public function getConvertedStream($audioBitrate, $filetype)
    {
        if (in_array($this->protocol, ['m3u8', 'm3u8_native'])) {
            throw new Exception(_('Conversion of M3U8 files is not supported.'));
        }

        $avconvProc = $this->getAvconvProcess($audioBitrate, $filetype, false);

        $stream = popen($avconvProc->getCommandLine(), 'r');

        if (!is_resource($stream)) {
            throw new Exception(_('Could not open popen stream.'));
        }

        return $stream;
    }