HD DVD Advantages?

[MatrixS2000]

Bringing this back to life as I found this example of 1080i vs 1080p:

1080i:


1080p:



Anyone still think there is no difference?

[sparksj]

Okay, first of all, since the difference is how the picture gets transmitted to the screen (interlaced vs. Progressive) I don't see how a still picture can show the difference in the two.

Obviuosly the lettering looks clearer in the 1080P pic. above. What I don't get is... isn't the resolution the same (1080 for both)? So, in theory, shouldn't they look the same in a still shot? I would think the only difference would be the fluidness of the movement on the screen. Am I missing somehting here?

Could it be that the picture was taken at a shutter speed of 1/60th of a second, in shich case it likely only caught 1 of the 2 interlaced images. which could be the difference. Although this is not what the human eye would see.

I'm not being a HD DVD fanboy here, but I truly though that since both are 1080 resolution, the only difference should be seen in the movement (fluidity) of the film and not the resoultion at which the picture is seen???

Are you sure that the first shot isn't from a 720P TV?

Does anyone share the same thought as me, or am I just way off here?

[Blaumann]

erm, the first picture is from the HDTV 1080i broadcast on HDNet if i´m not totally mistaken

[Tulsa]

I have always understood interlaced to be 540 lines drawn every other line the first 30th of a second and the second set of lines drawn the other 30th of a second. That's fine as long as the lines are different but (and I could be wrong here) I understand these are the same lines originally drawn the first go round. Which would/should produce those jaggies.

[sparksj]

I played around with the pics in Photoshop. One of them was named 1080i while the other was named BR, which makes me wonder if this was actually a comparison between a 1080i cable broadcast picture vs. a Blu Ray Picture.

See the close-ups attached. Any photo nuts out their will notice right away that the two pics look like they are compressed differently (like a digital pic being saved at high vs. low compression) notice the halo effect around the letters. BTW, I did not alter these in any way. I just blew them up and saved them both in the same file size. This of course might be due to the extra bitrate of the br player showing a less compressed image. But if that were the case, then the 1080i pic is not from a BR player as the jaggies would still be there, but they would be smoother.

I'd love to see the source of these pics.


1080i.jpg

1080p.jpg

[sparksj]

Originally Posted by Tulsa

I have always understood interlaced to be 540 lines drawn every other line the first 30th of a second and the second set of lines drawn the other 30th of a second. That's fine as long as the lines are different but (and I could be wrong here) I understand these are the same lines originally drawn the first go round. Which would/should produce those jaggies.

I agree. A still picture would definately show the jaggies. But they wouldn't necessarily be seen by the human eye, since the other half of the jaggies were filled in the next 30th of a second. That's just my opinion, but I could be wrong though.

[kjack]

In 1080i, the second set of 540 scan lines (occuring at time n + 1/60 sec) contain slightly different information that the first set of 540 scan lines (occuring at time n).

[bootman]

I tend to agree that comparing a 1080i to 1080p is difficult.
If you fed both signals to a 1080p set, the set would just convert the 1080i signal to 1080p.
No different really to a bluray player doing the same with a 1080i bluray disk.
With HD-DVDs there are many reports of people setting the players to output 1080i on purpose becasue of the poor handling by the toshiba players in this regard and letting their sets handle the conversion to 1080p.

[sparksj]

Matrixs2000,

Thanks for reviving the debate.... I kind of stalled it with my HD Camcorder questions.

[MatrixS2000]

Originally Posted by bootman

No different really to a bluray player doing the same with a 1080i bluray disk.
With HD-DVDs there are many reports of people setting the players to output 1080i on purpose becasue of the poor handling by the toshiba players in this regard and letting their sets handle the conversion to 1080p.

That does not mean the picture is the same between 1080i and 1080p. If the set de-interlaces properly, the pics are the same. If not, you get the above. Outputting 1080p from the player removes this problem. Hence why 1080i players are cheaper. You now have to go and make sure your set does this properly (and it most likely will cost more).

So to say that 1080i = 1080p is only half true unless you state all the above.

[MatrixS2000]

Originally Posted by kjack

In 1080i, the second set of 540 scan lines (occuring at time n + 1/60 sec) contain slightly different information that the first set of 540 scan lines (occuring at time n).

[MatrixS2000]

Originally Posted by Blaumann

erm, the first picture is from the HDTV 1080i broadcast on HDNet if i´m not totally mistaken

Yes, forget about the artifacts - the jagged edges are the results of 1080i. 1080i vs 1080p is not the same if your set cannot do the de-interlacing properly.

[sparksj]

Originally Posted by MatrixS2000

Yes, forget about the artifacts - the jagged edges are the results of 1080i. 1080i vs 1080p is not the same if your set cannot do the de-interlacing properly.

I might be stubborn here, but I would have to see two images with the same file compression before being convinced. If you look at my screen shots above, comparing the quality of these two images is like comparing a 2 megapixel processor in a camera to a 5 megapixel processor. It's not apples to apples. Poor quality compressing causes pixels to be grouped in blocks which will cause the jagged edges you're seeing above.

In all fairness though, I watch my 50 inch plasma from about 10 feet away, so the jaggies aren't noticable. .

When I buy my projector though, I'll definitely pony up for the 1080P.

[mgonzo2u]

HD DVD Advantages?

It gives smart people alot of good fodder for joke making.

[glenn22]

Originally Posted by MatrixS2000

Bringing this back to life as I found this example of 1080i vs 1080p:



Anyone still think there is no difference?

This is interesting. Where did you get these images? it would be nice to see more comparison images.

[sparksj]

Here is what I'm talking about.

The two pictures are form the same source, but one has been compressed more (as the picture above has). Notice the block grouping on the bottom picture and how it causes the edge of the building to have jagged edges.

Again, I would love to see a close-up comparison of 1080i vs. 1080p, but the file you posted is not apples to apples.

high Q.jpg

Low Q.jpg

[MatrixS2000]

Originally Posted by sparksj

Here is what I'm talking about.

The two pictures are form the same source, but one has been compressed more (as the picture above has). Notice the block grouping on the bottom picture and how it causes the edge of the building to have jagged edges.

Again, I would love to see a close-up comparison of 1080i vs. 1080p, but the file you posted is not apples to apples.

Attachment 996

Attachment 997

1080i vs 1080p has nothing to do with compression.

[MatrixS2000]

Originally Posted by glenn22

This is interesting. Where did you get these images? it would be nice to see more comparison images.

http://theintarweb.info/pics/

[glenn22]

Originally Posted by MatrixS2000

http://theintarweb.info/pics/

Thanks.

[sparksj]

Originally Posted by MatrixS2000

1080i vs 1080p has nothing to do with compression.

I realize that, But I'm pointing out that the two pictures you posted do not have the same file compression. You can see this in my closeup shot of them. The 1080i picture has the same blocking effect that you see in my example which proves that it was not saved with the same quality setting at the 1080P example. Based on this we do not know whether the jaggies were cause by the compression difference or if they are truly due to 1080i vs. 1080p. It does provide a compeling argument, but for it to prove anything, you would have to compare two files in the same format, with the same file compression. Only then could you truly say the difference was due to the interlacing.