SNES: add an option to not encode BRR with unstable filters

This is useful for seeking to anywhere within the sample using sample offset commands

papers/format.md

@@ -586,6 +586,7 @@ size | description
      | - 0: BRR emphasis
   1  | flags 2 (>=159) or reserved
      | - 0: dither
+     | - 1: no BRR filters (>=213)
   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, unsigned char emphasis) {
+long brrEncode(short* buf, unsigned char* out, long len, long loopStart, unsigned char emphasis, unsigned char noFilter) {
   if (len==0) return 0;
 
   // encoding process:
@@ -157,6 +157,7 @@ long brrEncode(short* buf, unsigned char* out, long len, long loopStart, unsigne
   long total=0;
   unsigned char filter=0;
   unsigned char range=0;
+  unsigned char numFilters=noFilter?2:4;
 
   short x0=0;
   short x1=0;
@@ -211,7 +212,7 @@ long brrEncode(short* buf, unsigned char* out, long len, long loopStart, unsigne
     }
 
     // encode
-    for (int j=0; j<4; j++) {
+    for (int j=0; j<numFilters; j++) {
       for (int k=0; k<13; k++) {
         brrEncodeBlock(in,possibleOut[j][k],k,j,&last1[j][k],&last2[j][k],&avgError[j][k]);
       }
@@ -228,7 +229,7 @@ long brrEncode(short* buf, unsigned char* out, long len, long loopStart, unsigne
         }
       }
     } else {
-      for (int j=0; j<4; j++) {
+      for (int j=0; j<numFilters; j++) {
         for (int k=0; k<13; k++) {
           if (avgError[j][k]<candError) {
             candError=avgError[j][k];
@@ -245,7 +246,7 @@ long brrEncode(short* buf, unsigned char* out, long len, long loopStart, unsigne
       out[j+1]=possibleOut[filter][range][j];
     }
 
-    for (int j=0; j<4; j++) {
+    for (int j=0; j<numFilters; j++) {
       for (int k=0; k<13; k++) {
         last1[j][k]=last1[filter][range];
         last2[j][k]=last2[filter][range];

src/engine/brrUtils.h

@@ -34,9 +34,10 @@ extern "C" {
  * @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.
+ * @param noFilter do not use filters in any block. this is used to allow seeking to any sample position.
  * @return number of written samples.
  */
-long brrEncode(short* buf, unsigned char* out, long len, long loopStart, unsigned char emphasis);
+long brrEncode(short* buf, unsigned char* out, long len, long loopStart, unsigned char emphasis, unsigned char noFilter);
 
 /**
  * read len bytes from buf, decode BRR and output to out.

src/engine/engine.h

@@ -54,8 +54,8 @@ class DivWorkPool;
 
 //#define DIV_UNSTABLE
 
-#define DIV_VERSION "0.6.4"
-#define DIV_ENGINE_VERSION 212
+#define DIV_VERSION "dev213"
+#define DIV_ENGINE_VERSION 213
 // for imports
 #define DIV_VERSION_MOD 0xff01
 #define DIV_VERSION_FC 0xff02

src/engine/fileOps/text.cpp

@@ -261,6 +261,7 @@ SafeWriter* DivEngine::saveText(bool separatePatterns) {
       w->writeText(fmt::sprintf("  - mode: %s\n",sampleLoopModes[sample->loopMode&3]));
     }
     w->writeText(fmt::sprintf("- BRR emphasis: %s\n",trueFalse[sample->brrEmphasis?1:0]));
+    w->writeText(fmt::sprintf("- no BRR filters: %s\n",trueFalse[sample->brrNoFilter?1:0]));
     w->writeText(fmt::sprintf("- dither: %s\n",trueFalse[sample->dither?1:0]));
 
     // TODO' render matrix

src/engine/sample.cpp

@@ -56,7 +56,7 @@ void DivSample::putSampleData(SafeWriter* w) {
   w->writeC(depth);
   w->writeC(loopMode);
   w->writeC(brrEmphasis);
-  w->writeC(dither);
+  w->writeC((dither?1:0)|(brrNoFilter?2:0));
   w->writeI(loop?loopStart:-1);
   w->writeI(loop?loopEnd:-1);
 
@@ -134,7 +134,9 @@ DivDataErrors DivSample::readSampleData(SafeReader& reader, short version) {
       reader.readC();
     }
     if (version>=159) {
-      dither=reader.readC()&1;
+      signed char c=reader.readC();
+      dither=c&1;
+      if (version>=213) brrNoFilter=c&2;
     } else {
       reader.readC();
     }
@@ -1423,7 +1425,7 @@ void DivSample::render(unsigned int formatMask) {
   if (NOT_IN_FORMAT(DIV_SAMPLE_DEPTH_BRR)) { // BRR
     int sampleCount=loop?loopEnd:samples;
     if (!initInternal(DIV_SAMPLE_DEPTH_BRR,sampleCount)) return;
-    brrEncode(data16,dataBRR,sampleCount,loop?loopStart:-1,brrEmphasis);
+    brrEncode(data16,dataBRR,sampleCount,loop?loopStart:-1,brrEmphasis,brrNoFilter);
   }
   if (NOT_IN_FORMAT(DIV_SAMPLE_DEPTH_VOX)) { // VOX
     if (!initInternal(DIV_SAMPLE_DEPTH_VOX,samples)) return;
@@ -1564,9 +1566,9 @@ 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,brrEmphasis,dither,loopMode);
+    h=new DivSampleHistory(duplicate,getCurBufLen(),samples,depth,rate,centerRate,loopStart,loopEnd,loop,brrEmphasis,brrNoFilter,dither,loopMode);
   } else {
-    h=new DivSampleHistory(depth,rate,centerRate,loopStart,loopEnd,loop,brrEmphasis,dither,loopMode);
+    h=new DivSampleHistory(depth,rate,centerRate,loopStart,loopEnd,loop,brrEmphasis,brrNoFilter,dither,loopMode);
   }
   if (!doNotPush) {
     while (!redoHist.empty()) {
@@ -1600,6 +1602,7 @@ DivSampleHistory* DivSample::prepareUndo(bool data, bool doNotPush) {
   loopEnd=h->loopEnd; \
   loop=h->loop; \
   brrEmphasis=h->brrEmphasis; \
+  brrNoFilter=h->brrNoFilter; \
   dither=h->dither; \
   loopMode=h->loopMode;
 

src/engine/sample.h

@@ -65,10 +65,10 @@ struct DivSampleHistory {
   unsigned int length, samples;
   DivSampleDepth depth;
   int rate, centerRate, loopStart, loopEnd;
-  bool loop, brrEmphasis, dither;
+  bool loop, brrEmphasis, brrNoFilter, dither;
   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, bool be, bool di, 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, bool bf, bool di, DivSampleLoopMode lm):
     data((unsigned char*)d),
     length(l),
     samples(s),
@@ -79,10 +79,11 @@ struct DivSampleHistory {
     loopEnd(le),
     loop(lp),
     brrEmphasis(be),
+    brrNoFilter(bf),
     dither(di),
     loopMode(lm),
     hasSample(true) {}
-  DivSampleHistory(DivSampleDepth de, int r, int cr, int ls, int le, bool lp, bool be, bool di, DivSampleLoopMode lm):
+  DivSampleHistory(DivSampleDepth de, int r, int cr, int ls, int le, bool lp, bool be, bool bf, bool di, DivSampleLoopMode lm):
     data(NULL),
     length(0),
     samples(0),
@@ -93,6 +94,7 @@ struct DivSampleHistory {
     loopEnd(le),
     loop(lp),
     brrEmphasis(be),
+    brrNoFilter(bf),
     dither(di),
     loopMode(lm),
     hasSample(false) {}
@@ -118,7 +120,7 @@ struct DivSample {
   // - 13: IMA ADPCM
   // - 16: 16-bit PCM
   DivSampleDepth depth;
-  bool loop, brrEmphasis, dither;
+  bool loop, brrEmphasis, brrNoFilter, dither;
   // valid values are:
   // - 0: Forward loop
   // - 1: Backward loop
@@ -337,6 +339,7 @@ struct DivSample {
     depth(DIV_SAMPLE_DEPTH_16BIT),
     loop(false),
     brrEmphasis(true),
+    brrNoFilter(false),
     dither(false),
     loopMode(DIV_SAMPLE_LOOP_FORWARD),
     data8(NULL),

src/gui/doAction.cpp

@@ -931,6 +931,7 @@ void FurnaceGUI::doAction(int what) {
               sample->loop=prevSample->loop;
               sample->loopMode=prevSample->loopMode;
               sample->brrEmphasis=prevSample->brrEmphasis;
+              sample->brrNoFilter=prevSample->brrNoFilter;
               sample->dither=prevSample->dither;
               sample->depth=prevSample->depth;
               if (sample->init(prevSample->samples)) {

src/gui/sampleEdit.cpp

@@ -541,6 +541,19 @@ void FurnaceGUI::drawSampleEdit() {
               }
             }
           }
+          if (sample->depth!=DIV_SAMPLE_DEPTH_BRR && isThereSNES) {
+            bool bf=sample->brrNoFilter;
+            if (ImGui::Checkbox(_("no BRR filters"),&bf)) {
+              sample->prepareUndo(true);
+              sample->brrNoFilter=bf;
+              e->renderSamplesP(curSample);
+              updateSampleTex=true;
+              MARK_MODIFIED;
+            }
+            if (ImGui::IsItemHovered()) {
+              ImGui::SetTooltip(_("enable this option to not use BRR blocks with filters\nand allow sample offset commands to be used safely."));
+            }
+          }
           if (sample->depth!=DIV_SAMPLE_DEPTH_8BIT && e->getSampleFormatMask()&(1L<<DIV_SAMPLE_DEPTH_8BIT)) {
             bool di=sample->dither;
             if (ImGui::Checkbox(_("8-bit dither"),&di)) {