Comments noted, thanks!
To maximize quality of copies, I'm saving dual layer disc data to dual layer disc again, for now. I'll look at compressing data to single layer discs again later.
Basically what I'm trying to do is to copy each episode from a disc and apply some de-graining/de-noising (and, as required, possibly one or two other) filters to clean up the video images, and then save the cleaned video back to (another) disc.
Although I've looked a quite a few guides, tips, and tutorials online, I'm still not clear on what the (best/easiest) procedure is to "clean up" the videos.
What I've done so far is -
1) Copied original disc contents onto HDD via AnyDVD
2) Converted copied disc files from VOB format to d2v video and ac3 audio formats so that they can be read and processed using AVISynth.
3) Created AVISynth script and added a de-grain/de-noise plugin to AVISynth. Running the script using VirtualDub, grain/noise seemed to be removed quite well from the video images!
4) Processing ONE episode at a time, as each episode may require different filters and different settings depending on what has to be done to clean up the video images.
Now is where I get stuck!
After the episode has been filtered, what should the filtered file be saved as? AVI format? Or something else? And what is/are the best tools for doing this?
Then should the filtered file be reconverted to VOB format again in preparation for creating a new disc later on after all episodes have been filtered and converted? Or what other procedure is better? What tools are required for this?
Is/are there better programs for doing conversions and filtering?