HDTV Basics

HDTV in theory brings TV screens ability to make it like a computer screen. Also it breaks direct linkage of analogue clock system starting from content provider and ending to tv screen. With HDTV you can replay any refresh rate you would ever want, so in theory it would be possible to broadcast movie with 1080p24 and commercials 576i. Set-top-box just changes resolution / timing on its output based on received transport stream over DVB.

Difference in HDTV formats

Format	Field/Frame resolution	Field rate	Frame rate	Bandwidth	Standard
720p24	1280x720	-	24 / 23.976	-	-
1080p24	1920x1080	-	24 / 23.976	-	-
1080i48	1920x540	48	24	-	-
720p50	1280x720	-	50	-	SMPTE 296M
1080i50	1920x540	50	25	-	SMPTE 274
1080p50	1920x1080	-	50	-	SMPTE 274
720p60	1280x720	-	60 / 59.94	74.25MHz	-
1080i60	1920x540	60 / 59.94	30 / 29.97	74.25MHz	-
1080p60	1920x1080	-	60 / 59.94	148.50MHz	-

To view relative field/frame sizes, follow this link.

To view how you perceive your image on your HD Ready TV with panel resolution 1366x768, follow this link.

Why HDTV?

You need to see it yourselves to be a believer. First 2 example images are from Olympic Games Hockey Finals Finland - Sweden. I used VLC player snapshot feature from moving pictures so deinterlacer based motion blur is present. HDTV is not to remove motion blur on 1080i because interleaved material captures half frame at the time, and deinterlacers combine frames differently. Here it is blend option which isn't the best one. Also JPEG compression artefacts are there.

I edited image for better color balance, then I needed to manually generate SDTV reference frame by cropping to 4:3 and dropping resolution to 720x576i. Scoreboard is used in guiding the crop, this is what you see in SDTV.

I do not argue about whether 1080i or 720p HDTV formats are better for sports. Or why Europe don't use 60Hz HDTV formats for better motion because new television sets removed synchronized clock artifical linkage between TV systems field/framerate and electric current. HDTV sets are MONITORS and they support multiple frame rates. Today EU HDTV is worse than US HDTV. Same frame resolution but lower framerate. But on the air more bandwidth can be used per frame as in second 10 frames less to send.

To view examples please make browser full screen.

Simulated full width of your screen images, like TV shows it.

First 2 images simulate what would you see on same TV set, your monitor. Note that you see scaling quality of your browser, which typically is bad. Just look for frame composition and cropping. Your SDTV game is filmed with HDTV equiptment and cropped into 4:3. Image should have almost the same height.

Ain't it nice to loose this much resolution, and to limit game happening into 4:3 box? Naturally the puck is small in HDTV and moves fast so no improvement on that.

Full frame resolution images

This is what kind of frames were assembled by VLC from 1080i stream with blend deinterlacing, still we are not talking about picture quality but lost information on cropping and lower resolution. This is fluid motion where puck is flying towards Sweden goal.

Full frame high resolution

This is 1080p stream shown on a HDTV set, image with full resolution. Typical HDTV image gimmick is used here, as original stream is 1440x1080p, so trick is by HDTV set to strect image to 1920 panel.

Image is from WMVHD democlip Discoverers (Imax).

Improvement

A good improvement is World Cup 2006, which is filmed in HD, and downscaled to 16:9 SDTV (some might say EDTV). Frame aspect ratio is more convenient for sports, and you don't miss so much happenings on the field. Just if resolution could be boosted.