I recommend Insane Artifect Reduction and 48-60 for sharpen for very noisy/blur videos, and Strong Artifect Reduction and 24 for a balanced improvement. Try Medium and 12 if you just want that subtle improvement without any visible side effect.
FYI, the pictures you see in this guide have been treated with Insane Artifect Reduction and sharpen by 48. The side effect is not so visible in still pictures, but can be seen more clearly in the actual video. Since in "enhancement", we aim to improve/restore the quality of the video without visible side effects, that's why you should also try the Strong/24 setting.
(If this part really came before Part Ia, the intro would be "Part Ia presented us with an interesting conclusion: that the MSU Cartoon Restore filter is close-to-useless or useless or even counter-productive when used with a source that is too clean with too much details. The main problem here is the lack of noise to reduce and the drop in sharpness. Now lets see what happens when we apply the sharpness filter which also introduces more noise in the process for the restore filter to reduce. Two filters that act on each others' side effects, will the outcome be overall better or even worse?")
I was in the shower, thinking that this works with varying degree depending on how bad the source is - poorer sources will see more noticable improvement. And since this works by reducing ringing and other edge noises and such, after all of these is removed, or rather, it would be possible to reduce this artifect totally leaving a "pefect" quality product.
But the quality of the video can only be improved by reducing artifecting; the sharpness remains the same (reduced slightly actually), and it has always been the determining factor in many current-day high-quality encodes.
So I thought, archerly hor... ("actually" in Singlish (Singaporean English)), I can apply a sharpen filter, then apply this Cartoon Restore filter to remove the sharpening artifects at the edges. Smart, isn't it?
Well now, I need to get ready to book in back to camp. But now you have an idea what I'm going to do, so stay tuned! :D
(But a teaser: It's good. And it looks to be an alternative to warpsharp, maybe even the replacement :))
Ok, continue...
Source #1 this time is Lucky Star OP (a.f.k.). The reason this clip came to my head immediately was because I've compared an upscaled-sharpened Chinese version of it versus the a.f.k. release, and the Chinese version does appear better at first but after resizing-sharpening, a.f.k. still won.
Now, lets reduce the artifects that's been keeping us from applying sharpening.
Resize only
Resize + Sharpen (strength 48)
Resized + Sharpen + Restore
As can be seen, the sharpening produces quite a bit of unwanted noise. The restore manages to reduce a lot of these noise at the expensive of a bit of sharpness, but the quality is on the whole better than just resize.
Now lets look at a more complicated picture.
Here, sharpening is important and produces a big improvement over resizing only. However, the amount of noise produced is proportional to the improvement of sharpness.
Resize only
Resize + Sharpen
Resize + Sharpen + Restore
Lose a bit of sharpness but lose a lot of sharpening artifects. That's just great. It's amazing how this filter reduces so much edge noise while not reducing sharpness by too much.
I also looked into whether it's better to do the restore or sharpening first. Do I create the noise first then reduce it later, or reduce potential noise before the sharpening? Lets see which is better.
Resize + Restore first + Sharpen
Not much of a difference. But to me restoring first gives just that slightly sharper and cleaner picture. Can you see the difference and do you have the same opinion as me?
Update: While looking at source #2 I found a scene that shows applying the Cartoon Restore filter first before the sharpen filter results in better quality:
Sharpen + Restore
Restore + Sharpen
Verdict: Applying MSU Cartoon Restore filter in this case has nothing to lose and everything to gain, sharper and cleaner pictures.
Part IIa
(So labelled as Part IIa for two reasons: It's a continuation of Part Ia, and it's after PartII)
I'm going to keep it brief since y'all should already know what I'm going to find out and what I'm going to do, so the pic:
Ahhhh, now that's the way to go. Pic 2a (original) for comparison is below in Part Ia in case you've forgotten.
Only one pic is needed, since it can already be guessed that sharpening + restoring (restoring + sharpening to be precise) yields overall better picture quality. This one just acts as a confirmation (and if acting as counter-evidence, just one is enough).
Verdict #2a: See above
BTW I also found out something else interesting (and explains a mystery I came across when encoding the video in Part I):
Do not apply the MSU Deblocking filter (or possibly any other deblocking filter) after the MSU Cartoon Restore filter since it introduces more noise; apply it before the Cartoon Restore filter instead
Also, applying resizing after everything else gives a slightly sharper and noisier picture. Which (putting it before or after) is better I'm not so sure yet and may even boil down to personal preference, but I recommend doing it after. Reasons being that 1) well, it's sharper, 2) it's better to reduce the noise before doing anything that will increase it as shown in previous cases, and 3) the effect of Cartoon Restore decreases as resolution increases, up till a point where it's next to useless when used on a picture that's been resized for printing from a small and bad-quality original.
And putting sharpen after resize is quite logical, since there's more pixels to work with and hence the aliasing effect is reduced, and the lines can become thinner and noise smaller and hence less obvious.
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