According to your link PCM in WAV is the only format that works on 3 of the 5 browsers completely including iPhone Safari. Those are my requirements. If I want to include all browsers I have to use a Flash Player in addition, since iPhones don't do Flash. This will be easy since I already have the AU/uLaw file data. The header is only a few constant bytes which do not depend on length. I will process the whole file at once. uLaw does not work together with HTML5 audio in WAV. PCM is required for 3 out of 5 browser compatibility. So I will create 2 files. PCM and AU. Perhaps I will truncate the WAV data to 8 bits while the uLaw stays at 10 for better quality. The file sizes will then be the same. If I choose I can archive the uLaw data only. So much work to do...