Memory leak in QAudioDecoder

call of QAudioDecoder::read() method leads to memory leaks

I initialize QAudioDecoder* decoder by a way:

decoder = new QAudioDecoder;
decoder->setSourceFilename(audioFileName);
connect(decoder, SIGNAL(bufferReady()), SLOT(processBuffer()));

and then in a method

MyClass::processBuffer()

if i just invoke decoder->read() many times it leads to big memory leaks

Note: delete of decoder not solve that issue

---------
Is there is a fast way to avoid this problem? Or Is there are another ways to process coded audio files without QAudioDecoder?