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dev159 - add 8-bit dither option

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This commit is contained in:
tildearrow 2023-06-05 04:28:07 -05:00
parent 8d07441d2e
commit 5e0eb9aa23
6 changed files with 54 additions and 14 deletions
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34
src/engine/sample.cpp
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@ -54,7 +54,7 @@ void DivSample::putSampleData(SafeWriter* w) {
w->writeC(depth);
w->writeC(loopMode);
w->writeC(brrEmphasis);
w->writeC(0); // reserved
w->writeC(dither);
w->writeI(loop?loopStart:-1);
w->writeI(loop?loopEnd:-1);
@ -131,8 +131,11 @@ DivDataErrors DivSample::readSampleData(SafeReader& reader, short version) {
} else {
reader.readC();
}
// reserved
reader.readC();
if (version>=159) {
dither=reader.readC()&1;
} else {
reader.readC();
}
loopStart=reader.readI();
loopEnd=reader.readI();
@ -1196,8 +1199,23 @@ void DivSample::render(unsigned int formatMask) {
}
if (NOT_IN_FORMAT(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;
if (dither) {
unsigned short lfsr=0x6438;
unsigned short lfsr1=0x1283;
signed char errorLast=0;
signed char errorCur=0;
for (unsigned int i=0; i<samples; i++) {
signed char val=CLAMP(data16[i]+128,-32768,32767)>>8;
errorLast=errorCur;
errorCur=(val<<8)-data16[i];
data8[i]=CLAMP(val-((((errorLast+errorCur)>>1)+(lfsr&0xff))>>8),-128,127);
lfsr=(lfsr<<1)|(((lfsr>>1)^(lfsr>>2)^(lfsr>>4)^(lfsr>>15))&1);
lfsr1=(lfsr1<<1)|(((lfsr1>>1)^(lfsr1>>2)^(lfsr1>>4)^(lfsr1>>15))&1);
}
} else {
for (unsigned int i=0; i<samples; i++) {
data8[i]=data16[i]>>8;
}
}
}
if (NOT_IN_FORMAT(DIV_SAMPLE_DEPTH_BRR)) { // BRR
@ -1277,9 +1295,9 @@ 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,loopMode);
h=new DivSampleHistory(duplicate,getCurBufLen(),samples,depth,rate,centerRate,loopStart,loopEnd,loop,brrEmphasis,dither,loopMode);
} else {
h=new DivSampleHistory(depth,rate,centerRate,loopStart,loopEnd,loop,brrEmphasis,loopMode);
h=new DivSampleHistory(depth,rate,centerRate,loopStart,loopEnd,loop,brrEmphasis,dither,loopMode);
}
if (!doNotPush) {
while (!redoHist.empty()) {
@ -1312,6 +1330,8 @@ DivSampleHistory* DivSample::prepareUndo(bool data, bool doNotPush) {
loopStart=h->loopStart; \
loopEnd=h->loopEnd; \
loop=h->loop; \
brrEmphasis=h->brrEmphasis; \
dither=h->dither; \
loopMode=h->loopMode;