Conflicts and resolutions

摘要

For the September issue feature on portable audio and video formats I tactfully glossed over the pantomime of trying to get simple clear facts from the manufacturers. Let's now strip the gloss. Whereas just about every portable player plays MP3 (MPEC-1 Audio Layer 3) audio, the words 'MP4' and 'MPEG-4' mean very little. There are many different flavours of MPEC-4, of which the two most important are Simple Profile Part 2 'X' Video and Part 10 AVC/H.264, and MP4 is often used as a generic word for MPEC-4. There are different audio systems to go with the video and different Digital Rights Managements systems to prevent unauthorised play. After a month of asking Sony UK what kind of MPEG-4 video its latest Video Walkmen handle, I still had no useful answer. After a month Sony's mobile phone division, Sony Ericsson, first said its mobiles used 'MP4'. Then, when I asked what MP4 meant, I got a reply I shall treasure for ever: 'Whilst I appreciate that you're keen to know about MP4 formats, Sony Ericsson has let me know that it is not something that they can speak about. They feel it is better coming from a production company or similar - who actually make the movies/videos.' It took two dozen emails before I found the only human inside Motorola and Paramount who really understood their grand plan to sell Paramount downloads for Moto's portable player phones. I then gave up on asking manufacturers and ran a series of trial and error tests, converting audio and video files into different formats, and trying them on different players. From the results I was able to shake out a few simple guidelines for anyone buying a new portable.