Smoothing and Denoising Your Video
My experience with removing the extra noise (extra pixels) in a video has been restricted to using a denoise filter in Final Cut and using a small and free application called JES Video Cleaner. (No Windows version, sorry.) I wanted to give you some examples of what denoising and video "cleaning" or "smoothing" can do, and let you decide for yourself whether it's something you want to investigate.
Here are two screencaps from the same video—one before running it through JES VideoCleaner, one after. Ignoring the minor color differences, what other changes do you notice?
Screencap of Richard Armitage from a Robin Hood video, saved as a high quality video file, but with no "Denoise" or "Smoothing."
Screencap from the same video, after smoothing and denoising.
In my limited experience, smoothing or denoising can be overdone, or done badly. JES VideoCleaner seems to do a good job. The video is still sharp, but larger areas of color are smoother, and when watching the video in motion, there are almost no "dancing pixels" (little moving pixels, often noticeable in the background).
Another benefit to denoising is that it makes the file size smaller. I compare a non-denoised and denoised version of the same video, same detail level, and the denoised version is often quite a bit smaller in size. Less itty bitty pixels for the encoder to have to worry about—they've been "cleaned" away!
There will probably always be videos which might not benefit from denoising. With some videos, the end result is too "slick," and the smoothing settings should either be lowered, or denoising not be done at all.
Downloadable Video Samples:
I patched some clips together in Final Cut to make a short video and exported the finished project as an uncompressed file. This uncompressed video was run through JES Video Cleaner, which created its own uncompressed version of the original. Then both these uncompressed videos were encoded to the XviD format using the same bitrate and settings.
Both clips are XviD AVI files, playable with the XviD codec installed, in VLC Player, or with the DivX Player. (Right-click to download clips to desktop.)
Sample video, no smoothing or noise reduction. 11.4 MB.
Sample video, with smoothing and noise reduction. 9 MB.
TIPS FOR USING JES VIDEO CLEANER: (Mac only)
JES Video Cleaner is a small application made by an independent programmer, and made available to us at no cost. I cannot describe how grateful I am to this developer! However, it is still a work in progress, and can be persnickety or perhaps unstable for some systems. The interface for the program seems pretty intuitive, so with a little experimentation, you should be able to figure it out. Do some tests on small video clips first, just to get a feel for how it works.
I'm using it on a G4 Mac Mini, which is a nice little workhorse with its 1 GB of RAM, but not a speed demon. "Cleaning" times can be rather long—at least an hour for a typical fan video.
I find that I get best results when I reboot the Mac, don't have any other applications running, and then run JES. Sometimes it needs a "goose" to get it started. If it does not seem to be analyzing your video for noise levels after a few moments, quit the program and start again.
If I am smoothing more than one video at a time, I find that rebooting between sessions gives me the best results. Sometimes the second smoothing session (if no rebooting happens) will be horribly slow.
Video Cleaning or Smoothing for Windows
So far I know of two Windows-based video processing applications which include smoothers or cleaners: Avidemux (which also is available for Mac) and the AMV.org's AMVapp (still in Beta, but an older version is available). Both these applications are free, but have a learning curve. I'm sure there are other video cleaners available, but some come at a cost.
The techniques for smoothing can be used before you import your clips for editing, or afterwards, when you have prepared a finished, uncompressed video, ready to be encoded for the web. I choose to do it afterwards, because of the time it takes to encode even a few minutes of footage.