Aspect Ratio

[DanielB11]

To this day I still find aspect ratios a little baffling. What I've noticed more and more often is that the black bands usually at the top and bottom of videos keeping the aspect ratio are more often than not, not part of the encoded video but rather added by the player to keep the aspect ratio. I find it more often in AVI files but it does occur in MPG's. Looking at the 'Placebo - Black-Eyed (Rock Am Ring 2006) - videopimp.mpg' (would go for the whole concert i would imagine) rip, this 'phenomenon' occurs here. How and why is this done.
The only way I can imagine (though probably sounds really dumb) is that you crop / clip the original captured black bands that are part of the encoded video and choose the aspect ratio so that you do not waste encoding on the black bands, and the player then must adjust the ratio when viewing the video.

Hope I'm making sense here. Please try explain if possible.
Thanks

[Serch]

It's done in wide aspect ratio 16:9 beacuse tv station aired it that way, chaning aspect ratio to regular 4:3 would only mess it up.