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480i vs 480p?


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9 replies to this topic

#1 of 10 OFFLINE   Tom Martin

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Posted December 13 2003 - 12:13 AM

why is it that some movies look better in 480i than in 480p? for instance, i was watching Curse of Frankenstein(1957) on my Samsung hdtv and it looked clearer and crisper in 480i than in 480p.

#2 of 10 OFFLINE   Jack Briggs

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Posted December 13 2003 - 03:45 AM

Are you using your player's internal doubler/scaler or the TV's? As a rule, though it's not always the case, a player's progressive-scan circuitry does a better job than a display's equivalent circuitry.

#3 of 10 OFFLINE   Tom Martin

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Posted December 13 2003 - 01:07 PM

i'm not sure what you mean. i'm turning the progressive scan on and off through the dvd player. if my tv does it also, i have no idea how to do it. it's a samsung 55" hdtv

#4 of 10 OFFLINE   Allan Jayne

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Posted December 13 2003 - 01:48 PM

All movies or just some movies look clearer in 480i?

When you have the DVD player output 480p, a higher quality cable is needed compared with 480i.

If the cable you are using has red, white, and yellow plugs instead of red, green, and blue plugs, the quality will be uncertain.

If you use "HDTV grade" cables you should not have problesm with 480p.

Because it is hard to predict what cables are adequate, experts often suggest a safety margin. All cables used for component, composite, or S-video need to be 75 ohm. For 480p the bandwidth needs to be 15 megahertz when the cable goes directly from DVD player to TV. If you have an A/V receiver in the video signal path (requiring two sets of cables) I suggest doubling that to give a safety margin, to 30 MHz. (480i needs half the bandwidth of 480p)

When you turn on progressive scan in your DVD player, the TV's progressive scan conversion (de-interlacing) becomes inactive. When you turn off progressive in your DVD player, the TV's progressive scan conversion comes on. Both ways (most TV sets) the picture is being drawn on the screen the same way, either as progressive scan, or as HDTV without so much detail in each scan line. Sometimes you must use different jacks behind the TV for 480i versus 480p.

Video hints:
http://members.aol.c...ynejr/video.htm
.

#5 of 10 OFFLINE   Tom Martin

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Posted December 17 2003 - 01:53 PM

i'm using a monster component cable. and only some movies look sharper in 480i than in 480p.

#6 of 10 OFFLINE   Donnie Eldridge

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Posted December 18 2003 - 09:49 AM

What player are you using?
Master Poe: Close your eyes. What do you hear?
Caine: I hear the water. I hear the birds.
Master Poe: Do you hear your own heart beat.
Caine: No.
Master Poe: Do you hear the grasshopper, which is at your feet.Caine: Old man, how is it that you hear these things?Master Poe: Young man, how is it...

#7 of 10 OFFLINE   JohnnyG

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Posted December 18 2003 - 10:12 AM

I sumbit 2 theories:

Is the movie in question black and white? If it is, then a flat luma curve will be more obvious than with material in colour. Your DVD player might easily pass the 15.75kHz 480i singal, but 'struggles' somewhat with a 31.5kHz 480p signal, causing a loss in horizontal detail.

It's also possible that this particular movie is not flagged properly for 2:3 pulldown and your DVD player is locking into 'video' mode and applying line doubling instead of frame resconstruction, while your TV's processing might be more intelligent in this regard.

{edit: just checked imdb.com and answered the first question myself. It's in colour, but my 'theory' is still valid nonetheless}

#8 of 10 OFFLINE   Bob McElfresh

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Posted December 18 2003 - 10:29 AM

Is that the Samsung DLP television with the Farjuda chipset?

It has been noticed that the Samsung HDTV's with the Farjuda chip actually look better with a Interlace feed rather than a progressive feed. The Farjuda chip is the engine that de-interlaces and cleans things up.

This is why there is a lot of buzz over in the Audio/Video sources fourm about DVD players with the same chip. People have noticed the better picture.

#9 of 10 OFFLINE   Jeremy Scott

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Posted December 20 2003 - 10:57 AM

how can you tell that progressive scan looks better? I have the panasonic f-85 dvd changer/player and a jvc 36" HDTV

what type of differences are there?

#10 of 10 OFFLINE   John S

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Posted December 23 2003 - 03:59 AM

Jeremey:

If you look closely, especialy on a very large picture, the larger the more aparent it becomes. You will see NTSC grainy-ness on 480i. 480p goes along way to getting rid of this completely.

Be mindfull, that many sets now offer two levels of Progressive Scan / line doubbling. One presents it Interlaced and one presents it Progressive. They are very hard to tell apart indeed.