Google\Cloud\Speech\SpeechClient::determineEncoding PHP Method

    private function determineEncoding($fileFormat)
    {
        switch ($fileFormat) {
            case 'flac':
                return 'FLAC';
            case 'amr':
                return 'AMR';
            case 'awb':
                return 'AMR_WB';
            default:
                return null;
        }
    }