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Discussion Starter · #1 ·

So my neighbour was setting up his new TV and a PS3. When I was checking if it was a full-HD TV or not (turned out it wasn't), I noticed a difference between 1080i and 720p in terms of picture clarity. When I set the PS3 to 1080i it looked like it was displaying a higher resolution than when I set it to 720p. So my question is: What resolution was the TV displaying when I set the PS3 to 1080i? Was it displaying 1366x768 (I've read that this is a common resolution for HD ready TVs) or 1920x1080? Is deinterlacing 1080i and displaying at 1920x1080 even possible on a non full-HD TV?
 

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What make model TV?

Either way... it's the neighbor's TV, use whatever resolution looks best to him/her.
 

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Discussion Starter · #3 ·

I'm not sure of the model, but it's a Panasonic. He will probably use 1080i for movies and 720p for gaming. But I'm still curious though... can a non-1080p TV display deinterlaced 1080i in 1920x1080?
 

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A TV/display can/will only display at it's native resolution. You can feed it whatever you like. It still poops the same.



Provide the model number and perhaps someone can provide you with the native resolution of that Panasonic TV.
 
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Discussion Starter · #5 ·

Thank you for explaining! It was actually a LG, and the resolution is 1366x768. It totally makes sense that it can only display at native resolution though, as the screen is made up by pixels in that resolution (I don't even know what I was thinking).. So it stretches 720p to native res and deinterlaces and shrinks 1080i to native res then.. 
 

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NO it doesn't shrink or stretch.

It upconverts/deinterlaces 480i or upconverts 480p to native resolution.

It converts 720p to it's native resolution.

It downconverts and deinterlaces 1080i to native resolution.


As discussed over the years, set and/or change the source device's output resolution to compare the TV to the PS3. You need to decide which does a better job of converting.
 

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Be advised that many older (pre-120-Hz) LCD's and DLP's with either 720p or 768p native resolution didn't do a proper "deinterlacing" of the 1080i input (see Sound and Vision tests cited below). Many took the short cut of simply using every other frame (NO deinterlacing), resulting in 540p that could then be displayed as 720p by inserting duplicate pixels throughout the frame. For these sets, it would be best to let the SOURCE do the deinterlacing process to output 720p.


See: http://www.digitalhome.ca/forum/showthread.php?t=44096

Missing link found here: http://www.soundandvision.com/content/are-you-getting-all-hdtv-resolution-you-expected

And follow-on articles: http://www.soundandvision.com/writer/12697
 

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Quote:
Originally Posted by holl_ands  /t/1525709/quick-question-about-720p-and-1080i-and-ps3#post_24568780


Be advised that many older (pre-120-Hz) LCD's and DLP's with either 720p or 768p native resolution didn't do a proper "deinterlacing" of the 1080i input ...
How about plasma?
 

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I found on a 1366 x 768 set I have the 1080i option looked best from a satellite receiver. There was more difference than I expected. Neither was perfect so I chose the best compromise.


While it's true that the resolution cannot exceed the pixel count of the display, the sharpness can vary. Scaling from one resolution to another involves low pass filters (taking out the higher frequencies) and pixel interpolation (averaging based on source to target position). The implementation of the filter can have a big effect on how sharp the picture looks. In a perfect world, a low pass filter would neither increase or decrease the amplitude right up to its cutoff frequency (flat response), and then allow no information right after that frequency. In the real world that change in behavior around the cut-off frequency is more gradual and forms a slope. Because of that, compromises are made in the filter. These include the frequencies where slope starts and ends for steepness (filter complexity) and position (high frequency response vs aliasing), and how flat the response is. A filter can be designed to emphasize higher frequencies before the cut-off. This would seem to make a sharper picture, but would have the consequence of creating outlines on some edges.


Also, as mentioned, the de-interlacing method can also have an effect. An adaptive de-interlacer tries to preserve full frame resolution mode on the static areas of the image. On areas with motion, they will typically fall back to field resolution mode and use interpolation to create every other line (pixel row). The threshold of how much motion causes a switch between frame and field modes is a compromise between keeping resolution and preventing interlace artifacts such as jagged edges. Many TVs can detect whether the source material was shot in a progressive format, such as 24P, and use an altogether different approach called reverse pulldown (aka reverse telecine) to re-create the progressive image.


How much extra detail there is in full frame resolution over frame depends on the source material. Material shot in 24P, which usually includes film transfers, can have better vertical sharpness (mainly on static or low motion areas as the normally longer shutter time results in greater motion blur) than from sources which used live type TV cameras operating in interlace mode. The reason is cameras in interlace mode update the motion at the field rate, which is twice the frame rate, and allows it to look smoother. This is why 1080i at 30 fps has the same motion smoothness as 720p at 60 fps. The interlace trade-off is the the camera's sensors deliberately makes each imager element effectively twice as tall to minimize jagged edges on motion. Early CCD cameras did not do this and were criticized for their coarse look. Because the pixels are taller, the amplitude of the higher vertical frequencies is reduced which decreases visibility. Much of that finer information could be lost in compression. When CRTs were more common, sometimes 24P material was processed when converted to 1080i to reduce detail above field resolution to minimize twitter flicker on interlaced displays.


One other issue is that 720p has 1280 active pixels horizontally while 1080i has 1920. That reduction of 86 pixels of the source compared to the display might make a minor difference, but the aforementioned filtering may be a bigger factor.
 

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Short Version

Yeah, try both resolutions and use what looks best.
 

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Shortest Version

Use what's gooder.
 

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Another version

Use the bestest, not the one that's worstest.
 

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Quote:
Originally Posted by Ratman  /t/1525709/quick-question-about-720p-and-1080i-and-ps3#post_24569078


How about plasma?
See 2006 Test Results cited above.....some Plasmas had deinterlacing problems...and some didn't....perhaps some manufacturers were using the SAME circuitry in LCD, DLP and Plasma models....


Of course, when 120 Hz (and 240 Hz) LCD's & DLP's came along (and 600 Hz Plasma's) with "Adaptive Motion" (et.al.) algorithms that calculated "in-between" display frames, deinterlacing took a giant leap forward...including being able to reproduce scrolling test text with MUCH better readability. But, as always, YMMV.....
 

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Post 2 and 10 apply.
 

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Post 9 has proven more effective than Sleep EZE.
 

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Quote:
Originally Posted by TVOD  /t/1525709/quick-question-about-720p-and-1080i-and-ps3#post_24580299


Post 9 has proven more effective than Sleep EZE.

yea but I learned quite a bit ofc l will probably forget half of it .. interesting none the less
 
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