improve scaling accuracy, prevent overflow

4 files changed, 16 insertions, 6 deletions

diff --git a/src/atrac/atrac1_scale.cpp b/src/atrac/atrac1_scale.cpp
index 9346a68..627513a 100644
--- a/src/atrac/atrac1_scale.cpp
+++ b/src/atrac/atrac1_scale.cpp
@@ -7,7 +7,7 @@ using std::vector;
 using std::map;
 
 using namespace std;
-map<uint32_t, uint8_t> TScaler::ScaleIndex;
+map<double, uint8_t> TScaler::ScaleIndex;
 static const uint32_t MAX_SCALE = 65536;
 
 static bool absComp(double a, double b) {
@@ -17,7 +17,7 @@ static bool absComp(double a, double b) {
 TScaler::TScaler() {
     if (ScaleIndex.empty()) {
         for (int i = 0; i < 64; i++) {
-            ScaleIndex[ScaleTable[i] * 256] = i;
+            ScaleIndex[ScaleTable[i]] = i;
         }
     }
 }
@@ -41,12 +41,14 @@ vector<TScaledBlock> TScaler::Scale(const vector<double>& specs, const TBlockSiz
                     }
                 }
             }
-            const map<uint32_t, uint8_t>::const_iterator scaleIter = ScaleIndex.lower_bound(maxAbsSpec * 256);
-            const double scaleFactor = scaleIter->first / 256.0;
+            const map<double, uint8_t>::const_iterator scaleIter = ScaleIndex.lower_bound(maxAbsSpec);
+            const double scaleFactor = scaleIter->first;
             const uint8_t scaleFactorIndex = scaleIter->second;
             scaledBlocks.push_back(TScaledBlock(scaleFactorIndex));
             for (uint16_t specNum = specNumStart; specNum < specNumEnd; ++specNum) {
-            const double scaledValue = specs[specNum] / scaleFactor;
+                const double scaledValue = specs[specNum] / scaleFactor;
+                if (scaledValue > 1.0)
+                    cerr << "got "<< scaledValue << " value - wrong scalling" << endl;
                 scaledBlocks.back().Values.push_back(scaledValue);
 			}
 		}
diff --git a/src/atrac/atrac1_scale.h b/src/atrac/atrac1_scale.h
index 7bbfa56..0a0e852 100644
--- a/src/atrac/atrac1_scale.h
+++ b/src/atrac/atrac1_scale.h
@@ -14,7 +14,7 @@ struct TScaledBlock {
 };
 
 class TScaler : public TAtrac1Data {
-    static std::map<uint32_t, uint8_t>ScaleIndex;
+    static std::map<double, uint8_t>ScaleIndex;
 public:
     TScaler();
     std::vector<TScaledBlock> Scale(const std::vector<double>& specs, const TBlockSize& blockSize);
diff --git a/src/atracdenc.cpp b/src/atracdenc.cpp
index 98c741e..86ac0a7 100644
--- a/src/atracdenc.cpp
+++ b/src/atracdenc.cpp
@@ -158,6 +158,11 @@ TPCMEngine<double>::TProcessLambda TAtrac1Processor::GetDecodeLambda() {
             IMdct(&specs[0], mode, &PcmBufLow[channel][0], &PcmBufMid[channel][0], &PcmBufHi[channel][0]);
             SynthesisFilterBank[channel].Synthesis(&sum[0], &PcmBufLow[channel][0], &PcmBufMid[channel][0], &PcmBufHi[channel][0]);
             for (int i = 0; i < NumSamples; ++i) {
+                if (sum[i] > PcmValueMax)
+                    sum[i] = PcmValueMax;
+                if (sum[i] < PcmValueMin)
+                    sum[i] = PcmValueMin;
+
                 data[i][srcChannels - 1-channel] = sum[i];
             }
         }
diff --git a/src/atracdenc.h b/src/atracdenc.h
index 8a50cf1..03e85ea 100644
--- a/src/atracdenc.h
+++ b/src/atracdenc.h
@@ -41,6 +41,9 @@ class TAtrac1Processor : public TAtrac1MDCT, public virtual TAtrac1Data {
     double PcmBufMid[2][256 + 16];
     double PcmBufHi[2][512 + 16];
 
+    int32_t PcmValueMax = 32767;
+    int32_t PcmValueMin = -32767;
+
     Atrac1SynthesisFilterBank<double> SynthesisFilterBank[2];
     Atrac1SplitFilterBank<double> SplitFilterBank[2];