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Thread ID: 84986	2007-11-26 01:30:00	1080i and 1080p and HD-DVD and Blu-Ray - I'll going to kill someone soon	Pourhommenz (104)	PC World Chat

Post ID	Timestamp	Content	User
615168	2007-11-28 06:39:00	1080i v . 1080p The most frequently asked questions I've received this year have been about the difference between 1080i and 1080p . Many people felt—or others erroneously told them—that their brand-new 1080p TVs were actually 1080i, as that was the highest resolution they could accept on any input . I did a blog post on this topic and received excellent questions, which I followed up on . It is an important enough question—and one that creates a significant amount of confusion—that I felt I should address it here, as well . There Is No Difference Between 1080p and 1080i My bold-printed, big-lettered breaker above is a little sensationalistic, but, as far as movies are concerned, this is basically true . Here's why . Movies (and most TV shows) are shot at 24 frames per second (either on film or on 24-frame-per-second HD cameras) . Every TV sold in the United States has a refresh rate of 60 hertz . This means that the screen refreshes 60 times per second . In order to display 24-frame-per-second content on a display that essentially shows 60 frames per second, you need to make up or create new frames . This is accomplished by a method called 3:2 pulldown (or, more accurately, 2:3 pulldown) . It doubles the first frame of film, triples the second frame, doubles the third frame, and so on, creating a 2-3-2-3-2-3 sequence . (Check out Figure 1 for a more colorful depiction . ) So, the new frames don't have new information; they are just duplicates of the original film frames . This process converts 24-frame-per-second film to be displayed on a 60-Hz display . It's Deinterlacing, Not Scaling HD DVD and Blu-ray content is 1080p/24 . If your player outputs a 60-Hz signal (that is, one that your TV can display), the player is adding (creating) the 3:2 sequence . So, whether you output 1080i or 1080p, it is still inherently the same information . The only difference is in whether the player interlaces it and your TV deinterlaces it, or if the player just sends out the 1080p signal directly . If the TV correctly deinterlaces 1080i, then there should be no visible difference between deinterlaced 1080i and direct 1080p (even with that extra step) . There is no new information—nor is there more resolution, as some people think . This is because, as you can see in Figure 1, there is no new information with the progressive signal . It's all based on the same original 24 frames per second . In the case of Samsung's BD-P1000 Blu-ray player, the player interlaces the image and then deinterlaces it to create 1080p . So, you get that step regardless . Two caveats: Other Blu-ray players can output 1080p/24 . If your TV can accept 1080p/24, then it is adding the 3:2 sequence, unless it is one of the very few TVs that can change its refresh rate . Pioneer plasmas can change their refresh rate to 72 Hz, and they do a simple 3:3 pulldown (showing each film frame three times) . This looks slightly less jerky . If you're a gamer, then there is a difference, as 1080p/60 from a computer can be 60 different frames per second (instead of 24 different frames per second doubled and tripled, as with movie content) . It is unlikely that native 1080p/60 content will ever be broadcast or distributed in wide numbers . The reasons for this are too numerous to get into here, but I list them in my follow-up blog . So Don't Worry (Or Only Worry a Little) Without question, it would be better if all TVs accepted a 1080p input . (Read that again before you start sending your e-mails . ) What I hope this article points out is that, if you have a 1080p TV that only accepts 1080i, you're not missing any resolution from the Blu-ray or HD DVD source . If a TV doesn't correctly deinterlace 1080i, on the other hand . . . well, that's a different article (which is conveniently located on page 64) . Taken from and read more at . hometheatermag . com/gearworks/1106gear/" target="_blank">www . hometheatermag . com	radium (8645)
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