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AV1@Scale: Film Grain Synthesis, The Awakening
111–120 of 230 posts
Re: AV1@Scale: Film Grain Synthesis, The Awakening
#112This fails to acknowledge that synthesized noise can lack the detail and information in the original noise . When you watch a high-quality encode that includes the actual noise, there is a startling increase in resolution from seeing a still to seeing the video. The noise is effectively dancing over a signal, and at 24 fps the signal is still perfectly clear behind it. Whereas if you lossily encode a still that disca…
The noise does not contain a signal, does not dance over it, and is not detail. It is purely random fluctuations that are added to a signal.
If you have a few static frames and average them, you improve SNR by retaining the unchanged signal and having the purely random noise cancel itself out. Retaining noise itself is not useful.
I suspect the effect you might be seeing is either just an aesthetic preference for the original grain behavior, or that you are comparing low bandwidth content with heavy compression artifacts like smoothing/low pass filtering (not storing fine detail saves significant bandwidth) to high bandwidth versions that maintain full detail, entirely unrelated to the grain overlaid on top.
Re: AV1@Scale: Film Grain Synthesis, The Awakening
#113This fails to acknowledge that synthesized noise can lack the detail and information in the original noise . When you watch a high-quality encode that includes the actual noise, there is a startling increase in resolution from seeing a still to seeing the video. The noise is effectively dancing over a signal, and at 24 fps the signal is still perfectly clear behind it. Whereas if you lossily encode a still that disca…
Grain is independent frame-to-frame. It doesn't move with the objects in the scene (unless the video's already been encoded strangely). So long as the synthesized noise doesn't have an obvious temporal pattern, comparing stills should be fine. Regarding aesthetics, I don't think AV1 synthesized grain takes into account the size of the grains in the source video, so chunky grain from an old film source, with its big s…
I think you've missed the point here: the noise in the originals acts as dithering, and increases the resolution of the original video. This is similar to the noise introduced intentionally in astronomy[1] and in signal processing[2].
Smoothing the noise out doesn't make use of that additional resolution, unless the smoothing happens over the time axis as well.
Perfectly replicating the noise doesn't help in this situation.
[1]: https://telescope.live/blog/improve-image-quality-dithering [2] https://electronics.stackexchange.com/questions/69748/using-...
Re: AV1@Scale: Film Grain Synthesis, The Awakening
#114I remember years ago when digital projection was just becoming the norm. I saw a movie (I don't remember which one) and during the opening scene I remember thinking "why are the credits jittering around? Oh. This is actually being projected on film!"
I'm in my early 50s so I remember film quite well. Just like vinyl or cassettes, I ain't going back and unless it is an artistic choice I don't want films to emulate what I consider to be an inferior technology.
Re: AV1@Scale: Film Grain Synthesis, The Awakening
#115> 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
film grain adds realism in the same way that high frame rate films look wrong or vinyl sounds "warmer" or tube guitar amps sound "better" - It is what we are used to.
Re: AV1@Scale: Film Grain Synthesis, The Awakening
#116Yup, yet another example of the thing I'll never stop finding fascinating: ANY noticeable percieved "flaw" in any creative media will eventually become an aesthetic choice.
For an example, watch Shogun. Director apparently thought that most of the screen being out of focus was a positive. Quite distracting.
I've noticed this in a few things the last few years. The top and bottom of the shot are out of focus and it is super distracting to me. Maybe it is meant to draw the eye to the middle of the frame.
Re: AV1@Scale: Film Grain Synthesis, The Awakening
#117Earlier quoted context omitted.
Netflix has their own in-house studio, right? The encoding and lossy compression is going to happen anyway. It seems like an easy win, for their directors to provide a description of the grain they want, so it can be replicated on the user side.
what does having an in-house studio have to do with it? they stream more content than just their own, and so they would not have creative license to alter content. they would only have some type of distribution license to stream the content as provided
Because they previously did not do commercials their original TV shows were not written with pauses every few minutes. They have approved cameras. They spend heavily on movie star salaries and skimp on set production.
Re: AV1@Scale: Film Grain Synthesis, The Awakening
#118Earlier quoted context omitted.
Grain is independent frame-to-frame. It doesn't move with the objects in the scene (unless the video's already been encoded strangely). So long as the synthesized noise doesn't have an obvious temporal pattern, comparing stills should be fine. Regarding aesthetics, I don't think AV1 synthesized grain takes into account the size of the grains in the source video, so chunky grain from an old film source, with its big s…
I think you've missed the point here: the noise in the originals acts as dithering, and increases the resolution of the original video. This is similar to the noise introduced intentionally in astronomy[1] and in signal processing[2]. Smoothing the noise out doesn't make use of that additional resolution, unless the smoothing happens over the time axis as well. Perfectly replicating the noise doesn't help in this sit…
Your first link doesn't seem to be about introducing noise, but removing it by averaging the value of multiple captures. The second is to mask quantizer-correlated noise in audio, which I'd compare to spatial masking of banding artifacts in video.
Noise is reduced to make the frame more compressible. This reduces the resolution of the original only because it inevitably removes some of the signal that can't be differentiated from noise. But even after noise reduction, successive frames of a still scene retain some frame-to-frame variance, unless the noise removal is too aggressive. When you play back that sequence of noise-reduced frames you still get a temporal dithering effect.
Re: AV1@Scale: Film Grain Synthesis, The Awakening
#119This fails to acknowledge that synthesized noise can lack the detail and information in the original noise . When you watch a high-quality encode that includes the actual noise, there is a startling increase in resolution from seeing a still to seeing the video. The noise is effectively dancing over a signal, and at 24 fps the signal is still perfectly clear behind it. Whereas if you lossily encode a still that disca…
Grain is independent frame-to-frame. It doesn't move with the objects in the scene (unless the video's already been encoded strangely). So long as the synthesized noise doesn't have an obvious temporal pattern, comparing stills should be fine. Regarding aesthetics, I don't think AV1 synthesized grain takes into account the size of the grains in the source video, so chunky grain from an old film source, with its big s…
The AR coefficients described in the paper are what allow basic modeling of the scale of the noise.
> In this case, L = 0 corresponds to the case of modeling Gaussian noise whereas higher values of L may correspond to film grain with larger size of grains.
Re: AV1@Scale: Film Grain Synthesis, The Awakening
#120Earlier quoted context omitted.
> If a director/producer wants film grain added to their digital content, that's where it should be done in post. Not by some devs working for a streaming platform. The use of grain or not is a creative decision made by the creators of the work. That's where it should remain Why? If you're spending a significant chunk of your bits just transmitting data that could be effectively recreated on the client for free, isn'…
> Why? If you're spending a significant chunk of your bits just transmitting data that could be effectively recreated on the client for free, isn't that wasteful? Sure, maybe the grains wouldn't be at the exact same coordinates, but it's not like the director purposefully placed each grain in the first place. I'm sorry your tech isn't good enough to recreate the original. That does not mean you get to change the orig…
> I'm sorry your tech isn't good enough to recreate the original. That does not mean you get to change the original because your tech isn't up to the task.
The market has spoken and it says that people want to watch movies even when they don't have access to a 35mm projector or a projector than can handle digital cinema packages, so nobody is seeing the original outside a theater.
Many viewers are bandwidth limited, so there's tradeoffs ... if this film grain stuff improves available picture quality at a given bandwidth, that's a win. IMHO, Netflix blogs about codec things seem to focus on bandwidth reduction, so I'm never sure if users with ample bandwidth end up getting less quality or not; that's a valid question to ask.