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AV1@Scale: Film Grain Synthesis, The Awakening

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Re: AV1@Scale: Film Grain Synthesis, The Awakening

#61
The original grain that is captured is actually a detail and not total random noise. I believe you can make up the vague sense of original scene if you could somehow extract that grain/noise alone.

It's like reducing an image to tiny dots with dithering (reminds of Atinkson dithering). Those grains are not a noise, they are a detail, actual data. That's why real grain looks good IMO.

Re: AV1@Scale: Film Grain Synthesis, The Awakening

#62
post #33

It's a bit frustrating that the footage is first shot, then denoised in post, then renoised in post, then denoised in encoding and then renoised at decoding.

You worry too much, it's all fake. What you think is the "footage" will be many layers from various sources composited together.

Fake lights, fake shadows, fake sky, ...

Re: AV1@Scale: Film Grain Synthesis, The Awakening

#64

> This grain, formed from tiny particles during the film’s development, is more than just a visual effect. It plays a key role in storytelling by enhancing the film’s depth and contributing to its realism. I never understood the “grain = realism” thing. my real eyes don’t have grain. I do appreciate the role of grain as an artistic tool though, so this is still cool tech

Grain = realism because real captured grain isn't total random noise. It's authentic noisy data. It's part of captured scene. It adds subtle tiny but real detail to the scene. Unless I am corrected here and that real grain is also total random noise.

Re: AV1@Scale: Film Grain Synthesis, The Awakening

#65

Earlier quoted context omitted.

> both it and the synthesized grain image look noticeably less sharp than the source That's true, but at a given bitrate (until you get to very high bitrates), the compressed original will usually look worse and less sharp because so many bits are spent trying to encode the original grain. As a result, that original grain tends to get "smeared" over larger areas, making it look muddy. You lose sharpness in areas of t…

It seems like a shame that they didn’t include a screenshot of the original (with natural grain), after suffering from low-bitrate streaming. Aka the actual baseline. I can see why they want to compare against the actual local copy of the video with the natural grain. But that’s the perfect copy that they can’t actually hope to match.

They did.

Re: AV1@Scale: Film Grain Synthesis, The Awakening

#66

Earlier quoted context omitted.

> They’re just strips that are applied to give the impressions that there are multiple smaller panes because people are used to that and it feels “correct”. It is more than just 'feeling correct': windows and their various (sub-)elements that make them up (can) change the architectural proportions and how the building is perceived as a whole: * https://www.youtube.com/watch?v=uAMyUoDz4Og * https://www.youtube.com/wat…

I strongly doubt that multiple smaller panes would have ever become a common style if we could have always made large glass panes. This is a perfect example of people becoming very used to a style forced by a technological limitation that is emulated even after the limitation doesn't exist.

> I strongly doubt that multiple smaller panes would have ever become a common style if we could have always made large glass panes.

Perhaps, but if you're going to have them anyways you might as well make a conscious choice as to how they add to the overall design of the structure.

Re: AV1@Scale: Film Grain Synthesis, The Awakening

#67

To the comments hating on grain: everything naturally has some amount of noise or grain - even the best digital sensors. Heck, even your eyes do. It's useful beyond just aesthetics. It tends to increase perceived sharpness and hides flaws like color banding and compression artifacts. That's not to say that all noise and grain is good . It can be unavoidable, due to inferior technology, or a result of poor creative ch…

My issue is that grain is good based on the creative decisions of the creators of the content. It is not something that a group of nerds compressing 1s and 0s should be making

I agree. However, let's look at it practically. Let's assume someone is watching content streamed on a low bandwidth connection. As a content creator, what version of the compressed content would you rather your audience experience:

a) Compressed original with significant artifacts from the codec trying to represent original grain

b) A denoised version with fewer compression artifacts, but looks "smoothed" by the denoising

c) A denoised version with synthesized grain that looks almost as good as the original, though the grain doesn't exactly match

I personally think the FGS needs better grain simulation (to look more realistic), but even in its current state, I think I'd probably go with choice C. I'm all for showing the closest thing to the author's intent. We just need to remember that compression artifacts are not the author's intent.

In an ideal world where we can deliver full, uncompressed video to everyone, then obviously - don't mess with it at all!

Re: AV1@Scale: Film Grain Synthesis, The Awakening

#68
post #60

Earlier quoted context omitted.

It seems like a shame that they didn’t include a screenshot of the original (with natural grain), after suffering from low-bitrate streaming. Aka the actual baseline. I can see why they want to compare against the actual local copy of the video with the natural grain. But that’s the perfect copy that they can’t actually hope to match.

> It seems like a shame that they didn’t include a screenshot of the original (with natural grain), after suffering from low-bitrate streaming. Isn't that the image captioned "Regular AV1 (without FGS) @ 8274 kbps"?

I think I misread the figures.

But still, they have:

> A source video frame from They Cloned Tyrone

> Regular AV1 (without FGS) @ 8274 kbps

> AV1 with FGS @ 2804 kbps

Just to emphasize the problem, would it be nice to see:

Regular AV1 (without FGS) @ 2804 kbps

It should look really bad, right? Which would emphasize their results.

Re: AV1@Scale: Film Grain Synthesis, The Awakening

#69
post #60

Earlier quoted context omitted.

It seems like a shame that they didn’t include a screenshot of the original (with natural grain), after suffering from low-bitrate streaming. Aka the actual baseline. I can see why they want to compare against the actual local copy of the video with the natural grain. But that’s the perfect copy that they can’t actually hope to match.

> It seems like a shame that they didn’t include a screenshot of the original (with natural grain), after suffering from low-bitrate streaming. Isn't that the image captioned "Regular AV1 (without FGS) @ 8274 kbps"?

I think the distinction here is, they provide the "regular" stream, and the FGS stream noting that it's much smaller yet looks similar. What they don't have is a lower-bandwidth "regular" one, what 2000-or-so kbps looks like without FGS.

Re: AV1@Scale: Film Grain Synthesis, The Awakening

#70
post #3

There are definite philosophical questions over the merits of adding noise, but the problem with their example here is their denoising process appears to excessively blur everything, so both it and the synthesized grain image look noticeably less sharp than the source. The grain itself also looks too much like basic noise, and not really grain like.

Agree, as someone who has spent way too much time studying the way motion picture film looks up close, this isn’t very realistic looking. It’s really just a form of dithering.
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