[Orry Verducci]

HD channels normally show the correct aspect ratio because they can broadcast with pillar boxes (or letterboxes for movies) because I think they do it within the broadcast itself rather than an ARC signal to someone's TV which they can't do through an HMDI connection.

I may have got that completely wrong technically, however, for example:

[*]If I watch Brookside in the lounge on an HDMI link, it's stretchy-vision, which I have to manually change
[*]If I watch the same recording in my bedroom via the RF TV Link from the Sky STB, it is shown correctly as the TV knows to change it.


I hope that made sense.

That's not what happened. They broadcast a 16:9 programme in a 16:9 frame but as 4:3 pillarbox. You can see the channel bug in black pillarbox area. It's a playout error in which the wrong AFD had been selected, so the playout servers ARC'd it to pillarbox it.

It seems the new Sky Mix HD channels that are testing are being played out separately to the existing Pick service, and that one was played out correctly. The interesting bit about that being that the existing Pick service is already played out in HD.

Also HDMI is able to signal 4:3 and 16:9 for SD sources, allowing TV's to switch mode as appropriate. This however doesn't work for HD sources which are of course always 16:9.

The issue you describe is unique to Sky's set top boxes, as when upscaling to HD they always (incorrectly) stretch 4:3 SD broadcasts to 16:9. Other set top boxes (e.g. Freeview, Freesat, etc) correctly pillarbox 4:3 broadcasts. Thankfully as HD channels become the norm, in which the broadcasters pillarbox on their end, this is becoming less of an issue.