Noise modeling and reduction in Video when we have just noisy video
Reduction of Noise in a video depends on what type of noise is present in the video.
The noise can be reduced by filters which are all present [There are software for this] and many type of filters such as median ,mean,wiener filter.
And The noise model can be build to add noise to the video there are many matlab code as well as software also there.
Gaussian ,salt and pepper,poisson and speckle noise model can be build and by adding the image sequence with the video you will get a noisy video.

imnoise(video,noisename);


this will give noisy video as output.

If you have any doubt ask me.