Video Noise Restoration
Here are some short clips I transferred from Emma the movie originally taken from a VHS video tape demonstrating video noise restoration.
On the left side is the original video as transferred from the VHS tape. On the right hand side of the screen a special process was applied in the computer to reduce video picture noise.
As you play the clips through, look for speckled noise . Particularly in the shadows and darker colours. This kind of noise is often described as frying pan noise!
VHS Video – Original and Restored
In the computer I use a specially designed program to compare each pixel with some of the surrounding pixels. Also possibly with those in the same location in the previous or following image. In this way any random and spurious changes in the picture can be evened out. At least that is the broad explanation. In reality the whole process is something of a black art and requires quite a lot of skill to achieve a good result.
As I found, it also requires a very fast and powerful computer to manage this. Considering that the computer not only has to handle maybe 3 times the data from each frame or picture image. It also needs to be able to compare all that data with a lot of other data and produce a new image based upon multiple comparisons. and calculations. Generally this means that the actual process can take many times longer than the actual playing time of the video itself.
When I first started to do this type of processing, a reasonably good computer would take around 25 to 30 times the actual video time to process. And yes, that means a 1 1/2 hour movies say, would take maybe 40 hours ish. More recently this has come down to maybe 10 times. Still quite a lot and considering also that you would first need to process a number of short samples to get the settings right, you still need to process the whole video before you can be sure you have it right. All of which simply takes time.
The upshot is,
that unless your video is an irreplaceable one only copy, if it were just a movie for example it would probably be better to just go and find a DVD copy of it. Much cheaper and easier, plus you get the subtitles to help you understand the not quite so clear to your ears dialogue!
Please explore more of the ways I can restore media on my samples page here.