Question about "Artifact Removal"

questions about practical use of Neat Video, examples of use
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jpsdr
Posts: 221
Joined: Mon Aug 11, 2008 7:33 am

Question about "Artifact Removal"

Post by jpsdr »

I've read the doc.
If i'm correct, it's a new feature of NV4, not in NV3.

I want to check if i've understood properly this feature, and explain my cases.
I personnaly denoise either from Blu-Ray or DVDs.
I've noticed on clean (without noise) videos, that when bitrate is high and encoding good, on Blu-Ray, compression artifacts are almost not visible. But on DVDs, MPEG2 produce more visible artifacts.
So, for exemple, if i've a noised video is encoded on DVD, if i only denoise, compression artifact will stay, and in that case, this feature can be interesting, am i right ?

I'm allways more more reluctant with features like these than noise. Because noise is everywhere on the whole frame, and it's on all frames. So, there is no risk to apply the denoiser to a part it shouldn't, because noise is everywhere (accuracy of profile is another thing).
But, on features like artifact removal, i'm allways affraid of a part of picture which trig the algorithm, but isn't finaly an artifact, so the "false detection" part.

As i've no idea of "how strong" the default setting is, what setting would you suggest for a DVD (so 480p frame size), for a case with relatively strong noise (old film) video encoded on DVD, but with a good bitrate.
NVTeam
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Joined: Thu Sep 01, 2005 4:12 pm
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Re: Question about "Artifact Removal"

Post by NVTeam »

jpsdr wrote:I've read the doc.
If i'm correct, it's a new feature of NV4, not in NV3.

I want to check if i've understood properly this feature, and explain my cases.
I personnaly denoise either from Blu-Ray or DVDs.
I've noticed on clean (without noise) videos, that when bitrate is high and encoding good, on Blu-Ray, compression artifacts are almost not visible. But on DVDs, MPEG2 produce more visible artifacts.
So, for exemple, if i've a noised video is encoded on DVD, if i only denoise, compression artifact will stay, and in that case, this feature can be interesting, am i right ?
Not exactly. The regular noise filter will also reduce some of the artifacts (just like NV3 did) but it is possible that some stubborn artifacts that are significantly stronger than the regular noise may remain intact unless you enable (and possibly adjust settgings of) the artifact filter.
So basically, if you see that the regular filter is not removing all objectionable artifact spots and lines, then enable the artifact filter and try to adjust its settings to make those elements reduced.
jpsdr wrote:I'm allways more more reluctant with features like these than noise. Because noise is everywhere on the whole frame, and it's on all frames. So, there is no risk to apply the denoiser to a part it shouldn't, because noise is everywhere (accuracy of profile is another thing).
But, on features like artifact removal, i'm allways affraid of a part of picture which trig the algorithm, but isn't finaly an artifact, so the "false detection" part.

As i've no idea of "how strong" the default setting is, what setting would you suggest for a DVD (so 480p frame size), for a case with relatively strong noise (old film) video encoded on DVD, but with a good bitrate.
I recommend to directly play with that filter on different clips to get a better idea of what it does and what settings should be used. It is quite conservative, so I would not worry about losing details with the default settings. Anyway, please try it directly.

Thank you,
Vlad
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