public function transmute(InputDescriptor $input, $targetFormat)
    {
        if (!in_array($targetFormat, array('image', 'audio', 'video', 'flash', 'text'))) {
            return null;
        }

        $mediaType = $this->mediaTypeManager->find($input->getMediaType());

        return $this->extractor->extract($input, $mediaType, $targetFormat);
    }