[HN Gopher] AV1@Scale: Film Grain Synthesis, The Awakening
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AV1@Scale: Film Grain Synthesis, The Awakening
Author : CharlesW
Score : 127 points
Date : 2025-07-03 16:34 UTC (6 hours ago)
(HTM) web link (netflixtechblog.com)
(TXT) w3m dump (netflixtechblog.com)
| jedbrooke wrote:
| > 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
| bob1029 wrote:
| Film grain can create stochastic resonance with the underlying
| ground truth. In practice, this can improve the perceived image
| quality over having none.
| tiluha wrote:
| Mine do, at least when it's very dark
| 01HNNWZ0MV43FF wrote:
| Yeah I've had visual snow, I think only when I'm tired, stood
| up too fast, dehydrated, etc.
| https://en.wikipedia.org/wiki/Visual_snow_syndrome
| GuB-42 wrote:
| The way I see it is that grain makes the film look more
| detailed than it really is, it can also hide compression
| artefacts and blurriness.
|
| I don't know the psychovisuals behind that. Maybe it adds some
| high frequencies that compression often washes out, or maybe
| acts like some kind of dithering.
|
| As for your eyes, I am pretty sure that they have grain, that's
| how quantum physics work, you just don't perceive it because
| your brain filters it out. But again, I don't know how it
| interacts with film grain.
| plastic3169 wrote:
| Video signal without the noise or grain is annoying to watch
| as it makes everything in the "out of focus" zone look smooth
| blurry. Your eyes want to focus yet it is an illusion of
| depth without an actual depth. Noise texture emphasizes that
| this is just a 2D plane after all so your eyes can rest and
| the viewer doesn't feel like they need glasses. This is just
| my theory of it based on observation. No research behind it.
| dinfinity wrote:
| > As for your eyes, I am pretty sure that they have grain
|
| And lots of it, actually. Just close your eyes or look at any
| non-textured surface. Tons of noise.
|
| The decreasing signal-to-noise ratio is also highly
| noticeable when it gets darker.
| observationist wrote:
| People are always trying to rationalize and justify aesthetic
| preferences. The depth and nuance of your understanding of a
| thing will change how you perceive variations of that thing,
| whether it's guitar tonewoods, style of music, types of paint,
| flavor of beer, or the grain in film. If you know a lot about a
| subject, you can tell a lot about the history of a thing, and
| that's going to change how you feel about a thing.
|
| A child watching a Buster Keaton skit and gasping and giggling
| and enjoying it is going to have a different subjective
| aesthetic experience of the media than a film critic who knows
| exactly what type of film and camera were used, and what the
| meaning of all the different abstractions imply about the
| scene, and the fabric of Keaton's costume, and so on, and so
| forth.
|
| Subjective aesthetic preferences are in the realm of cognition
| - we need a formal theory of intelligence mapped to the human
| brain, and all of these subjective phenomena collapse into
| individualized data processing and initial conditions.
|
| There's something about film grain contrasted against clean cel
| animation which might make it easier for people to suspend
| disbelief. They are conditioned to think that absence of grain
| is associated with unreal animation, particular types of media,
| and CGI. Home video and news and so forth had grain and low
| quality, so grain gets correlated with "real". In my view,
| there's nothing deeper than that - we're the product of our
| times. In 40 years, media will have changed, and it may be that
| film grain is associated with surrealism, or edited out
| completely, as it's fundamentally noise.
| Kina wrote:
| This reminds me of modern windows having fake panes. 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".
|
| I have to imagine past glassmakers would have been absolutely
| enthralled by the ability we now have to make uniform, large
| sheets of glass, but here we are emulating the compromises they
| had to make because we are used to how it looks.
| throw0101d wrote:
| > _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/watch?v=_c8Ahs9Tcnc&t=49
|
| It is similar with columns: they're not just 'tall-and-
| narrow', but rather have certain proportions and shapes
| depending on the style and aesthetic/feeling one wishes to
| convey:
|
| * https://en.wikipedia.org/wiki/Classical_order
|
| And these proportions can even be 'fractal': the window panes
| related to windows as a whole, related to the building as a
| whole:
|
| * https://www.youtube.com/watch?v=J-0XJpPnlrA&t=3m13s
|
| * https://en.wikipedia.org/wiki/Golden_rectangle
|
| * https://en.wikipedia.org/wiki/List_of_works_designed_with_t
| h...
|
| * https://www.nngroup.com/articles/golden-ratio-ui-design/
| UltraSane wrote:
| 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.
| throw0101d wrote:
| > _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.
| haiku2077 wrote:
| My vision is grainy because of visual snow. Which is why I turn
| off film grain in games, it stacks on my vision and makes a
| visual mess.
| recursive wrote:
| If your eyes _did_ have grain, then it would still be applied
| to watching an "ungrained" film, as you're still using the
| same eyes.
| sneak wrote:
| grain and 24fps and widescreen trigger certain contextual
| emotions around the movie-watching experience. remove them and
| your brain contextualizes the video very differently.
|
| this is likely the result of ~100 years of film-based
| filmmaking and projection. hell, we still call it filmmaking.
| UltraSane wrote:
| Yes, it is only the result of familiarity. We could gradually
| increase the frame rate of movies made in a year by 1 fps per
| year and then no one would even notice after 24 years every
| new movie would be 48fps.
| kderbe wrote:
| The article points out the masking effect of grain, which hides
| the fake-looking compression artifacts, and also the
| familiarity/nostalgia aspect. But I will offer an additional
| explanation.
|
| Look around you: nearly all surfaces have some kind of fine
| texture and are not visually uniform. When this is recorded as
| video, the fine texture is diminished due to things like camera
| optics, limited resolution, and compression smoothing. Film
| grain supplies some of the high frequency visual stimulus that
| was lost.
|
| Our eyes and brains like that high frequency stimulation and
| aren't choosy about whether the exact noise pattern from the
| original scene is reproduced. That's why the x265 video encoder
| (which doesn't have grain synthesis since it produces H.265
| video) has a psy-rd parameter that basically says, "try to keep
| the compressed video as 'energetic' as the original, even if
| the energy isn't in the exact same spot", and even a psy-rdoq
| parameter that says, "prefer higher 'energy' in general". These
| parameters can be adjusted to make a compressed video look
| better without needing to store more data.
| UltraSane wrote:
| Film grain and 24fps are both examples of people being far too
| attached to the technical limitations of film.
| supertrope wrote:
| 23.976 fps has been put on a pedestal as the "correct" look.
| Just look at the reaction to The Hobbit. However it does
| provide some objective advantages. 60 fps requires more
| lighting. Adding more lights means more electric setup and
| heat for actors in heavy makeup and costume. In post
| production that's more frames to edit.
| smusamashah wrote:
| 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.
| dmbche wrote:
| It used to be a bigger deal (when digital cameras started being
| used) since people felt like digital video didn't look real/as
| good - movies shot on film were generally better looking (as
| crews were used shooting with it and digital video wasn't as
| sophisticated as today) and HAD grain.
|
| It might be that there is a large part of the population that
| still has that association.
|
| Cinephiles are also more likely to watch older (i.e. with
| grain) movies that ARE well shot and beautiful (which is why
| they are classics and watched by cinephiles) and not see bad
| film movies, only the cream of the crop, while being exposed to
| the whole gamut of quality when watching todays movies shot
| digitally. Would reinforce that grain = good while not being
| necessarily the case - and their opinion might be heard more
| than gen pop.
|
| At any rate, it can be a neat tool to lower sharpness!
| tshaddox wrote:
| It's doubling back on itself. The film grain makes the footage
| look "cinematic" because it's how old movies looked.
| crazygringo wrote:
| > _my real eyes don't have grain._
|
| They definitely do at night when it's dark out. There's a kind
| of "sparkling" or "static" that comes in faint light.
|
| Fortunately, our eyes have way better sensitivity than cameras.
| But the "realism" just comes from how it was captured using the
| technology of the day. It's no different from phonograph hiss
| or the way a CRT signal blurs. The idea is to be "real" to the
| technology that the filmmaker used, and the way they knew their
| movie would be seen.
|
| It's the same way Van Gogh's brush strokes were real to his
| paintings. You wouldn't want his oil paintings sanded down to
| become flat. It's the reality of the original medium. And so
| even when we have a digital print of the film, we want to
| retain as much of the reality of the original as we can.
| Wowfunhappy wrote:
| Your Van Gogh analogy makes sense for old movies. It doesn't
| quite explain why we're still adding grain to new movies,
| except for those few which are purposefully evoking older
| movies.
| jccalhoun wrote:
| 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.
| fidotron wrote:
| 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.
| 999900000999 wrote:
| Since the beginning of film editors have added tricks in post.
|
| I would love for them to provide an option to view it with film
| simulation vs without.
|
| One of my favorite movies of all time, The Holdovers, did film
| simulation extremely well. It's set in the '70s so it attempts
| to look like a movie of that era.
|
| It looked great to me, but if you're an actual film nerd you're
| going to notice a lot of things aren't exactly accurate.
|
| Maybe in the near future we'll see Netflix being able to
| process some post effects on the client. So if you're color
| blind, you get a mode for that. If you don't want fake grain
| you can turn it off.
| ndriscoll wrote:
| mpv can already do this: `--vf=format:film-grain=no` turns
| off grain synthesis. There are also people making custom
| shaders for things like emulating CRT monitors (originally
| for retro gaming, but I see there are also mpv versions).
| bee_rider wrote:
| Holdovers was pretty great. Sorta like an 80's school comedy
| but with the perspective of the adults included, making it a
| totally different type of movie.
| rainworld wrote:
| These days, when we see noise/grain in an end product it has
| likely been added in post-production. So, ideally, studios
| would provide distributors with a noiseless source plus grain
| synthesis parameters. Bonus: many viewers would welcome an
| option to turn it off.
| NoMoreNicksLeft wrote:
| I'll keep the film grain, I just want to be able to turn off
| laugh tracks.
| dylan604 wrote:
| > provide distributors with a noiseless source plus grain
| synthesis parameters.
|
| What parameters would that be? Make it look like Eastman
| Ektachrome High-Speed Daylight Film 7251 400D? For years,
| people have taken film negative onto telecines and created
| content of grain to be used as overlays. For years, colorists
| have come up with ways of simulating the color of specific
| film stocks by using reference film with test patterns that's
| been made available.
|
| 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
| bee_rider wrote:
| 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.
| dylan604 wrote:
| 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
| rainworld wrote:
| And yet here we are: DNR -> fancy grain -> DNR -> basic,
| approximated grain. Because noise doesn't compress. And you
| get compression artifacts even in Blu-ray releases. What's
| the point of applying fancy grain when what a lot viewers
| end up seeing is an ugly smudge?
| dylan604 wrote:
| The grain is there to hide the ugly smudge. that's the
| question they rather you didn't ask
| kridsdale1 wrote:
| Because it looks amazing in the editing studio. Just like
| the sound mix is incredible on the Atmos monitors in the
| sound mixing room, even though the home viewers have a
| soundbar at best and tiny stereo speakers in a flat panel
| typically. The dynamics and dialog channel will be
| fucked. But that's user error.
| wbl wrote:
| Movies are best enjoyed in the theater.
| Wowfunhappy wrote:
| This is exactly why theatrical releases are so important
| to movie producers, isn't it?
| dylan604 wrote:
| Theatrical release qualifies for certain awards and shiny
| statues. That's their concern. If a streaming platform
| wants to give them enough cash to beat out projected box
| office earnings, then they'll take it if they don't have
| any grandiose visions of golden statues.
| Wowfunhappy wrote:
| > 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'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 recognize that the locally-produced grain doesn't look
| quite right at the moment, but travel down the hypothetical
| with me for a moment. If you could make this work, _why
| wouldn 't you?_
|
| --------
|
| ...and yes, I acknowledge that once the grain is being
| added client side, the next logical step would be "well, we
| might as well let viewers turn it off." But, once we've
| established that client-side grain makes sense, what are
| you going to do about people having preferences? Should we
| outlaw de-noising video filters too?
|
| I agree that the default setting should always match what
| the film maker intended--let's not end up with a TV motion
| smoothing situation, please for the love of god--but if
| someone actively decides "I want to watch this without the
| grain for my own viewing experience"... okay? You do you.
|
| ...and I will further acknowledge that _I_ would in fact be
| that person! I hate grain. I modded Cuphead to remove the
| grain and I can 't buy the Switch version because I know it
| will have grain. I respect the artistic decision but _I don
| 't like it_ and I'm not hurting anyone.
| dylan604 wrote:
| > 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
| original because your tech isn't up to the task. Update
| your task to better handle the original. That's like
| saying an image of the Starry Night doesn't retain the
| details, so we're going to smear the original to fit the
| tech better. No. Go fix the tech. And no, this is not
| fixing the tech. It is a band-aid to cover the flaws in
| the tech.
| Wowfunhappy wrote:
| Because the specks of grain aren't at the exact same
| coordinates? What differences are we talking about here
| exactly?
| dylan604 wrote:
| The differences are actual film grain vs some atrocious
| RGB noise artificially added by the streamer. How is that
| unclear? What else could we be talking about?
| Wowfunhappy wrote:
| Right, the current implementation is bad.
|
| In theory though, I don't see any reason why client-side
| grain that looks identical to the real thing shouldn't be
| achievable, with massive bandwidth savings in the
| process.
|
| It won't be, like, pixel-for-pixel identical, but that
| was why I said no director is placing individual grain
| specks anyway.
| dperfect wrote:
| > 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 the actual scene because it's trying (and
| often failing) to encode sharp grains.
|
| Film Grain Synthesis makes sense for streaming where bandwidth
| is limited, but I'll agree that in the examples, the
| synthesized grain doesn't look very grain-like. And, depending
| on the amount and method of denoising, it can definitely blur
| details from the scene.
| bee_rider wrote:
| 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.
| joemi wrote:
| > 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"?
| bee_rider wrote:
| 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.
| joemi wrote:
| But why do they need to emphasize it even more than the
| examples they gave? The "AV1 with FGS @ 2804 kbps"
| already looks as good or better than the "AV1 (without
| FGS) @ 8274 kbps", so it'll definitely look better than
| AV1 without FGS at an even lower bandwidth.
| zerocrates wrote:
| 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.
| Zee2 wrote:
| They did.
| hypertexthero wrote:
| A film that explores this is Antonioni's Blowup:
| https://en.wikipedia.org/wiki/Blowup
| dylan604 wrote:
| > and not really grain like
|
| that's an understatement. it just looks like RGB noise effect
| was added. film grain does not look like RGB noise. to me, film
| grain is only one part of what gave film the film look. the way
| the highlights bloom rather than clip. it also was more
| natural/organic/some descriptive other than the ultrasharp of
| modern digital acquisition. using some SoftFX or Black Mist
| type filters help, but it's just not the same as it is a
| digital vs analog type of acquisition. all of these attempts at
| making something look like it's not just keep falling down in
| the same ways. but hey, there's a cool tech blog about it this
| time. film grain filters have been around for a long time, yet
| people just don't care for them. even in Blu-ray time frame,
| there was attempts at removing the grain in the encode and
| applying it in playback. Netflix isn't coming up with anything
| new, and apparently nothing exciting either based on the
| results.
| isx726552 wrote:
| 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.
| ByThyGrace wrote:
| Forget the film grain, give us film lint and film hair!
| ricardobeat wrote:
| Video codecs use a lot of tricks based on human perception,
| perhaps it's much closer to the real thing when in motion vs
| a still image?
| aidenn0 wrote:
| AV1 has tunable FGS levels, and to my eye they went very
| slightly higher than they should have (though there are
| tradeoffs; at some bitrates the blurring+renoising is so much
| better than the other visual artifacts you will otherwise get,
| that you do want it that high).
|
| A few things to note:
|
| - still-frames are also a mediocre way to evaluate video
| quality.
|
| - a theoretically perfect[1] noise-removal filter will always
| look less detailed than the original source, since your
| brain/eye system will invent more detail for a noisy image than
| for a blurry image.
|
| 1: By which I mean a filter that preserves 100% of the non-
| grain detail present, not one that magically recovers detail
| lost due to noise.
| p1necone wrote:
| Get the retro gaming nerds on this, they'll make a film grain
| shader that's indistinguishable from reality in no time flat.
| jrm4 wrote:
| Yup, 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.
| 0cf8612b2e1e wrote:
| For an example, watch Shogun. Director apparently thought that
| most of the screen being out of focus was a positive. Quite
| distracting.
| UltraSane wrote:
| Or Snyder's terrible zombie movie Army of the Dead where he
| uses lenses with very shallow depth of field that makes
| almost everything look out of focus. It is very annoying.
| jccalhoun wrote:
| 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.
| sharkbot wrote:
| Agree. Purely opining, but I assume that it's because of the
| emotional connection that artistic media has on people, despite
| the flaws.
|
| People remember the emotions the artwork engendered, and thus
| the whole work is associated with the feelings, flaws and all.
| If the work is particularly widely known, the flaws can become
| a stand-in for the work itself.
|
| I see this in video games - I'm fond of the NES-era "flaws" and
| limitations (palette limits, sprite limits, sound channel
| limits), but less connected to the Atari 2600 or
| SNES/PS1/NDS/etc flaws. Shovel Knight is charming; A Short
| Hike, while great, doesn't resonate on a style level.
| postalrat wrote:
| I think there is a bit more to it. For example when developing
| a game when CRTs were popular they were using CRTs to view
| their game and making decisions based on what they saw on the
| CRT. If you display the same game with perfect square pixels it
| looks different. If the developers were viewing square pixels
| when developing the game they would make different decisions.
| jrm4 wrote:
| I don't think this conflicts with what I'm saying; I've seen
| what you talk about -- and yet in modern days people will
| emulate the "square pixel bad style" regardless.
| vachina wrote:
| When you ran out of things to innovate on.
| derf_ wrote:
| The "at scale" part is the real story here. Film Grain Synthesis
| has been available in the usual AV1 encoders for a while, but
| required some amount of manual tweaking to avoid creating
| problems, meaning it was only used in production when you had a
| very limited catalog, or for particularly important titles. They
| do not provide a lot of details here about how they overcame
| those problems, but it is nice to see it being deployed more
| broadly.
| brcmthrowaway wrote:
| They should use FPGA acceleration for this.
| shashanoid wrote:
| I love grain! 16mm vibes
| sharpshadow wrote:
| Fake grain really disgusts me.
| ricardobeat wrote:
| This is not fake grain - it's a reproduction of the original
| grain pattern, compressed separately from the underlying image
| content. The result is closer to the original picture than the
| denoised / compressed version.
| ChrisArchitect wrote:
| How much grain is there in IMAX films?
|
| There's an influx of high-profile directors/films right now and
| in pipeline filmed for IMAX (F1: The Movie I think, Mission
| Impossible, etc) and Christopher Nolan's _Odyssey_ coming next
| year shot entirely on IMAX film with newly developed smaller
| /quieter cameras made to accomplish it.
| CharlesW wrote:
| > _How much grain is there in IMAX films?_
|
| I've read that a 15-perf 65mm IMAX negative shot with slower
| film stocks is "virtually grainless", even when viewed on a
| 70ft screen. Grain is apparently noticeable in IMAX films when
| large/fast stocks are used and pushed toward their limits, and
| (of course) when smaller-format film stocks have been blown up.
| eviks wrote:
| > Picture this: you're watching a classic film, and the subtle
| dance of film grain adds a layer of authenticity and nostalgia to
| every scene
|
| It just adds visual noise that obscures details of the authentic
| scene, and nothing prevents nostalgia from being tied to many of
| the more prominent visual cues like old actors or your own old
| memories from when you watched it first...
|
| > contributing to [film's] realism
|
| But there is no grain in reality, so it does the opposite
|
| Otherwise I'm glad AV1 marches along and instead of wasting
| bitrate encoding visual garbage has an algorithmic replacement
| mechanism- which also means you could turn it off easier.
| messe wrote:
| > It just adds visual noise that obscures details of the
| authentic scene
|
| Does it add any more than modern video compression techniques?
| What constitutes noise in cinema, is somewhat subjective.
| eviks wrote:
| Which modern compression artifacts that are still visible at
| high bitrates do you have in mind that would similarly
| detail-obscuring?
| meatmanek wrote:
| > But there is no grain in reality, so it does the opposite
|
| Well ackchually -- illumination is inherently random, so all
| time-bounded captures of a scene (including what your eyes do)
| are subject to shot noise:
| https://en.wikipedia.org/wiki/Shot_noise
| eviks wrote:
| You misackchuallied grain with any noise, for example, the
| bottom right square of the image at the wiki page is not
| grainy despite being technically shot-noisy
| kibwen wrote:
| Documentaries might care about accurately representing reality.
| For every other cinematic genre, "authenticity" is not an
| inherent goal. If film grain is part of the director's vision,
| then that's just as valid as a choice to have dramatic non-
| diagetic music playing in the background of a scene (which is
| highly inauthentic, but also highly effective at evoking
| emotion, which is the point of art).
| kelsey98765431 wrote:
| happier and happier about leaving behind digital media to return
| to physical. to me this is literally slop. i want the
| uncompressed file stop selling me stepped on product
| ConanRus wrote:
| agree
| aidenn0 wrote:
| Your statement makes me think that one of the following is
| true:
|
| 1. You prefer Betamax or VHS to digital media (highly unlikely)
|
| 2. You own laserdiscs (limited to 480i)
|
| 3. You own 35mm prints of film.
|
| Since all other formats film has been made available on are
| both digital media and compressed.
| recursive wrote:
| Uncompressed 4k video is ~5Gbps (3840 * 2160 * 3 * 24 * 8). A
| 2-hour movie clocks in at about 4.3TB. (3840 * 2160 * 3 * 24 *
| 60 * 60 * 2)
|
| All that is 24fps.
|
| That's without audio, which I assume you also want to be
| uncompressed.
| ConanRus wrote:
| Everything is fake now. I want a technology which works with a
| raw film scans, not even compressing them to JPEG, which is a 1st
| step in loosing the details BTW. Motion detection, key frames,
| delta frames - fine. But with a lossless video. On a Blu Ray off
| course, i don't care much about streaming.
| zerocrates wrote:
| I wonder how much you'd get with such a technology... truly
| uncompressed 4K video you're talking about something on the
| order of a few terabytes for a 90-minute movie, so way way
| bigger than the biggest 4K Blu-ray discs. Lossless compression
| would get you under that number, but far enough to matter?
| CharlesW wrote:
| A 4K/24p film encoded with Apple ProRes 4444 XQ (not even
| ProRes RAW) is 716 GB per hour, so you would need to swap a
| total of 30 Blu-ray discs once every 4 minutes in order to
| watch a 2 hour movie.
| _bent wrote:
| 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.
| sneak wrote:
| Only if you are aware of it, which 99.9% of people consuming
| video content are not. It's simply an unimportant
| implementation detail (from a viewer's perspective who doesn't
| really care about bitrate-as-cost).
| dist-epoch wrote:
| 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, ...
| UltraSane wrote:
| Between 24fps and film grain people are way too attached to
| fundamentally inferior technology. With how strongly people
| resist frame rates faster than 24 I'm surprised people accepted
| color and sound, which were much bigger changes.
| vessenes wrote:
| I like this. Not really because I feel modern media should have
| added grain, but because for older media this is a method to get
| closer to the original but at much lower bitrates without
| excessive smoothing. What's not to like?
|
| Also, the author had me at God of Gamblers 2. So good. I will
| take him up on his recommendation to rewatch.
| dperfect wrote:
| 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 choices. It can even be distracting. But the alternative
| where _everything_ undergoes denoising (which many of our cameras
| do by default now) is much worse in my opinion. To my eyes, the
| smoothing that happens with denoising often looks unrealistic and
| far more distracting.
| dylan604 wrote:
| 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
| dperfect wrote:
| 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!
| dylan604 wrote:
| For content that we're concerning ourselves with this level
| of detail, I'd prefer the old iTunes method of prefetching
| the file and not stream it. For typical YT content,
| streaming is fine. For typical sitcom or other content,
| streaming is fine. For something like a feature that I'm so
| concerned about the details of grain, I have no problem
| downloading to play a local version. No, not a torrent.
| smusamashah wrote:
| 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.
| mmastrac wrote:
| If you extract the grain (e.g. by subtracting a blurred version
| of the image), the result contains mostly noise, not meaningful
| scene information outside of some variation according to image
| brightness. Film grain is random, so the extracted "grain
| layer" doesn't encode original image detail but film grain
| itself encodes relative lightness in its _density_.
| dan-robertson wrote:
| This is just a fact of lossy compression: you want to throw
| away information that contributes less to the perception of the
| video so that you can describe it with fewer bits of
| information.
|
| There are two possible advantages for this kind of grain
| synthesis. For Netflix, they could produce the same perceived
| quality at lower bitrates, which reduces costs per view and
| allows customers with marginally slow connections to get a
| higher quality version. For a consumer, the advantage would be
| getting more non-grain detail for a fixed bitrate.
|
| You are right that if you subtract the dentists frame from the
| raw one, showing only the estimated noise, you would get some
| impression of the scene. I think there's two reasons for this.
| Firstly, the places where the denoiser produced a blurry line
| that should be sharp may show up as faint lines. I don't think
| this is 'hidden information' so much as it is information lost
| to lossy compression. In the same way, if you look at the
| difference between a raw image and one with compression, you
| may see some emphasized edges due to compression artefacts.
| Secondly, the less exposed regions of the film will have more
| noise so noisiness becomes a proxy for darkness, allowing some
| reproduction of the scene. I would expect this detail to be
| lost after adjusting for the piecewise linear function for
| grain intensity at different brightness levels.
|
| Perhaps a third thing is the level of noise in the blacks and
| the 'grain size' or other statistical properties tell you about
| the kind of film being used, but I think those things are
| captured in the film grain simulation model.
|
| Possibly there are some other artefacts like evidence of
| special effects, post processing, etc.
| periodjet wrote:
| "Your scientists were so preoccupied with whether or not they
| could, they didn't stop to think if they should."
| supertrope wrote:
| When you talk on a cellphone the codec AMR-WB nominally captures
| 50 Hz - 7000 Hz. However that's only on the optional highest
| bitrate 23.85 Kbps. The most common bitrate 12.65 Kbps only goes
| up to 6400 Hz and synthesizes 6400 - 7000 Hz from lower
| frequencies and noise as it sounds better than not having the
| noise!
| lampiaio wrote:
| This sent me down a very interesting rabbit hole, thanks!
| dudeinjapan wrote:
| Please also add more noise to the audio track.
| crazygringo wrote:
| This 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 discards the noise and
| then adds back artificial noise to match the original
| "aesthetically", the original detail is non-recoverable if this
| is done frame-by-frame. Watching at 24 fps produces a
| fundamentally blurrier viewing experience. And it's not subtle --
| on old noisy movies the difference in detail can be 2x.
|
| Now, if h.265 or AV1 is actually building its "noise-removed"
| frames by always taking into account several preceding and
| following frames while accounting for movement, it could in
| theory discover the signal of the full detail across time and
| encode that, and there wouldn't be any loss in detail. But I
| don't think it does? I'd love to know if I'm mistaken.
|
| But basically, the point is: comparing noise removal and
| synthesis can't be done using still images. You have to see an
| actual video comparison side-by-side to determine if detail is
| being thrown away or preserved. Noise isn't just noise -- noise
| is detail too.
| kderbe wrote:
| 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 silver
| halide crystals, will appear as fine grain in the synthesis,
| which looks wrong (this might be mitigated by a good film
| denoiser). It also doesn't model film's separate color
| components properly, but supposedly that doesn't matter because
| Netflix's video sources are often chroma subsampled to begin
| with: https://norkin.org/pdf/DCC_2018_AV1_film_grain.pdf
|
| Disclaimer: I just read about this stuff casually so I could be
| wrong.
| alright2565 wrote:
| 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-...
| arghwhat wrote:
| 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.
| lossolo wrote:
| When I watch an 80 GB 4K movie from Blu-ray, the last thing I
| want is film grain, which makes it look like a VHS recording from
| the 90s.
| Animats wrote:
| Film grain needs to die. Its time is past. Sepia photographs and
| running 16 FPS silent film at 24 FPS are already dead. Next, film
| grain.
|
| Eastman Business Park in Rochester has been demolished.
|
| Also, please stop putting dust and scratches on YouTube videos.
| Thank you.
| jccalhoun wrote:
| I 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.
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