Interesting fact about noise reduction filter + question on

[chasmanian]

checking the noise reduction box should not affect block noise. try a setting of 40/40. what bitrate is your avi?

chas

[Snoopy007]

I never use noise reduction unless the source material is really bad. and in ur case it is of the highest quality (dvd rip). besides I don't think it will have any impact on block noise considering urs is a dvd rip

to reduce block noise I would just stick with the soften block noise option in quantize matrix

[N0SoopForU]

ed_101,

The reason you are seeing significantly less block noise when using noise filters is probably due to the fact that noise filtering tends to blur the image a bit and therefore making it easier to compress. You can achieve the same result without increasing encoding time by using Virtual Dub's blur filters on the original AVI before encoding. I don't use this technique simply because I like a nice sharp image. But if you are desperate to reduce block noise give it a try and see if it helps.