diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 6cfd1a5e4..fea380863 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -3676,13 +3676,11 @@ DivSample* DivEngine::sampleFromFileRaw(const char* path, DivSampleDepth depth,
     return NULL;
   }
   if (channels<1) {
-    lastError="invalid channel count";
-    return NULL;
+    channels=1;
   }
   if (depth!=DIV_SAMPLE_DEPTH_8BIT && depth!=DIV_SAMPLE_DEPTH_16BIT) {
     if (channels!=1) {
-      lastError="channel count has to be 1 for non-8/16-bit format";
-      return NULL;
+      channels=1;
     }
   }
   BUSY_BEGIN;
@@ -3767,6 +3765,7 @@ DivSample* DivEngine::sampleFromFileRaw(const char* path, DivSampleDepth depth,
       samples=lenDivided*2;
       break;
     case DIV_SAMPLE_DEPTH_8BIT:
+    case DIV_SAMPLE_DEPTH_MULAW:
       samples=lenDivided;
       break;
     case DIV_SAMPLE_DEPTH_BRR:
@@ -3836,11 +3835,45 @@ DivSample* DivEngine::sampleFromFileRaw(const char* path, DivSampleDepth depth,
   }
   delete[] buf;
 
-  // swap nibbles if needed
   if (swapNibbles) {
     unsigned char* b=(unsigned char*)sample->getCurBuf();
-    for (unsigned int i=0; i<sample->getCurBufLen(); i++) {
-      b[i]=(b[i]<<4)|(b[i]>>4);
+    switch (depth) {
+      case DIV_SAMPLE_DEPTH_1BIT:
+      case DIV_SAMPLE_DEPTH_1BIT_DPCM:
+        // reverse bit order
+        for (unsigned int i=0; i<sample->getCurBufLen(); i++) {
+          b[i]=(
+            ((b[i]&128)?1:0)|
+            ((b[i]&64)?2:0)|
+            ((b[i]&32)?4:0)|
+            ((b[i]&16)?8:0)|
+            ((b[i]&8)?16:0)|
+            ((b[i]&4)?32:0)|
+            ((b[i]&2)?64:0)|
+            ((b[i]&1)?128:0)
+          );
+        }
+        break;
+      case DIV_SAMPLE_DEPTH_YMZ_ADPCM:
+      case DIV_SAMPLE_DEPTH_QSOUND_ADPCM:
+      case DIV_SAMPLE_DEPTH_ADPCM_A:
+      case DIV_SAMPLE_DEPTH_ADPCM_B:
+      case DIV_SAMPLE_DEPTH_VOX:
+        // swap nibbles
+        for (unsigned int i=0; i<sample->getCurBufLen(); i++) {
+          b[i]=(b[i]<<4)|(b[i]>>4);
+        }
+        break;
+      case DIV_SAMPLE_DEPTH_MULAW:
+        // Namco to G.711
+        // Namco: smmmmxxx
+        // G.711: sxxxmmmm (^0xff)
+        for (unsigned int i=0; i<sample->getCurBufLen(); i++) {
+          b[i]=(((b[i]&7)<<4)|(((b[i]>>3)&15)^((b[i]&0x80)?15:0))|(b[i]&0x80))^0xff;
+        }
+        break;
+      default:
+        break;
     }
   }
 
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index 3369381de..e1cf93acc 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -5766,23 +5766,45 @@ bool FurnaceGUI::loop() {
         pendingRawSampleBigEndian=false;
       }
 
-      ImGui::BeginDisabled(pendingRawSampleDepth!=DIV_SAMPLE_DEPTH_8BIT && pendingRawSampleDepth!=DIV_SAMPLE_DEPTH_16BIT);
-      ImGui::AlignTextToFramePadding();
-      ImGui::Text("Channels");
-      ImGui::SameLine();
-      if (ImGui::InputInt("##RSChans",&pendingRawSampleChannels)) {
+      if (pendingRawSampleDepth==DIV_SAMPLE_DEPTH_8BIT || pendingRawSampleDepth==DIV_SAMPLE_DEPTH_16BIT) {
+        ImGui::AlignTextToFramePadding();
+        ImGui::Text("Channels");
+        ImGui::SameLine();
+        ImGui::SetNextItemWidth(120.0f*dpiScale);
+        if (ImGui::InputInt("##RSChans",&pendingRawSampleChannels)) {
+        }
+        ImGui::Text("(will be mixed down to mono)");
+        ImGui::Checkbox("Unsigned",&pendingRawSampleUnsigned);
       }
-      ImGui::Text("(will be mixed down to mono)");
-      ImGui::Checkbox("Unsigned",&pendingRawSampleUnsigned);
-      ImGui::EndDisabled();
 
-      ImGui::BeginDisabled(pendingRawSampleDepth!=DIV_SAMPLE_DEPTH_16BIT);
-      ImGui::Checkbox("Big endian",&pendingRawSampleBigEndian);
-      ImGui::EndDisabled();
+      if (pendingRawSampleDepth==DIV_SAMPLE_DEPTH_16BIT) {
+        ImGui::Checkbox("Big endian",&pendingRawSampleBigEndian);
+      }
 
-      ImGui::BeginDisabled(pendingRawSampleDepth==DIV_SAMPLE_DEPTH_16BIT);
-      ImGui::Checkbox("Swap nibbles",&pendingRawSampleSwapNibbles);
-      ImGui::EndDisabled();
+      if (pendingRawSampleDepth==DIV_SAMPLE_DEPTH_YMZ_ADPCM ||
+          pendingRawSampleDepth==DIV_SAMPLE_DEPTH_QSOUND_ADPCM ||
+          pendingRawSampleDepth==DIV_SAMPLE_DEPTH_ADPCM_A ||
+          pendingRawSampleDepth==DIV_SAMPLE_DEPTH_ADPCM_B ||
+          pendingRawSampleDepth==DIV_SAMPLE_DEPTH_VOX) {
+        ImGui::Checkbox("Swap nibbles",&pendingRawSampleSwapNibbles);
+      }
+
+      if (pendingRawSampleDepth==DIV_SAMPLE_DEPTH_MULAW) {
+        ImGui::Text("Encoding:");
+        ImGui::Indent();
+        if (ImGui::RadioButton("G.711",pendingRawSampleSwapNibbles==0)) {
+          pendingRawSampleSwapNibbles=0;
+        }
+        if (ImGui::RadioButton("Namco",pendingRawSampleSwapNibbles==1)) {
+          pendingRawSampleSwapNibbles=1;
+        }
+        ImGui::Unindent();
+      }
+
+      if (pendingRawSampleDepth==DIV_SAMPLE_DEPTH_1BIT ||
+          pendingRawSampleDepth==DIV_SAMPLE_DEPTH_1BIT_DPCM) {
+        ImGui::Checkbox("Reverse bit order",&pendingRawSampleSwapNibbles);
+      }
 
       if (ImGui::Button("OK")) {
         DivSample* s=e->sampleFromFileRaw(pendingRawSample.c_str(),(DivSampleDepth)pendingRawSampleDepth,pendingRawSampleChannels,pendingRawSampleBigEndian,pendingRawSampleUnsigned,pendingRawSampleSwapNibbles);