The memory allocated for info.buffer has been done with malloc().

src/Mp3Decoder.cpp

@@ -37,6 +37,7 @@ using namespace nqr;
 #include "minimp3/minimp3.h"
 #include "minimp3/minimp3_ex.h"
 
+#include <cstdlib>
 #include <cstring>
 
 void mp3_decode_internal(AudioData * d, const std::vector<uint8_t> & fileData)
@@ -55,7 +56,7 @@ void mp3_decode_internal(AudioData * d, const std::vector<uint8_t> & fileData)
     d->samples.resize(info.samples);
     std::memcpy(d->samples.data(), info.buffer, sizeof(float) * info.samples);
 
-    delete info.buffer;
+    std::free(info.buffer);
 }
 
 //////////////////////