Add check and normalization for more than 16 bits per sample FLAC-files

src/flactomp3.cpp

@@ -294,16 +294,28 @@ bool FLACtoMP3::scaleJPEG(const FLAC__StreamMetadata_Picture& picture) {
     return true;
 }
 
-bool FLACtoMP3::decodeFrame(const int32_t * const buffer[], uint32_t size) {
+bool FLACtoMP3::decodeFrame(const int32_t * const buffer[], uint32_t size, const uint32_t bitsPerSample) {
     if (!outputInitilized) {
         bool success = initializeOutput();
         if (!success)
             return false;
     }
 
+    if (bitsPerSample >= 16)
+        return decodeFrameImpl(buffer, size, 1 << (bitsPerSample - 16));
+
+    return false;
+}
+
+bool FLACtoMP3::decodeFrameImpl(const int32_t * const buffer[], uint32_t size, const uint32_t divisor)
+{
     for (size_t i = 0; i < size; ++i) {
-        pcm[pcmCounter++] = (int16_t)buffer[0][i];
-        pcm[pcmCounter++] = (int16_t)buffer[1][i];
+        int32_t left = buffer[0][i];
+        int32_t right = buffer[1][i];
+        left /= divisor;
+        right /= divisor;
+        pcm[pcmCounter++] = (int16_t)left;
+        pcm[pcmCounter++] = (int16_t)right;
 
         if (pcmCounter == pcmSize)
             return flush();
@@ -394,8 +406,8 @@ FLAC__StreamDecoderWriteStatus FLACtoMP3::write(
         self->logger.fatal("ERROR: buffer [1] is NULL");
         return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
     }
-
-    bool result = self->decodeFrame(buffer, frame->header.blocksize);
+    
+    bool result = self->decodeFrame(buffer, frame->header.blocksize, frame->header.bits_per_sample);
 
     if (result)
         return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;

src/flactomp3.h

@@ -29,7 +29,8 @@ private:
     void processTags(const FLAC__StreamMetadata_VorbisComment& tags);
     void processInfo(const FLAC__StreamMetadata_StreamInfo& info);
     void processPicture(const FLAC__StreamMetadata_Picture& picture);
-    bool decodeFrame(const int32_t * const buffer[], uint32_t size);
+    bool decodeFrame(const int32_t * const buffer[], uint32_t size, const uint32_t bitsPerSample);
+    bool decodeFrameImpl(const int32_t * const buffer[], uint32_t size, const uint32_t divisor);
     bool flush();
     bool initializeOutput();
     bool scaleJPEG(const FLAC__StreamMetadata_Picture& picture);