fixes for issue #21

src/app/basicWavReader.cpp

@@ -458,10 +458,11 @@ unsigned BasicWavReader::read (int32_t* const frameBuf, const uint16_t frameCoun
   {
     m_bytesRead = unsigned (m_bytesRead + m_bytesRemaining);
     framesRead  = m_bytesRead / m_waveFrameSize;
-    if (framesRead < framesTotal) memset (&frameBuf[framesRead * m_waveChannels], 0, (framesTotal - framesRead) * m_waveChannels * sizeof (int32_t));
   }
   m_chunkLength += m_bytesRead;
 
+  if (framesRead < framesTotal) eaExtrapolate (frameBuf, framesRead, framesTotal, m_waveChannels); // fade-out, for gapless playback on more content
+
   return framesRead;
 }
 

src/app/exhaleApp.cpp

@@ -926,6 +926,10 @@ int main (const int argc, char* argv[])
         else
         if (enableResampler) eaApplyDownsampler (inPcmData, inPcmRsmp, frameLength, numChannels, true);
       }
+      // extrapolate samples in padding region of first frame since exhaleLib can't
+      // take over this job when inPadLength > 0. Improves gapless playback.
+      else if (inPadLength > 0) eaExtrapolate (inPcmData, inPadLength, frameLength, numChannels, true); // fade-in
+
       // signal 1-frame skip and PCM priming
       outAuData[0] = 1 | zeroDelayForSbrEncoding * (uint8_t) __min (254, (firstLength - inPadLength) << (resampShift + 1));
 #endif
@@ -1356,28 +1360,13 @@ int main (const int argc, char* argv[])
 mainFinish:
 
   // free all dynamic memory
-  if (inPcmData != nullptr)
-  {
-    free ((void*) inPcmData);
-    inPcmData = nullptr;
-  }
-  if (inPcmRsmp != nullptr)
-  {
-    free ((void*) inPcmRsmp);
-    inPcmRsmp = nullptr;
-  }
+  MFREE (inPcmData);
+  MFREE (inPcmRsmp);
 #if EA_USE_WORK_DIR
-  if (currPath != nullptr)
-  {
-    free ((void*) currPath);
-    currPath = nullptr;
-  }
+  MFREE (currPath);
 #endif
-  if (outAuData != nullptr)
-  {
-    free ((void*) outAuData);
-    outAuData = nullptr;
-  }
+  MFREE (outAuData);
+
   // close input file
   if (inFileHandle != -1)
   {

src/app/exhaleApp.rc

@@ -13,7 +13,7 @@
 
 0 ICON "exhaleApp.ico"
 VS_VERSION_INFO VERSIONINFO
-FILEVERSION 1,1,8
+FILEVERSION 1,1,8,1
 BEGIN
   BLOCK "StringFileInfo"
   BEGIN

src/app/exhaleAppPch.cpp

@@ -1,5 +1,5 @@
 /* exhaleAppPch.cpp - pre-compiled source file for source code of exhale application
- * written by C. R. Helmrich, last modified in 2020 - see License.htm for legal notices
+ * written by C. R. Helmrich, last modified in 2021 - see License.htm for legal notices
  *
  * The copyright in this software is being made available under the exhale Copyright License
  * and comes with ABSOLUTELY NO WARRANTY. This software may be subject to other third-
@@ -16,6 +16,25 @@ static const unsigned supportedSamplingRates[16] = {
   57600, 38400, 19200 // BL USAC
 };
 
+// public extrapolation function
+void eaExtrapolate (int32_t* const pcmBuffer, const uint16_t pcmOffset, // start/end of PCM fades
+                    const uint16_t frameSize, const uint16_t numChannels, const bool fadeIn /*= false*/)
+{
+  const int32_t delta = (fadeIn ? -1 : 1) * numChannels;
+  const uint16_t size = (fadeIn ? pcmOffset : frameSize - pcmOffset);
+
+  if ((pcmOffset == 0 && fadeIn) || (pcmOffset >= frameSize) || !pcmBuffer) return;
+
+  for (uint16_t ch = 0; ch < numChannels; ch++)
+  {
+    int32_t* chPcmBuf = pcmBuffer + ch + (pcmOffset - (fadeIn ? 0 : 1)) * numChannels;
+    int32_t  result32 = (pcmOffset == 0 ? 0 : *chPcmBuf << 8); // input is known to be 24-bit PCM
+    const int32_t s32 = result32 / size;
+
+    for (uint16_t i = size; i > 0; i--) *(chPcmBuf += delta) = ((result32 -= s32) + 128) >> 8;
+  }
+}
+
 // public sampling rate function
 bool isSamplingRateSupported (const unsigned samplingRate)
 {

src/app/exhaleAppPch.h

@@ -1,5 +1,5 @@
 /* exhaleAppPch.h - pre-compiled header file for source code of exhale application
- * written by C. R. Helmrich, last modified in 2020 - see License.htm for legal notices
+ * written by C. R. Helmrich, last modified in 2021 - see License.htm for legal notices
  *
  * The copyright in this software is being made available under the exhale Copyright License
  * and comes with ABSOLUTELY NO WARRANTY. This software may be subject to other third-
@@ -45,6 +45,13 @@
 #if !defined (fwprintf_s) && !defined (__MINGW32__)
 # define fwprintf_s            fwprintf
 #endif
+#ifndef MFREE
+# define MFREE(x)              if (x != nullptr) { free ((void*) x); x = nullptr; }
+#endif
+
+// public extrapolation function
+void eaExtrapolate (int32_t* const pcmBuffer, const uint16_t pcmOffset,
+                    const uint16_t frameSize, const uint16_t numChannels, const bool fadeIn = false);
 
 // public sampling rate function
 bool isSamplingRateSupported (const unsigned samplingRate);