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Content delivery costs a lot for streaming services. After content is produced, this is basically the only remaining cost. It’s not surprising that they would g
by strogonoff 1y ago
Content delivery costs a lot for streaming services. After content is produced, this is basically the only remaining cost. It’s not surprising that they would go to extreme measures in reducing bitrate.
That’s why, presumably, Netflix came up with the algorithm for removing camera grain and adding synthetically generated noise on the client[0], and why YouTube shorts were recently in the news for using extreme denoising[1]. Noise is random and therefore difficult to compress while preserving its pleasing appearance, so they really like the idea of serving everything denoised as much as possible. (The catch, of course, is that removing noise from live camera footage generally implies compromising the very fine details captured by the camera as a side effect.)
[0] https://news.ycombinator.com/item?id=44456779 https://news.ycombinator.com/item?id=44456779
[1] https://news.ycombinator.com/item?id=45022184 https://news.ycombinator.com/item?id=45022184
- abound 1y agoThis isn't strictly Netflix per se, it's part of the AV1 codec itself, e.g. https://github.com/BlueSwordM/SVT-AV1/blob/master/Docs/Appendix-Film-Grain-Synthesis.md https://github.com/BlueSwordM/SVT-AV1/blob/master/Docs/Appen...
- strogonoff 1y agoYes, I was not strictly correct, it is a feature of AV1, but Netflix played an active role in its development, in rolling out the first implementation, and in AV1 codec development overall.
- astrange 1y agoPrior codecs all had film grain synthesis too (at least back to H264), but nobody used it. Partly because it was obviously artificial and partly because it was too expensive to render, since you had to copy each frame to apply effects to it.
- tverbeure 1y agoAFAIK, FGS support is the exception instead of the rule. h.264 only had FGS as an afterthought, introduced years after the spec was ratified. No wonder it wasn’t widely adopted. VP9, h.265 and h.266 don’t have FGS.
- astrange 1y agoDid they remove it from the specs? Wouldn't surprise me. But since it's just extra metadata and doesn't affect encoding you could still use the old spec.
- tverbeure 1y agoI don’t think it was ever part of the spec. It would surprise me if it was, because once a spec has been finalized and voted on, changing it is complicated. Getting agreement the first time is already difficult enough.
- codedokode 1y agoThere might be also copyright owners requirements, e.g. contract that limits the quality of material.
- franga2000 1y agoSo: 1. camera manufacturers and film crews both do their best to produce a noise-free image 2. in post-production, they add fake noise to the image so it looks more "cinematic" 3. to compress better, streaming services try to remove the noise 4. to hide the insane compression and make it look even slightly natural, the decoder/player adds the noise back Anyone else finding this a bit...insane?
- mjevans 1y agoYes, just stop doing step 2 the way they're doing and instead if they _must_ do noise modify parameters for step 4 directly.
- trenchpilgrim 1y ago> camera manufacturers and film crews both do their best to produce a noise-free image This is not correct, camera manufacturers and filmakers engineer _aesthetically pleasing_ noise (randomized grains appear smoother to the human eye than clean uniform pixels). The rest is still as silly as it sounds.
- benjiro 1y ago> randomized grains appear smoother to the human eye than clean uniform pixels Does this explain why i dislike 4K content on a 4K TV? Where some series and movies look too realistic, what in turn gives me a amateur film feeling (like somebody made a movie with a smartphone).
- ZeroGravitas 1y agoThis sounds like what is called the soap opera effect: https://en.wikipedia.org/wiki/Soap_opera_effect https://en.wikipedia.org/wiki/Soap_opera_effect Which is generally associated with excess denoisong rather than with excess grain.
- dataflow 1y agoAre you sure? That seems to be about motion interpolation. Not even about smooth motion, but about it being interpolated. Here the concern seems to be about how the individual, still images look, not anything about the motion between them.
- dan-robertson 1y agoIt feels to me like there are two different things going on: 1. Video codecs like the denoise, compress, synthetic grain approach because their purpose is to get the perceptually-closest video to the original with a given number of bits. I think we should be happy to spend the bits on more perceptually useful information. Certainly I am happy with this. 2. Streaming services want to send as few bytes as they can get away with. So improvements like #1 tend to be spent on decreasing bytes while holding perceived quality constant rather than increasing perceived quality while holding bitrate constant. I think one should focus on #2 and not be distracted by #1 which I think is largely orthogonal.
- astrange 1y agoFor #1 the problem with keeping grain in the compressed video is that it doesn't follow the motion of the scene so it makes it much more expensive to code future frames.
- strogonoff 1y agoI disagree, because 1) complete denoising is simply impossible while preserving fine detail and 2) noise is a serious artistic choice—just like anamorphic flare, lens FOV with any distortion artifacts, chromatic aberration, etc. Even if it is synthetic film grain that is added in post, that has been somebody’s artful decision; removing it and simulating noise on the client butchers the work.
- charcircuit 1y ago>Content delivery costs a lot for streaming services. The hard disk space to store an episode of a show is $0.01. With peering agreements, the bandwidth of sending the show to a user is free.
- pixl97 1y ago>With peering agreements bandwidth of sending the show to a user is free. I'm not sure why you think this, but it's one of the oddest things I've seen today. The more streams you can send from a single server the lower your costs are.
- charcircuit 1y agoSure, but buying a server is not buying bandwidth. The point of my post is to counter the narrative that streaming video is very expensive.
- kwanbix 1y agoI recall Netflix saying that streaming cost was nothing compared to all other costs.
- strogonoff 1y agoI am curious to see their breakdown. It seems very counter-intuitive of them to invest so much into reducing bitrate if the cost of delivery is negligible. R&D and codec design efforts cost money and running more optimized codecs and aggressive denoising cost compute.
- EasyMark 1y agoIt probably is but the bean counters do not want to hear this, they want to cut everything to the point that it's just above the limit that consumers will accept before they throw in the towel and cancel their membership (ads, low quality compression, etc)
- matt-attack 1y agoImproved compression also saved on storage costs. We would have to hear them state the same about storage.