720p Vs 1080i Hdtv
Is 720p vs 1080i worth being involved about? Yes and no. If you're a buyer seeing for a new Tv, you can happily ignore the 720p vs 1080i turn over because every Tv which is described as Hdtv or Hdtv Ready is required to support both formats.
Note: You should be aware though that lots of Tvs which support 1080i have fewer than 1080 lines and so scale the 1080 signal down. That's not a huge issue as even scaled down 1080i is far ahead of a quarterly Ntsc signal. It is worth bearing in mind that more high-priced Hdtvs tend to have great scalers than economy ones, and this may be an issue.
However, for broadcasters it's a live issue. Should they broadcast 1080 lines of interlaced video or 720 lines of progressive scan? They could just broadcast two signals, one in each format, but that would use up a huge chunk of bandwidth and be hugely high-priced for very diminutive gain.
To reply the question, it's important to understand the discrepancy between 720p vs 1080i. A 720p signal is made up of 720 horizontal lines. Each frame is displayed in its entirety on-screen for 1/30th of a second. This is know as progressive scan (hence the 'p')The quality is like watching 30 photographic images a second on Tv. A 1080i signal comprises 1080 horizontal lines but all the lines are not displayed on-screen simultaneously. Instead, they are interlaced (hence the 'i'), ie every other lines is displayed for 1/60th of a second and then the alternate lines are displayed for 1/60th of a second. So, the frame rate is still 30 frames per second, but each frame is split into two fields, which your brain then puts together subconsciously.
Most of the time interlacing works fine, but for fast keen images, such as sports like baseball and hockey it can cause problems which manifest themselves as a 'stepping' consequent on-screen. Progressive scan signals don't have this problem and so are great suited to sports.
Espn puts it like this: 'Progressive scan technology produces great images for the fast keen orientation of sports television. Plainly put, with 104 mph fastballs in baseball and 120 mph shots on goal in hockey, the line-by-line basis of progressive scan technology great captures the possible fast action of sports. For Espn, progressive scan technology makes exquisite sense.'
Bottom line? For us, as consumers 720p vs 1080i is not a turn over worth worrying about, so you can relax and focus on all the other criteria on your list when you buy your next Hdtv.
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