(Video) Noise Thread - DVX100A - Request for help

[dberton]

For the past year I have been trying to eliminate "noise" in the video signal from my DVX100A. There have been various posts about various amounts of noise in the video signal, with various suggestions on how to reduce or eliminate it in order to achieve the cleanest image possible. Specifically, the noise I am referring to is the 'digital snow' which appears in dark areas or mid-range colors (greys or other flat colors). Despite my best efforts, I have been unable to eliminate (or reduce to an acceptable level) the noise I get from my DVX.

First, a recap on my strategy to reduce noise. From tips from various respected members of this board over the past year or so, I have used the following guidelines when composing a shot:

- Lots of light. Wherever possible, more light is used to properly illuminate a shot.
- Correct white balance and black balance
- Master PED between -4 and -8
- Lowered Detail setting between -3 and -5
- Gamma curve "Black Press"
- Coring raised to reduce noise
- Chroma level down

Despite all of this, I still get noise. I am beginning to think there is something wrong with my camera. I know that the image looks 'good' overall, however I still see noise in certain areas of almost every shot.

Here is the result of a small experiment. The following is a 6 second shot of a car across the street from my house, which follows the guidelines listed above. f2.8, 24PA, zoomed all the way in, on an overcast day (so there is an even spread of daylight all around). I did not record this to tape -- I went straight to my laptop over firewire and capture the clip in final cut pro. Here is the original raw DV file, with no modifications or filters, which is 18MB. Please go easy on my server, and download this clip locally and do not stream it:

http://mosey.org/film/2007/noise/car.dv

Here is a smaller version (4MB) of the very same clip which has been encoded with h264 using a compression setting that faithfully reproduces the original DV file pretty closely (iow, the noise is retained):

http://mosey.org/film/2007/noise/car-14-x264-aac.mp4

When you look at this clip (especially at full screen), you will notice noise in the upper left of the frame, in the area of the green door. You will also notice noise along the bottom of the frame along the entire bottom of the grey car. With the above settings in place I should be able to turn on my camera and capture footage that is clean and crisp and ready for editing. Instead, I am constantly plagued by noise, which makes its way into my editor and spoils (IMO) a good deal of my footage.

OK. So here are my questions, and requests for help.

- Do you see the noise? Am I crazy and there is really nothing out of the ordinary? I have seen many other clips of DVX footage that look fantastic, and have no noise at all. Why do I get noise?

- Do my settings listed above ensure a noise-free image? If not, what should I try next?

- Could there be something physically wrong with my camera? If so, what do I do about it?

- Is someone willing to go outside their residence and film a neutral-colored car in their neighborhood in such a way as to contain absolutely no noise? I want to be reassured that it -can- be done, and which settings were used to achieve it. I have ftp space available -- please PM me and I will send you upload instructions for your 6-second raw DV clip.

I hope the root cause of the noise I get in the DVX100A will be found, so I can eliminate it altogether.

Thanks for helping.

db

Update: I've added a screenshot indicating the areas of noise, which are visible when the clip is playing:

http://mosey.org/film/2007/noise/car-14-x264-aac.png

[matt s.]

neither of your links worked for me. could it be that you have the gain on? check the gain setting inside camera menu mybe you have the lowest setting on the switch actually set to have gain. thats all i can say without seeing the clip.

[matador43]

Hi,

I don't have the same kind of shot for now, but i quickly compare with some shots of my own Pal DVX100B (one revision after your's) :
I have strickly the same kind of noise in the quiets part of the frame, like little dots dancing.
You (and me for sure) have look too much HVX footage !!!

Hope this help

[dberton]

matt s.: I've checked both links again, and they appear to be working fine. What specific error are you having? Perhaps there is a high server load at the moment; please try again, since I'm interested in your opinion.

As far as the gain issue, I have also double-checked that and I am not using any gain at all (it is on the "L" setting in the side of the camera). I am not aware of a setting which will change the value or effect of the "L" setting (only "M" and "H" can be adjusted via the menu); can you be more specific?

[dberton]

Hi,

I don't have the same kind of shot for now, but i quickly compare with some shots of my own Pal DVX100B (one revision after your's) :
I have strickly the same kind of noise in the quiets part of the frame, like little dots dancing.
You (and me for sure) have look too much HVX footage !!!

Hope this help

Well, it only helps me in that I don't feel completely crazy. There is noise-- subtle sometimes, but always there, dancing about in the darker or mid-range colors of the frame. I was under the impression that the DVX100B had much less of a noise issue. The fact that it is there at all is a little disturbing.

The questions remain though: why is this happening, and how do you get rid of it (or at least reduce it to an acceptable level)?

[jamesh]

It looks more to me like heat wave refraction. Also, did you have it fixed on a manual focus, because it also looks like it might be on auto and therefor it will keep readjusting. ?

[dberton]

It looks more to me like heat wave refraction. Also, did you have it fixed on a manual focus, because it also looks like it might be on auto and therefor it will keep readjusting. ?

Yes, I see a partial heatwave-type refraction happening in that clip. However, that is not what I am concerned about. The digital noise in the clip is separate from that slight refraction, and is independent of it.

Here is an image which indicates the three areas to watch carefully while the clip is playing (the noise is difficult to see unless the clip is playing):

http://mosey.org/film/2007/noise/car-14-x264-aac.png

Regarding the autofocus issue: the autofocus setting seems to have no impact on the presence of noise. The noise exists whether or not the shot is in focus or not, or whether autofocus is enabled or not. If the shot is out of focus, there will simply be noise on top of the unfocused footage.

db

[flex]

well dberton you are not crazy at at alli do see noise two .thi is what you can do you need a plug in that can take the noise out completly the name of the plog in is Dynamic Noise Reduction 1.0.1 is goin to help u aloat and the good thing about this is that is free you can down load it here http://www.mikecrash.com/modules.php...ownload&cid=13 i down load your clip and i use the plug in it and toock all the noise away if u interested on seen the result who it came out you can down load it here http://rapidshare.com/files/26806432/car.avi.html i hoap thi may help u

[dberton]

well dberton you are not crazy at at alli do see noise two .thi is what you can do you need a plug in that can take the noise out completly the name of the plog in is Dynamic Noise Reduction 1.0.1

Thank you for pointing this out. This plugin does appear to reduce the noise problem a good deal. However, there are two issues with it.

The first is, it is only for Vegas (I am a final cut pro user). The second is, it only addresses the symptom, not the disease. There is still noise in the source DV file which should not be there. Removing it after the fact is useful and perhaps necessary in certain cases. However, IMO, the default footage captured by the DVX100A should not contain such a noticable amount of noise. I would like to find a solution that addresses the root cause of the problem, whatever that may be.

[matador43]

What i try to say to you with my HVX joke is that, for me, the amount of noise you see is normal for the DVX. It is maybe increased by the fact that your looking for noise and on a mac monitor. On a TV, the noise will certainly be less.
And add the fact that with all his quality, the DVX rely on DV compression, who certainly add noise…