Median Filter

MarkFoley wrote on 1/28/2004, 6:01 AM

I'm curious to how/what the median filter works on the pixels. I've started using it with my captured Canon XL1 footage...and have some great successes...especially in situations where I've had to crank up the gain on the camera a bit to overcome low-light situations. I found quicky that I save it for a final process on a project...then engage it before I go to bed as it is a big CPU consumer to render.

For those who use it regularly (espeically fellow XL1s users), what settings/modifications to the presets you use?

Comments

BillyBoy wrote on 1/28/2004, 7:11 AM

The Median fliter is basically a blur. It is EXTREMELY slow, the slowest of all Vegas filters. It can take literally DAYS to render a sizeable project if you use it for the whole length. I would suggest you try a small (30-second) section and see if it gives you the effect you want and if you can live with the extensive rendering time before trying it on a whole project. The other blur filters work just as well in most conditions and are much faster.

Give more specifics as to what you're trying to accomplish and I'm sure you'll get more suggestions. If what you hinted at noise from low light is the main problem, then Menida probably isn't the right choice.

MarkFoley wrote on 1/28/2004, 7:32 AM

I'm using it for video noise reduction of footage and for slight softnening of the video.....

I guess a slight gaussian blur on duplicate track at 50% maybe better/faster?

BillyBoy wrote on 1/28/2004, 1:47 PM

I would try the gaussian blur, at very low settings.

Or...

Vegas isn't that good at getting rid of video noise. You could try frame serving to VitrualDub (free) which does an excellent job having many differnt third party noise filters (do web search to find them) the only down side is you need to do it first or render out to uncompressed AVI which can get huge. While VD can open many file types it won't open rendered MPEG-2 made in Vegas, due the CODEC used.

AudioIvan wrote on 1/28/2004, 2:26 PM

VirtualDub is good & free,but if you want to do better noise reduction I suggest AVISynth & filters.AVISynth is faster & works in any colorspace,codec,......VD can open many file types & it WILL open rendered MPEG-2 made in Vegas,look for version of VD that supports opening AC3 & MPEG-2 files.Also I recomend using HUFFYUV Losless codec(not lossy compression),because it is faster,no chroma upsampling bugs,stable,FREE.
AudioIvan

MarkFoley wrote on 1/29/2004, 4:50 AM

Thanks For the suggestion Bill....I can't believe I hadn't got around to playing with frame server and virtual dub...wow...found the look I wanted....:-)

farss wrote on 1/29/2004, 6:03 AM

Maybe a bit more consideration to not getting the noise there in the first place would be a better idea. The processes involved in getting rid of it in the first place invariably mean the image suffers in other ways. A bit more light in the first place would not only reduce the noise but also improve depth of field and reduce the risk of the autofocus hunting. Even if you've been sensible enough to switch to manual focus at those light levels it can be pretty difficult to get the focus right.

MarkFoley wrote on 1/29/2004, 12:48 PM

Thanks for stating the obvious...but some events you have no control over the ambient lighting...
:-)

farss wrote on 1/29/2004, 1:03 PM

Sorry,
I was being trite and yes I've been caught out the same way myslef, actually it was far worse than just a bit of noise in the blacks. I just worry that a lot of newcomers may not understand that the system does have limitations and you have to learn to work within them.
There's now about 100 times more people with a video camera than there was 10 years ago. 10 years ago this stuff was so damn expensive you spent a lot of time learning up front.