Hi I have read over a few posted here removing grain from videos. I have a 2 and half hours of my sister's 30th Birthday party and has a lot of dark parts and what to brigthing it up. I brighting it up a bit and it comes up with grain which is expected. I viewed some tutorials on Youtube but they only show a 10mins clips. However mines is a 2 hours video also i don't know how the box remove grain works. Most of the video is filled with grain. I cut bad parts out in Adobe Premiere Pro CS6 and then imported it to After Effects but only shows 30mins on the timeline.
Hope this makes sense.