Multimedia 1: The

sound of music?As Earthlings we may have different definitions of multimedia. It’s a word too commonly used incorrectly by fast PC-salespeople trying to convince us of the quality of their PC and its capabilities. Lets take a minute to explain it in plain English.

Firstly, let’s take the word media. In computer terms that means “delivery method”. That is either CD, disk or tape, in the first instance, but at a slightly altered understanding of the word “method”, can also be used to describe the TYPE of delivery, thus it can be used to describe digital video, pictures, photographs, music etc.

It is with this second, more subtle definition that we associate the word “multi” to give us “multimedia”, and therefore by a word-for-word definition, we are basically saying that a PC with multimedia capabilities, has capabilities to deliver using many, many different methods, and many, many different file types. Unfortunately, this has not been the case with many so-called multimedia PCs until very recently. Multimedia has become synonymous with entertainment, and as such, PCs can now deliver photo-realistic gaming, surround-sound quality music, DVD and streaming video and hosts of other cool features.

The first one we’re going to look at is music. You will recall that we covered the basics as to how sound is recorded digitally and then replayed to us, in a previous column (over 12 months ago). There are several formats of recorded sound, the most popular being MP3, which you will probably have heard of.

MP3 is so curiously named, because the recording standard and protocol belongs to a specialist group of standards for the encoding of audio-visual data. The group, called the “Moving Pictures Expert Group” (and hence MPEG), is largely responsible for bringing about high standards in recording methods, low costs (or lowering costs), flexibility and making these media files available to the masses, and therefore, us Earthlings.

MP3 is MPEG audio-layer 3, and the most widely available, efficient (because of the amount of high-quality sound it can record in such a small file), and, at the correct sampling level, almost “lossless”.

So wait. Sampling-level (as I’ve covered before) represents the number of times the recording “checks back” with the original to ensure it is close. Thus the higher the sampling level, the more times it will have checked back with the original whilst recording, and the closer to the original it will be in clarity and quality. “Lossless”, refers to the fact that hardly any reduction in quality has taken place.

MP3 files of your favourite tunes will typically be around 3-4MB, and will be of a generally high quality. They can be copied between your PC and various other electronic devices — such as cell-phones and MP3-players, which can play them at your will.

One item that confuses many Earthlings is the difference between an MP3 CD and a standard audio CD, and I have had a lot of correspondence about it, so here goes: An audio CD is recorded specifically for playback on recognised audio-equipment such as CD players and car-stereos. The fact that you CAN play it on your PC is immaterial — that is just clever software at work, effectively emulating your CD player.

MP3 CDs are simply data CDs containing MP3 files. They cannot be played back on standard audio equipment such as your car stereo (although more and more equipment is<$> coming with MP3 support). It is more about how the recorded information is being interpreted than it is about something wrong with your CD-player.

Imagine if someone started to speak to you in Latin and you had no understanding of the language. That is precisely how a standard CD-player interprets the MP3 information from an MP3 CD — nonsense — and therefore it will not play anything back to you and it may even recognise it as a defective disk.

Other music and sound formats are around — and there are plenty — RM, AVI, AIFF, MIDI, WAV, to name but a few, and each has its plusses and minuses. Many of these formats we’ll revisit when we look at recorded video, because they share the same protocols.

Next time - Photos and Digital Cameras.

Bob Mellor is a senior business technologist with twenty years experience in the IT industry. He is a Professional Member of the British Computer Society, and currently Professional Services & Technical Support Manager at Bermuda Microsystems Group. He can be contacted oob<$>[AT]bmg.bm