One of my biggest complaints about HD broadcast TV is that so-called HD channels program a serious amount of SD content. So From channel to channel and within a single channel, the content quality fluctuates wildly and goes from pillarbox to letterbox within pillarbox.

The thing I have noticed most frequently is that the TV reports a 1080i/60 signal and I get a 16:9 picture with pillarbox framing a 4:3 image, but the picture quality is considerably lower than 1080i. It looks like 480i SD that is being upscaled to 1080i.

Is this in fact the case with all 4:3 broadcasts? Some commercials in 4:3 look better than 480i, but still don't look HD. In particular I was watching an episode of the syndicated re-mastered Star Trek series which I know is supposed to be HD. The broadcaster appears to be pillarboxing the 4:3 content in a 16:9 1080i broadcast, but the quality of the image appears no better than upscaled SD. By comparison, some 4:3 commercials seem better quality and some seem worse and unlike other broadcasts all the commercials were pillarboxed, no 16:9 content at all, though that could just be a co-incidence.

Lots of info, but I was just curious if anyone knows the answer to pillarboxed content quality, to help explain some of these observations.

To answer quickly: The Star Trek series was recently remastered in HD, but probably was down-resolved to SD for syndicated TV distribution, to save money. Some 4x3 SD stuff looks better than others, but for the most part, anything in pillarboxed 4x3 is technically not HD. There are a few exceptions, like with CBS's national broadcast of Rudolph the Red-Nosed Reindeer.

Also - not all 480i 4:3 SD content is the same quality.

There is a MASSIVE difference between SD 4:3 NTSC analogue composite and SD 4:3 digital component content. They may both have 480 (give or take a few) lines - but the quality difference is huge.

If a signal is originated SD digital component and stays that way prior to upconversion, then it should look a good deal better than a signal that has been unfortunate enough to pass through an analogue NTSC path somewhere between origination and the upconverter...

There are also a relatively small number of 4:3 film originations which have been re-mastered in HD and retained the 4:3 aspect ratio (some have been re-framed for 16:9 AIUI)

The Star Trek series was recently remastered in HD, but probably was down-resolved to SD for syndicated TV distribution, to save money.

Yes, Star Trek TOS is distributed for syndication as SD only. The actual broadcast picture quality varies widely from one station to another, because it's up to the station to upconvert it to HD for broadcast if necessary, and some stations do a better job than others. I can watch the series on two different stations, and the picture is noticeably different between them.

To see this show in true HD, you need to buy the HD DVD transfer of Season 1 which was released a year and a half ago, or the Blu-ray transfer which is coming out on Tuesday. I've read that some episodes have been available in HD as Xbox downloads, but I don't know if that's still true.

The only "answers" to poor quality SD-to-HD upconverts are (a) the station buys new upconverting equipment, or (b) the show starts being recorded in HD to begin with, and the station has the ability to pass it on in HD. Some popular syndicated shows are now distributed in HD (e.g. Oprah, Ellen, Jeopardy, Wheel of Fortune) but many stations still show them in SD because they don't have equipment that can record the shows in HD for later playback.

Yes and it's not just Star Trek, but Prime Time network shows like FOX' "Family Guy". And FOX is only 720p and Family Guy is animated, but still looks horrible – some of the 16:9 commercials look much better than the program itself! It's amazing that a show that is being produced now would be transferred in anything less than 720p/1080i (irrespective of ratio).