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Cine 7
Joined: 06 Jan 2008
Posts: 26
Location: Singapore
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| Posted: Thu Jan 10, 2008 5:03 pm Post subject: |
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| Quote: | | Scalers will not output interlaced signals other than 1080. Many scalers such as the lumagen will let you scale to any progressive resolution you want (up to max). So, if you want 692p, you can do that. With a Lumagen, you can also do whatever refresh rate you want. |
I see what you mean. So the scaler would not be able to accept a 1080i field as an 540p frame and up-scale it to 720p and then output it @72Hz in the earlier described pattern of At - Ab - At?
| Quote: | | With a Lumagen, you can also do whatever refresh rate you want. |
Of course this would have to be clean and judder free. I own a LUMAGEN Vision from 2003. While this scaler can output 480p standard DVDs at 72Hz it does not provide a clean 3:3 pulldown. For "PAL" DVDs at 75Hz it works flawlessly however.
| Quote: | | You should not seen scan lines very bad on much other than bright white content unless you sit something like 1x screen width away. |
I am sitting less than 1.5 screen width away and I am quite sensitive to scan lines.
| Quote: | | You can partially minimize the presence of scan lines by changing your spot shape from round to elliptical with a height to width ratio of 1.33:1. |
Might be a good idea. I have no clue how to do that though on the Cine 7? 
| Quote: | | This will also help you eek out a bit more horizontal resolution. The Cine7 will likely still not do the full 1920 but should get a little more and look a little sharper. |
This is actually another thing I would like to know? How can I find out how many horizontal "pixels" the Cine 7 can reproduce?
If I were to take how many horizontal lines it can produce (which are about 650 in a 16:9 frame / 867 in full 4:3 setup) I would end up with 1156 (867 : 3 x 4)? I guess that is not really accurate though?
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Person99
Joined: 09 Mar 2006
Posts: 4899
Location: Flower Mound, TX
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| Posted: Thu Jan 10, 2008 5:27 pm Post subject: |
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| Cine 7 wrote: | | Quote: | | Scalers will not output interlaced signals other than 1080. Many scalers such as the lumagen will let you scale to any progressive resolution you want (up to max). So, if you want 692p, you can do that. With a Lumagen, you can also do whatever refresh rate you want. |
I see what you mean. So the scaler would not be able to accept a 1080i field as an 540p frame and up-scale it to 720p and then output it @72Hz in the earlier described pattern of At - Ab - At? |
No good scaler will scale a 540p field--that is what cheap crap scalers do. The buffer two so they can deinterlace the fields to 1080, then scale to what you want. So, if you want 720p@72, the Lumagen will do that. It will take the (example is a film at 1080i/60):
At Ab At Bb Bt Cb Ct Cb...
And output a 720p/72 of:
A A A B B B C C C
| Cine 7 wrote: | | Quote: | | With a Lumagen, you can also do whatever refresh rate you want. |
Of course this would have to be clean and judder free. I own a LUMAGEN Vision from 2003. While this scaler can output 480p standard DVDs at 72Hz it does not provide a clean 3:3 pulldown. For "PAL" DVDs at 75Hz it works flawlessly however. |
Yeah, I had one of these too. Trust me, the processing has gotten a lot better. The 3:3 is much better. The only Vision would fall into video mode on NTSC film too much.
| Cine 7 wrote: | | Quote: | | You can partially minimize the presence of scan lines by changing your spot shape from round to elliptical with a height to width ratio of 1.33:1. |
Might be a good idea. I have no clue how to do that though on the Cine 7? |
When you do astig and flare with the CPC magnets.
| Cine 7 wrote: | | This is actually another thing I would like to know? How can I find out how many horizontal pixels the Cine 7 can reproduce? |
Actual content is easier than "worst case". For worst case, put up a pattern made up of vertical lines 1 black, 1 white. You can start with a pattern 1920 lines wide. You lines will not be black and white on any CRT PJ. But, on one that can do it pretty well, you'll have visible lines that are dark dark gray and light gray. The worse the PJ does, the lighter the black line is, and the darker the white line is. When you can see lines at all, you are at a resolution that you PJ cannot resolve at all. You can make other patterns of 1800 lines, etc. Just make sure you actually set you PC to the resolution of the number of lines in the patter when testing this.
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Dave
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
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OzMillsy
Joined: 10 Dec 2007
Posts: 25
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| Posted: Fri Jan 11, 2008 5:35 am Post subject: |
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| Person99 wrote: | | See my posts above, especially the one posted: Wed Jan 02, 2008 9:59 am. |
Thanks for all your feedback in this thread Dave.
Your post on that date wasnt clear if you have actually set 1080i96. So reading between the lines, you have.
And was it sharp, completely judder free - on the HDP ?
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Person99
Joined: 09 Mar 2006
Posts: 4899
Location: Flower Mound, TX
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| Posted: Fri Jan 11, 2008 3:41 pm Post subject: |
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| OzMillsy wrote: | | Person99 wrote: | | See my posts above, especially the one posted: Wed Jan 02, 2008 9:59 am. |
Thanks for all your feedback in this thread Dave.
Your post on that date wasnt clear if you have actually set 1080i96. So reading between the lines, you have.
And was it sharp, completely judder free - on the HDP ? |
when given a 1080i/60 film source it was pretty good since it was just frame rate conversion. If it drops to video mode, then it deinterlaces (bob and weave) then re-interlaces, so that can have small issues.
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Dave
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
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Cine 7
Joined: 06 Jan 2008
Posts: 26
Location: Singapore
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| Posted: Sun Jan 13, 2008 2:56 pm Post subject: |
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| Quote: | | No good scaler will scale a 540p field--that is what cheap crap scalers do. The buffer two so they can deinterlace the fields to 1080, then scale to what you want. So, if you want 720p@72, the Lumagen will do that. It will take the (example is a film at 1080i/60): |
Well, the thing is that my projector can't resolve the 1080 lines of a HD source so I would do better if I feed it an interlaced 1080i signal. This way I would not have a loss in resolution. This however will cause the line structure to be visible since it is only 540 lines at a time.
If the scaler were able to scale up that "540 lines field" to say 650 I would get rid of the scan lines and still have the full 1080 lines of resolution. Add frame rate conversion @72Hz and the flickering would be gone as well!
| Quote: | | When you do astig and flare with the CPC magnets. |
Will have to look into this. Could be an easy way to increase picture quality.
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Person99
Joined: 09 Mar 2006
Posts: 4899
Location: Flower Mound, TX
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| Posted: Tue Jan 15, 2008 12:32 am Post subject: |
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| Cine 7 wrote: | | Quote: | | No good scaler will scale a 540p field--that is what cheap crap scalers do. The buffer two so they can deinterlace the fields to 1080, then scale to what you want. So, if you want 720p@72, the Lumagen will do that. It will take the (example is a film at 1080i/60): |
Well, the thing is that my projector can't resolve the 1080 lines of a HD source so I would do better if I feed it an interlaced 1080i signal. This way I would not have a loss in resolution. This however will cause the line structure to be visible since it is only 540 lines at a time.
If the scaler were able to scale up that "540 lines field" to say 650 I would get rid of the scan lines and still have the full 1080 lines of resolution. Add frame rate conversion @72Hz and the flickering would be gone as well! |
Honestly, I'm not sure what you are trying to say, Do you want 650p or 1300i, which are you trying to achieve?
If 650p, you don't want the 540 fields scaled, because then the scaler has to "invent info" what you want is the two 540 fields deinterlace to 1080, then the 1080 downscaled to 650. This leads to a better picture because the scaler does not have "invent" as much. This is what a good scaler does. A crap scaler scales the 540 fields. That is what I was saying.
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Dave
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
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Cine 7
Joined: 06 Jan 2008
Posts: 26
Location: Singapore
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| Posted: Tue Jan 15, 2008 2:37 pm Post subject: |
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| Quote: | | Do you want 650p or 1300i, which are you trying to achieve? |
What I want is that the scaler scales the "1080i field (540 lines)" to 650 lines.
| Quote: | | If 650p, you don't want the 540 fields scaled, because then the scaler has to "invent info" |
Yes, I want the scaler to scale the 540 lines field. I would think that with the scalers available today it would not result in a much worse picture if the scaler had to "invent" information?
| Quote: | | you want is the two 540 fields deinterlace to 1080, then the 1080 downscaled to 650. |
No, that is exactly what I don't want. I don't want to downscale and loose resolution.
Let me put it a different way:
As mentioned before my CRT can't resolve 1080p it is only a 7 inch projector. It is capable of about 650 lines in 16:9 mode. So I can't afford to have the entire content of a frame on the phosphor surface at once.
But if I were to watch 1080 content in interlaced mode then I would not loose any resolution since only 540 lines are drawn on the phosphor each time and the content of one frame is divided into two fields thus preserving the full resolution.
However at only 540 lines I am still able to see the line structure which would disappear if the field were to be scaled to 650 lines.
Basically what I want is to watch 1080 content in 1080i but with 650 lines (instead of 540) per field.... and @72Hz. 
To me this seems to be the best solution of a 7 inch CRT?
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OzMillsy
Joined: 10 Dec 2007
Posts: 25
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| Posted: Tue Jan 15, 2008 10:52 pm Post subject: |
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| Person99 wrote: | | when given a 1080i/60 film source it was pretty good since it was just frame rate conversion. If it drops to video mode, then it deinterlaces (bob and weave) then re-interlaces, so that can have small issues. |
Another question for you mate.
When you set an output of 1080i96 , did you use 23.976x4 = 95.904 Hz ?
A hdp user has come forward on the Lumagen forums, stating that 1080i@71.94 output wasnt recognised by his NEC CRT. But changing the output to straight 72.0Hz worked.
If we are using 96.0 Hz output (rather than 95.904), would the HDP be inserting or duplicating some frames if the source was 23.976 ?
Do you recommend multiplying 23.976 ?
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Person99
Joined: 09 Mar 2006
Posts: 4899
Location: Flower Mound, TX
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| Posted: Wed Jan 16, 2008 12:12 am Post subject: |
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| OzMillsy wrote: | | Person99 wrote: | | when given a 1080i/60 film source it was pretty good since it was just frame rate conversion. If it drops to video mode, then it deinterlaces (bob and weave) then re-interlaces, so that can have small issues. |
Another question for you mate.
When you set an output of 1080i96 , did you use 23.976x4 = 95.904 Hz ? |
Sorry, yes. 96 is shorthhand. You should multiply by 23.976.
| OzMillsy wrote: | | A hdp user has come forward on the Lumagen forums, stating that 1080i@71.94 output wasnt recognised by his NEC CRT. But changing the output to straight 72.0Hz worked. |
I'd need more detail. I don't have an NEC but you could as the experts. I will tell you that any CRT will use the same memory block for 72 and 71.94 by default because it is not a big enough difference to pop into a new memory block.
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Dave
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
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Person99
Joined: 09 Mar 2006
Posts: 4899
Location: Flower Mound, TX
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| Posted: Wed Jan 16, 2008 12:16 am Post subject: |
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| Cine 7 wrote: | | Quote: | | Do you want 650p or 1300i, which are you trying to achieve? |
What I want is that the scaler scales the "1080i field (540 lines)" to 650 lines.
| Quote: | | If 650p, you don't want the 540 fields scaled, because then the scaler has to "invent info" |
Yes, I want the scaler to scale the 540 lines field. I would think that with the scalers available today it would not result in a much worse picture if the scaler had to "invent" information?
| Quote: | | you want is the two 540 fields deinterlace to 1080, then the 1080 downscaled to 650. |
No, that is exactly what I don't want. I don't want to downscale and loose resolution.
Let me put it a different way:
As mentioned before my CRT can't resolve 1080p it is only a 7 inch projector. It is capable of about 650 lines in 16:9 mode. So I can't afford to have the entire content of a frame on the phosphor surface at once.
But if I were to watch 1080 content in interlaced mode then I would not loose any resolution since only 540 lines are drawn on the phosphor each time and the content of one frame is divided into two fields thus preserving the full resolution.
However at only 540 lines I am still able to see the line structure which would disappear if the field were to be scaled to 650 lines.
Basically what I want is to watch 1080 content in 1080i but with 650 lines (instead of 540) per field.... and @72Hz.
To me this seems to be the best solution of a 7 inch CRT? |
OK, I think I understand what you are asking for, but can't even understand how it would work (being a software guy that does imagining. Interlaced is two fields with even line spacing painted shifted. So like this:
If you do 650 in each field, I have no idea how that would space correctly and sum up to 1080. You can't dup lines because they will be placed in different spaces. It just logically won't work unless I still don't understand what you are saying.
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Dave
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
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OzMillsy
Joined: 10 Dec 2007
Posts: 25
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| Posted: Wed Jan 16, 2008 5:41 am Post subject: |
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| Cine 7 wrote: | However at only 540 lines I am still able to see the line structure which would disappear if the field were to be scaled to 650 lines.
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Cine7, 1080i should look better than 540p , they are not strictly equivalent.
With 1080i, 1080 lines are still being drawn, but in 2 passes. In each pass, the lines are adjacent to the last pass - and if drawn quickly enough, should give your eyes the illusion that you are seeing 1080 lines (not 540).
So, if you are already running 1080i and you see line structure, then if you up'd the refresh rate it may fix the problem (as the lines are being drawn more quickly).
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ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
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| Posted: Wed Jan 16, 2008 6:01 am Post subject: |
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I've stayed out of this discussion and only lurked because I didn't think I had much to add... But, I can say one thing for certain: On my lowly old Sony 1271, I would take 1080i in a HEARTBEAT over 540p (or anything scaled up from it). I'm not even vaguely uncertain about that. I miss the sharpness and resolution of 1080i even in 720p.
Seriously... 650p? That's only 35% more resolution than NTSC/SD-DVD. That's crazy to do that to HD! ESPECIALLY by throwing away half the fields, and interpolating 540p back UP to 650p. That means you're starting with an image that's only 3x NTSC (as opposed to 6x!). 540p would only have 12.5% more vertical res than NTSC, and you're not even considering the additional softness introduced by the vertical resampling. You can do MUCH better.
Cine7, have you actually TRIED 1080i at your seating position, or are you just guessing? I can't believe the Cine 7 would be THAT much sharper than my 1271. I mean, Dave (Person99) has what is essentially a Cine 8 Onyx, and HE runs and likes 1080i well enough!
I sit at about 10-11 feet from my 8-foot wide screen and I LOVE 1080i. Of course, my projector is soft enough that I can barely detect scan lines standing right at the screen. Conversely, it's sharp enough that I can easily read Windows desktop icon text at 1080i.
SC
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Person99
Joined: 09 Mar 2006
Posts: 4899
Location: Flower Mound, TX
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| Posted: Wed Jan 16, 2008 2:49 pm Post subject: |
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| ecrabb wrote: | | I miss the sharpness and resolution of 1080i even in 720p. |
I agree. Even though a good 720p DLP machine is sharper than my PJ (mostly seen on a windows desktop or the like), I still see more detail in HD content on my PJ at 1080i from a true 1080i/p source than I do on those machines.
| ecrabb wrote: | | Seriously... 650p? That's only 35% more resolution than NTSC/SD-DVD. That's crazy to do that to HD! ESPECIALLY by throwing away half the fields, and interpolating 540p back UP to 650p. That means you're starting with an image that's only 3x NTSC (as opposed to 6x!). 540p would only have 12.5% more vertical res than NTSC, and you're not even considering the additional softness introduced by the vertical resampling. You can do MUCH better. |
I think like I did, you are missing what he is saying. What he is saying doesn't work logically so you are not getting it (I think  ). What he wants is 1080i, but instead of two 1920x540 fields, he wants two 1920x650 fields. There is of course no logical way to have two interlaced fields of 650 and have the resulting frame be 1080 so it is impossible. The only way is the resulting frame being 1300, so there is no way to do this.
| ecrabb wrote: | Cine7, have you actually TRIED 1080i at your seating position, or are you just guessing? I can't believe the Cine 7 would be THAT much sharper than my 1271. I mean, Dave (Person99) has what is essentially a Cine 8 Onyx, and HE runs and likes 1080i well enough!
I sit at about 10-11 feet from my 8-foot wide screen and I LOVE 1080i. Of course, my projector is soft enough that I can barely detect scan lines standing right at the screen. Conversely, it's sharp enough that I can easily read Windows desktop icon text at 1080i.
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Perhaps this does need a discussion of viewing distances. My screen is 92" wide and I sit 11-12 feet away (depending if I recline or not. If I don't recline, my eyeballs are exactly 132" from the 92" wide screen for a ratio of 1.44x screen width. At this distance with my elliptical spot shapre, I can see scan lines on white areas but they are not horrible. Most other content is fine. From the above, SC is at about 1.25x viewing distance. On my machine, if I move up to 1.25x distance, the scan lines are visible on all but the darkest content and visible to the point of distraction. I'd have to soften focus at that distance to be able to handle it.
I would think that the Cine7 gets a little sharper than SC's 1271, but I'd guess not night and day (as I suspect from screen shots and comments SC's 1271 is very well set up). So, my guess is:
1) He's watching from a pretty close viewing distance, and/or
2) The visibility of ANY scan lines is unacceptable to him.
If scan lines bother you that much, I would say try scaling to some horizontal res the PJ will handle well (like 1600 or 1700) and some progressive vertical resolution that makes scan lines discernable close to the screen but not from 4 feet away. I suspect this will be somewhere between 680 and 720 depending upon how well the machine is set up and its condition.
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Dave
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
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Cine 7
Joined: 06 Jan 2008
Posts: 26
Location: Singapore
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| Posted: Wed Jan 16, 2008 4:27 pm Post subject: |
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ecrabb wrote:
| Quote: | | Cine7, have you actually TRIED 1080i at your seating position, or are you just guessing? |
Yes, of course I tried. The line structure is well visible to me in the mode.
| Quote: | | If you do 650 in each field, I have no idea how that would space correctly and sum up to 1080. |
It would sum up to 1300p -> displayed in two fields of 650 lines.
| Quote: | | What he wants is 1080i, but instead of two 1920x540 fields, he wants two 1920x650 fields. |
Yes, that is correct!
| Quote: | | What he is saying doesn't work logically |
| Quote: | | There is of course no logical way to have two interlaced fields of 650 and have the resulting frame be 1080 so it is impossible. The only way is the resulting frame being 1300, so there is no way to do this. |
Frankly, I don't understand why this wouldn't work? You are correct the resulting frame would be 1080p upscaled to 1300p but instead in two separate fields of 540p upscaled to 650p.
Why can't a field be scaled instead of a frame? Is it because the content of each line is not the continuation of the previous line and is also not the beginning of the next line? 
| Quote: | 1) He's watching from a pretty close viewing distance, and/or
2) The visibility of ANY scan lines is unacceptable to him. |
1) 1.2 times the screen width. My screen is 93" wide.
2) Well, yes to a certain degree.
| Quote: | | If scan lines bother you that much, I would say try scaling to some horizontal res the PJ will handle well (like 1600 or 1700) and some progressive vertical resolution that makes scan lines discernable close to the screen but not from 4 feet away. I suspect this will be somewhere between 680 and 720 depending upon how well the machine is set up and its condition. |
Well, if I were to scale the 1080p frame to these resolution I WILL lose picture information which would not happen if I use 1080i.
| Quote: | | I would say try scaling to some horizontal res the PJ will handle well (like 1600 or 1700) |
Do you think that a 7" CRT can reproduce 1600 - 1700 horizontal "pixels" per line? That seems to be quite high but I would love to be wrong on this!
OZMillsy wrote:
| Quote: | | With 1080i, 1080 lines are still being drawn, but in 2 passes. In each pass, the lines are adjacent to the last pass |
Yes, that is exactly my point. That is why I don't want to downscale a full 1080p frame and loose resolution.
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Person99
Joined: 09 Mar 2006
Posts: 4899
Location: Flower Mound, TX
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| Posted: Wed Jan 16, 2008 5:52 pm Post subject: |
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| Cine 7 wrote: |
| Quote: | | What he wants is 1080i, but instead of two 1920x540 fields, he wants two 1920x650 fields. |
Yes, that is correct! |
This is what is confusing. This is NOT correct based upon the other things you have said. This is what is logically impossible, you can have two 650 fields result in 1080i, no way, no how. 1080i made up of two 650 fields is what is not logically possible. Given that it is logically not possible, that is why you see everyone assuming you want 650p which IS logically possible.
What you want is 1080i scaled to 1300i (which is two 650 fields).
Implementation is irrelevant to the discussion, but I have to clear this up. Even if you could get 1300i, you would not want it to be the two 540 fields independently scaled to 650 fields. That would look bad. The correct implementation (which would give the best picture) is actually:
1080i -> 1080p -> 1300p -> 1300i
You threw me because you kept insisting on scaling the two 540 fields independently which is a crap implementation. (BTW, one of my (many) pet peeves is people that think describing implementation is specifying requirements--that what you have done--concentrate on requirements). Also, constantly saying you wanted 1080i threw us too. We could have both saved alot of time (and some of SC's) if you would have just said you wanted to scale a 1080i source to 1300i. 
| Cine 7 wrote: |
Well, if I were to scale the 1080p frame to these resolution I WILL lose picture information which would not happen if I use 1080i. |
Correct, but if scan lines bother you that much, you probably have 4 options:
1) Downscale (as I suggested)
2) Sit further away or get a smaller screen.
3) Upgrade to a CRT PJ that can do 1080p
4) Upgrade to a digital PJ that can do 1080p
The reason I say "probably" is because no scaler will do what you want, and there is not nearly enough demand for it for them to add it (only CRT PJs can handle 1300i). So, I would talk to the HTPC guys to see if Powerstrip and XYZ video card will let you do 1300i. This will not be a complete solutions since an HTPC cannot scale all of your sources, but would work for HD DVD, BD, DVD, and OTA content if it is possible.
Not to sound like an a$$, but you can't buy a Kia and assume you can get Porsche performance!
| Quote: | | I would say try scaling to some horizontal res the PJ will handle well (like 1600 or 1700) |
Do you think that a 7" CRT can reproduce 1600 - 1700 horizontal "pixels" per line? That seems to be quite high but I would love to be wrong on this![/QUOTE]
In a one on/one off pattern? Not even close. You'll only get around 1300. But, if well set up with normal content that is not essentially a square wave, then you should be able to get a reasonably sharp looking picture out of that, so an "effective" resolution of that.
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Dave
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
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mike calcott
Joined: 18 May 2006
Posts: 307
Location: Australia
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| Posted: Thu Jan 17, 2008 12:58 am Post subject: |
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I agree totally with Person99, You cannot get a device to output one resolution which magically ends up at another. It mathematically does not happen, but the arguement regarding interlaced vs progressive is interesting. If we go back to basics, when we used a interlaced source as nothing else was available, the big advance in picture quality was when DVD players arrived with progressive scan via component input. The principles still apply. Yes an interlaced signal with give an apparently more edgy picture because they are providing a coarser image at any one time, eg 1080i is only presenting 540 lines at any one time and the two interlaced fields make 1080. The progresive signal presents all of the field in one pass, as Person99 quotes it would take two fields of 650 lines two achieve 1300i. Most people think that the progressive image is softer than the interlaced image, this is mainly caused by overscaling to a degree that the scan lines overlap causing a softening of the image. A projector with 7" tubes normally has a sweet spot between 600-700 lines which ever way you wish to use them, and dialing up a higher resolution will result in a degraded image or in extreme cases can damage your projector.
The scaler I use can be calibrated in two line increments vertically and horizontally, and the refresh rates can be adjusted in 0.1hz increments in progressive or interlaced formats, I also can adjust luma, chroma, and gamma, and front and back porch adjustment.
I am happy with my scan line free image, but others like the interlaced image, each to their own preference.
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AnalogRocks
Forum Moderator
Joined: 08 Mar 2006
Posts: 26706
Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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| Posted: Thu Jan 17, 2008 1:15 am Post subject: |
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| mike calcott wrote: | I agree totally with Person99, You cannot get a device to output one resolution which magically ends up at another. It mathematically does not happen, but the arguement regarding interlaced vs progressive is interesting. If we go back to basics, when we used a interlaced source as nothing else was available, the big advance in picture quality was when DVD players arrived with progressive scan via component input. The principles still apply. Yes an interlaced signal with give an apparently more edgy picture because they are providing a coarser image at any one time, eg 1080i is only presenting 540 lines at any one time and the two interlaced fields make 1080. The progresive signal presents all of the field in one pass, as Person99 quotes it would take two fields of 650 lines two achieve 1300i. Most people think that the progressive image is softer than the interlaced image, this is mainly caused by overscaling to a degree that the scan lines overlap causing a softening of the image. A projector with 7" tubes normally has a sweet spot between 600-700 lines which ever way you wish to use them, and dialing up a higher resolution will result in a degraded image or in extreme cases can damage your projector.
The scaler I use can be calibrated in two line increments vertically and horizontally, and the refresh rates can be adjusted in 0.1hz increments in progressive or interlaced formats, I also can adjust luma, chroma, and gamma, and front and back porch adjustment.
I am happy with my scan line free image, but others like the interlaced image, each to their own preference. |
Which scaller are you running Mike?
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mike calcott
Joined: 18 May 2006
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Location: Australia
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| Posted: Thu Jan 17, 2008 1:32 am Post subject: |
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TAW ROCK PRO
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OzMillsy
Joined: 10 Dec 2007
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| Posted: Thu Jan 17, 2008 1:46 am Post subject: |
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| Cine 7 wrote: | OZMillsy wrote:
| Quote: | | With 1080i, 1080 lines are still being drawn, but in 2 passes. In each pass, the lines are adjacent to the last pass |
Yes, that is exactly my point. That is why I don't want to downscale a full 1080p frame and loose resolution. |
Yes mate, but my point is, I would play with the refresh rate rather than the resolution, in order to get rid of the line structure you see.
The faster the interlacing is drawing, the more invisible the lines become, and your eyes are fooled into thinking you are actually watching 1080 distinct lines at once.
If I were you, I'd try 1080i72 and if you still see lines, go to 1080i96 (maybe pushing the bandwidth limits of the Cine7?).
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mike calcott
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| Posted: Thu Jan 17, 2008 1:49 am Post subject: |
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I run at 720p at 72hz, No Lines
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