If you’re an avid listener of tech talk radio, then you’ve no doubt hear the discussions on the panel about the quality of audio which has been compressed into a MP3. Chances are you’ve even heard the compression when listening to music on a good quality sound system or through headphones other than those ear buds that seem to be surgically implanted in the ears of the youth of today.

It’s that strange watery sound which is extremely noticeable on instruments that make sharp sounds such as symbols and high hats.

Here’s a techy insight into MP3. MP3 compression is an acronym for MPEG-1 or MPEG-2 audio layer 3. MP3 is the file extension for MPEG audio layer 3. Layer 3 is one of three coding schemes (layer 1, layer 2 and layer 3) for the compression of audio signals. Layer 3 uses perceptual audio coding and psycho acoustic compression to remove all superfluous information (more specifically, the redundant and irrelevant parts of a sound signal. The stuff the human ear doesn't hear anyway). It also adds a Modified Discrete Cosine Transform that implements a filter bank, increasing the frequency resolution 18 times higher than that of layer 2.

Now that’s clear, the reality behind compression is that it is a loss process. Take your favorite track of music with say runs 3 or so minutes. In its uncompressed format, such as a wav or aif file, it would take require about 50Mb of storage to save the 3 minutes on a disk. The same track would take about 3Mb when compressed to an MP3. There’s a bit more to it than that, but that’s really all it is. The process of removing data from the file and reconstituting it on replay creates this watery sound. The same can be said for television.

I found myself wandering through a white goods store last Friday night looking at this large flat screen LCD and Plasma TVs. My background is broadcast television, and maybe I’m spoilt looking at pictures straight of the back of a Standard definition or high definition camera, but by the time these amazing images are broadcast to consumers via free to air television and delivered to our flat screen TV in the lounge room, the same degradation that happened to MP3s happens to video as well. Every time an audio or video is compressed and re constituted, the signal is degraded. By the time your HD picture leaves the TV station, it is squashed into a bandwidth pipe which now carries four standard definition pictures, an electronic program guide and a toke HD channel. The more detail in a picture, the more data is required to keep the detail. When the bandwidth limit is reached, the picture just falls apart.

Back in the old days when VHS machines were all the rage, Broadcast quality television exceeded that of what we had at home, now we’re seeing a reversal of that, what we can play off our DVD and Bluray players at home, can now exceed the quality of an off air TV signal. Even some Divx downloads off the internet are superior in quality.

Compression of audio and video signals is a necessary evil in this day of limited spectrum and bandwidth, but at what cost? If you’ve never had the awesome experience of seeing a true high definition television picture, then you’ll never appreciate the amount of degradation these images go through to be broadcast to our homes. And if you hadn’t notice, you can’t buy an old CRT TV these days no matter how hard you try, and to this day, I’m yet to see a large flat screen TV even come close to the quality of my CRT 16x9 tube TV. Then there’s pay TV – don’t start me on that!

This week on Tech Talk Radio
Channel 7 buys unwired
Prime TV launchs new online service
Adam Turner talks adblock plus and
ABC TV show the others how it's done online.