Thought some of you might be interested in this.
I took a screen shot of the same frame of a video, from a rage-encoded video before 2012 (I think it was from 2009) vs. one taken after they changed their digital encoding method (or so I think), to show someone the difference betweeen the two. You may need to right click View Image if this doesn't display correctly (or go to the image hosting page directly here - http://i.imgur.com/0a3h6xg.jpg
edit - it won't display full-size for me in this thread, so you'll need to visit the link above to view it properly.
It's a black and white video, so maybe not the best example to use.
On the left is from the 2009 airing of 'Your Woman', and on the right is a more-recent (I think 2015) airing. Rage, for some reason, have presumably re-digitised the video from the source tape between then. They don't routinely do this - normally they will air a video from their library that has already been digitised, but I've noticed that they have re-encoded some videos that have already aired in the digital era. Sometimes this is done because the fade-out (to black) wasn't captured completely on the first digital encoding.
Anyway, aside from the obvious difference in the font size, I think the newer encoding method results in a picture that is less sharp/more fuzzy (compare the detail evident on the woman's coat, and the pointed edges of the picket fence), more 'white'/transparent (compare the colour of the blinds in the window on the right), and with fewer distinct colours (compare the colour of the bricks).
What do you think?
I'm not sure this is a result of re-encoding the videos, but is a transmission issue. rage is live to air, meaning they line all the clip tapes up in carts (I believe they still use tapes not hard disks... yet) and play them out like advertisements one after the other. They use two playback decks which alternate, clip 1 plays from cart 1 while clip 2 is loaded and cued in cart 2 to play as soon as clip 1 finishes, then clip 3 is loaded and cued in cart 1 ready for when clip 2 finishes etc.
I think there is an issue with the second transmission chain, because sometimes in the past I reckon every second clip aired has the issue you describe - it looks a bit fuzzy and the titles have horizontal banding in it. It's almost as if they are being magnified some small percentage like 102% and you get badly aliased images as a result. See how in your second image the super with the artist and song title is bigger than the one in the first image.
I don't have hard evidence for this, just theorising from what I think I've seen.
^ I don't actually think it's a transmission issue, because there are several clips they have encoded the 'old way' that also have the 'new encoding', and the newer versions often have an extra second or two fade out (to black) at the end, where the older format version cuts out earlier. An example of this is Madonna's 'Like a Prayer', although they tend to alternate between which encoding they air. For it to be a transmission issue, surely all videos would be affected, and not just alternating ones.
Silverchair's 'Freak' is a video I have a capture of the rage encoding done the pre-2012 way, and the current way. The earlier version runs for 3:45, and the newer version runs for 3:50 and has a few extra seconds at the start plus a longer fade-out at the end.
I don't think rage dig out the tapes to air videos anymore, like you described, as videos that have faults with them (e.g. the speed warping in Sheena Easton's 'Sugar Walls') have the errors at the same place each time they air. You don't see the occasional transmission faults unique to that particular airing of the video, as used to occur back in the 80s/90s.
I agree with your enlarging hypothesis though. It looks to me almost as if they have digitised the videos in a 'windowboxed' 4:3 (postage stamp)/letterboxed 4:3 aspect ratio, and then enlarge them (the videos that have been encoded the 2012 onwards way) to full 4:3/16:9 when they air. The images themselves aren't actually enlarged on the screen, but they've been created by a smaller/lower resolution image. As a result, the image looks blurred, and the superscript letters look fuzzy.
Whatever the cause may be, I do wonder why rage/ABC have decided to use this inferior method. Perhaps it is quicker/cheaper to do, or maybe there is some copyright issue where they're not allowed to air the clips in pristine condition and have to degrade them slightly