*WHY* are channels still 4:3?

Why is 14:9 "no loss" (since it's wider than 4:3) - do you mean because overscan would have lost some picture? Why not, if you can (if guidelines allowed), show the 4:3 sections in 4:3 - is it because you'd get complaints about black bars or too much of a distracting jump between 16:9 and 4:3 sections? Surely it would be better (though 'guidelines' might say otherwise) to show content in it's original aspect ratio, without cropping or zooming (OAR is what you usually get when you buy a film on Blu-ray).

"No loss" of the original image within a 16:9 show.
You cannot use 4:3 image on a 16:9 transmission because of distortion.
Footballs are round, bike wheels are round, circles are round...
If you really can't figure this out shoot a testcard full frame 4:3 and then try editing it into a 16:9 programme and see what I mean. If you've no testcard scan a piece of 4:3 paper with a circle drawn on it instead.
It has nothing to do with guidelines BTW.

Round wheels would still be round if you show it with pillarbox bars around the 4:3 video if broadcasting within a 16:9 frame/project - that way there will be no distortion (ie. tell the editor program to maintain the original aspect ratio of the 4:3 footage, when it's in a 16:9 project).


It is when the guidelines want you to zoom/crop (the opposite of OAR - any reviewer of a film that was released on Blu-ray 'zoomed to 16:9' would likely say bad things about the picture quality).
eg.
http://www.bbc.co.uk/guidelines/dq/pdf/tv/tv_delivery_of_programmes_to_worldwide_v1.0-2011.pdf

Sorry I think my original post was unclear. I wasn't talking about older footage within shows, rather full stand alone shows themselves. What I was trying to say was that channels such as ITV3 / E4 are able to have a 16:9 advert break and then send a flag for the TV to switch back to 4:3 (or however it interprets 4:3).

I remember CBBC was the exception to this for a while because all their output came directly out of TC9's gallery rather than through pres.

That was what I was meaning rather than badly butchering old content (such as some of the archive shows where only talking heads are native widescreen but they crop everything else to death).

Yes agreed. It was the mixing of material I was referring to. The poster below clarifies their comments.
I also note the points below and comply with them.
I personally discourage enlargement of frame of 4:3 material because picture quality usually suffers unless it's essential. I personally prefer to use original frame within 16:9 as that is what was originally produced.
Incidently when we were 4:3, we had problems going the other way where Panavision movie clips were used. My producer could not understand why we could not see the edges of the clip where the actors stood when he asked me to fill the 4:3 frame

3.7.2 Aspect ratio - archive
Archive material should be zoomed to fill the 16:9 raster where possible without compromising the image
quality or composition, otherwise it may be presented in a pillar-box format, which:
• may be of an intermediate ratio between 4:3 and 16:9, but must be of consistent width across sequences,
• must be centrally framed in the 16:9 raster,
• must show no geometrical distortion,
• must have clean and sharp pillar-box edges (i.e. any video or film edge artefacts may need to be
blanked.)
• must be black outside the active picture, unless otherwise specified by the broadcaster.
Note however, that consumer TV sets operating in Auto Zoom / Auto mode may enlarge the picture to fill the
screen horizontally. The resulting unpredictable zooming can be annoying for the viewer and undermine the artistic intent.

Understood.
Yes archive shows do present problems if not TX correctly.
I noticed last week that Ch4 tranmitted an Ep of Fraser 16:9 when it was quite clearly distorted. All the others have been pillarboxed so it looks like this one slipped through.

So the BBC's recommendation is to crop to 16:9 wherever possible, spoiling the picture for everyone to avoid annoying a select few? Great logic.

Exactly - that's a bad recommendation, people who have their TV on a zoom mode where it would crop or distort the picture on purpose shouldn't have priority of people who want OAR and the original framing.

Also, if people have the picture on some auto-zoom mode which auto zooms when it sees black bars and it was the frequency of the zooming which was a problem, surely they could put additional options in set top boxes/TVs so eg. you could tell it for programs/films with lots of aspect ratio switching to not keep zooming in those cases or to zoom so it doesn't quite fill the screen (leaves some black bars/pillar box bars). Also, maybe having something other than plain black pillarbox bars within a program (eg. using grey or other types of bars instead) would stop the auto-zooming for programmes with frequent aspect ratio switching.

Sorry, but you can't as you have about a third more screen to fill than the original.