1080i and 1080p difference

[MetalHead84]

I have make another post (HERE) about a problem I have with my ps3, and a "glitch" when I play some game in 1080p.

My question is, am I suppose to see a really big difference when I play game or watch blu-ray in 1080i instead of 1080p ? I currently have a Sony Bravia 32'' and I have heard that smaller than 46 or 52'' who don't really see a difference.
Cause if there's not really any difference, or hard to see difference (I can still watch VHS and find the picture ok: )I will stay in 1080i instead of always changing the resolution depending of what I'm doing

[BIslander]

Originally Posted by MetalHead84

My question is, am I suppose to see a really big difference when I play game or watch blu-ray in 1080i instead of 1080p ? I currently have a Sony Bravia 32'' and I have heard that smaller than 46 or 52'' who don't really see a difference.
Cause if there's not really any difference, or hard to see difference (I can still watch VHS and find the picture ok: )I will stay in 1080i instead of always changing the resolution depending of what I'm doing

When the source is 1080p, there shouldn't be any difference.

[jerwin]

Sometimes there's a little flicker on credit rolls, though that depends on your TV.

[PCFan]

Well even though you asked about 1080p vs 1080i, I did compare 720p to 1080i on my blu-ray player and I prefer 720p. I have a 1366x768 res tv that accepts a 1080i signal. 720p looks more solid that 1080i to me. Also I would get combing artifacts watching Perfect Strangers DVDs at 1080i but none at 720p. So I leave my blu-ray player at 720p to avoid the combing and also DVDs look slightly better to me at 720p than 1080i on my TV but blu-rays look slightly better to me at 1080i than 720p on my TV. So I believe you would get a more solid picture at 1080p than 1080i and can avoid potential combing artifacts with a progressive signal to your TV unless the video was really encoded badly. Also I have a 1080p monitor and tested the PS3 on it when I had one and 1080i would cause flicker in the dashboard but with 1080p the PS3 dashboard looked solid.

[BIslander]

With a 768 display, using a 720p output means you are discarding 48 lines of actual resolution that you would get with a 1080i output.

[dobyblue]

1080i is twice the resolution of 720p, but your TV has to deinterlace properly otherwise you might be dropping to 540 lines of resolution doubled if your TV throws away all the odd or even lines.

1080i:

1
~2
3
~4
5
~6

First you get the odd lines, then the even lines.

Deinterlaced correctly:

1
2
3
4
5
6

Deinterlaced incorrectly:

1
1
3
3
5
5

Pretty crude, but should give you the right idea. You'd really need a test disc to ascertain your TV's processing capabilities. If it fails deinterlacing then 720p or 1080p will be the better choice. If it passes deinterlacing then 1080i should look better than 720p and the same as 1080p.

[SpaceDog]

Originally Posted by dobyblue

Pretty crude, but should give you the right idea. You'd really need a test disc to ascertain your TV's processing capabilities. If it fails deinterlacing then 720p or 1080p will be the better choice. If it passes deinterlacing then 1080i should look better than 720p and the same as 1080p.

Close, but not exactly. 1080i upconverted to 1080p is still an interpolation of data that is not consistantly present. Each frame only has 1/2 the data, so the interpolation is based on the frame that preceded it and the frame that will follow. With 1080p, all lines are activated at all time with current frame data.

[dobyblue]

Originally Posted by SpaceDog

Close, but not exactly. 1080i upconverted to 1080p is still an interpolation of data that is not consistantly present. Each frame only has 1/2 the data, so the interpolation is based on the frame that preceded it and the frame that will follow. With 1080p, all lines are activated at all time with current frame data.

That is only if you're dealing with an interlaced source and then you're talking about fields, not frames. One frame is still 1920x1080, it's the time-axis that's off between the two. 1080i sources were designed for 1080i CRT's that would actually display the signal the way it's shot, no interpolation.

Nearly 100% of 1080i content these days is shot on film or progressively (HD Digital) and converted to 1080i before broadcast, hence there is no interpolation of data when properly reconstructed.

1080p24 converts to 1080i60 and back to 1080p24 again with no loss, no upconversion and no interpolation.

[crackinhedz]

fields not frames.


1080i vs 1080p - Similarities and Differences Between 1080i and 1080p

In 1080i each frame of video is sent or displayed in alternative fields. The fields in 1080i are composed of 540 rows of pixels or lines of pixels running from the top to the bottom of the screen, with the odd fields displayed first and the even fields displayed second. Together, both fields create a full frame, made up of all 1,080 pixel rows or lines, every 30th of a second.

In 1080p, each frame of video is sent or displayed progressively. This means that both the odd and even fields (all 1,080 pixel rows or pixel lines) that make up the full frame are displayed together.

[crackinhedz]

the human eye/brain does a pretty good job of deinterlacing at 60Hz...

[crackinhedz]

But if the TV only has 768p pixel resolution, then the 1080 debate is moot.

[jibucha]

Hello

Not often that the technical information is properly related; highly appreciated!

Thank You

Originally Posted by dobyblue

That is only if you're dealing with an interlaced source and then you're talking about fields, not frames. One frame is still 1920x1080, it's the time-axis that's off between the two. 1080i sources were designed for 1080i CRT's that would actually display the signal the way it's shot, no interpolation.

Nearly 100% of 1080i content these days is shot on film or progressively (HD Digital) and converted to 1080i before broadcast, hence there is no interpolation of data when properly reconstructed.

1080p24 converts to 1080i60 and back to 1080p24 again with no loss, no upconversion and no interpolation.

[R23]

I've got a question,

If some media such as Blu Ray films are being recorded in 1080i/50 or 1080i/60 then is it true that these two formats have similar compatibility issues to the old PAL & NTSC problems.

I ask because when the world went Blu Ray people thought this Hz stuff was a thing of the past. US players cannot play 1080i/50 (Blu Ray 'PAL') films even if they are region free. However EU players can play both formats and every player in the world can play 1080p encoded content.

Yet most films dont say what they are encoded in so its really hit and miss!

Am I right with all this info? because it still quite confusing to me! Could someone explain it better?

[Rob J in WNY]

Originally Posted by dobyblue

1080i is twice the resolution of 720p, but your TV has to deinterlace properly otherwise you might be dropping to 540 lines of resolution doubled if your TV throws away all the odd or even lines.

1080i:

1
~2
3
~4
5
~6

First you get the odd lines, then the even lines.

Deinterlaced correctly:

1
2
3
4
5
6

Deinterlaced incorrectly:

1
1
3
3
5
5

Pretty crude, but should give you the right idea. You'd really need a test disc to ascertain your TV's processing capabilities. If it fails deinterlacing then 720p or 1080p will be the better choice. If it passes deinterlacing then 1080i should look better than 720p and the same as 1080p.

Spot on, and fantastic illustration. A TVs ability to deinterlace is the key to maximum picture quality from any interlaced video source. Properly deinterlaced 1080i should resolve as well as 1080p source material (assuming video capture/encoding quality is identical).