Artifacting in Video

[Rick Patterson]

Hello,

I've been shooting some with my new XL2 and I've noticed some strange stairstepping or mosaic patterns in the same areas of the video. I've uploaded a recent commercial spot I've created, and I am greatly concerned with this. Can anyone identify what the problem might be and whether service is in order. Thanks!!

http://rapidshare.com/files/35301824..._test.wmv.html

RP

[Jay Gladwell]

Looks to me like a perfect example of interlaced video on a computer monitor.

If this is for viewing on television, it will take care of itself.

If this is for viewing on the Web, you need to convert from interlaced to progressive.

[Rick Patterson]

This video was rendered as a high quality .wmv. Isn't that format non-interlaced? I have also rendered this from the timeline as a progressive scan mpeg-2 with the same result. Is there something I'm missing?
Thanks!

RP

[Rick Patterson]

No one else has any suggestions? My previous DV camcorders never exhibited this issue. Can it be a service issue? Is there a possibility that there's a pc problem or my NLE...anyone..please????/

RP

[Martin Chab]

Hi Rick,
To me it looks like oversaturated reds. I saw (and experiment) that issue many times with very strong reds (and specially with canon cameras). Possible solutions:
1. avoid strong reds
2. turn down a bit the saturation when shooting
3. turn a bit down the red gain

You can make a simple test. Pick a very red object and try some seconds with the normal saturation and with the saturation down and even with an oversaturation and look at the footage. It will take only some minutes to do it. I bet that 99,9% thats the problem.
On how to solve the already shooted footage is more complex but is also possible (not to 100% but to make look better)

[Rick Patterson]

Martin,

Thanks for the reply. I am going to do some testing shortly and see if the factory default setting exhibits the same issue. FYI, I used the "Technicolor" preset found here in the DVI Forums; I wonder, has anyone else had this issue arise when using this preset?

For the interim, I have contacted Canon service and if the factory default test yields the same results as the "Technicolor" preset, I'll drop it off at the Jamesburg facility.

Any additional wisdom is greatly apreciated!

Thanks to all

RP

[Mike Andrade]

Rick,

Martin is right on with the reds. This was my first problem with this camera. The first thing I ever shot with it was a sailboat race that happened to have one boat with a bright red sail. I also used the Technicolor preset since there were some nice vibrant colors on the lake that day. It freaked me out too since the camera I had before my XL-2 never showed much of this. After alot of research on this site and others I've found thats just the way 4:1:1 DV handles reds. I also borrowed my friends XL-2 and did a side by side test and they were identical with red artifacts. The scopes matched perfectly in FCP for both cameras.

If I have control over my set or location now I try to avoid the color completely. If you have no choice or have already shot some footage you have to use, you can use a chroma blur filter like the one available in the Nattress set in conjunction with a 3 way color corrector that most NLE's have. It took me alot of experimenting to get around this but it is possible.

[Rick Patterson]

Mike,

Thanks for the confirmation; you and Martin have likely saved me a trip to Canon service. I must admit though, what a heinous design flaw. I mean I shoot commercials like the example "run-and-gun" style all the time and I just don't have the time or freedom to simply avoid one of only 3 spectral colors which the camera sees. I never had experienced this type of limitation with a DV cam before - maybe I should try and dump this XL2 and get another SD sub 5K cam? I don't mean to gripe, but suggesting avoiding reds with a new video camera is like suggesting avoiding turns with a new car...isn't it?

Thanks again,

RP

[Richard Hunter]

Hi Rick. Rather than avoiding reds, can't you just turn down the red gain a bit? Or reduce the overall colour gain if you don't want to change the balance? Just a suggestion.

Richard

[Rick Patterson]

Richard,

Of course I can reduce the saturation, but from what Mike stated, this is an inherent problem with this cam and as he suggested "avoid reds completely."
I'm going to try shooting with the factory default in the field and adjust saturation in post - hopefully this artifacting issue can be contained, although I'm really disappointed that I cannot acquire the vivid "poppy" shots I was looking for my digital signage commercials. I still may consider a different camera. I'm pretty bummed out at the moment I must admit.

RP

[Richard Hunter]

Hi Rick. I just looked at an old thread where Barry Goyette introduced his technicolor preset. Extract below. So basically it looks like you are setting the saturation too high for the conditions.

Of course you should never have to avoid reds completely, maybe just avoid presets that boost reds when it is not appropriate. I very much doubt that is a camera problem. Try some different settings, that is one of the great strengths of this cam, that you can adjust so many things to get the results you want in different conditions.

Richard

":Barry's SuperPolarized Technicolor Dream

Gamma: Cine
Knee & Black: Middle
Color Matrix: Cine
Color Gain: +4
Color Phase: neutral
R gain: +2
G gain: +3
B Gain: -2

Realistically your white balance will effect how you position the R,G,B Gains...Mine was designed to pump the yellow-red portion of the spectrum. Also, for anyone with sane mind...this setting is really too saturated...so I would play with adjusting the Color Gain down to +1 or +2 for a saturated, but more natural display of color. I'll try to post some images later."

[Mike Andrade]

Rick,

I didn't mean to say that you should avoid reds completely. There are ways of dealing with it before it gets on to tape as many have mentioned. I should have been more specific and said that I avoid bright highly saturated reds if I can. I shoot them all the time and the muted reds or variations of pink and purple are fine.

Dropping the color saturation and the red gain does make a significant difference. Do some experiments at home with a decent monitor and adjust your settings accordingly to what you see. You will learn how to take the curve off of those blocky images and what to do in those situations when your shooting without a monitor. This is a fantastic camera and I have seen this issue in many different cameras. Its not specific to Canon cameras by any means but from what I understand more of a color compression issue inherent to the format.

[Rick Patterson]

Hey Guys,

Thanks for taking the time to clarify this issue further. I am not an indy film maker, nor am I doing lengthy productions of any sort at this time. I produce brief spots for display on my rapidly growing out-of-home video/dynamic ad network (digital signage).

I include video production with my ad rates to entice large numbers of advertisers and I respectively permit 90 minutes of shooting time per client which includes setting up a couple of pre-assembled tungsten lights, finishing my coffee, and packing it up.

Hence, I simply don't have the luxury of time to get overly technical with this camera on any single location. Moreover, at this time a field monitor is not practical both in terms of time constraints and expense. Currently, all I have is an LCD and the camera’s settings do not really show up on it.

To simplify things for my purposes - again namely run and gun stuff in unlimited circumstances, seeking vivid, eye-catching pop with minimal danger of inducing the artifacting - is there a good general purpose preset to use with this camera to achieve this without blowing the proverbial curve?

Also, I am experiencing some other anomalies which I’ll get into another day with this XL2. For now, I’d like to simplify the preset issue to preclude problems on the next shoot.

Thanks again!

RP

[Richard Hunter]

Hi Rick. To be honest, you need to be prepared to tweak this cam according to the shot conditions. But if you are able to invest some time (in advance of the next gig) into seeing what works best in different types of lighting, you can prepare a couple (maybe 3) of settings that will give you great results most of the time. What Mike Andrade says about using a monitor at home is spot on. Only by using a larger monitor will you really see the difference that the various settings are making. And only by playing around with these settings will you get a feel for what to adjust when you are out on a shoot.

If you don't want to do this (not a criticism - many people prefer not to have to adjust the camera all the time) then maybe you could look at a different camera such as a Sony PD170. It has better low light performance than the XL2, and will rarely produce a bad shot. The image is not as good as a well setup XL2, but it take less hassle to get it. (I'll probably get flak for posting this here, but it's what I believe).

But since you already have the XL2, I would advise that you try and work out how to get the results you need from it.

If it doesn't work out after a reasonable amount of time and effort, then you could think more seriously about replacing it.

Richard

[Martin Chab]

Hi Rick,
You dont need lots of time to avoid this problem (well, may be only in very special cases).
I´v made many filmings with strong reds and simply with turning down one or two notches the saturation or the red gain you can avoid the problem (that is not inherent to canon cameras even if canons are more sensitive to that issue, I saw this problem even with very expensive cameras from every brand).
That can take to you something around 10 to 20 seconds.
If you like exploding reds then you can turn up in post.
You dont have to avoid reds.