M Sparks
The HDTV broadcasting standard as chosen by ABC, ESPN, and Fox is 1280x720p60, not p30. Vs that standard, 1280x1080i30, or 1280x540i60 if you prefer, does contain less information and consumes less bandwidth.
Now, given that there are also 720p24 and 720p30 HDTV standards, which may be used at times by ABC. etc., there are 720p standards wherein 1280i (shorthand) would have more data.
My reluctance to accept the 1280 portion of 1280i, as opposed to the 1280 portion of 720p, is that they are not equivalent. Let's say a sporting event is captured by a 1920x1080i camera, then downconverted to 1280x1080i. 1/3rd of the original information is stripped away. Then when your receiver or TV upconverts the 1280 image, it will interprolate the missing lines via some algorithm, like averaging the 2nd and 3rd lines to create a new line, which is then inserted between the 2nd and 3rd "original" lines.
If this image is then sent to a 1280x720p TV, then the final image will be 2/3rds of the original horizontal information, along with a vertical where a 540i60 frame is likely upconverted to 720p60.
However the same sporting event captured on a 1280x720p camera will capture all of the information, albeit on larger pixels (and with lower resolution) than the 1920 camera. The 1280 lines represent the full, unaltered image When displayed on a 1280x720p HDTV, the final image should be a near perfect representation of the original image.
Thus I am reluctant to accept the argument that since one established HD standard has a horizontal resolution of 1280 lines, that a manipulated/altered version of another standard that also produces 1280 lines is an equivalent standard. I admit that it is relatively easy to market/sell the two as equivalent.
Likewise if one is watching a soccer game on ESPN in 1280x720p60 and flipping to Rave to watch another soccer game in 1280x1080i30, then the Rave image has less information than ESPN.
Now, all of that said, I understand your point about the standards not being codified in law and that the universal references to DTV standards are simply 1080i and 720p, with no mention of horizontal resolutions. This worries me because they could drop down to 960x1080i and still claim to be HD.