SD Vs HD, depends on your perspective and what you're doing with the video. SD is fine if you are making DVDs, because the SD stream is MPEG, there will be little, if any re-encoding if you are going from PVR (like a Topfield recorder) to PC to DVD. However, ABC has greatly reduced the SD bitrate over the years, I have digital recordings in SD from ten years ago that look great but these days, they just look :hankey:, as more people have HD sets, the quality of the SD feed has deteriorated.
Original broadcasts of Countdown might not have originally shot in HD, but ABCHD is broadcast in MPEG4, a newer format. It should look better, you may even find part of the transferring process at the ABC is upscaling the content digitally before it's aired on Rage.
Another argument supporting HD is if you are uploading to YouTube, YouTube gives a higher bitrate allowance to HD videos, so again, they should look much better on YouTube than uploading an SD quality MPEG2 video.
One area where SD wins against HD is DVD creation. If you are making a DVD from the HD video, you're going from about a 50 frames per second to 25 fps, so when you look at movement in your end product, it will look fuzzy, not to mention with a HD video you're scaling down the video. So SD wins if you're making DVDs.
ABC SD & HD are both 50i so it makes no difference to that aspect of DVD creation
If that's true, then you're going to lose quality creating DVDs from SD broadcasts, I haven't recorded SD for a long time, I just looked at an SD recording from 2014 and that was 25f/s.
50i is 25 full frames/sec, interlaced.
It's what analogue tv was, and it's what a lot of digital tv still is.