMX address is dimmer in DMX_MODE_MULTIPLE_DRGB mode.
           if (DMXMode == DMX_MODE_MULTIPLE_DRGB) {
             strip.setBrightness(e131_data[dmxOffset++], true);
+            ledsTotal = (availDMXLen - 1) / dmxChannelsPerLed;
+          } else {
+            ledsTotal = availDMXLen / dmxChannelsPerLed;
           }
         } else {
           // All subsequent universes start at the first channel.
           dmxOffset = (protocol == P_ARTNET) ? 0 : 1;
-          uint16_t ledsInFirstUniverse = (MAX_CHANNELS_PER_UNIVERSE - DMXAddress) / dmxChannelsPerLed;
+          uint16_t dimmerOffset = (DMXMode == DMX_MODE_MULTIPLE_DRGB) ? 1 : 0;
+          uint16_t ledsInFirstUniverse = ((MAX_CHANNELS_PER_UNIVERSE - DMXAddress + 1) - dimmerOffset) / dmxChannelsPerLed;
           previousLeds = ledsInFirstUniverse + (previousUniverses - 1) * ledsPerUniverse;
+          ledsTotal = previousLeds + (dmxChannels / dmxChannelsPerLed);
         }
-        uint16_t ledsTotal = previousLeds + (dmxChannels - dmxOffset +1) / dmxChannelsPerLed;
         if (!is4Chan) {
           for (uint16_t i = previousLeds; i < ledsTotal; i++) {
             setRealtimePixel(i, e131_data[dmxOffset], e131_data[dmxOffset+1], e131_data[dmxOffset+2], 0);