diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 9b3fa06f..659ea6b9 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -2226,7 +2226,7 @@ int DivEngine::addSampleFromFile(const char* path) {
 
       sample->rate=33144;
       sample->centerRate=33144;
-      sample->depth=1;
+      sample->depth=DIV_SAMPLE_DEPTH_1BIT_DPCM;
       sample->init(len*8);
 
       if (fread(sample->dataDPCM,1,len,f)==0) {
@@ -2301,9 +2301,9 @@ int DivEngine::addSampleFromFile(const char* path) {
 
   int index=0;
   if ((si.format&SF_FORMAT_SUBMASK)==SF_FORMAT_PCM_U8) {
-    sample->depth=8;
+    sample->depth=DIV_SAMPLE_DEPTH_8BIT;
   } else {
-    sample->depth=16;
+    sample->depth=DIV_SAMPLE_DEPTH_16BIT;
   }
   sample->init(si.frames);
   if ((si.format&SF_FORMAT_SUBMASK)==SF_FORMAT_PCM_U8) {
@@ -2358,6 +2358,7 @@ int DivEngine::addSampleFromFile(const char* path) {
     if(inst.loop_count && inst.loops[0].mode == SF_LOOP_FORWARD)
     {
       sample->loopStart=inst.loops[0].start;
+      sample->loopEnd=inst.loops[0].end;
       if(inst.loops[0].end < (unsigned int)sampleCount)
         sampleCount=inst.loops[0].end;
     }
diff --git a/src/engine/fileOps.cpp b/src/engine/fileOps.cpp
index 3aa432fd..40932a37 100644
--- a/src/engine/fileOps.cpp
+++ b/src/engine/fileOps.cpp
@@ -799,17 +799,17 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
         sample->rate=ymuSampleRate*400;
       }
       if (ds.version>0x15) {
-        sample->depth=reader.readC();
-        if (sample->depth!=8 && sample->depth!=16) {
+        sample->depth=(DivSampleDepth)reader.readC();
+        if (sample->depth!=DIV_SAMPLE_DEPTH_8BIT && sample->depth!=DIV_SAMPLE_DEPTH_16BIT) {
           logW("%d: sample depth is wrong! (%d)",i,sample->depth);
-          sample->depth=16;
+          sample->depth=DIV_SAMPLE_DEPTH_16BIT;
         }
       } else {
         if (ds.version>0x08) {
-          sample->depth=16;
+          sample->depth=DIV_SAMPLE_DEPTH_16BIT;
         } else {
           // it appears samples were stored as ADPCM back then
-          sample->depth=3;
+          sample->depth=DIV_SAMPLE_DEPTH_YMZ_ADPCM;
         }
       }
       if (length>0) {
@@ -838,7 +838,7 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
             if (k>=sample->samples) {
               break;
             }
-            if (sample->depth==8) {
+            if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
               float next=(float)(data[(unsigned int)j]-0x80)*mult;
               sample->data8[k++]=fmin(fmax(next,-128),127);
             } else {
@@ -1631,7 +1631,7 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
       logD("reading sample %d at %x...",i,samplePtr[i]);
 
       sample->name=reader.readString();
-      sample->samples=reader.readI();
+      sample->samples=sample->loopEnd=reader.readI();
       sample->rate=reader.readI();
       if (ds.version<58) {
         vol=reader.readS();
@@ -1639,7 +1639,7 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
       } else {
         reader.readI();
       }
-      sample->depth=reader.readC();
+      sample->depth=(DivSampleDepth)reader.readC();
 
       // reserved
       reader.readC();
@@ -1657,6 +1657,13 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
         reader.readI();
       }
 
+/*
+      if (ds.version>=100) {
+        sample->loopEnd=reader.readI();
+      } else {
+        reader.readI();
+      }
+*/
       if (ds.version>=58) { // modern sample
         sample->init(sample->samples);
         reader.read(sample->getCurBuf(),sample->getCurBufLen());
@@ -1670,9 +1677,9 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
         }
 
         // render data
-        if (sample->depth!=8 && sample->depth!=16) {
+        if (sample->depth!=DIV_SAMPLE_DEPTH_8BIT && sample->depth!=DIV_SAMPLE_DEPTH_16BIT) {
           logW("%d: sample depth is wrong! (%d)",i,sample->depth);
-          sample->depth=16;
+          sample->depth=DIV_SAMPLE_DEPTH_16BIT;
         }
         sample->samples=(double)sample->samples/samplePitches[pitch];
         sample->init(sample->samples);
@@ -1683,7 +1690,7 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
           if (k>=sample->samples) {
             break;
           }
-          if (sample->depth==8) {
+          if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
             float next=(float)(data[(unsigned int)j]-0x80)*mult;
             sample->data8[k++]=fmin(fmax(next,-128),127);
           } else {
@@ -1877,7 +1884,7 @@ bool DivEngine::loadMod(unsigned char* file, size_t len) {
     logD("reading samples... (%d)",insCount);
     for (int i=0; i<insCount; i++) {
       DivSample* sample=new DivSample;
-      sample->depth=8;
+      sample->depth=DIV_SAMPLE_DEPTH_8BIT;
       sample->name=reader.readString(22);
       logD("%d: %s",i+1,sample->name);
       int slen=((unsigned short)reader.readS_BE())*2;
@@ -1897,8 +1904,8 @@ bool DivEngine::loadMod(unsigned char* file, size_t len) {
         loopLen=0;
       }
       if (loopLen>=2) {
-        if (loopEnd<slen) slen=loopEnd;
         sample->loopStart=loopStart;
+        sample->loopEnd=loopEnd;
       }
       sample->init(slen);
       ds.sample.push_back(sample);
@@ -3043,6 +3050,7 @@ SafeWriter* DivEngine::saveFur(bool notPrimary) {
     w->writeC(0);
     w->writeS(sample->centerRate);
     w->writeI(sample->loopStart);
+    //w->writeI(sample->loopEnd);
 
     w->write(sample->getCurBuf(),sample->getCurBufLen());
 
diff --git a/src/engine/platform/amiga.cpp b/src/engine/platform/amiga.cpp
index 65b44136..1b007530 100644
--- a/src/engine/platform/amiga.cpp
+++ b/src/engine/platform/amiga.cpp
@@ -114,12 +114,10 @@ void DivPlatformAmiga::acquire(short* bufL, short* bufR, size_t start, size_t le
               if (chan[i].audPos<s->samples) {
                 writeAudDat(s->data8[chan[i].audPos++]);
               }
-              if (chan[i].audPos>=s->samples || chan[i].audPos>=131071) {
-                if (s->loopStart>=0 && s->loopStart<(int)s->samples) {
-                  chan[i].audPos=s->loopStart;
-                } else {
-                  chan[i].sample=-1;
-                }
+              if (s->isLoopable() && chan[i].audPos>=MIN(131071,s->getEndPosition())) {
+                chan[i].audPos=s->loopStart;
+              } else if (chan[i].audPos>=MIN(131071,s->samples)) {
+                chan[i].sample=-1;
               }
             } else {
               chan[i].sample=-1;
diff --git a/src/engine/platform/genesis.cpp b/src/engine/platform/genesis.cpp
index afd59b33..b6dbb8d1 100644
--- a/src/engine/platform/genesis.cpp
+++ b/src/engine/platform/genesis.cpp
@@ -153,14 +153,13 @@ void DivPlatformGenesis::processDAC() {
           if (chan[i].dacPeriod>=(chipClock/576)) {
             if (s->samples>0) {
               while (chan[i].dacPeriod>=(chipClock/576)) {
-                if (++chan[i].dacPos>=s->samples) {
-                  if (s->loopStart>=0 && s->loopStart<(int)s->samples && !chan[i].dacDirection) {
-                    chan[i].dacPos=s->loopStart;
-                  } else {
-                    chan[i].dacSample=-1;
-                    chan[i].dacPeriod=0;
-                    break;
-                  }
+                ++chan[i].dacPos;
+                if (!chan[i].dacDirection && (s->isLoopable() && chan[i].dacPos>=s->getEndPosition())) {
+                  chan[i].dacPos=s->loopStart;
+                } else if (chan[i].dacPos>=s->samples) {
+                  chan[i].dacSample=-1;
+                  chan[i].dacPeriod=0;
+                  break;
                 }
                 chan[i].dacPeriod-=(chipClock/576);
               }
@@ -200,14 +199,13 @@ void DivPlatformGenesis::processDAC() {
               chan[5].dacReady=false;
             }
           }
-          if (++chan[5].dacPos>=s->samples) {
-            if (s->loopStart>=0 && s->loopStart<(int)s->samples && !chan[5].dacDirection) {
-              chan[5].dacPos=s->loopStart;
-            } else {
-              chan[5].dacSample=-1;
-              if (parent->song.brokenDACMode) {
-                rWrite(0x2b,0);
-              }
+          chan[5].dacPos++;
+          if (!chan[5].dacDirection && (s->isLoopable() && chan[5].dacPos>=s->getEndPosition())) {
+            chan[5].dacPos=s->loopStart;
+          } else if (chan[5].dacPos>=s->samples) {
+            chan[5].dacSample=-1;
+            if (parent->song.brokenDACMode) {
+              rWrite(0x2b,0);
             }
           }
           while (chan[5].dacPeriod>=rate) chan[5].dacPeriod-=rate;
diff --git a/src/engine/platform/lynx.cpp b/src/engine/platform/lynx.cpp
index 3f5e92c0..7c349e5a 100644
--- a/src/engine/platform/lynx.cpp
+++ b/src/engine/platform/lynx.cpp
@@ -158,12 +158,10 @@ void DivPlatformLynx::acquire(short* bufL, short* bufR, size_t start, size_t len
               WRITE_OUTPUT(i,(s->data8[chan[i].samplePos++]*chan[i].outVol)>>7);
             }
 
-            if (chan[i].samplePos>=(int)s->samples) {
-              if (s->loopStart>=0 && s->loopStart<(int)s->samples) {
-                chan[i].samplePos=s->loopStart;
-              } else {
-                chan[i].sample=-1;
-              }
+            if (s->isLoopable() && chan[i].samplePos>=(int)s->getEndPosition()) {
+              chan[i].samplePos=s->loopStart;
+            } else if (chan[i].samplePos>=(int)s->samples) {
+              chan[i].sample=-1;
             }
           }
         }
diff --git a/src/engine/platform/mmc5.cpp b/src/engine/platform/mmc5.cpp
index dc9e5aba..bafbda3f 100644
--- a/src/engine/platform/mmc5.cpp
+++ b/src/engine/platform/mmc5.cpp
@@ -62,12 +62,11 @@ void DivPlatformMMC5::acquire(short* bufL, short* bufR, size_t start, size_t len
           if (!isMuted[2]) {
             rWrite(0x5011,((unsigned char)s->data8[dacPos]+0x80));
           }
-          if (++dacPos>=s->samples) {
-            if (s->loopStart>=0 && s->loopStart<(int)s->samples) {
-              dacPos=s->loopStart;
-            } else {
-              dacSample=-1;
-            }
+          dacPos++;
+          if (s->isLoopable() && dacPos>=s->getEndPosition()) {
+            dacPos=s->loopStart;
+          } else if (dacPos>=s->samples) {
+            dacSample=-1;
           }
           dacPeriod-=rate;
         } else {
diff --git a/src/engine/platform/nes.cpp b/src/engine/platform/nes.cpp
index d801fe66..bd1be94a 100644
--- a/src/engine/platform/nes.cpp
+++ b/src/engine/platform/nes.cpp
@@ -108,12 +108,11 @@ void DivPlatformNES::doWrite(unsigned short addr, unsigned char data) {
             rWrite(0x4011,next); \
           } \
         } \
-        if (++dacPos>=s->samples) { \
-          if (s->loopStart>=0 && s->loopStart<(int)s->samples) { \
-            dacPos=s->loopStart; \
-          } else { \
-            dacSample=-1; \
-          } \
+        dacPos++; \
+        if (s->isLoopable() && dacPos>=s->getEndPosition()) { \
+          dacPos=s->loopStart; \
+        } else if (dacPos>=s->samples) { \
+          dacSample=-1; \
         } \
         dacPeriod-=rate; \
       } else { \
diff --git a/src/engine/platform/opl.cpp b/src/engine/platform/opl.cpp
index 823e764b..36dd2c66 100644
--- a/src/engine/platform/opl.cpp
+++ b/src/engine/platform/opl.cpp
@@ -771,7 +771,7 @@ int DivPlatformOPL::dispatch(DivCommand c) {
             int end=s->offB+s->lengthB-1;
             immWrite(11,(end>>2)&0xff);
             immWrite(12,(end>>10)&0xff);
-            immWrite(7,(s->loopStart>=0)?0xb0:0xa0); // start/repeat
+            immWrite(7,(s->isLoopable())?0xb0:0xa0); // start/repeat
             if (c.value!=DIV_NOTE_NULL) {
               chan[c.chan].note=c.value;
               chan[c.chan].baseFreq=NOTE_ADPCMB(chan[c.chan].note);
@@ -807,7 +807,7 @@ int DivPlatformOPL::dispatch(DivCommand c) {
           int end=s->offB+s->lengthB-1;
           immWrite(11,(end>>2)&0xff);
           immWrite(12,(end>>10)&0xff);
-          immWrite(7,(s->loopStart>=0)?0xb0:0xa0); // start/repeat
+          immWrite(7,(s->isLoopable())?0xb0:0xa0); // start/repeat
           int freq=(65536.0*(double)s->rate)/(double)chipRateBase;
           immWrite(16,freq&0xff);
           immWrite(17,(freq>>8)&0xff);
diff --git a/src/engine/platform/pce.cpp b/src/engine/platform/pce.cpp
index 9e1302a0..f1eb5a10 100644
--- a/src/engine/platform/pce.cpp
+++ b/src/engine/platform/pce.cpp
@@ -90,12 +90,10 @@ void DivPlatformPCE::acquire(short* bufL, short* bufR, size_t start, size_t len)
           chWrite(i,0x04,0xdf);
           chWrite(i,0x06,(((unsigned char)s->data8[chan[i].dacPos]+0x80)>>3));
           chan[i].dacPos++;
-          if (chan[i].dacPos>=s->samples) {
-            if (s->loopStart>=0 && s->loopStart<(int)s->samples) {
-              chan[i].dacPos=s->loopStart;
-            } else {
-              chan[i].dacSample=-1;
-            }
+          if (s->isLoopable() && chan[i].dacPos>=s->getEndPosition()) {
+            chan[i].dacPos=s->loopStart;
+          } else if (chan[i].dacPos>=s->samples) {
+            chan[i].dacSample=-1;
           }
           chan[i].dacPeriod-=rate;
         }
diff --git a/src/engine/platform/qsound.cpp b/src/engine/platform/qsound.cpp
index 6eb14be7..faeaf6a9 100644
--- a/src/engine/platform/qsound.cpp
+++ b/src/engine/platform/qsound.cpp
@@ -301,7 +301,7 @@ void DivPlatformQSound::tick(bool sysTick) {
       qsound_bank = 0x8000 | (s->offQSound >> 16);
       qsound_addr = s->offQSound & 0xffff;
 
-      int length = s->samples;
+      int length = s->getEndPosition();
       if (length > 65536 - 16) {
         length = 65536 - 16;
       }
diff --git a/src/engine/platform/rf5c68.cpp b/src/engine/platform/rf5c68.cpp
index 176b6e7c..e4a39d44 100644
--- a/src/engine/platform/rf5c68.cpp
+++ b/src/engine/platform/rf5c68.cpp
@@ -142,7 +142,7 @@ void DivPlatformRF5C68::tick(bool sysTick) {
         if (chan[i].audPos>0) {
           start=start+MIN(chan[i].audPos,s->length8);
         }
-        if (s->loopStart>=0) {
+        if (s->isLoopable()) {
           loop=start+s->loopStart;
         }
         start=MIN(start,getSampleMemCapacity()-31);
@@ -393,7 +393,7 @@ void DivPlatformRF5C68::renderSamples() {
   size_t memPos=0;
   for (int i=0; i<parent->song.sampleLen; i++) {
     DivSample* s=parent->song.sample[i];
-    int length=s->length8;
+    int length=s->getEndPosition(DIV_SAMPLE_DEPTH_8BIT);
     int actualLength=MIN((int)(getSampleMemCapacity()-memPos)-31,length);
     if (actualLength>0) {
       s->offRF5C68=memPos;
diff --git a/src/engine/platform/segapcm.cpp b/src/engine/platform/segapcm.cpp
index 71d45298..d66fcce0 100644
--- a/src/engine/platform/segapcm.cpp
+++ b/src/engine/platform/segapcm.cpp
@@ -56,12 +56,10 @@ void DivPlatformSegaPCM::acquire(short* bufL, short* bufR, size_t start, size_t
           pcmR+=(s->data8[chan[i].pcm.pos>>8]*chan[i].chVolR);
         }
         chan[i].pcm.pos+=chan[i].pcm.freq;
-        if (chan[i].pcm.pos>=(s->samples<<8)) {
-          if (s->loopStart>=0 && s->loopStart<(int)s->samples) {
-            chan[i].pcm.pos=s->loopStart<<8;
-          } else {
-            chan[i].pcm.sample=-1;
-          }
+        if (s->isLoopable() && chan[i].pcm.pos>=(s->getEndPosition()<<8)) {
+          chan[i].pcm.pos=s->loopStart<<8;
+        } else if (chan[i].pcm.pos>=(s->samples<<8)) {
+          chan[i].pcm.sample=-1;
         }
       } else {
         oscBuf[i]->data[oscBuf[i]->needle++]=0;
@@ -202,7 +200,7 @@ int DivPlatformSegaPCM::dispatch(DivCommand c) {
         chan[c.chan].macroInit(ins);
         if (dumpWrites) { // Sega PCM writes
           DivSample* s=parent->getSample(chan[c.chan].pcm.sample);
-          int actualLength=(int)s->length8;
+          int actualLength=(int)(s->getEndPosition(DIV_SAMPLE_DEPTH_8BIT));
           if (actualLength>0xfeff) actualLength=0xfeff;
           addWrite(0x10086+(c.chan<<3),3+((s->offSegaPCM>>16)<<3));
           addWrite(0x10084+(c.chan<<3),(s->offSegaPCM)&0xff);
@@ -235,7 +233,7 @@ int DivPlatformSegaPCM::dispatch(DivCommand c) {
         chan[c.chan].furnacePCM=false;
         if (dumpWrites) { // Sega PCM writes
           DivSample* s=parent->getSample(chan[c.chan].pcm.sample);
-          int actualLength=(int)s->length8;
+          int actualLength=(int)(s->getEndPosition(DIV_SAMPLE_DEPTH_8BIT));
           if (actualLength>65536) actualLength=65536;
           addWrite(0x10086+(c.chan<<3),3+((s->offSegaPCM>>16)<<3));
           addWrite(0x10084+(c.chan<<3),(s->offSegaPCM)&0xff);
diff --git a/src/engine/platform/su.cpp b/src/engine/platform/su.cpp
index f3be01a7..48d0ba9a 100644
--- a/src/engine/platform/su.cpp
+++ b/src/engine/platform/su.cpp
@@ -213,7 +213,7 @@ void DivPlatformSoundUnit::tick(bool sysTick) {
           DivInstrument* ins=parent->getIns(chan[i].ins,DIV_INS_SU);
           DivSample* sample=parent->getSample(ins->amiga.getSample(chan[i].note));
           if (sample!=NULL) {
-            unsigned int sampleEnd=sample->offSU+sample->samples;
+            unsigned int sampleEnd=sample->offSU+(sample->getEndPosition());
             unsigned int off=sample->offSU+chan[i].hasOffset;
             chan[i].hasOffset=0;
             if (sampleEnd>=getSampleMemCapacity(0)) sampleEnd=getSampleMemCapacity(0)-1;
@@ -221,7 +221,7 @@ void DivPlatformSoundUnit::tick(bool sysTick) {
             chWrite(i,0x0b,off>>8);
             chWrite(i,0x0c,sampleEnd&0xff);
             chWrite(i,0x0d,sampleEnd>>8);
-            if (sample->loopStart>=0 && sample->loopStart<(int)sample->samples) {
+            if (sample->isLoopable()) {
               unsigned int sampleLoop=sample->offSU+sample->loopStart;
               if (sampleLoop>=getSampleMemCapacity(0)) sampleLoop=getSampleMemCapacity(0)-1;
               chWrite(i,0x0e,sampleLoop&0xff);
diff --git a/src/engine/platform/swan.cpp b/src/engine/platform/swan.cpp
index b3e83319..b6da2327 100644
--- a/src/engine/platform/swan.cpp
+++ b/src/engine/platform/swan.cpp
@@ -83,12 +83,10 @@ void DivPlatformSwan::acquire(short* bufL, short* bufR, size_t start, size_t len
           continue;
         }
         rWrite(0x09,(unsigned char)s->data8[dacPos++]+0x80);
-        if (dacPos>=s->samples) {
-          if (s->loopStart>=0 && s->loopStart<(int)s->samples) {
-            dacPos=s->loopStart;
-          } else {
-            dacSample=-1;
-          }
+        if (s->isLoopable() && dacPos>=s->getEndPosition()) {
+          dacPos=s->loopStart;
+        } else if (dacPos>=s->samples) {
+          dacSample=-1;
         }
         dacPeriod-=rate;
       }
diff --git a/src/engine/platform/vera.cpp b/src/engine/platform/vera.cpp
index 092bbb6a..6376cc19 100644
--- a/src/engine/platform/vera.cpp
+++ b/src/engine/platform/vera.cpp
@@ -96,13 +96,11 @@ void DivPlatformVERA::acquire(short* bufL, short* bufR, size_t start, size_t len
           rWritePCMData(tmp_r&0xff);
         }
         chan[16].pcm.pos++;
-        if (chan[16].pcm.pos>=s->samples) {
-          if (s->loopStart>=0 && s->loopStart<(int)s->samples) {
-            chan[16].pcm.pos=s->loopStart;
-          } else {
-            chan[16].pcm.sample=-1;
-            break;
-          }
+        if (s->isLoopable() && chan[16].pcm.pos>=s->getEndPosition()) {
+          chan[16].pcm.pos=s->loopStart;
+        } else if (chan[16].pcm.pos>=s->samples) {
+          chan[16].pcm.sample=-1;
+          break;
         }
       }
     } else {
@@ -267,12 +265,12 @@ int DivPlatformVERA::dispatch(DivCommand c) {
         chan[16].pcm.pos=0;
         DivSample* s=parent->getSample(chan[16].pcm.sample);
         unsigned char ctrl=0x90|chan[16].vol; // always stereo
-        if (s->depth==16) {
+        if (s->depth==DIV_SAMPLE_DEPTH_16BIT) {
           chan[16].pcm.depth16=true;
           ctrl|=0x20;
         } else {
           chan[16].pcm.depth16=false;
-          if (s->depth!=8) chan[16].pcm.sample=-1;
+          if (s->depth!=DIV_SAMPLE_DEPTH_8BIT) chan[16].pcm.sample=-1;
         }
         rWritePCMCtrl(ctrl);
       }
diff --git a/src/engine/platform/vrc6.cpp b/src/engine/platform/vrc6.cpp
index 88fcb37b..8a34d925 100644
--- a/src/engine/platform/vrc6.cpp
+++ b/src/engine/platform/vrc6.cpp
@@ -77,13 +77,11 @@ void DivPlatformVRC6::acquire(short* bufL, short* bufR, size_t start, size_t len
             chWrite(i,0,0x80|chan[i].dacOut);
           }
           chan[i].dacPos++;
-          if (chan[i].dacPos>=s->samples) {
-            if (s->loopStart>=0 && s->loopStart<(int)s->samples) {
-              chan[i].dacPos=s->loopStart;
-            } else {
-              chan[i].dacSample=-1;
-              chWrite(i,0,0);
-            }
+          if (s->isLoopable() && chan[i].dacPos>=s->getEndPosition()) {
+            chan[i].dacPos=s->loopStart;
+          } else if (chan[i].dacPos>=s->samples) {
+            chan[i].dacSample=-1;
+            chWrite(i,0,0);
           }
           chan[i].dacPeriod-=rate;
         }
diff --git a/src/engine/platform/ym2608.cpp b/src/engine/platform/ym2608.cpp
index b70efaf0..c3cf52a0 100644
--- a/src/engine/platform/ym2608.cpp
+++ b/src/engine/platform/ym2608.cpp
@@ -761,7 +761,7 @@ int DivPlatformYM2608::dispatch(DivCommand c) {
             immWrite(0x104,(end>>5)&0xff);
             immWrite(0x105,(end>>13)&0xff);
             immWrite(0x101,(isMuted[c.chan]?0:(chan[c.chan].pan<<6))|2);
-            immWrite(0x100,(s->loopStart>=0)?0xb0:0xa0); // start/repeat
+            immWrite(0x100,(s->isLoopable())?0xb0:0xa0); // start/repeat
             if (c.value!=DIV_NOTE_NULL) {
               chan[c.chan].note=c.value;
               chan[c.chan].baseFreq=NOTE_ADPCMB(chan[c.chan].note);
@@ -796,7 +796,7 @@ int DivPlatformYM2608::dispatch(DivCommand c) {
           immWrite(0x104,(end>>5)&0xff);
           immWrite(0x105,(end>>13)&0xff);
           immWrite(0x101,(isMuted[c.chan]?0:(chan[c.chan].pan<<6))|2);
-          immWrite(0x100,(s->loopStart>=0)?0xb0:0xa0); // start/repeat
+          immWrite(0x100,(s->isLoopable())?0xb0:0xa0); // start/repeat
           int freq=(65536.0*(double)s->rate)/((double)chipClock/144.0);
           immWrite(0x109,freq&0xff);
           immWrite(0x10a,(freq>>8)&0xff);
diff --git a/src/engine/platform/ym2610.cpp b/src/engine/platform/ym2610.cpp
index 1a67c428..4e01b005 100644
--- a/src/engine/platform/ym2610.cpp
+++ b/src/engine/platform/ym2610.cpp
@@ -793,7 +793,7 @@ int DivPlatformYM2610::dispatch(DivCommand c) {
             immWrite(0x14,(end>>8)&0xff);
             immWrite(0x15,end>>16);
             immWrite(0x11,isMuted[c.chan]?0:(chan[c.chan].pan<<6));
-            immWrite(0x10,(s->loopStart>=0)?0x90:0x80); // start/repeat
+            immWrite(0x10,(s->isLoopable())?0x90:0x80); // start/repeat
             if (c.value!=DIV_NOTE_NULL) {
               chan[c.chan].note=c.value;
               chan[c.chan].baseFreq=NOTE_ADPCMB(chan[c.chan].note);
@@ -828,7 +828,7 @@ int DivPlatformYM2610::dispatch(DivCommand c) {
           immWrite(0x14,(end>>8)&0xff);
           immWrite(0x15,end>>16);
           immWrite(0x11,isMuted[c.chan]?0:(chan[c.chan].pan<<6));
-          immWrite(0x10,(s->loopStart>=0)?0x90:0x80); // start/repeat
+          immWrite(0x10,(s->isLoopable())?0x90:0x80); // start/repeat
           int freq=(65536.0*(double)s->rate)/((double)chipClock/144.0);
           immWrite(0x19,freq&0xff);
           immWrite(0x1a,(freq>>8)&0xff);
diff --git a/src/engine/platform/ym2610b.cpp b/src/engine/platform/ym2610b.cpp
index 600c89fd..1a1f7f0a 100644
--- a/src/engine/platform/ym2610b.cpp
+++ b/src/engine/platform/ym2610b.cpp
@@ -775,7 +775,7 @@ int DivPlatformYM2610B::dispatch(DivCommand c) {
             immWrite(0x14,(end>>8)&0xff);
             immWrite(0x15,end>>16);
             immWrite(0x11,isMuted[c.chan]?0:(chan[c.chan].pan<<6));
-            immWrite(0x10,(s->loopStart>=0)?0x90:0x80); // start/repeat
+            immWrite(0x10,(s->isLoopable())?0x90:0x80); // start/repeat
             if (c.value!=DIV_NOTE_NULL) {
               chan[c.chan].note=c.value;
               chan[c.chan].baseFreq=NOTE_ADPCMB(chan[c.chan].note);
@@ -810,7 +810,7 @@ int DivPlatformYM2610B::dispatch(DivCommand c) {
           immWrite(0x14,(end>>8)&0xff);
           immWrite(0x15,end>>16);
           immWrite(0x11,isMuted[c.chan]?0:(chan[c.chan].pan<<6));
-          immWrite(0x10,(s->loopStart>=0)?0x90:0x80); // start/repeat
+          immWrite(0x10,(s->isLoopable())?0x90:0x80); // start/repeat
           int freq=(65536.0*(double)s->rate)/((double)chipClock/144.0);
           immWrite(0x19,freq&0xff);
           immWrite(0x1a,(freq>>8)&0xff);
diff --git a/src/engine/platform/ymz280b.cpp b/src/engine/platform/ymz280b.cpp
index d8d98478..87193da5 100644
--- a/src/engine/platform/ymz280b.cpp
+++ b/src/engine/platform/ymz280b.cpp
@@ -136,9 +136,9 @@ void DivPlatformYMZ280B::tick(bool sysTick) {
       DivSample* s=parent->getSample(chan[i].sample);
       unsigned char ctrl;
       switch (s->depth) {
-        case 3: ctrl=0x20; break;
-        case 8: ctrl=0x40; break;
-        case 16: ctrl=0x60; break;
+        case DIV_SAMPLE_DEPTH_YMZ_ADPCM: ctrl=0x20; break;
+        case DIV_SAMPLE_DEPTH_8BIT: ctrl=0x40; break;
+        case DIV_SAMPLE_DEPTH_16BIT: ctrl=0x60; break;
         default: ctrl=0;
       }
       double off=(s->centerRate>=1)?((double)s->centerRate/8363.0):1.0;
@@ -146,40 +146,44 @@ void DivPlatformYMZ280B::tick(bool sysTick) {
       if (chan[i].freq<0) chan[i].freq=0;
       if (chan[i].freq>511) chan[i].freq=511;
       // ADPCM has half the range
-      if (s->depth==3 && chan[i].freq>255) chan[i].freq=255;
-      ctrl|=(chan[i].active?0x80:0)|((s->loopStart>=0)?0x10:0)|(chan[i].freq>>8);
+      if (s->depth==DIV_SAMPLE_DEPTH_YMZ_ADPCM && chan[i].freq>255) chan[i].freq=255;
+      ctrl|=(chan[i].active?0x80:0)|((s->isLoopable())?0x10:0)|(chan[i].freq>>8);
       if (chan[i].keyOn) {
         unsigned int start=s->offYMZ280B;
-        unsigned int loop=0;
+        unsigned int loopStart=0;
+        unsigned int loopEnd=0;
         unsigned int end=MIN(start+s->getCurBufLen(),getSampleMemCapacity()-1);
         if (chan[i].audPos>0) {
           switch (s->depth) {
-            case 3: start+=chan[i].audPos/2; break;
-            case 8: start+=chan[i].audPos; break;
-            case 16: start+=chan[i].audPos*2; break;
+            case DIV_SAMPLE_DEPTH_YMZ_ADPCM: start+=chan[i].audPos/2; break;
+            case DIV_SAMPLE_DEPTH_8BIT: start+=chan[i].audPos; break;
+            case DIV_SAMPLE_DEPTH_16BIT: start+=chan[i].audPos*2; break;
+            default: break;
           }
           start=MIN(start,end);
         }
-        if (s->loopStart>=0) {
+        if (s->isLoopable()) {
           switch (s->depth) {
-            case 3: loop=start+s->loopStart/2; break;
-            case 8: loop=start+s->loopStart; break;
-            case 16: loop=start+s->loopStart*2; break;
+            case DIV_SAMPLE_DEPTH_YMZ_ADPCM: loopStart=start+s->loopStart/2; loopEnd=start+s->loopEnd/2; break;
+            case DIV_SAMPLE_DEPTH_8BIT: loopStart=start+s->loopStart; loopEnd=start+s->loopEnd; break;
+            case DIV_SAMPLE_DEPTH_16BIT: loopStart=start+s->loopStart*2; loopEnd=start+s->loopEnd*2; break;
+            default: break;
           }
-          loop=MIN(loop,end);
+          loopEnd=MIN(loopEnd,end);
+          loopStart=MIN(loopStart,loopEnd);
         }
         rWrite(0x01+i*4,ctrl&~0x80); // force keyoff first
         rWrite(0x20+i*4,(start>>16)&0xff);
-        rWrite(0x21+i*4,(loop>>16)&0xff);
-        rWrite(0x22+i*4,(end>>16)&0xff);
+        rWrite(0x21+i*4,(loopStart>>16)&0xff);
+        rWrite(0x22+i*4,(loopEnd>>16)&0xff);
         rWrite(0x23+i*4,(end>>16)&0xff);
         rWrite(0x40+i*4,(start>>8)&0xff);
-        rWrite(0x41+i*4,(loop>>8)&0xff);
-        rWrite(0x42+i*4,(end>>8)&0xff);
+        rWrite(0x41+i*4,(loopStart>>8)&0xff);
+        rWrite(0x42+i*4,(loopEnd>>8)&0xff);
         rWrite(0x43+i*4,(end>>8)&0xff);
         rWrite(0x60+i*4,start&0xff);
-        rWrite(0x61+i*4,loop&0xff);
-        rWrite(0x62+i*4,end&0xff);
+        rWrite(0x61+i*4,loopStart&0xff);
+        rWrite(0x62+i*4,loopEnd&0xff);
         rWrite(0x63+i*4,end&0xff);
         if (!chan[i].std.vol.had) {
           chan[i].outVol=chan[i].vol;
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index 329c5b54..bff0c3c3 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -1204,17 +1204,17 @@ void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsi
         blip_add_delta(samp_bb,i,samp_temp-samp_prevSample);
         samp_prevSample=samp_temp;
 
-        if (sPreview.pos>=s->samples || (sPreview.pEnd>=0 && (int)sPreview.pos>=sPreview.pEnd)) {
-          if (s->loopStart>=0 && s->loopStart<(int)s->samples && (int)sPreview.pos>=s->loopStart) {
+        if (sPreview.pos>=s->getEndPosition() || (sPreview.pEnd>=0 && (int)sPreview.pos>=sPreview.pEnd)) {
+          if (s->isLoopable() && (int)sPreview.pos>=s->loopStart) {
             sPreview.pos=s->loopStart;
           }
         }
       }
 
-      if (sPreview.pos>=s->samples || (sPreview.pEnd>=0 && (int)sPreview.pos>=sPreview.pEnd)) {
-        if (s->loopStart>=0 && s->loopStart<(int)s->samples && (int)sPreview.pos>=s->loopStart) {
+      if (sPreview.pos>=s->getEndPosition() || (sPreview.pEnd>=0 && (int)sPreview.pos>=sPreview.pEnd)) {
+        if (s->isLoopable() && (int)sPreview.pos>=s->loopStart) {
           sPreview.pos=s->loopStart;
-        } else {
+        } else if (sPreview.pos>=s->samples) {
           sPreview.sample=-1;
         }
       }
diff --git a/src/engine/sample.cpp b/src/engine/sample.cpp
index 908b9a0d..60eb35bb 100644
--- a/src/engine/sample.cpp
+++ b/src/engine/sample.cpp
@@ -38,6 +38,65 @@ DivSampleHistory::~DivSampleHistory() {
   if (data!=NULL) delete[] data;
 }
 
+bool DivSample::isLoopable() {
+  return (loopStart>=0 && loopStart<loopEnd) && (loopEnd>loopStart && loopEnd<=(int)samples);
+}
+
+unsigned int DivSample::getEndPosition(DivSampleDepth depth) {
+  int end=loopEnd;
+  unsigned int len=samples;
+  switch (depth) {
+    case DIV_SAMPLE_DEPTH_1BIT:
+      end=(loopEnd+7)/8;
+      len=length1;
+      break;
+    case DIV_SAMPLE_DEPTH_1BIT_DPCM:
+      end=(loopEnd+7)/8;
+      len=lengthDPCM;
+      break;
+    case DIV_SAMPLE_DEPTH_YMZ_ADPCM:
+      end=(loopEnd+1)/2;
+      len=lengthZ;
+      break;
+    case DIV_SAMPLE_DEPTH_QSOUND_ADPCM:
+      end=(loopEnd+1)/2;
+      len=lengthQSoundA;
+      break;
+    case DIV_SAMPLE_DEPTH_ADPCM_A:
+      end=(loopEnd+1)/2;
+      len=lengthA;
+      break;
+    case DIV_SAMPLE_DEPTH_ADPCM_B:
+      end=(loopEnd+1)/2;
+      len=lengthB;
+      break;
+    case DIV_SAMPLE_DEPTH_8BIT:
+      end=loopEnd;
+      len=length8;
+      break;
+    case DIV_SAMPLE_DEPTH_BRR:
+      end=9*((loopEnd+15)/16);
+      len=lengthBRR;
+      break;
+    case DIV_SAMPLE_DEPTH_VOX:
+      end=(loopEnd+1)/2;
+      len=lengthVOX;
+      break;
+    case DIV_SAMPLE_DEPTH_16BIT:
+      end=loopEnd*2;
+      len=length16;
+      break;
+    default:
+      break;
+  }
+  return isLoopable()?end:len;
+}
+
+void DivSample::setSampleCount(unsigned int count) {
+  samples=count;
+  if ((!isLoopable()) || loopEnd<0 || loopEnd>(int)samples) loopEnd=samples;
+}
+
 bool DivSample::save(const char* path) {
 #ifndef HAVE_SNDFILE
   logE("Furnace was not compiled with libsndfile!");
@@ -53,7 +112,7 @@ bool DivSample::save(const char* path) {
   si.channels=1;
   si.samplerate=rate;
   switch (depth) {
-    case 8: // 8-bit
+    case DIV_SAMPLE_DEPTH_8BIT: // 8-bit
       si.format=SF_FORMAT_PCM_U8|SF_FORMAT_WAV;
       break;
     default: // 16-bit
@@ -76,17 +135,17 @@ bool DivSample::save(const char* path) {
   inst.detune = 50 - (pitch % 100);
   inst.velocity_hi = 0x7f;
   inst.key_hi = 0x7f;
-  if(loopStart != -1)
+  if(isLoopable())
   {
     inst.loop_count = 1;
     inst.loops[0].mode = SF_LOOP_FORWARD;
     inst.loops[0].start = loopStart;
-    inst.loops[0].end = samples;
+    inst.loops[0].end = loopEnd;
   }
   sf_command(f, SFC_SET_INSTRUMENT, &inst, sizeof(inst));
 
   switch (depth) {
-    case 8: {
+    case DIV_SAMPLE_DEPTH_8BIT: {
       // convert from signed to unsigned
       unsigned char* buf=new unsigned char[length8];
       for (size_t i=0; i<length8; i++) {
@@ -108,65 +167,65 @@ bool DivSample::save(const char* path) {
 }
 
 // 16-bit memory is padded to 512, to make things easier for ADPCM-A/B.
-bool DivSample::initInternal(unsigned char d, int count) {
+bool DivSample::initInternal(DivSampleDepth d, int count) {
   switch (d) {
-    case 0: // 1-bit
+    case DIV_SAMPLE_DEPTH_1BIT: // 1-bit
       if (data1!=NULL) delete[] data1;
       length1=(count+7)/8;
       data1=new unsigned char[length1];
       memset(data1,0,length1);
       break;
-    case 1: // DPCM
+    case DIV_SAMPLE_DEPTH_1BIT_DPCM: // DPCM
       if (dataDPCM!=NULL) delete[] dataDPCM;
       lengthDPCM=(count+7)/8;
       dataDPCM=new unsigned char[lengthDPCM];
       memset(dataDPCM,0,lengthDPCM);
       break;
-    case 3: // YMZ ADPCM
+    case DIV_SAMPLE_DEPTH_YMZ_ADPCM: // YMZ ADPCM
       if (dataZ!=NULL) delete[] dataZ;
       lengthZ=(count+1)/2;
       // for padding AICA sample
       dataZ=new unsigned char[(lengthZ+3)&(~0x03)];
       memset(dataZ,0,(lengthZ+3)&(~0x03));
       break;
-    case 4: // QSound ADPCM
+    case DIV_SAMPLE_DEPTH_QSOUND_ADPCM: // QSound ADPCM
       if (dataQSoundA!=NULL) delete[] dataQSoundA;
       lengthQSoundA=(count+1)/2;
       dataQSoundA=new unsigned char[lengthQSoundA];
       memset(dataQSoundA,0,lengthQSoundA);
       break;
-    case 5: // ADPCM-A
+    case DIV_SAMPLE_DEPTH_ADPCM_A: // ADPCM-A
       if (dataA!=NULL) delete[] dataA;
       lengthA=(count+1)/2;
       dataA=new unsigned char[(lengthA+255)&(~0xff)];
       memset(dataA,0,(lengthA+255)&(~0xff));
       break;
-    case 6: // ADPCM-B
+    case DIV_SAMPLE_DEPTH_ADPCM_B: // ADPCM-B
       if (dataB!=NULL) delete[] dataB;
       lengthB=(count+1)/2;
       dataB=new unsigned char[(lengthB+255)&(~0xff)];
       memset(dataB,0,(lengthB+255)&(~0xff));
       break;
-    case 8: // 8-bit
+    case DIV_SAMPLE_DEPTH_8BIT: // 8-bit
       if (data8!=NULL) delete[] data8;
       length8=count;
       // for padding X1-010 sample
       data8=new signed char[(count+4095)&(~0xfff)];
       memset(data8,0,(count+4095)&(~0xfff));
       break;
-    case 9: // BRR
+    case DIV_SAMPLE_DEPTH_BRR: // BRR
       if (dataBRR!=NULL) delete[] dataBRR;
       lengthBRR=9*((count+15)/16);
       dataBRR=new unsigned char[lengthBRR];
       memset(dataBRR,0,lengthBRR);
       break;
-    case 10: // VOX
+    case DIV_SAMPLE_DEPTH_VOX: // VOX
       if (dataVOX!=NULL) delete[] dataVOX;
       lengthVOX=(count+1)/2;
       dataVOX=new unsigned char[lengthVOX];
       memset(dataVOX,0,lengthVOX);
       break;
-    case 16: // 16-bit
+    case DIV_SAMPLE_DEPTH_16BIT: // 16-bit
       if (data16!=NULL) delete[] data16;
       length16=count*2;
       data16=new short[(count+511)&(~0x1ff)];
@@ -180,34 +239,34 @@ bool DivSample::initInternal(unsigned char d, int count) {
 
 bool DivSample::init(unsigned int count) {
   if (!initInternal(depth,count)) return false;
-  samples=count;
+  setSampleCount(count);
   return true;
 }
 
 bool DivSample::resize(unsigned int count) {
-  if (depth==8) {
+  if (depth==DIV_SAMPLE_DEPTH_8BIT) {
     if (data8!=NULL) {
       signed char* oldData8=data8;
       data8=NULL;
-      initInternal(8,count);
+      initInternal(DIV_SAMPLE_DEPTH_8BIT,count);
       memcpy(data8,oldData8,MIN(count,samples));
       delete[] oldData8;
     } else {
-      initInternal(8,count);
+      initInternal(DIV_SAMPLE_DEPTH_8BIT,count);
     }
-    samples=count;
+    setSampleCount(count);
     return true;
-  } else if (depth==16) {
+  } else if (depth==DIV_SAMPLE_DEPTH_16BIT) {
     if (data16!=NULL) {
       short* oldData16=data16;
       data16=NULL;
-      initInternal(16,count);
+      initInternal(DIV_SAMPLE_DEPTH_16BIT,count);
       memcpy(data16,oldData16,sizeof(short)*MIN(count,samples));
       delete[] oldData16;
     } else {
-      initInternal(16,count);
+      initInternal(DIV_SAMPLE_DEPTH_16BIT,count);
     }
-    samples=count;
+    setSampleCount(count);
     return true;
   }
   return false;
@@ -218,11 +277,11 @@ bool DivSample::strip(unsigned int begin, unsigned int end) {
   if (end>samples) end=samples;
   int count=samples-(end-begin);
   if (count<=0) return resize(0);
-  if (depth==8) {
+  if (depth==DIV_SAMPLE_DEPTH_8BIT) {
     if (data8!=NULL) {
       signed char* oldData8=data8;
       data8=NULL;
-      initInternal(8,count);
+      initInternal(DIV_SAMPLE_DEPTH_8BIT,count);
       if (begin>0) {
         memcpy(data8,oldData8,begin);
       }
@@ -234,13 +293,13 @@ bool DivSample::strip(unsigned int begin, unsigned int end) {
       // do nothing
       return true;
     }
-    samples=count;
+    setSampleCount(count);
     return true;
-  } else if (depth==16) {
+  } else if (depth==DIV_SAMPLE_DEPTH_16BIT) {
     if (data16!=NULL) {
       short* oldData16=data16;
       data16=NULL;
-      initInternal(16,count);
+      initInternal(DIV_SAMPLE_DEPTH_16BIT,count);
       if (begin>0) {
         memcpy(data16,oldData16,sizeof(short)*begin);
       }
@@ -252,7 +311,7 @@ bool DivSample::strip(unsigned int begin, unsigned int end) {
       // do nothing
       return true;
     }
-    samples=count;
+    setSampleCount(count);
     return true;
   }
   return false;
@@ -262,31 +321,31 @@ bool DivSample::trim(unsigned int begin, unsigned int end) {
   int count=end-begin;
   if (count==0) return true;
   if (begin==0 && end==samples) return true;
-  if (depth==8) {
+  if (depth==DIV_SAMPLE_DEPTH_8BIT) {
     if (data8!=NULL) {
       signed char* oldData8=data8;
       data8=NULL;
-      initInternal(8,count);
+      initInternal(DIV_SAMPLE_DEPTH_8BIT,count);
       memcpy(data8,oldData8+begin,count);
       delete[] oldData8;
     } else {
       // do nothing
       return true;
     }
-    samples=count;
+    setSampleCount(count);
     return true;
-  } else if (depth==16) {
+  } else if (depth==DIV_SAMPLE_DEPTH_16BIT) {
     if (data16!=NULL) {
       short* oldData16=data16;
       data16=NULL;
-      initInternal(16,count);
+      initInternal(DIV_SAMPLE_DEPTH_16BIT,count);
       memcpy(data16,&(oldData16[begin]),sizeof(short)*count);
       delete[] oldData16;
     } else {
       // do nothing
       return true;
     }
-    samples=count;
+    setSampleCount(count);
     return true;
   }
   return false;
@@ -294,11 +353,11 @@ bool DivSample::trim(unsigned int begin, unsigned int end) {
 
 bool DivSample::insert(unsigned int pos, unsigned int length) {
   unsigned int count=samples+length;
-  if (depth==8) {
+  if (depth==DIV_SAMPLE_DEPTH_8BIT) {
     if (data8!=NULL) {
       signed char* oldData8=data8;
       data8=NULL;
-      initInternal(8,count);
+      initInternal(DIV_SAMPLE_DEPTH_8BIT,count);
       if (pos>0) {
         memcpy(data8,oldData8,pos);
       }
@@ -307,15 +366,15 @@ bool DivSample::insert(unsigned int pos, unsigned int length) {
       }
       delete[] oldData8;
     } else {
-      initInternal(8,count);
+      initInternal(DIV_SAMPLE_DEPTH_8BIT,count);
     }
-    samples=count;
+    setSampleCount(count);
     return true;
-  } else if (depth==16) {
+  } else if (depth==DIV_SAMPLE_DEPTH_16BIT) {
     if (data16!=NULL) {
       short* oldData16=data16;
       data16=NULL;
-      initInternal(16,count);
+      initInternal(DIV_SAMPLE_DEPTH_16BIT,count);
       if (pos>0) {
         memcpy(data16,oldData16,sizeof(short)*pos);
       }
@@ -324,9 +383,9 @@ bool DivSample::insert(unsigned int pos, unsigned int length) {
       }
       delete[] oldData16;
     } else {
-      initInternal(16,count);
+      initInternal(DIV_SAMPLE_DEPTH_16BIT,count);
     }
-    samples=count;
+    setSampleCount(count);
     return true;
   }
   return false;
@@ -337,15 +396,15 @@ bool DivSample::insert(unsigned int pos, unsigned int length) {
   int finalCount=(double)samples*(r/(double)rate); \
   signed char* oldData8=data8; \
   short* oldData16=data16; \
-  if (depth==16) { \
+  if (depth==DIV_SAMPLE_DEPTH_16BIT) { \
     if (data16!=NULL) { \
       data16=NULL; \
-      initInternal(16,finalCount); \
+      initInternal(DIV_SAMPLE_DEPTH_16BIT,finalCount); \
     } \
-  } else if (depth==8) {  \
+  } else if (depth==DIV_SAMPLE_DEPTH_8BIT) {  \
     if (data8!=NULL) { \
       data8=NULL; \
-      initInternal(8,finalCount); \
+      initInternal(DIV_SAMPLE_DEPTH_8BIT,finalCount); \
     } \
   } else { \
     return false; \
@@ -353,19 +412,20 @@ bool DivSample::insert(unsigned int pos, unsigned int length) {
 
 #define RESAMPLE_END \
   if (loopStart>=0) loopStart=(double)loopStart*(r/(double)rate); \
+  if (loopEnd>=0) loopEnd=(double)loopEnd*(r/(double)rate); \
   centerRate=(int)((double)centerRate*(r/(double)rate)); \
   rate=r; \
   samples=finalCount; \
-  if (depth==16) { \
+  if (depth==DIV_SAMPLE_DEPTH_16BIT) { \
     delete[] oldData16; \
-  } else if (depth==8) { \
+  } else if (depth==DIV_SAMPLE_DEPTH_8BIT) { \
     delete[] oldData8; \
   }
 
 bool DivSample::resampleNone(double r) {
   RESAMPLE_BEGIN;
 
-  if (depth==16) {
+  if (depth==DIV_SAMPLE_DEPTH_16BIT) {
     for (int i=0; i<finalCount; i++) {
       unsigned int pos=(unsigned int)((double)i*((double)rate/r));
       if (pos>=samples) {
@@ -374,7 +434,7 @@ bool DivSample::resampleNone(double r) {
         data16[i]=oldData16[pos];
       }
     }
-  } else if (depth==8) {
+  } else if (depth==DIV_SAMPLE_DEPTH_8BIT) {
     for (int i=0; i<finalCount; i++) {
       unsigned int pos=(unsigned int)((double)i*((double)rate/r));
       if (pos>=samples) {
@@ -396,7 +456,7 @@ bool DivSample::resampleLinear(double r) {
   unsigned int posInt=0;
   double factor=(double)rate/r;
 
-  if (depth==16) {
+  if (depth==DIV_SAMPLE_DEPTH_16BIT) {
     for (int i=0; i<finalCount; i++) {
       short s1=(posInt>=samples)?0:oldData16[posInt];
       short s2=(posInt+1>=samples)?((loopStart>=0 && loopStart<(int)samples)?oldData16[loopStart]:0):oldData16[posInt+1];
@@ -409,7 +469,7 @@ bool DivSample::resampleLinear(double r) {
         posInt++;
       }
     }
-  } else if (depth==8) {
+  } else if (depth==DIV_SAMPLE_DEPTH_8BIT) {
     for (int i=0; i<finalCount; i++) {
       short s1=(posInt>=samples)?0:oldData8[posInt];
       short s2=(posInt+1>=samples)?((loopStart>=0 && loopStart<(int)samples)?oldData8[loopStart]:0):oldData8[posInt+1];
@@ -436,7 +496,7 @@ bool DivSample::resampleCubic(double r) {
   double factor=(double)rate/r;
   float* cubicTable=DivFilterTables::getCubicTable();
 
-  if (depth==16) {
+  if (depth==DIV_SAMPLE_DEPTH_16BIT) {
     for (int i=0; i<finalCount; i++) {
       unsigned int n=((unsigned int)(posFrac*1024.0))&1023;
       float* t=&cubicTable[n<<2];
@@ -456,7 +516,7 @@ bool DivSample::resampleCubic(double r) {
         posInt++;
       }
     }
-  } else if (depth==8) {
+  } else if (depth==DIV_SAMPLE_DEPTH_8BIT) {
     for (int i=0; i<finalCount; i++) {
       unsigned int n=((unsigned int)(posFrac*1024.0))&1023;
       float* t=&cubicTable[n<<2];
@@ -493,7 +553,7 @@ bool DivSample::resampleBlep(double r) {
 
   memset(s,0,16*sizeof(float));
 
-  if (depth==16) {
+  if (depth==DIV_SAMPLE_DEPTH_16BIT) {
     memset(data16,0,finalCount*sizeof(short));
     for (int i=0; i<finalCount; i++) {
       if (posInt<samples) {
@@ -529,7 +589,7 @@ bool DivSample::resampleBlep(double r) {
         }
       }
     }
-  } else if (depth==8) {
+  } else if (depth==DIV_SAMPLE_DEPTH_8BIT) {
     memset(data8,0,finalCount);
     for (int i=0; i<finalCount; i++) {
       if (posInt<samples) {
@@ -582,7 +642,7 @@ bool DivSample::resampleSinc(double r) {
 
   memset(s,0,16*sizeof(float));
 
-  if (depth==16) {
+  if (depth==DIV_SAMPLE_DEPTH_16BIT) {
     for (int i=0; i<finalCount+8; i++) {
       unsigned int n=((unsigned int)(posFrac*8192.0))&8191;
       float result=0;
@@ -607,7 +667,7 @@ bool DivSample::resampleSinc(double r) {
         s[15]=(posInt>=samples)?0:oldData16[posInt];
       }
     }
-  } else if (depth==8) {
+  } else if (depth==DIV_SAMPLE_DEPTH_8BIT) {
     for (int i=0; i<finalCount+8; i++) {
       unsigned int n=((unsigned int)(posFrac*8192.0))&8191;
       float result=0;
@@ -639,7 +699,7 @@ bool DivSample::resampleSinc(double r) {
 }
 
 bool DivSample::resample(double r, int filter) {
-  if (depth!=8 && depth!=16) return false;
+  if (depth!=DIV_SAMPLE_DEPTH_8BIT && depth!=DIV_SAMPLE_DEPTH_16BIT) return false;
   switch (filter) {
     case DIV_RESAMPLE_NONE:
       return resampleNone(r);
@@ -669,15 +729,15 @@ bool DivSample::resample(double r, int filter) {
 
 void DivSample::render() {
   // step 1: convert to 16-bit if needed
-  if (depth!=16) {
-    if (!initInternal(16,samples)) return;
+  if (depth!=DIV_SAMPLE_DEPTH_16BIT) {
+    if (!initInternal(DIV_SAMPLE_DEPTH_16BIT,samples)) return;
     switch (depth) {
-      case 0: // 1-bit
+      case DIV_SAMPLE_DEPTH_1BIT: // 1-bit
         for (unsigned int i=0; i<samples; i++) {
           data16[i]=((data1[i>>3]>>(i&7))&1)?0x7fff:-0x7fff;
         }
         break;
-      case 1: { // DPCM
+      case DIV_SAMPLE_DEPTH_1BIT_DPCM: { // DPCM
         int accum=0;
         for (unsigned int i=0; i<samples; i++) {
           accum+=((dataDPCM[i>>3]>>(i&7))&1)?1:-1;
@@ -687,27 +747,27 @@ void DivSample::render() {
         }
         break;
       }
-      case 3: // YMZ ADPCM
+      case DIV_SAMPLE_DEPTH_YMZ_ADPCM: // YMZ ADPCM
         ymz_decode(dataZ,data16,samples);
         break;
-      case 4: // QSound ADPCM
+      case DIV_SAMPLE_DEPTH_QSOUND_ADPCM: // QSound ADPCM
         bs_decode(dataQSoundA,data16,samples);
         break;
-      case 5: // ADPCM-A
+      case DIV_SAMPLE_DEPTH_ADPCM_A: // ADPCM-A
         yma_decode(dataA,data16,samples);
         break;
-      case 6: // ADPCM-B
+      case DIV_SAMPLE_DEPTH_ADPCM_B: // ADPCM-B
         ymb_decode(dataB,data16,samples);
         break;
-      case 8: // 8-bit PCM
+      case DIV_SAMPLE_DEPTH_8BIT: // 8-bit PCM
         for (unsigned int i=0; i<samples; i++) {
           data16[i]=data8[i]<<8;
         }
         break;
-      case 9: // BRR
+      case DIV_SAMPLE_DEPTH_BRR: // BRR
         // TODO!
         break;
-      case 10: // VOX
+      case DIV_SAMPLE_DEPTH_VOX: // VOX
         oki_decode(dataVOX,data16,samples);
         break;
       default:
@@ -716,16 +776,16 @@ void DivSample::render() {
   }
 
   // step 2: render to other formats
-  if (depth!=0) { // 1-bit
-    if (!initInternal(0,samples)) return;
+  if (depth!=DIV_SAMPLE_DEPTH_1BIT) { // 1-bit
+    if (!initInternal(DIV_SAMPLE_DEPTH_1BIT,samples)) return;
     for (unsigned int i=0; i<samples; i++) {
       if (data16[i]>0) {
         data1[i>>3]|=1<<(i&7);
       }
     }
   }
-  if (depth!=1) { // DPCM
-    if (!initInternal(1,samples)) return;
+  if (depth!=DIV_SAMPLE_DEPTH_1BIT_DPCM) { // DPCM
+    if (!initInternal(DIV_SAMPLE_DEPTH_1BIT_DPCM,samples)) return;
     int accum=63;
     for (unsigned int i=0; i<samples; i++) {
       int next=((unsigned short)(data16[i]^0x8000))>>9;
@@ -739,84 +799,88 @@ void DivSample::render() {
       if (accum>127) accum=127;
     }
   }
-  if (depth!=3) { // YMZ ADPCM
-    if (!initInternal(3,samples)) return;
+  if (depth!=DIV_SAMPLE_DEPTH_YMZ_ADPCM) { // YMZ ADPCM
+    if (!initInternal(DIV_SAMPLE_DEPTH_YMZ_ADPCM,samples)) return;
     ymz_encode(data16,dataZ,(samples+7)&(~0x7));
   }
-  if (depth!=4) { // QSound ADPCM
-    if (!initInternal(4,samples)) return;
+  if (depth!=DIV_SAMPLE_DEPTH_QSOUND_ADPCM) { // QSound ADPCM
+    if (!initInternal(DIV_SAMPLE_DEPTH_QSOUND_ADPCM,samples)) return;
     bs_encode(data16,dataQSoundA,samples);
   }
   // TODO: pad to 256.
-  if (depth!=5) { // ADPCM-A
-    if (!initInternal(5,samples)) return;
+  if (depth!=DIV_SAMPLE_DEPTH_ADPCM_A) { // ADPCM-A
+    if (!initInternal(DIV_SAMPLE_DEPTH_ADPCM_A,samples)) return;
     yma_encode(data16,dataA,(samples+511)&(~0x1ff));
   }
-  if (depth!=6) { // ADPCM-B
-    if (!initInternal(6,samples)) return;
+  if (depth!=DIV_SAMPLE_DEPTH_ADPCM_B) { // ADPCM-B
+    if (!initInternal(DIV_SAMPLE_DEPTH_ADPCM_B,samples)) return;
     ymb_encode(data16,dataB,(samples+511)&(~0x1ff));
   }
-  if (depth!=8) { // 8-bit PCM
-    if (!initInternal(8,samples)) return;
+  if (depth!=DIV_SAMPLE_DEPTH_8BIT) { // 8-bit PCM
+    if (!initInternal(DIV_SAMPLE_DEPTH_8BIT,samples)) return;
     for (unsigned int i=0; i<samples; i++) {
       data8[i]=data16[i]>>8;
     }
   }
   // TODO: BRR!
-  if (depth!=10) { // VOX
-    if (!initInternal(10,samples)) return;
+  if (depth!=DIV_SAMPLE_DEPTH_VOX) { // VOX
+    if (!initInternal(DIV_SAMPLE_DEPTH_VOX,samples)) return;
     oki_encode(data16,dataVOX,samples);
   }
 }
 
 void* DivSample::getCurBuf() {
   switch (depth) {
-    case 0:
+    case DIV_SAMPLE_DEPTH_1BIT:
       return data1;
-    case 1:
+    case DIV_SAMPLE_DEPTH_1BIT_DPCM:
       return dataDPCM;
-    case 3:
+    case DIV_SAMPLE_DEPTH_YMZ_ADPCM:
       return dataZ;
-    case 4:
+    case DIV_SAMPLE_DEPTH_QSOUND_ADPCM:
       return dataQSoundA;
-    case 5:
+    case DIV_SAMPLE_DEPTH_ADPCM_A:
       return dataA;
-    case 6:
+    case DIV_SAMPLE_DEPTH_ADPCM_B:
       return dataB;
-    case 8:
+    case DIV_SAMPLE_DEPTH_8BIT:
       return data8;
-    case 9:
+    case DIV_SAMPLE_DEPTH_BRR:
       return dataBRR;
-    case 10:
+    case DIV_SAMPLE_DEPTH_VOX:
       return dataVOX;
-    case 16:
+    case DIV_SAMPLE_DEPTH_16BIT:
       return data16;
+    default:
+      return NULL;
   }
   return NULL;
 }
 
 unsigned int DivSample::getCurBufLen() {
   switch (depth) {
-    case 0:
+    case DIV_SAMPLE_DEPTH_1BIT:
       return length1;
-    case 1:
+    case DIV_SAMPLE_DEPTH_1BIT_DPCM:
       return lengthDPCM;
-    case 3:
+    case DIV_SAMPLE_DEPTH_YMZ_ADPCM:
       return lengthZ;
-    case 4:
+    case DIV_SAMPLE_DEPTH_QSOUND_ADPCM:
       return lengthQSoundA;
-    case 5:
+    case DIV_SAMPLE_DEPTH_ADPCM_A:
       return lengthA;
-    case 6:
+    case DIV_SAMPLE_DEPTH_ADPCM_B:
       return lengthB;
-    case 8:
+    case DIV_SAMPLE_DEPTH_8BIT:
       return length8;
-    case 9:
+    case DIV_SAMPLE_DEPTH_BRR:
       return lengthBRR;
-    case 10:
+    case DIV_SAMPLE_DEPTH_VOX:
       return lengthVOX;
-    case 16:
+    case DIV_SAMPLE_DEPTH_16BIT:
       return length16;
+    default:
+      return 0;
   }
   return 0;
 }
@@ -831,9 +895,9 @@ DivSampleHistory* DivSample::prepareUndo(bool data, bool doNotPush) {
       duplicate=new unsigned char[getCurBufLen()];
       memcpy(duplicate,getCurBuf(),getCurBufLen());
     }
-    h=new DivSampleHistory(duplicate,getCurBufLen(),samples,depth,rate,centerRate,loopStart);
+    h=new DivSampleHistory(duplicate,getCurBufLen(),samples,depth,rate,centerRate,loopStart,loopEnd);
   } else {
-    h=new DivSampleHistory(depth,rate,centerRate,loopStart);
+    h=new DivSampleHistory(depth,rate,centerRate,loopStart,loopEnd);
   }
   if (!doNotPush) {
     while (!redoHist.empty()) {
@@ -863,7 +927,8 @@ DivSampleHistory* DivSample::prepareUndo(bool data, bool doNotPush) {
   } \
   rate=h->rate; \
   centerRate=h->centerRate; \
-  loopStart=h->loopStart;
+  loopStart=h->loopStart; \
+  loopEnd=h->loopEnd;
 
 
 int DivSample::undo() {
diff --git a/src/engine/sample.h b/src/engine/sample.h
index 70f8418c..103bcaa2 100644
--- a/src/engine/sample.h
+++ b/src/engine/sample.h
@@ -17,9 +17,28 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
+#ifndef _SAMPLE_H
+#define _SAMPLE_H
+
+#pragma once
+
 #include "../ta-utils.h"
 #include <deque>
 
+enum DivSampleDepth: unsigned char {
+  DIV_SAMPLE_DEPTH_1BIT=0,
+  DIV_SAMPLE_DEPTH_1BIT_DPCM=1,
+  DIV_SAMPLE_DEPTH_YMZ_ADPCM=3,
+  DIV_SAMPLE_DEPTH_QSOUND_ADPCM=4,
+  DIV_SAMPLE_DEPTH_ADPCM_A=5,
+  DIV_SAMPLE_DEPTH_ADPCM_B=6,
+  DIV_SAMPLE_DEPTH_8BIT=8,
+  DIV_SAMPLE_DEPTH_BRR=9,
+  DIV_SAMPLE_DEPTH_VOX=10,
+  DIV_SAMPLE_DEPTH_16BIT=16,
+  DIV_SAMPLE_DEPTH_MAX // boundary for sample depth
+};
+
 enum DivResampleFilters {
   DIV_RESAMPLE_NONE=0,
   DIV_RESAMPLE_LINEAR,
@@ -32,10 +51,10 @@ enum DivResampleFilters {
 struct DivSampleHistory {
   unsigned char* data;
   unsigned int length, samples;
-  unsigned char depth;
-  int rate, centerRate, loopStart;
+  DivSampleDepth depth;
+  int rate, centerRate, loopStart, loopEnd;
   bool hasSample;
-  DivSampleHistory(void* d, unsigned int l, unsigned int s, unsigned char de, int r, int cr, int ls):
+  DivSampleHistory(void* d, unsigned int l, unsigned int s, DivSampleDepth de, int r, int cr, int ls, int le):
     data((unsigned char*)d),
     length(l),
     samples(s),
@@ -43,8 +62,9 @@ struct DivSampleHistory {
     rate(r),
     centerRate(cr),
     loopStart(ls),
+    loopEnd(le),
     hasSample(true) {}
-  DivSampleHistory(unsigned char de, int r, int cr, int ls):
+  DivSampleHistory(DivSampleDepth de, int r, int cr, int ls, int le):
     data(NULL),
     length(0),
     samples(0),
@@ -52,13 +72,14 @@ struct DivSampleHistory {
     rate(r),
     centerRate(cr),
     loopStart(ls),
+    loopEnd(le),
     hasSample(false) {}
   ~DivSampleHistory();
 };
 
 struct DivSample {
   String name;
-  int rate, centerRate, loopStart, loopOffP;
+  int rate, centerRate, loopStart, loopEnd, loopOffP;
   // valid values are:
   // - 0: ZX Spectrum overlay drum (1-bit)
   // - 1: 1-bit NES DPCM (1-bit)
@@ -70,7 +91,7 @@ struct DivSample {
   // - 9: BRR (SNES)
   // - 10: VOX ADPCM
   // - 16: 16-bit PCM
-  unsigned char depth;
+  DivSampleDepth depth;
 
   // these are the new data structures.
   signed char* data8; // 8
@@ -93,6 +114,23 @@ struct DivSample {
   std::deque<DivSampleHistory*> undoHist;
   std::deque<DivSampleHistory*> redoHist;
 
+  /**
+   * check if sample is loopable.
+   * @return whether it is loopable.
+   */
+  bool isLoopable();
+
+  /**
+   * get sample end position
+   * @return the samples end position.
+   */
+  unsigned int getEndPosition(DivSampleDepth depth=DIV_SAMPLE_DEPTH_MAX);
+
+  /**
+   * @warning DO NOT USE - internal functions
+   */
+  void setSampleCount(unsigned int count);
+
   /**
    * @warning DO NOT USE - internal functions
    */
@@ -116,7 +154,7 @@ struct DivSample {
    * @param count number of samples.
    * @return whether it was successful.
    */
-  bool initInternal(unsigned char d, int count);
+  bool initInternal(DivSampleDepth d, int count);
 
   /**
    * initialize sample data. make sure you have set `depth` before doing so.
@@ -212,8 +250,9 @@ struct DivSample {
     rate(32000),
     centerRate(8363),
     loopStart(-1),
+    loopEnd(-1),
     loopOffP(0),
-    depth(16),
+    depth(DIV_SAMPLE_DEPTH_16BIT),
     data8(NULL),
     data16(NULL),
     data1(NULL),
@@ -253,3 +292,5 @@ struct DivSample {
     samples(0) {}
   ~DivSample();
 };
+
+#endif
diff --git a/src/engine/vgmOps.cpp b/src/engine/vgmOps.cpp
index 0d1ad4f5..ef1c5dc3 100644
--- a/src/engine/vgmOps.cpp
+++ b/src/engine/vgmOps.cpp
@@ -512,7 +512,7 @@ void DivEngine::performVGMWrite(SafeWriter* w, DivSystem sys, DivRegWrite& write
           w->writeC(streamID);
           w->writeS(write.val); // sample number
           w->writeC((sample->loopStart==0)|(sampleDir[streamID]?0x10:0)); // flags
-          if (sample->loopStart>0 && !sampleDir[streamID]) {
+          if (sample->isLoopable() && !sampleDir[streamID]) {
             loopTimer[streamID]=sample->length8;
             loopSample[streamID]=write.val;
           }
@@ -1549,7 +1549,7 @@ SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop, int version) {
     size_t memPos=0;
     for (int i=0; i<song.sampleLen; i++) {
       DivSample* sample=song.sample[i];
-      unsigned int alignedSize=(sample->length8+0xff)&(~0xff);
+      unsigned int alignedSize=(sample->getEndPosition(DIV_SAMPLE_DEPTH_8BIT)+0xff)&(~0xff);
       if (alignedSize>65536) alignedSize=65536;
       if ((memPos&0xff0000)!=((memPos+alignedSize)&0xff0000)) {
         memPos=(memPos+0xffff)&0xff0000;
@@ -1559,8 +1559,8 @@ SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop, int version) {
       sample->offSegaPCM=memPos;
       unsigned int readPos=0;
       for (unsigned int j=0; j<alignedSize; j++) {
-        if (readPos>=sample->length8) {
-          if (sample->loopStart>=0 && sample->loopStart<(int)sample->length8) {
+        if (readPos>=sample->getEndPosition(DIV_SAMPLE_DEPTH_8BIT)) {
+          if (sample->isLoopable()) {
             readPos=sample->loopStart;
             pcmMem[memPos++]=((unsigned char)sample->data8[readPos]+0x80);
           } else {
@@ -1663,7 +1663,7 @@ SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop, int version) {
       memcpy(sampleMem,writeZ280[i]->getSampleMem(),sampleMemLen);
       for (int i=0; i<song.sampleLen; i++) {
         DivSample* s=song.sample[i];
-        if (s->depth==16) {
+        if (s->depth==DIV_SAMPLE_DEPTH_16BIT) {
           unsigned int pos=s->offYMZ280B;
           for (unsigned int j=0; j<s->samples; j++) {
             unsigned char lo=sampleMem[pos+j*2];
@@ -1871,12 +1871,12 @@ SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop, int version) {
         if (loopSample[nextToTouch]<song.sampleLen) {
           DivSample* sample=song.sample[loopSample[nextToTouch]];
           // insert loop
-          if (sample->loopStart<(int)sample->length8) {
+          if (sample->loopStart<(int)sample->getEndPosition(DIV_SAMPLE_DEPTH_8BIT)) {
             w->writeC(0x93);
             w->writeC(nextToTouch);
             w->writeI(sample->off8+sample->loopStart);
             w->writeC(0x81);
-            w->writeI(sample->length8-sample->loopStart);
+            w->writeI(sample->getEndPosition(DIV_SAMPLE_DEPTH_8BIT)-sample->loopStart);
           }
         }
         loopSample[nextToTouch]=-1;
diff --git a/src/gui/debugWindow.cpp b/src/gui/debugWindow.cpp
index d9739f68..12e775b5 100644
--- a/src/gui/debugWindow.cpp
+++ b/src/gui/debugWindow.cpp
@@ -18,6 +18,7 @@
  */
 
 #include "gui.h"
+#include "guiConst.h"
 #include "debug.h"
 #include "IconsFontAwesome4.h"
 #include <SDL_timer.h>
@@ -154,12 +155,19 @@ void FurnaceGUI::drawDebug() {
           ImGui::Text("rate: %d",sample->rate);
           ImGui::Text("centerRate: %d",sample->centerRate);
           ImGui::Text("loopStart: %d",sample->loopStart);
+          ImGui::Text("loopEnd: %d", sample->loopEnd);
           ImGui::Text("loopOffP: %d",sample->loopOffP);
-          ImGui::Text("depth: %d",sample->depth);
+          if (sampleDepths[sample->depth]!=NULL) {
+            ImGui::Text("depth: %d (%s)",(unsigned char)sample->depth,sampleDepths[sample->depth]);
+          } else {
+            ImGui::Text("depth: %d (<NULL!>)",(unsigned char)sample->depth);
+          }
+
           ImGui::Text("length8: %d",sample->length8);
           ImGui::Text("length16: %d",sample->length16);
           ImGui::Text("length1: %d",sample->length1);
           ImGui::Text("lengthDPCM: %d",sample->lengthDPCM);
+          ImGui::Text("lengthZ: %d",sample->lengthZ);
           ImGui::Text("lengthQSoundA: %d",sample->lengthQSoundA);
           ImGui::Text("lengthA: %d",sample->lengthA);
           ImGui::Text("lengthB: %d",sample->lengthB);
@@ -170,6 +178,7 @@ void FurnaceGUI::drawDebug() {
           ImGui::Text("off16: %x",sample->off16);
           ImGui::Text("off1: %x",sample->off1);
           ImGui::Text("offDPCM: %x",sample->offDPCM);
+          ImGui::Text("offZ: %x",sample->offZ);
           ImGui::Text("offQSoundA: %x",sample->offQSoundA);
           ImGui::Text("offA: %x",sample->offA);
           ImGui::Text("offB: %x",sample->offB);
@@ -179,6 +188,8 @@ void FurnaceGUI::drawDebug() {
           ImGui::Text("offQSound: %x",sample->offQSound);
           ImGui::Text("offX1_010: %x",sample->offX1_010);
           ImGui::Text("offSU: %x",sample->offSU);
+          ImGui::Text("offYMZ280B: %x",sample->offYMZ280B);
+          ImGui::Text("offRF5C68: %x",sample->offRF5C68);
 
           ImGui::Text("samples: %d",sample->samples);
           ImGui::TreePop();
diff --git a/src/gui/doAction.cpp b/src/gui/doAction.cpp
index 60c9d5c3..ca640d62 100644
--- a/src/gui/doAction.cpp
+++ b/src/gui/doAction.cpp
@@ -709,6 +709,7 @@ void FurnaceGUI::doAction(int what) {
               sample->centerRate=prevSample->centerRate;
               sample->name=prevSample->name;
               sample->loopStart=prevSample->loopStart;
+              sample->loopEnd=prevSample->loopEnd;
               sample->depth=prevSample->depth;
               if (sample->init(prevSample->samples)) {
                 if (prevSample->getCurBuf()!=NULL) {
@@ -838,7 +839,7 @@ void FurnaceGUI::doAction(int what) {
         if (!sample->insert(pos,sampleClipboardLen)) {
           showError("couldn't paste! make sure your sample is 8 or 16-bit.");
         } else {
-          if (sample->depth==8) {
+          if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
             for (size_t i=0; i<sampleClipboardLen; i++) {
               sample->data8[pos+i]=sampleClipboard[i]>>8;
             }
@@ -864,7 +865,7 @@ void FurnaceGUI::doAction(int what) {
       if (pos<0) pos=0;
 
       e->lockEngine([this,sample,pos]() {
-        if (sample->depth==8) {
+        if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
           for (size_t i=0; i<sampleClipboardLen; i++) {
             if (pos+i>=sample->samples) break;
             sample->data8[pos+i]=sampleClipboard[i]>>8;
@@ -894,7 +895,7 @@ void FurnaceGUI::doAction(int what) {
       if (pos<0) pos=0;
 
       e->lockEngine([this,sample,pos]() {
-        if (sample->depth==8) {
+        if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
           for (size_t i=0; i<sampleClipboardLen; i++) {
             if (pos+i>=sample->samples) break;
             int val=sample->data8[pos+i]+(sampleClipboard[i]>>8);
@@ -948,7 +949,7 @@ void FurnaceGUI::doAction(int what) {
         SAMPLE_OP_BEGIN;
         float maxVal=0.0f;
 
-        if (sample->depth==16) {
+        if (sample->depth==DIV_SAMPLE_DEPTH_16BIT) {
           for (unsigned int i=start; i<end; i++) {
             float val=fabs((float)sample->data16[i]/32767.0f);
             if (val>maxVal) maxVal=val;
@@ -963,7 +964,7 @@ void FurnaceGUI::doAction(int what) {
               sample->data16[i]=val;
             }
           }
-        } else if (sample->depth==8) {
+        } else if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
           for (unsigned int i=start; i<end; i++) {
             float val=fabs((float)sample->data8[i]/127.0f);
             if (val>maxVal) maxVal=val;
@@ -994,14 +995,14 @@ void FurnaceGUI::doAction(int what) {
       e->lockEngine([this,sample]() {
         SAMPLE_OP_BEGIN;
 
-        if (sample->depth==16) {
+        if (sample->depth==DIV_SAMPLE_DEPTH_16BIT) {
           for (unsigned int i=start; i<end; i++) {
             float val=sample->data16[i]*float(i-start)/float(end-start);
             if (val<-32768) val=-32768;
             if (val>32767) val=32767;
             sample->data16[i]=val;
           }
-        } else if (sample->depth==8) {
+        } else if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
           for (unsigned int i=start; i<end; i++) {
             float val=sample->data8[i]*float(i-start)/float(end-start);
             if (val<-128) val=-128;
@@ -1024,14 +1025,14 @@ void FurnaceGUI::doAction(int what) {
       e->lockEngine([this,sample]() {
         SAMPLE_OP_BEGIN;
 
-        if (sample->depth==16) {
+        if (sample->depth==DIV_SAMPLE_DEPTH_16BIT) {
           for (unsigned int i=start; i<end; i++) {
             float val=sample->data16[i]*float(end-i)/float(end-start);
             if (val<-32768) val=-32768;
             if (val>32767) val=32767;
             sample->data16[i]=val;
           }
-        } else if (sample->depth==8) {
+        } else if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
           for (unsigned int i=start; i<end; i++) {
             float val=sample->data8[i]*float(end-i)/float(end-start);
             if (val<-128) val=-128;
@@ -1058,11 +1059,11 @@ void FurnaceGUI::doAction(int what) {
       e->lockEngine([this,sample]() {
         SAMPLE_OP_BEGIN;
 
-        if (sample->depth==16) {
+        if (sample->depth==DIV_SAMPLE_DEPTH_16BIT) {
           for (unsigned int i=start; i<end; i++) {
             sample->data16[i]=0;
           }
-        } else if (sample->depth==8) {
+        } else if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
           for (unsigned int i=start; i<end; i++) {
             sample->data8[i]=0;
           }
@@ -1116,7 +1117,7 @@ void FurnaceGUI::doAction(int what) {
       e->lockEngine([this,sample]() {
         SAMPLE_OP_BEGIN;
 
-        if (sample->depth==16) {
+        if (sample->depth==DIV_SAMPLE_DEPTH_16BIT) {
           for (unsigned int i=start; i<end; i++) {
             unsigned int ri=end-i-1+start;
             if (ri<=i) break;
@@ -1124,7 +1125,7 @@ void FurnaceGUI::doAction(int what) {
             sample->data16[ri]^=sample->data16[i];
             sample->data16[i]^=sample->data16[ri];
           }
-        } else if (sample->depth==8) {
+        } else if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
           for (unsigned int i=start; i<end; i++) {
             unsigned int ri=end-i-1+start;
             if (ri<=i) break;
@@ -1148,12 +1149,12 @@ void FurnaceGUI::doAction(int what) {
       e->lockEngine([this,sample]() {
         SAMPLE_OP_BEGIN;
 
-        if (sample->depth==16) {
+        if (sample->depth==DIV_SAMPLE_DEPTH_16BIT) {
           for (unsigned int i=start; i<end; i++) {
             sample->data16[i]=-sample->data16[i];
             if (sample->data16[i]==-32768) sample->data16[i]=32767;
           }
-        } else if (sample->depth==8) {
+        } else if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
           for (unsigned int i=start; i<end; i++) {
             sample->data8[i]=-sample->data8[i];
             if (sample->data16[i]==-128) sample->data16[i]=127;
@@ -1174,11 +1175,11 @@ void FurnaceGUI::doAction(int what) {
       e->lockEngine([this,sample]() {
         SAMPLE_OP_BEGIN;
 
-        if (sample->depth==16) {
+        if (sample->depth==DIV_SAMPLE_DEPTH_16BIT) {
           for (unsigned int i=start; i<end; i++) {
             sample->data16[i]^=0x8000;
           }
-        } else if (sample->depth==8) {
+        } else if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
           for (unsigned int i=start; i<end; i++) {
             sample->data8[i]^=0x80;
           }
@@ -1261,8 +1262,8 @@ void FurnaceGUI::doAction(int what) {
       e->lockEngine([this,sample]() {
         SAMPLE_OP_BEGIN;
 
-        sample->trim(0,end);
         sample->loopStart=start;
+        sample->loopEnd=end;
         updateSampleTex=true;
 
         e->renderSamples();
diff --git a/src/gui/guiConst.cpp b/src/gui/guiConst.cpp
index 80f9b5d8..64e7b18d 100644
--- a/src/gui/guiConst.cpp
+++ b/src/gui/guiConst.cpp
@@ -116,7 +116,7 @@ const char* insTypes[DIV_INS_MAX+1]={
   NULL
 };
 
-const char* sampleDepths[17]={
+const char* sampleDepths[DIV_SAMPLE_DEPTH_MAX]={
   "1-bit PCM",
   "1-bit DPCM",
   NULL,
diff --git a/src/gui/guiConst.h b/src/gui/guiConst.h
index 69085c32..a6df68f6 100644
--- a/src/gui/guiConst.h
+++ b/src/gui/guiConst.h
@@ -40,7 +40,7 @@ extern const char* noteNames[180];
 extern const char* noteNamesG[180];
 extern const char* pitchLabel[11];
 extern const char* insTypes[];
-extern const char* sampleDepths[17];
+extern const char* sampleDepths[];
 extern const char* resampleStrats[];
 extern const int availableSystems[];
 extern const FurnaceGUIActionDef guiActions[];
diff --git a/src/gui/sampleEdit.cpp b/src/gui/sampleEdit.cpp
index b684a0c7..e9b5cfb3 100644
--- a/src/gui/sampleEdit.cpp
+++ b/src/gui/sampleEdit.cpp
@@ -41,7 +41,7 @@ void FurnaceGUI::drawSampleEdit() {
     } else {
       DivSample* sample=e->song.sample[curSample];
       String sampleType="Invalid";
-      if (sample->depth<17) {
+      if (sample->depth<DIV_SAMPLE_DEPTH_MAX) {
         if (sampleDepths[sample->depth]!=NULL) {
           sampleType=sampleDepths[sample->depth];
         }
@@ -61,11 +61,11 @@ void FurnaceGUI::drawSampleEdit() {
           ImGui::SameLine();
           ImGui::SetNextItemWidth(ImGui::GetContentRegionAvail().x);
           if (ImGui::BeginCombo("##SampleType",sampleType.c_str())) {
-            for (int i=0; i<17; i++) {
+            for (int i=0; i<DIV_SAMPLE_DEPTH_MAX; i++) {
               if (sampleDepths[i]==NULL) continue;
               if (ImGui::Selectable(sampleDepths[i])) {
                 sample->prepareUndo(true);
-                sample->depth=i;
+                sample->depth=(DivSampleDepth)i;
                 e->renderSamplesP();
                 updateSampleTex=true;
                 MARK_MODIFIED;
@@ -93,22 +93,43 @@ void FurnaceGUI::drawSampleEdit() {
           }
 
           ImGui::TableNextColumn();
-          bool doLoop=(sample->loopStart>=0);
+          bool doLoop=(sample->isLoopable());
           if (ImGui::Checkbox("Loop",&doLoop)) { MARK_MODIFIED
             if (doLoop) {
               sample->loopStart=0;
+              sample->loopEnd=sample->samples;
             } else {
               sample->loopStart=-1;
+              sample->loopEnd=sample->samples;
             }
             updateSampleTex=true;
           }
           if (doLoop) {
+            ImGui::TableNextRow();
+            ImGui::TableNextColumn();
+            ImGui::Text("Loop Start");
             ImGui::SameLine();
             ImGui::SetNextItemWidth(ImGui::GetContentRegionAvail().x);
-            if (ImGui::InputInt("##LoopPosition",&sample->loopStart,1,10)) { MARK_MODIFIED
-              if (sample->loopStart<0 || sample->loopStart>=(int)sample->samples) {
+            if (ImGui::InputInt("##LoopStartPosition",&sample->loopStart,1,10)) { MARK_MODIFIED
+              if (sample->loopStart<0) {
                 sample->loopStart=0;
               }
+              if (sample->loopStart>sample->loopEnd) {
+                sample->loopStart=sample->loopEnd;
+              }
+              updateSampleTex=true;
+            }
+            ImGui::TableNextColumn();
+            ImGui::Text("Loop End");
+            ImGui::SameLine();
+            ImGui::SetNextItemWidth(ImGui::GetContentRegionAvail().x);
+            if (ImGui::InputInt("##LoopEndPosition",&sample->loopEnd,1,10)) { MARK_MODIFIED
+              if (sample->loopEnd<sample->loopStart) {
+                sample->loopEnd=sample->loopStart;
+              }
+              if (sample->loopEnd>=(int)sample->samples) {
+                sample->loopEnd=sample->samples;
+              }
               updateSampleTex=true;
             }
           }
@@ -123,7 +144,7 @@ void FurnaceGUI::drawSampleEdit() {
         */
         ImGui::Separator();
 
-        ImGui::BeginDisabled(sample->depth!=8 && sample->depth!=16);
+        ImGui::BeginDisabled(sample->depth!=DIV_SAMPLE_DEPTH_8BIT && sample->depth!=DIV_SAMPLE_DEPTH_16BIT);
 
         ImGui::PushStyleColor(ImGuiCol_Button,TOGGLE_COLOR(!sampleDragMode));
         if (ImGui::Button(ICON_FA_I_CURSOR "##SSelect")) {
@@ -275,14 +296,14 @@ void FurnaceGUI::drawSampleEdit() {
               SAMPLE_OP_BEGIN;
               float vol=amplifyVol/100.0f;
 
-              if (sample->depth==16) {
+              if (sample->depth==DIV_SAMPLE_DEPTH_16BIT) {
                 for (unsigned int i=start; i<end; i++) {
                   float val=sample->data16[i]*vol;
                   if (val<-32768) val=-32768;
                   if (val>32767) val=32767;
                   sample->data16[i]=val;
                 }
-              } else if (sample->depth==8) {
+              } else if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
                 for (unsigned int i=start; i<end; i++) {
                   float val=sample->data8[i]*vol;
                   if (val<-128) val=-128;
@@ -466,7 +487,7 @@ void FurnaceGUI::drawSampleEdit() {
 
               double power=(sampleFilterCutStart>sampleFilterCutEnd)?0.5:2.0;
 
-              if (sample->depth==16) {
+              if (sample->depth==DIV_SAMPLE_DEPTH_16BIT) {
                 for (unsigned int i=start; i<end; i++) {
                   double freq=sampleFilterCutStart+(sampleFilterCutEnd-sampleFilterCutStart)*pow(double(i-start)/double(end-start),power);
                   double cut=sin((freq/double(sample->rate))*M_PI);
@@ -482,7 +503,7 @@ void FurnaceGUI::drawSampleEdit() {
                   if (val>32767) val=32767;
                   sample->data16[i]=val;
                 }
-              } else if (sample->depth==8) {
+              } else if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
                 for (unsigned int i=start; i<end; i++) {
                   double freq=sampleFilterCutStart+(sampleFilterCutEnd-sampleFilterCutStart)*pow(double(i-start)/double(end-start),power);
                   double cut=sin((freq/double(sample->rate))*M_PI);
@@ -574,11 +595,11 @@ void FurnaceGUI::drawSampleEdit() {
           ImGui::SameLine();
           ImGui::SetNextItemWidth(ImGui::GetContentRegionAvail().x);
           if (ImGui::BeginCombo("##SampleType",sampleType.c_str())) {
-            for (int i=0; i<17; i++) {
+            for (int i=0; i<DIV_SAMPLE_DEPTH_MAX; i++) {
               if (sampleDepths[i]==NULL) continue;
               if (ImGui::Selectable(sampleDepths[i])) {
                 sample->prepareUndo(true);
-                sample->depth=i;
+                sample->depth=(DivSampleDepth)i;
                 e->renderSamplesP();
                 updateSampleTex=true;
                 MARK_MODIFIED;
@@ -607,22 +628,43 @@ void FurnaceGUI::drawSampleEdit() {
           }
 
           ImGui::TableNextColumn();
-          bool doLoop=(sample->loopStart>=0);
+          bool doLoop=(sample->isLoopable());
           if (ImGui::Checkbox("Loop",&doLoop)) { MARK_MODIFIED
             if (doLoop) {
               sample->loopStart=0;
+              sample->loopEnd=sample->samples;
             } else {
               sample->loopStart=-1;
+              sample->loopEnd=sample->samples;
             }
             updateSampleTex=true;
           }
           if (doLoop) {
+            ImGui::TableNextRow();
+            ImGui::TableNextColumn();
+            ImGui::Text("Loop Start");
             ImGui::SameLine();
             ImGui::SetNextItemWidth(ImGui::GetContentRegionAvail().x);
-            if (ImGui::InputInt("##LoopPosition",&sample->loopStart,1,10)) { MARK_MODIFIED
-              if (sample->loopStart<0 || sample->loopStart>=(int)sample->samples) {
+            if (ImGui::InputInt("##LoopStartPosition",&sample->loopStart,1,10)) { MARK_MODIFIED
+              if (sample->loopStart<0) {
                 sample->loopStart=0;
               }
+              if (sample->loopStart>sample->loopEnd) {
+                sample->loopStart=sample->loopEnd;
+              }
+              updateSampleTex=true;
+            }
+            ImGui::TableNextColumn();
+            ImGui::Text("Loop End");
+            ImGui::SameLine();
+            ImGui::SetNextItemWidth(ImGui::GetContentRegionAvail().x);
+            if (ImGui::InputInt("##LoopEndPosition",&sample->loopEnd,1,10)) { MARK_MODIFIED
+              if (sample->loopEnd<sample->loopStart) {
+                sample->loopEnd=sample->loopStart;
+              }
+              if (sample->loopEnd>=(int)sample->samples) {
+                sample->loopEnd=sample->samples;
+              }
               updateSampleTex=true;
             }
           }
@@ -637,7 +679,7 @@ void FurnaceGUI::drawSampleEdit() {
         */
         ImGui::Separator();
 
-        ImGui::BeginDisabled(sample->depth!=8 && sample->depth!=16);
+        ImGui::BeginDisabled(sample->depth!=DIV_SAMPLE_DEPTH_8BIT && sample->depth!=DIV_SAMPLE_DEPTH_16BIT);
 
         ImGui::PushStyleColor(ImGuiCol_Button,TOGGLE_COLOR(!sampleDragMode));
         if (ImGui::Button(ICON_FA_I_CURSOR "##SSelect")) {
@@ -820,7 +862,7 @@ void FurnaceGUI::drawSampleEdit() {
 
               double power=(sampleFilterCutStart>sampleFilterCutEnd)?0.5:2.0;
 
-              if (sample->depth==16) {
+              if (sample->depth==DIV_SAMPLE_DEPTH_16BIT) {
                 for (unsigned int i=start; i<end; i++) {
                   double freq=sampleFilterCutStart+(sampleFilterCutEnd-sampleFilterCutStart)*pow(double(i-start)/double(end-start),power);
                   double cut=sin((freq/double(sample->rate))*M_PI);
@@ -836,7 +878,7 @@ void FurnaceGUI::drawSampleEdit() {
                   if (val>32767) val=32767;
                   sample->data16[i]=val;
                 }
-              } else if (sample->depth==8) {
+              } else if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
                 for (unsigned int i=start; i<end; i++) {
                   double freq=sampleFilterCutStart+(sampleFilterCutEnd-sampleFilterCutStart)*pow(double(i-start)/double(end-start),power);
                   double cut=sin((freq/double(sample->rate))*M_PI);
@@ -890,14 +932,14 @@ void FurnaceGUI::drawSampleEdit() {
               SAMPLE_OP_BEGIN;
               float vol=amplifyVol/100.0f;
 
-              if (sample->depth==16) {
+              if (sample->depth==DIV_SAMPLE_DEPTH_16BIT) {
                 for (unsigned int i=start; i<end; i++) {
                   float val=sample->data16[i]*vol;
                   if (val<-32768) val=-32768;
                   if (val>32767) val=32767;
                   sample->data16[i]=val;
                 }
-              } else if (sample->depth==8) {
+              } else if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
                 for (unsigned int i=start; i<end; i++) {
                   float val=sample->data8[i]*vol;
                   if (val<-128) val=-128;
@@ -1138,7 +1180,7 @@ void FurnaceGUI::drawSampleEdit() {
             for (int i=0; i<availY; i++) {
               for (int j=0; j<availX; j++) {
                 int scaledPos=samplePos+(j*sampleZoom);
-                if (sample->loopStart>=0 && sample->loopStart<(int)sample->samples && scaledPos>=sample->loopStart) {
+                if (sample->isLoopable() && (scaledPos>=sample->loopStart && scaledPos<=sample->loopEnd)) {
                   data[i*availX+j]=bgColorLoop;
                 } else {
                   data[i*availX+j]=bgColor;
@@ -1158,7 +1200,7 @@ void FurnaceGUI::drawSampleEdit() {
               if (xCoarse>=sample->samples) break;
               int y1, y2;
               int totalAdvance=0;
-              if (sample->depth==8) {
+              if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
                 y1=((unsigned char)sample->data8[xCoarse]^0x80)*availY/256;
               } else {
                 y1=((unsigned short)sample->data16[xCoarse]^0x8000)*availY/65536;
@@ -1171,7 +1213,7 @@ void FurnaceGUI::drawSampleEdit() {
               totalAdvance+=xAdvanceCoarse;
               if (xCoarse>=sample->samples) break;
               do {
-                if (sample->depth==8) {
+                if (sample->depth==DIV_SAMPLE_DEPTH_8BIT) {
                   y2=((unsigned char)sample->data8[xCoarse]^0x80)*availY/256;
                 } else {
                   y2=((unsigned short)sample->data16[xCoarse]^0x8000)*availY/65536;
@@ -1209,11 +1251,11 @@ void FurnaceGUI::drawSampleEdit() {
             sampleSelStart=0;
             sampleSelEnd=sample->samples;
           } else {
-            if (sample->samples>0 && (sample->depth==16 || sample->depth==8)) {
+            if (sample->samples>0 && (sample->depth==DIV_SAMPLE_DEPTH_16BIT || sample->depth==DIV_SAMPLE_DEPTH_8BIT)) {
               sampleDragStart=rectMin;
               sampleDragAreaSize=rectSize;
-              sampleDrag16=(sample->depth==16);
-              sampleDragTarget=(sample->depth==16)?((void*)sample->data16):((void*)sample->data8);
+              sampleDrag16=(sample->depth==DIV_SAMPLE_DEPTH_16BIT);
+              sampleDragTarget=(sample->depth==DIV_SAMPLE_DEPTH_16BIT)?((void*)sample->data16):((void*)sample->data8);
               sampleDragLen=sample->samples;
               sampleDragActive=true;
               sampleSelStart=-1;
@@ -1312,7 +1354,7 @@ void FurnaceGUI::drawSampleEdit() {
             posX=samplePos+pos.x*sampleZoom;
             if (posX>(int)sample->samples) posX=-1;
           }
-          posY=(0.5-pos.y/rectSize.y)*((sample->depth==8)?255:32767);
+          posY=(0.5-pos.y/rectSize.y)*((sample->depth==DIV_SAMPLE_DEPTH_8BIT)?255:32767);
           if (posX>=0) {
             statusBar+=fmt::sprintf(" | (%d, %d)",posX,posY);
           }
@@ -1362,7 +1404,7 @@ void FurnaceGUI::drawSampleEdit() {
           }
         }
 
-        if (sample->depth!=8 && sample->depth!=16) {
+        if (sample->depth!=DIV_SAMPLE_DEPTH_8BIT && sample->depth!=DIV_SAMPLE_DEPTH_16BIT) {
           statusBar="Non-8/16-bit samples cannot be edited without prior conversion.";
         }