Custom Presets/Vertical Detail at DVinfo.net

Lucinda Luvaas · July 8th, 2005, 03:35 PM

I find the info on this preset confusing in the Manual. It says that if you use the NORMAL setting for Vertical Detail you may see horizontal lines flicker on interlaced televisions. However, the manual recommends using NORMAL for non-interlaced TV, computer work and output to dvd's.

I'm not sure, because of the above, what to do about this setting. I want to get rid of the horizontal flickering lines, but if I use the LOW setting, how will that affect my post work and outputting to dvd?

Any help or advice would be greatly appreciated!

Lucinda

Richard Hunter · July 9th, 2005, 10:04 PM

My understanding is that the interlace flicker happens with progressive scan video on interlaced displays when you have fine horizontal details. Setting vertical detail to LOW should reduce flicker in that situation. If you are shooting interlaced video you can usually keep the vertical detail setting NORMAL, however the high resolution of the XL2 mens does seem to make flickering worse than other cameras.

Richard

Lucinda Luvaas · July 9th, 2005, 11:01 PM

Thanks Richard. I did set Vertical Detail to Low and that might work slightly, but I guess the thing to try to do is get rid of it in post, but I hate to blur much. It does seem to flicker more than my other camcorder. I also set the sharpening a tad below the mid level in the Custom Presets. Interesting that when you zoom in it does seem to help.

Lucinda Luvaas · July 10th, 2005, 01:49 PM

I've read many posts here and elsewhere about the interlace flicker issue. I'm wondering if anyone has more info, or places I could check to learn more.

I know that when I zoom in to objects the flicker disappears, and that the flicker happens primarily at some distance away from the objects.

Also, I have removed this problem in post, but I would like to avoid it to some extent while shooting.

Is it true that a diffusion filter would help? anything else?

As I mentioned, setting Vertical Detail to Low and reducing the Sharpening some didn't really help much.

Any help would be much appreciated!

Lucinda

Richard Hunter · July 11th, 2005, 07:36 PM

Hi Lucinda. If you search on "moire" I'm sure you will find many references, but probably no real solution that works every time.

The flickering happens when you view a high-res image containing fine details, on a lower resolution display or medium. The reason why zooming in on the image helps is that this makes the fine features larger, until they can be resolved on the display without flickering so much.

I've tried various filtering techniques during the editing stage, but so far have not found any way to remove the flicker totally without making the picture unacceptably blurred. Keeping the video as progressive and using a progressive display helps a lot though.

Richard

Lucinda Luvaas · July 11th, 2005, 08:33 PM

Richard,

I appreciate your reply. I did read the posts on the moire issue. Clive even emailed me today to let me know that this camcorder is no good which is his opinion. I've owned Canon products for 30 years or so and I've always been pleased with the quality of their items.

Anyway, Barry mentioned on that post that you can change the angle of the shot and that this can help get rid of the flickering and jittering. I tried that this morning, but it didn't work. Have you tried that? what do you think he meant, change the angle of the shot and the position...I understand position very well, but not sure about the angle bit.

What do you think?

Lucinda

Richard Hunter · July 11th, 2005, 11:20 PM

Hi Lucinda. I assume Barry means to move the camera nearer to (or further from) the subject, and maybe change the view if possible so that fine detail lines are not running too close to horizontal. Problem is, unless you have a good monitor with you to check it out at the time of shooting, you won't know whether you have a flicker problem until too late.

Since you can sometimes see flickering through the EVF, I used to think that this could be used to avoid the problem. However, the EVF resolution is not as high as a TV's, so unfortunately this just doesn't work.

I've also tried applying various blurs and anti-flicker filters in an NLE (both Vegas and Edius) but so far haven't found anything that works really well. Maybe need to stick to close-ups in future!

Richard

Lucinda Luvaas · July 12th, 2005, 12:36 AM

Yes, I know....I can sort of see the flickering at times. I will have to get a monitor before long and I'm going to need to decide on that too. But, I must say, despite this problem, the resolution and richness of tonal values is wonderful on the Canon XL2.

I was watching a program on PBS tonight and saw interlace flicker on a roof and it was bad!

So, I know we're not alone...but I don't want any of it in my final production.

Thanks for your imput!

Lucinda

Greg Boston · July 12th, 2005, 01:40 AM

I see it a lot on various programs. It's easier to avoid in scripted productions, but can't always be avoided when shooting live events.

-gb-

Barry Green · July 12th, 2005, 02:41 AM

If you want to read volumes about the issue, search on DVX boards about "thick" and "thin" -- it's the same subject.

Basically, interlaced cameras have to employ a vertical blur in order to avoid flickering on interlaced televisions. It's the way it's always been -- all interlaced cameras blur the footage internally, which is why you'll pretty much never see an interlaced camera that delivers more than about 360 lines of vertical resolution (talking NTSC here; PAL has the same issue but obviously with some more vertical res).

Panasonic and Canon have produced these progressive-scan cameras, and they decided to let you have the option to turn that blur filter "off". This lets you get much higher vertical resolution (up to 480 lines, for 33% higher res!) BUT: if you try to display that higher res on an interlaced TV, guess what happens? You got it: flicker.

The cameras are actually capable of resolving higher vertical resolution than an interlaced television can display. It's the TV's fault, not the camera's.

But, the engineers know that we live in a world dominated by these interlaced TV's, and we have to be able to work with them. So, they provide the ability to internally vertically blur the footage to minimize the flicker. On the DVX it's done by selecting the "THICK" option, on the XL2 it's done by selecting "LOW".

The thing to keep in mind is: if you shoot with THICK/LOW, you'll be getting every bit as much resolution as an interlaced camera would. In THICK or LOW, you'll have footage that's just as high-resolution as any PD170, etc.

But: if you intend to display your footage on a progressive display (or transfer to film), why blur it if you don't need to? Those displays aren't interlaced, so they don't suffer from the same irritating interlace flicker artifacts. So when you know you're shooting for a plasma or film or something like that, you definitely turn the switch to "THIN" or "NORMAL" and use all the resolution you can get.

The blur is only necessary if you're displaying your footage on a regular interlaced TV. It is completely unnecessary if you're displaying on a progressive display device (meaning an LCD or Plasma or DLP television or computer monitor, etc).

The flicker is only a problem on interlaced televisions. It won't happen on any other type of display.

(and yes, high-def has the same problem when watching 1080i, so interlaced high-def cameras have to do the same type of internal blurring!)

Lauri Kettunen · July 12th, 2005, 04:51 AM

Barry, What you explain suggests the flickering problem can be removed in postproduction by removing some of the vertical lines. (For example, take the footage frame by frame to Photshop, reduce the number of vertical lines, and then bríng the frames back to Premiere/FCP/or equivalent. Bit slow and perhaps painful, but a possible approach.)

I've been filming only with the progressive mode of the XL2 (PAL), and the increased resolution you talk about is noticeable. Flickering does not appear in all footages, but instead, quite rarely. This may have to do with that I'm filming only outdoors, and consequently, there's seldom anything regular I'm in my shots.

Lucinda Luvaas · July 12th, 2005, 02:00 PM

So true that if you have a scripted shoot you can avoid this issue entirely! Thanks so much all of you for this imput. I'll read it later and respond....I am ordering a diffusion filter, which I've never used, but I want to see what that does. Generally, I agree, this isn't a problem. Since I'm new to this camcorder, I sort of freaked when it happened the first time. Now, I'm ok...hopefully.

Barry, you said something about changing the angle of the shot to get rid of the flicker.

I know from scanning picts that you can get rid of moire patterns by slanting the pict on the scanner bed. It works sometimes.

This sounds dumb, but I tried slanting the Canon XL2 while shooting some of the offending lines and it didn't seem to work.

What did you mean? other than zooming in or out, or changing the location a bit....?

As far as output goes: it's a bit complicated for me since I output to TV, film festivals, and various other types of venues...as to whether to use Normal or Low. And, the Low setting doesn't get rid of the flicker anyway.

July 8th, 2005, 03:35 PM	#1
Lucinda Luvaas Major Player Join Date: May 2005 Posts: 233	Custom Presets/Vertical Detail I find the info on this preset confusing in the Manual. It says that if you use the NORMAL setting for Vertical Detail you may see horizontal lines flicker on interlaced televisions. However, the manual recommends using NORMAL for non-interlaced TV, computer work and output to dvd's. I'm not sure, because of the above, what to do about this setting. I want to get rid of the horizontal flickering lines, but if I use the LOW setting, how will that affect my post work and outputting to dvd? Any help or advice would be greatly appreciated! Lucinda

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July 9th, 2005, 10:04 PM	#2
Richard Hunter Trustee Join Date: Dec 2004 Location: Lipa City Batangas, Philippines Posts: 1,110	My understanding is that the interlace flicker happens with progressive scan video on interlaced displays when you have fine horizontal details. Setting vertical detail to LOW should reduce flicker in that situation. If you are shooting interlaced video you can usually keep the vertical detail setting NORMAL, however the high resolution of the XL2 mens does seem to make flickering worse than other cameras. Richard

July 9th, 2005, 11:01 PM	#3
Lucinda Luvaas Major Player Join Date: May 2005 Posts: 233	Thanks Richard. I did set Vertical Detail to Low and that might work slightly, but I guess the thing to try to do is get rid of it in post, but I hate to blur much. It does seem to flicker more than my other camcorder. I also set the sharpening a tad below the mid level in the Custom Presets. Interesting that when you zoom in it does seem to help.

July 10th, 2005, 01:49 PM	#4
Lucinda Luvaas Major Player Join Date: May 2005 Posts: 233	I've read many posts here and elsewhere about the interlace flicker issue. I'm wondering if anyone has more info, or places I could check to learn more. I know that when I zoom in to objects the flicker disappears, and that the flicker happens primarily at some distance away from the objects. Also, I have removed this problem in post, but I would like to avoid it to some extent while shooting. Is it true that a diffusion filter would help? anything else? As I mentioned, setting Vertical Detail to Low and reducing the Sharpening some didn't really help much. Any help would be much appreciated! Lucinda

July 11th, 2005, 07:36 PM	#5
Richard Hunter Trustee Join Date: Dec 2004 Location: Lipa City Batangas, Philippines Posts: 1,110	Hi Lucinda. If you search on "moire" I'm sure you will find many references, but probably no real solution that works every time. The flickering happens when you view a high-res image containing fine details, on a lower resolution display or medium. The reason why zooming in on the image helps is that this makes the fine features larger, until they can be resolved on the display without flickering so much. I've tried various filtering techniques during the editing stage, but so far have not found any way to remove the flicker totally without making the picture unacceptably blurred. Keeping the video as progressive and using a progressive display helps a lot though. Richard

July 11th, 2005, 08:33 PM	#6
Lucinda Luvaas Major Player Join Date: May 2005 Posts: 233	Richard, I appreciate your reply. I did read the posts on the moire issue. Clive even emailed me today to let me know that this camcorder is no good which is his opinion. I've owned Canon products for 30 years or so and I've always been pleased with the quality of their items. Anyway, Barry mentioned on that post that you can change the angle of the shot and that this can help get rid of the flickering and jittering. I tried that this morning, but it didn't work. Have you tried that? what do you think he meant, change the angle of the shot and the position...I understand position very well, but not sure about the angle bit. What do you think? Lucinda

July 11th, 2005, 11:20 PM	#7
Richard Hunter Trustee Join Date: Dec 2004 Location: Lipa City Batangas, Philippines Posts: 1,110	Hi Lucinda. I assume Barry means to move the camera nearer to (or further from) the subject, and maybe change the view if possible so that fine detail lines are not running too close to horizontal. Problem is, unless you have a good monitor with you to check it out at the time of shooting, you won't know whether you have a flicker problem until too late. Since you can sometimes see flickering through the EVF, I used to think that this could be used to avoid the problem. However, the EVF resolution is not as high as a TV's, so unfortunately this just doesn't work. I've also tried applying various blurs and anti-flicker filters in an NLE (both Vegas and Edius) but so far haven't found anything that works really well. Maybe need to stick to close-ups in future! Richard

July 12th, 2005, 12:36 AM	#8
Lucinda Luvaas Major Player Join Date: May 2005 Posts: 233	Yes, I know....I can sort of see the flickering at times. I will have to get a monitor before long and I'm going to need to decide on that too. But, I must say, despite this problem, the resolution and richness of tonal values is wonderful on the Canon XL2. I was watching a program on PBS tonight and saw interlace flicker on a roof and it was bad! So, I know we're not alone...but I don't want any of it in my final production. Thanks for your imput! Lucinda

July 12th, 2005, 01:40 AM	#9
Greg Boston Wrangler Join Date: Oct 2003 Location: DFW area, TX Posts: 6,117 Images: 1	I see it a lot on various programs. It's easier to avoid in scripted productions, but can't always be avoided when shooting live events. -gb-

July 12th, 2005, 02:41 AM	#10
Barry Green Barry Wan Kenobi Join Date: Jul 2003 Location: North Carolina Posts: 3,863	If you want to read volumes about the issue, search on DVX boards about "thick" and "thin" -- it's the same subject. Basically, interlaced cameras have to employ a vertical blur in order to avoid flickering on interlaced televisions. It's the way it's always been -- all interlaced cameras blur the footage internally, which is why you'll pretty much never see an interlaced camera that delivers more than about 360 lines of vertical resolution (talking NTSC here; PAL has the same issue but obviously with some more vertical res). Panasonic and Canon have produced these progressive-scan cameras, and they decided to let you have the option to turn that blur filter "off". This lets you get much higher vertical resolution (up to 480 lines, for 33% higher res!) BUT: if you try to display that higher res on an interlaced TV, guess what happens? You got it: flicker. The cameras are actually capable of resolving higher vertical resolution than an interlaced television can display. It's the TV's fault, not the camera's. But, the engineers know that we live in a world dominated by these interlaced TV's, and we have to be able to work with them. So, they provide the ability to internally vertically blur the footage to minimize the flicker. On the DVX it's done by selecting the "THICK" option, on the XL2 it's done by selecting "LOW". The thing to keep in mind is: if you shoot with THICK/LOW, you'll be getting every bit as much resolution as an interlaced camera would. In THICK or LOW, you'll have footage that's just as high-resolution as any PD170, etc. But: if you intend to display your footage on a progressive display (or transfer to film), why blur it if you don't need to? Those displays aren't interlaced, so they don't suffer from the same irritating interlace flicker artifacts. So when you know you're shooting for a plasma or film or something like that, you definitely turn the switch to "THIN" or "NORMAL" and use all the resolution you can get. The blur is only necessary if you're displaying your footage on a regular interlaced TV. It is completely unnecessary if you're displaying on a progressive display device (meaning an LCD or Plasma or DLP television or computer monitor, etc). The flicker is only a problem on interlaced televisions. It won't happen on any other type of display. (and yes, high-def has the same problem when watching 1080i, so interlaced high-def cameras have to do the same type of internal blurring!)

July 12th, 2005, 04:51 AM	#11
Lauri Kettunen Major Player Join Date: Aug 2004 Location: Kangasala, Finland Posts: 445	Barry, What you explain suggests the flickering problem can be removed in postproduction by removing some of the vertical lines. (For example, take the footage frame by frame to Photshop, reduce the number of vertical lines, and then bríng the frames back to Premiere/FCP/or equivalent. Bit slow and perhaps painful, but a possible approach.) I've been filming only with the progressive mode of the XL2 (PAL), and the increased resolution you talk about is noticeable. Flickering does not appear in all footages, but instead, quite rarely. This may have to do with that I'm filming only outdoors, and consequently, there's seldom anything regular I'm in my shots.

July 12th, 2005, 02:00 PM	#12
Lucinda Luvaas Major Player Join Date: May 2005 Posts: 233	So true that if you have a scripted shoot you can avoid this issue entirely! Thanks so much all of you for this imput. I'll read it later and respond....I am ordering a diffusion filter, which I've never used, but I want to see what that does. Generally, I agree, this isn't a problem. Since I'm new to this camcorder, I sort of freaked when it happened the first time. Now, I'm ok...hopefully. Barry, you said something about changing the angle of the shot to get rid of the flicker. I know from scanning picts that you can get rid of moire patterns by slanting the pict on the scanner bed. It works sometimes. This sounds dumb, but I tried slanting the Canon XL2 while shooting some of the offending lines and it didn't seem to work. What did you mean? other than zooming in or out, or changing the location a bit....? As far as output goes: it's a bit complicated for me since I output to TV, film festivals, and various other types of venues...as to whether to use Normal or Low. And, the Low setting doesn't get rid of the flicker anyway.