"Grainy" video? at DVinfo.net

Adam Bray · April 19th, 2005, 11:37 AM

Why is the video on my GL2 "grainy". It not so obvious in daylight when you are zoomed out, but in lowlight it's bad and gets worse as you zoom. Like it on a TV when you tune to a channel that nothing is on, it's "fuzzy" or "grainy"

What's causing this? Do I need to adjust some settings?

Ken Tanaka · April 19th, 2005, 11:59 AM

You've either let the camera boost the gain (as in using P or green box automatic exposure modes) or you've boosted it manually.

Seun Osewa · January 13th, 2007, 03:34 PM

My camera introduces some grain even under harsh sunlight when the gain is 0db.

Benjamin Hill · January 13th, 2007, 05:40 PM

Quote:

Originally Posted by Adam Bray

Why is the video on my GL2 "grainy". It not so obvious in daylight when you are zoomed out, but in lowlight it's bad and gets worse as you zoom. Like it on a TV when you tune to a channel that nothing is on, it's "fuzzy" or "grainy"

What's causing this? Do I need to adjust some settings?

Adam,

Ken is right, it is a gain issue. Grain is what you get when the camera doesn't have enough light to record a decent image; it is the camera's way of trying to make something out of next-to-nothing.

Sometimes you can't really get around low light, like for documenting something or taping a wedding; but if you can get some light it will always make the image look clearer and less noisy. The GL2 is more susceptible to this than the DVX or PD170, possible because of smaller CCDs. It is a very gain-y camera to start with.

Michael Pulcinella · January 16th, 2007, 09:15 AM

It's seems funny to me that in one forum people will be complaining about grain in digital images and in another they will be trying to figure out how to make digital look more like film. Isn't grain one of the characteristics of the "film look"? I like the little bit of grain that I can get from my GL2. It softens the images slightly which is good when you want to flatter an interview buject.

Andy Wason · January 16th, 2007, 09:59 AM

Quote:

Originally Posted by Seun Osewa

My camera introduces some grain even under harsh sunlight when the gain is 0db.

Seun, check your sharpness setting.

Merlin Vandenbossche · January 17th, 2007, 02:01 PM

I also find the grain on the image (even on the 0dB gain setting) to be disturbing sometimes. And the problem indeed only occurs in low-lighted areas.

Does anyone know of any post-production means to decrease te grain effectively?

Benjamin Hill · January 17th, 2007, 03:46 PM

It is no coincidence that grain is happening in low-light situations. The video camera needs light. When it doesn't get it, it delivers a noisy, grainy image because it didn't have enough information (i.e. light) to give you a complete picture. If you don't like grainy DV, the easiest solution is to get more light on what you are shooting, anyway you can.

There are post-production filters and tricks for minimizing noise, but bear in mind you can't restore information that was never there to begin with.

Don Palomaki · January 18th, 2007, 05:36 AM

The grain effect is causd in part by the dark curent of individual pixels. Dark current is the baseline output of a pixel when no light hits it. This is normally well into black, but if you add gain (or have exceptionally sensitive eyes) it becomes more apparent. Also, because it is in the fixed pattern of the pixels, it is not "averaged out" to zero over several frames as is usually the case with movie film grain or random electronic noise, so you can see it, as you can see the grain in an individual frame of film.

Merlin Vandenbossche · January 18th, 2007, 10:43 AM

I have heard about dark current before and my courses photography say that it can be easily filtered out by taking a photo with the lens hood on and with the same camera settings, then use photoshop to filter it out. I'll be sure to ask the writer of the course to explain how you do this within photoshop so I can understand better. But I have no idea whatsoever that a remedy like this is available for video...

Don Palomaki · January 18th, 2007, 05:57 PM

I've not tried it. Might be implemented as a mask of some sort, and would probably require rendering. Maybe someone will give it a try.

Benjamin Hill · January 18th, 2007, 07:30 PM

Quote:

Originally Posted by Don Palomaki

The grain effect is causd in part by the dark curent of individual pixels. Dark current is the baseline output of a pixel when no light hits it. This is normally well into black, but if you add gain (or have exceptionally sensitive eyes) it becomes more apparent. Also, because it is in the fixed pattern of the pixels, it is not "averaged out" to zero over several frames as is usually the case with movie film grain or random electronic noise, so you can see it, as you can see the grain in an individual frame of film.

Thanks for providing the explanation, it makes perfect sense.

Caleb Hansen · February 3rd, 2007, 11:02 AM

I have found footage to become grainy when using the Custom Preset. For that reason, I choose not to use the Custom Preset at all. I try to get a correct white balance, or use auto indoor or outdoor, then color correct to the desired look in post.

Graham Bernard · February 4th, 2007, 02:02 AM

Quote:

Originally Posted by Caleb Hansen

I have found footage to become grainy when using the Custom Preset. For that reason, I choose not to use the Custom Preset at all. I try to get a correct white balance, or use auto indoor or outdoor, then color correct to the desired look in post.

Is that for ANY of the settings within CP? Is that for -ve Sharpness too?

Anyways, back to GRAIN.

We only have a 1/4 CCCD format camera. That is small, not the smallest, but small. If I'm correct, for example, the SONY PD170 has a 1/3 chip. Meaning it is bigger. Bigger chips equates with a lower light requirement, before getting GRAIN. Sooooo... the way I have understood, accepted this for OUR Camera - the XM2 - is that it is designed to deal with light levels just BRIGHTER than that which we would consider necessary. Meaning, we, humans, can drop a couple of levels - for example dimly light restaurants, home lounge environments, etc etc . . you see where I'm going with this?

The XM2 is designed with brighter environments in mind than we would "normally" need to deal with. Meaning us humans CAN operate in lower light environments.

Now, here's the kicker - and a lot of people will NOT like this - having a tad/touch of GRAIN within areas that are just below that which the XM2 can deal with, actually can ADD to the experience. See? Now if I need too strikeout with NO Grain, then lights will have to do it. But give GRAIN a chance. It aint a bad solution - IF THE CONTENT WARRANTS it!!

Bottom line here, Guys, if yah don't want grain:

* Get a better low light performer than the XM2

OR

* Add lighting

Oh, BTW, any of you guys tried out the HD options in low light?

Arthur Drogowski · February 4th, 2007, 08:15 PM

I use Neat video filter in Virtualdub to filter out the grain, there's a demo at
www.neatvideo.com , it is limited to 640x480 I think, but enough to evaluate
the product.
I also use Main Concepts DV codec to re-encode the video.
I also noticed that the output vids are slightly smaller, possibly due to lack
of grain producing better compression.
HOWEVER, for each hour of video, my 1.5Ghz notebook, takes 34 hours to filter :O , but the quality is impressive.
Art

April 19th, 2005, 11:37 AM	#1
Adam Bray Major Player Join Date: Sep 2004 Location: Houston/Austin Posts: 394	"Grainy" video? Why is the video on my GL2 "grainy". It not so obvious in daylight when you are zoomed out, but in lowlight it's bad and gets worse as you zoom. Like it on a TV when you tune to a channel that nothing is on, it's "fuzzy" or "grainy" What's causing this? Do I need to adjust some settings?

April 19th, 2005, 11:59 AM	#2
Ken Tanaka Retired DV Info Net Almunus Join Date: Dec 2001 Location: Chicago, IL Posts: 6,943	You've either let the camera boost the gain (as in using P or green box automatic exposure modes) or you've boosted it manually. __________________ Lady X Films: A lady with a boring wardrobe...and a global mission. Hey, you don't have enough stuff! Buy with confidence from our sponsors. Hand-picked as the best in the business...Really! See some of my work one frame at a time: www.KenTanaka.com

January 16th, 2007, 09:15 AM	#5
Michael Pulcinella Major Player Join Date: Oct 2006 Location: Ridley Park, PA, USA Posts: 269	Grain is good? It's seems funny to me that in one forum people will be complaining about grain in digital images and in another they will be trying to figure out how to make digital look more like film. Isn't grain one of the characteristics of the "film look"? I like the little bit of grain that I can get from my GL2. It softens the images slightly which is good when you want to flatter an interview buject.

January 17th, 2007, 03:46 PM	#8
Benjamin Hill Major Player Join Date: Nov 2005 Location: Iowa City, Iowa Posts: 670	It is no coincidence that grain is happening in low-light situations. The video camera needs light. When it doesn't get it, it delivers a noisy, grainy image because it didn't have enough information (i.e. light) to give you a complete picture. If you don't like grainy DV, the easiest solution is to get more light on what you are shooting, anyway you can. There are post-production filters and tricks for minimizing noise, but bear in mind you can't restore information that was never there to begin with. __________________ youtube.com/benhillmedia linkedin.com/in/benhillmedia

January 18th, 2007, 05:36 AM	#9
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,488	The grain effect is causd in part by the dark curent of individual pixels. Dark current is the baseline output of a pixel when no light hits it. This is normally well into black, but if you add gain (or have exceptionally sensitive eyes) it becomes more apparent. Also, because it is in the fixed pattern of the pixels, it is not "averaged out" to zero over several frames as is usually the case with movie film grain or random electronic noise, so you can see it, as you can see the grain in an individual frame of film. __________________ dpalomaki@dspalomaki.com

January 13th, 2007, 03:34 PM	#3
Seun Osewa Major Player Join Date: Oct 2006 Location: West Africa Posts: 255	My camera introduces some grain even under harsh sunlight when the gain is 0db.

January 17th, 2007, 02:01 PM	#7
Merlin Vandenbossche Regular Crew Join Date: Nov 2006 Location: Holsbeek BELGIUM Posts: 40	I also find the grain on the image (even on the 0dB gain setting) to be disturbing sometimes. And the problem indeed only occurs in low-lighted areas. Does anyone know of any post-production means to decrease te grain effectively?

January 18th, 2007, 10:43 AM	#10
Merlin Vandenbossche Regular Crew Join Date: Nov 2006 Location: Holsbeek BELGIUM Posts: 40	I have heard about dark current before and my courses photography say that it can be easily filtered out by taking a photo with the lens hood on and with the same camera settings, then use photoshop to filter it out. I'll be sure to ask the writer of the course to explain how you do this within photoshop so I can understand better. But I have no idea whatsoever that a remedy like this is available for video... __________________ Canon XM-2 AVID Xpress Pro 5.7

January 18th, 2007, 05:57 PM	#11
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,488	I've not tried it. Might be implemented as a mask of some sort, and would probably require rendering. Maybe someone will give it a try. __________________ dpalomaki@dspalomaki.com

February 3rd, 2007, 11:02 AM	#13
Caleb Hansen New Boot Join Date: Nov 2006 Location: East Lansing, MI Posts: 5	Grainy? I recommend NOT using Custom Preset I have found footage to become grainy when using the Custom Preset. For that reason, I choose not to use the Custom Preset at all. I try to get a correct white balance, or use auto indoor or outdoor, then color correct to the desired look in post.

February 4th, 2007, 08:15 PM	#15
Arthur Drogowski New Boot Join Date: Aug 2006 Location: Miami, FL Posts: 5	Grain in video solution? I use Neat video filter in Virtualdub to filter out the grain, there's a demo at www.neatvideo.com , it is limited to 640x480 I think, but enough to evaluate the product. I also use Main Concepts DV codec to re-encode the video. I also noticed that the output vids are slightly smaller, possibly due to lack of grain producing better compression. HOWEVER, for each hour of video, my 1.5Ghz notebook, takes 34 hours to filter :O , but the quality is impressive. Art