dev129 - SNES: add option to toggle BRR emphasis

papers/format.md

@@ -32,6 +32,8 @@ these fields are 0 in format versions prior to 100 (0.6pre1).
 
 the format versions are:
 
+- 129: Furnace dev129
+- 128: Furnace dev128
 - 127: Furnace dev127
 - 126: Furnace dev126
 - 125: Furnace dev125
@@ -1120,9 +1122,11 @@ size | description
      | - 16: 16-bit PCM
   1  | loop direction (>=123) or reserved
      | - 0: forward
-     | - 0: backward
+     | - 1: backward
-     | - 0: ping-pong
+     | - 2: ping-pong
-  2  | reserved
+  1  | flags (>=129) or reserved
+     | - 0: BRR emphasis
+  1  | reserved
   4  | loop start
      | - -1 means no loop
   4  | loop end

src/engine/brrUtils.c

@@ -138,7 +138,7 @@ void brrEncodeBlock(const short* buf, unsigned char* out, unsigned char range, u
   }
 }
 
-long brrEncode(short* buf, unsigned char* out, long len, long loopStart) {
+long brrEncode(short* buf, unsigned char* out, long len, long loopStart, unsigned char emphasis) {
   if (len==0) return 0;
 
   // encoding process:
@@ -158,7 +158,12 @@ long brrEncode(short* buf, unsigned char* out, long len, long loopStart) {
   unsigned char filter=0;
   unsigned char range=0;
 
-  short in[16];
+  short x0=0;
+  short x1=0;
+  short x2=0;
+  int emphOut=0;
+
+  short in[17];
 
   short last1[4][13];
   short last2[4][13];
@@ -172,9 +177,9 @@ long brrEncode(short* buf, unsigned char* out, long len, long loopStart) {
   memset(possibleOut,0,4*13*8);
 
   for (long i=0; i<len; i+=16) {
-    if (i+16>len) {
+    if (i+17>len) {
       long p=i;
-      for (int j=0; j<16; j++) {
+      for (int j=0; j<17; j++) {
         if (p>=len) {
           if (loopStart<0 || loopStart>=len) {
             in[j]=0;
@@ -187,7 +192,22 @@ long brrEncode(short* buf, unsigned char* out, long len, long loopStart) {
         }
       }
     } else {
-      memcpy(in,&buf[i],16*sizeof(short));
+      memcpy(in,&buf[i],17*sizeof(short));
+    }
+    
+    // emphasis
+    if (emphasis) {
+      for (int j=0; j<17; j++) {
+        x0=x1;
+        x1=x2;
+        x2=in[j];
+
+        if (j==0) continue;
+        emphOut=((x1<<11)-x0*370-in[j]*374)/1305;
+        if (emphOut<-32768) emphOut=-32768;
+        if (emphOut>32767) emphOut=32767;
+        in[j-1]=emphOut;
+      }
     }
 
     // encode
@@ -237,13 +257,27 @@ long brrEncode(short* buf, unsigned char* out, long len, long loopStart) {
   // encode loop block
   if (loopStart>=0) {
     long p=loopStart;
-    for (int i=0; i<16; i++) {
+    for (int i=0; i<17; i++) {
       if (p>=len) {
         p=loopStart;
       }
       in[i]=buf[p++];
     }
 
+    if (emphasis) {
+      for (int j=0; j<17; j++) {
+        x0=x1;
+        x1=x2;
+        x2=in[j];
+
+        if (j==0) continue;
+        emphOut=((x1<<11)-x0*370-in[j]*374)/1305;
+        if (emphOut<-32768) emphOut=-32768;
+        if (emphOut>32767) emphOut=32767;
+        in[j-1]=emphOut;
+      }
+    }
+
     // encode (filter 0/1 only)
     for (int j=0; j<2; j++) {
       for (int k=0; k<13; k++) {
@@ -315,9 +349,11 @@ long brrEncode(short* buf, unsigned char* out, long len, long loopStart) {
   *out=next<<1; \
   out++;
 
-long brrDecode(unsigned char* buf, short* out, long len) {
+long brrDecode(unsigned char* buf, short* out, long len, unsigned char emphasis) {
   if (len==0) return 0;
 
+  short* outOrig=out;
+
   long total=0;
 
   int last1=0;
@@ -344,5 +380,20 @@ long brrDecode(unsigned char* buf, short* out, long len) {
     buf+=9;
   }
 
+  if (emphasis) {
+    short x0=0;
+    short x1=0;
+    short x2=0;
+    for (long i=0; i<=total; i++) {
+      x0=x1;
+      x1=x2;
+      x2=(i>=total)?0:outOrig[i];
+
+      if (i==0) continue;
+
+      outOrig[i-1]=(x0*370+x1*1305+x2*374)>>11;
+    }
+  }
+
   return total;
 }

src/engine/brrUtils.h

@@ -33,18 +33,20 @@ extern "C" {
  * @param out output buffer. shall be at least 9*((15+len)/16) shorts in size (9 more if loopStart is not -1!)
  * @param len input length (should be a multiple of 16. if it isn't, the output will be padded).
  * @param loopStart beginning of loop area (may be -1 for no loop). this is used to ensure the respective block has no filter in order to loop properly.
+ * @param emphasis apply filter to compensate for Gaussian interpolation high frequency loss.
  * @return number of written samples.
  */
-long brrEncode(short* buf, unsigned char* out, long len, long loopStart);
+long brrEncode(short* buf, unsigned char* out, long len, long loopStart, unsigned char emphasis);
 
 /**
  * read len bytes from buf, decode BRR and output to out.
  * @param buf input data.
  * @param out output buffer. shall be at least 16*(len/9) shorts in size.
  * @param len input length (shall be a multiple of 9).
+ * @param emphasis apply filter to simulate Gaussian interpolation high frequency loss.
  * @return number of written bytes.
  */
-long brrDecode(unsigned char* buf, short* out, long len);
+long brrDecode(unsigned char* buf, short* out, long len, unsigned char emphasis);
 
 #ifdef __cplusplus
 }

src/engine/engine.h

@@ -47,8 +47,8 @@
 #define BUSY_BEGIN_SOFT softLocked=true; isBusy.lock();
 #define BUSY_END isBusy.unlock(); softLocked=false;
 
-#define DIV_VERSION "dev128"
+#define DIV_VERSION "dev129"
-#define DIV_ENGINE_VERSION 128
+#define DIV_ENGINE_VERSION 129
 // for imports
 #define DIV_VERSION_MOD 0xff01
 #define DIV_VERSION_FC 0xff02

src/engine/sample.cpp

@@ -52,8 +52,8 @@ void DivSample::putSampleData(SafeWriter* w) {
   w->writeI(centerRate);
   w->writeC(depth);
   w->writeC(loopMode);
+  w->writeC(brrEmphasis);
   w->writeC(0); // reserved
-  w->writeC(0);
   w->writeI(loop?loopStart:-1);
   w->writeI(loop?loopEnd:-1);
 
@@ -125,9 +125,13 @@ DivDataErrors DivSample::readSampleData(SafeReader& reader, short version) {
       reader.readC();
     }
 
+    if (version>=129) {
+      brrEmphasis=reader.readC();
+    } else {
+      reader.readC();
+    }
     // reserved
     reader.readC();
-    reader.readC();
 
     loopStart=reader.readI();
     loopEnd=reader.readI();
@@ -1041,7 +1045,7 @@ void DivSample::render(unsigned int formatMask) {
         }
         break;
       case DIV_SAMPLE_DEPTH_BRR: // BRR
-        brrDecode(dataBRR,data16,lengthBRR);
+        brrDecode(dataBRR,data16,lengthBRR,brrEmphasis);
         break;
       case DIV_SAMPLE_DEPTH_VOX: // VOX
         oki_decode(dataVOX,data16,samples);
@@ -1100,7 +1104,7 @@ void DivSample::render(unsigned int formatMask) {
   }
   if (NOT_IN_FORMAT(DIV_SAMPLE_DEPTH_BRR)) { // BRR
     if (!initInternal(DIV_SAMPLE_DEPTH_BRR,samples)) return;
-    brrEncode(data16,dataBRR,samples,loop?loopStart:-1);
+    brrEncode(data16,dataBRR,samples,loop?loopStart:-1,brrEmphasis);
   }
   if (NOT_IN_FORMAT(DIV_SAMPLE_DEPTH_VOX)) { // VOX
     if (!initInternal(DIV_SAMPLE_DEPTH_VOX,samples)) return;
@@ -1174,9 +1178,9 @@ 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,loopEnd,loop,loopMode);
+    h=new DivSampleHistory(duplicate,getCurBufLen(),samples,depth,rate,centerRate,loopStart,loopEnd,loop,brrEmphasis,loopMode);
   } else {
-    h=new DivSampleHistory(depth,rate,centerRate,loopStart,loopEnd,loop,loopMode);
+    h=new DivSampleHistory(depth,rate,centerRate,loopStart,loopEnd,loop,brrEmphasis,loopMode);
   }
   if (!doNotPush) {
     while (!redoHist.empty()) {

src/engine/sample.h

@@ -60,10 +60,10 @@ struct DivSampleHistory {
   unsigned int length, samples;
   DivSampleDepth depth;
   int rate, centerRate, loopStart, loopEnd;
-  bool loop;
+  bool loop, brrEmphasis;
   DivSampleLoopMode loopMode;
   bool hasSample;
-  DivSampleHistory(void* d, unsigned int l, unsigned int s, DivSampleDepth de, int r, int cr, int ls, int le, bool lp, DivSampleLoopMode lm):
+  DivSampleHistory(void* d, unsigned int l, unsigned int s, DivSampleDepth de, int r, int cr, int ls, int le, bool lp, bool be, DivSampleLoopMode lm):
     data((unsigned char*)d),
     length(l),
     samples(s),
@@ -73,9 +73,10 @@ struct DivSampleHistory {
     loopStart(ls),
     loopEnd(le),
     loop(lp),
+    brrEmphasis(be),
     loopMode(lm),
     hasSample(true) {}
-  DivSampleHistory(DivSampleDepth de, int r, int cr, int ls, int le, bool lp, DivSampleLoopMode lm):
+  DivSampleHistory(DivSampleDepth de, int r, int cr, int ls, int le, bool lp, bool be, DivSampleLoopMode lm):
     data(NULL),
     length(0),
     samples(0),
@@ -85,6 +86,7 @@ struct DivSampleHistory {
     loopStart(ls),
     loopEnd(le),
     loop(lp),
+    brrEmphasis(be),
     loopMode(lm),
     hasSample(false) {}
   ~DivSampleHistory();
@@ -106,7 +108,7 @@ struct DivSample {
   // - 10: VOX ADPCM
   // - 16: 16-bit PCM
   DivSampleDepth depth;
-  bool loop;
+  bool loop, brrEmphasis;
   // valid values are:
   // - 0: Forward loop
   // - 1: Backward loop
@@ -306,6 +308,7 @@ struct DivSample {
     loopOffP(0),
     depth(DIV_SAMPLE_DEPTH_16BIT),
     loop(false),
+    brrEmphasis(true),
     loopMode(DIV_SAMPLE_LOOP_FORWARD),
     data8(NULL),
     data16(NULL),

src/gui/sampleEdit.cpp

@@ -190,6 +190,31 @@ void FurnaceGUI::drawSampleEdit() {
             ImGui::EndCombo();
           }
 
+          bool isThereSNES=false;
+          for (int i=0; i<e->song.systemLen; i++) {
+            if (e->song.system[i]==DIV_SYSTEM_SNES) {
+              isThereSNES=true;
+              break;
+            }
+          }
+          if (sample->depth==DIV_SAMPLE_DEPTH_BRR || isThereSNES) {
+            bool be=sample->brrEmphasis;
+            if (ImGui::Checkbox("BRR emphasis",&be)) {
+              sample->prepareUndo(true);
+              sample->brrEmphasis=be;
+              e->renderSamplesP();
+              updateSampleTex=true;
+              MARK_MODIFIED;
+            }
+            if (ImGui::IsItemHovered()) {
+              if (sample->depth==DIV_SAMPLE_DEPTH_BRR) {
+                ImGui::SetTooltip("this is a BRR sample.\nenabling this option will muffle it (only affects non-SNES chips).");
+              } else {
+                ImGui::SetTooltip("enable this option to slightly boost high frequencies\nto compensate for the SNES' Gaussian filter's muffle.");
+              }
+            }
+          }
+
           ImGui::TableNextColumn();
           ImGui::Text("C-4 (Hz)");
           ImGui::SameLine();