Video and digital noise

Ok so I've no experience editing with video nor have I currently sought out the proper tools to edit video with. However I'm interested to know, in advance, roughtly how digital noise from the sensor affects video as compared to how it affects stills photos (since I'm currently reviewing on the LCD everything looks noise free ).

Can one remove the noise just like in regular shooting - is it as big an impact on the image quality for the same exposure as a still - can the presentation of video hide (eg like how websized image hide a large amount of noise as does printing) noise or does it show up even more?

What I'm trying to get is an idea of an ideal working ISO range with the 7D and what can be done to extend that range (eg noise reduction) and what might also limit that range (eg size of presentation)

Noose reduction is pretty tough to pull off in video. Noise is noise and behaves the same as stills, except for each frame of your video. Most people agree that keeping iso below 800 is key, and also that the multiples of 160 (160, 320, 640, 800) are the most "pure" - I don't understand that one as much so maybe someone who knows more will chime in.

As i expect to be shooting in doors a lot, and its pretty dark in my place i brought the Neat Video NR plug in for Sony Vegas.

Ive posted a couple of video's on Vimeo. These were both shot at ISO2000 and above, and both have had the exposure increased a bit. Apart from the light coming in from the hallway there was just the one lamp on in the room.

The clips are soft as i still need to get to grips with the profiling to get the best out of this plug-in but i think it will come in handy.
http://www.vimeo.com/1​9185431
http://www.vimeo.com/2​0936760

This third one was shot at ISO3200 with just a lamp (in shot), a small one in the ceiling and light coming in from another room behind the camera.
http://www.vimeo.com/1​9163447

*edited for correction*
For starters, Both Chippy and dave are one the right track, try to keep ISO below 800 and neat image is probably the only NR solution for video anyone should bother with.

Most professional camcorders use ISO800 as the native ISO, so anything below that will generally look very clean, though due to the heavy level of compression used in the codec, the noise will probably be less apparent.

About using ISO in multiples of 160... I really have no idea where that came from. ISO100 is the "native ISO" in Canon cameras, meaning that is the sensitivity of the sensor, and is set in stone, and every multiple of that (200, 400, 800) comes from a gain amplifier.
All of the extended ISO values, in-between values, and any ISO after ISO3200 (most likely) are created digitally and thus exist as some form of convenience, most likely for those who shoot in jpeg. Each ISO value on either end of a round value (640 - 800 - 1000) are generated by exposing the round value and then artificially darkening or lightening the image, which means ISO640 actually has less headroom in the highlights than 800 because it was exposed brighter and then darkened by a third of a stop, same goes for ISO50.

This is mainly of concern for those who shoot in RAW, however, because video has the quality of a very small and compressed jpeg, so losing some dynamic range by using a non-standard ISO value shouldn't of too much concern.

I don't go pass ISO 1600 for setting of f/1.4, 1/60(or 1/50) on both 5D and 7D.

ISOs that are multiples of 160 are recommended by pros who use the cameras for filming, (e.g. Shane Hurlbut, ASC). They say that the image is the cleanest in those, instead of the standard ISOs.

Kolor-Pikker wrote in post #12030056
ISO100 is the "native ISO" in Canon cameras, meaning that is the sensitivity of the sensor, and is set in stone, and every multiple of that (200, 400, 800) comes from the analog to digital converter which amplifies the signal.

Not true for all Canons for what it is worth the native ISO of the T2i is 200 ISO not 100 and dropping to 100 ISO actually reduces the dynamic range of the unit.

Also the A2D converter does not amplify the signal as that is done by an amplifier ahead of the actual A2D device.

Wayne

Channel One wrote in post #12054579
Not true for all Canons for what it is worth the native ISO of the T2i is 200 ISO not 100 and dropping to 100 ISO actually reduces the dynamic range of the unit.

Also the A2D converter does not amplify the signal as that is done by an amplifier ahead of the actual A2D device.

Wayne

Ah, thanks for the correction. I guess that makes the T2i similar to most Nikon cameras which have ISO200 as the base. This is all very general though, it usually isn't documented which settings are native to the camera.

nolimits882000 wrote in post #12052506
ISOs that are multiples of 160 are recommended by pros who use the cameras for filming, (e.g. Shane Hurlbut, ASC). They say that the image is the cleanest in those, instead of the standard ISOs.

It's probably because all the ISO values that fall under this multiple are reduced round values, and so noise, which usually appears in the shadows, gets pushed down when the exposure is adjusted in-camera. As I've said before, though, this may reduce dynamic range, even if only by a little.

Overread - Until you find and test a Pro level video noise reduction application, you might give Avidemux a try. It's free for Windows, Linux and Mac, so costs nothing to try out.

While it has many Filters for noise reduction, you might try one of the newer ones, MPlayer hqdn3d. The earlier version, MPlayerDenoise3d is still in the list, too, but while being a bit faster, isn't as "fine-adjustable".

With MPlayer hqdn3d, you might start with Spatial Luma at 0.00 or 0.50, 6.00 for Spatial Chroma, and 5 for Temporal strength.

You'll find that every piece of video, even from the same camera, has different noise qualities, so there's no "standard" settings. Use a Copy of a short clip, or cut a short piece from a long clip, to test with. Once you do your settings (including Audio) - there's a Preview function at the bottom right of the Filters dialog - it's a guide but not always fully accurate with the multi-settings Filters.

Use the 2-Pass mode whether retaining the same video format, or transcoding. Avidemux analyses and maps the video on the first pass, and saves that data to a text file. It then "knows ahead" what to do on the encoding second pass.

There are a lot of other Filters - you can change frame-rate while retaining duration, crop, rotate (handy when downsizing for hand-helds), resize, add black borders, alter colours, sharpen, so on.

Dave.

exwintech wrote in post #12054978
Overread - Until you find and test a Pro level video noise reduction application, you might give Avidemux a try. It's free for Windows, Linux and Mac, so costs nothing to try out.

So I'm actually finding myself in a bit of a situation. I shot some footage on the 5dII at iso 800 expecting it to not be that noisy. I forgot to take into account I was shooting in a dark space with the subject moving in front of a essentially black background. Anyways, I ended up with way more noise than what was exceptable.

I'm using premiere cs5 and I'm absolutely shocked there's no built in de-noiser option. It's a little ridiculous considering what the program is.

Anyways, aside from magic bullet denoiser, neat video, and re:vision de:noise are there any free or cheap plug-ins for de-noising? I just can't afford another $100-$150 on a plugin. know I could use after effects, but I really try to stay out of that program because my computer has so much trouble handling it and I'm just not really a fan of the way it operates.

Gibsonia - There are several free utilities/plugins claimed to do video de-noising in VirtualDub for Windows. They include versions for Vista and Windows-7, so might be worth a look.

Sorry, I can't comment on these, as I haven't used VirtualDub since 98SE days.

Dave.