Originally Posted by lotrjw:
“My TV will effectively 'overscan' anything at 480 or 576 whatever way it is input without means to change it.
If it gets a HD resolution it will 'overscan' by default but it can be turned on and off easily.
I assume thats quite normal behavior for a HD flatpanel TV?
The ragged edges, as you say, actually arent so bad, its more weird that there is very thin black bars (not proper pillarboxing) that were part of the analogue image to give it the correct shape on a CRT TV, but mean nothing in the HD domain! Also you get a row of off white dashes on the very top left of the picture, which I assume are from the old wide screen signalling, but my TV be blowed if it recognises that even though an analogue input! Its a shame my converter box doesnt see that either for some kind of aspect switching!”
Some TVs I have seen have an overall setting called "1:1 pixel mapping" (or something similar) which the user can turn off. Your TV sounds as if it has the opposite and "overscans" everything by default. For digital sources you'd normally want that 1:1 setting turned on (overscan disabled) so that you see everything in the picture. When it's turned off, for analogue sources at least, the TV scales up the picture to loose "beyond the edge of the screen" the edges of the image that look untidy.
If you're watching old off air recordings, the white patterns are probably teletext information encoded in the first few lines of the signal. In the days of of CRT TVs, these lines were not normally visible due to overscan. It's actually possible to recover the teletext data from old S-VHS recordings in most cases. Regular VHS doesn't have the bandwdth to do this.
The panel size of your TV may be influencing this as well. You mentioned that it's "HD Ready". This means the panel is probably either 720 or 768 pixels high with 1280 pixels in width. HD is broadcast with 720 or 1080 pixels vertically. If the panel is 720 pixels vertically, there's no issue (720 scales down from 1080 easily), but if the panel is 768 it may offer additional settings that affect scaling. 768 is a bit taller that 720 (giving roughly a 16:10 aspect ratio for the panel), so there may be an option to either fill the full height of the panel, at the expense of losing a bit off each side or, keep the full width, at the expense of slight letterboxing top and bottom. Or it may simply distort the image slightly to force a 16:9 image to fill a 16:10 screen.
For a 4:3 source, a 768 panel TV may enlarge it to fill the full height of the screen, giving slightly narrower pillar box bars.
It sounds as if you have a 768 panel TV.
The options available depend on the implementation in the particular model of TV.