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Slightly OT, but the one thing I hate about watching films on streaming services is the banding on the images. Any relatively dark scene with gradations of ligh

Slightly OT, but the one thing I hate about watching films on streaming services is the banding on the images. Any relatively dark scene with gradations of lighting in the background is a mess of shifting lines. I'd love to see something like this built in to a native Netflix client... although I realise hell will freeze over before that's a reality.

scaredginger 4y ago
I don't see why clever video post-processing couldn't help with this. Why do you say hell will freeze over? This seems like a much easier solution for them than to increase bitrates and thus, bandwidth
- zeta0134 4y ago
  The issue is that Netflix would have to do it, and they'd have to get permission from the content owners to modify the stream. I suspect hell would freeze over before anyone could agree on the relevant licensing arrangement
  - 1123581321 4y ago
    They might agree to a compression format, and the format could define post-processing. Third party desktop software could also do this were it not for HDCP. I'm pretty sure any attempt to front-run the stream with a full-screen image processor will blacken the display.
    - gwillen 4y ago
      You can do it in Chrome on macos without the screen going black, if you disable hardware acceleration. I dunno how long that will last, though.
    - kuschku 4y ago
      Every good chinese 10$ HDMI Splitter or Capture Card will just ignore HDCP entirely. It's actually refreshing, you just plug it in and it works fine.
  - exogen 4y ago
    FYI, they already do this by synthesizing film grain! https://waveletbeam.com/index.php/news/48-netflix-film-grain-synthesis https://waveletbeam.com/index.php/news/48-netflix-film-grain...
    - gffrd 4y ago
      Interesting! For each source, they must develop a "grain profile" (or, likely multiple profiles) so they're applying the right grain ""effect" when re-graining? And on the re-graining: is this being done on the client side??? Like, is my Roku adding back the grain to my Paul Thomas Anderson films? (Note: I'm only 5 min through the video, so these may be answered)
  - arrrg 4y ago
    TVs can do that, Netflix doesn’t have to. Our new top of the line Sony (A95K) has a debanding image setting. (But I think pretty much all Sony TVs have that setting.) However, it doesn’t seem extremely great and tends to smooth out things it shouldn’t. I have it turned off. It seems like debanding in realtime is still too big of a task even for the most expensive TVs.
    - notpushkin 4y ago
      Which is why Netflix are the ones who should do it. Even on low-powered devices, they could stream some pre-computed debanding data for each pixel in the video (e. g. as a separate channel encoded with video).
  - kristopolous 4y ago
    No that's in the decoder step which is up to the shared library that's used for it on your system - likely doing a hardware call to your graphics card which is the perfect place to do this stuff. The solution is a drop in decoder replacement. Heck it might already exist, it's a pretty obvious, easy and direct application.
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berkut 4y ago
Moving to higher bit depths than 8-bit will also help a bit - it's not helped by agressive compression, but even with lossless compression (PNG) 8-bit gradients like skies still suffer from the problem...
Gigachad 4y ago
Netflix has the originals though. They would sooner just start streaming better quality.
rgovostes 4y ago
Even the Apple TV 4K’s UI suffers from banding, such as when they generate blurred backgrounds in the Music app to match album artwork. They need to bring back their 1980s dithering algorithms or something.
- CharlesW 4y ago
  Interesting. I don't see this with my Dolby Vision-capable setup, presumably because it stays in 10-bit mode for both UI rendering and video playback.
deleted 4y ago
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njharman 4y ago
AI based compression is under current research https://www.youtube.com/watch?v=dVa1xRaHTA0 https://www.youtube.com/watch?v=dVa1xRaHTA0 Netflix has strong history of optimizing their streams. I bet they will be first to deploy.
- astrange 4y ago
  You don’t need AI for this. The problem is that dark areas are fundamentally harder to code (they need more bits), and how much the artifacts are visible depends strongly on how your TV and viewing environment are set up. It’s possible they’re viewing in a too bright setup and are seeing things they weren’t supposed to.
pornel 4y ago
This may be due to how Netflix’s VMAF metric judges frame quality and prefers images with more edges, even when these are false edges caused by banding: https://mobile.twitter.com/jonsneyers/status/1573371624132419585 https://mobile.twitter.com/jonsneyers/status/157337162413241...

scaredginger 4y ago

I don't see why clever video post-processing couldn't help with this. Why do you say hell will freeze over? This seems like a much easier solution for them than to increase bitrates and thus, bandwidth

zeta0134 4y ago
The issue is that Netflix would have to do it, and they'd have to get permission from the content owners to modify the stream. I suspect hell would freeze over before anyone could agree on the relevant licensing arrangement
- 1123581321 4y ago
  They might agree to a compression format, and the format could define post-processing. Third party desktop software could also do this were it not for HDCP. I'm pretty sure any attempt to front-run the stream with a full-screen image processor will blacken the display.
  - gwillen 4y ago
    You can do it in Chrome on macos without the screen going black, if you disable hardware acceleration. I dunno how long that will last, though.
  - kuschku 4y ago
    Every good chinese 10$ HDMI Splitter or Capture Card will just ignore HDCP entirely. It's actually refreshing, you just plug it in and it works fine.
- exogen 4y ago
  FYI, they already do this by synthesizing film grain! https://waveletbeam.com/index.php/news/48-netflix-film-grain-synthesis https://waveletbeam.com/index.php/news/48-netflix-film-grain...
  - gffrd 4y ago
    Interesting! For each source, they must develop a "grain profile" (or, likely multiple profiles) so they're applying the right grain ""effect" when re-graining? And on the re-graining: is this being done on the client side??? Like, is my Roku adding back the grain to my Paul Thomas Anderson films? (Note: I'm only 5 min through the video, so these may be answered)
- arrrg 4y ago
  TVs can do that, Netflix doesn’t have to. Our new top of the line Sony (A95K) has a debanding image setting. (But I think pretty much all Sony TVs have that setting.) However, it doesn’t seem extremely great and tends to smooth out things it shouldn’t. I have it turned off. It seems like debanding in realtime is still too big of a task even for the most expensive TVs.
  - notpushkin 4y ago
    Which is why Netflix are the ones who should do it. Even on low-powered devices, they could stream some pre-computed debanding data for each pixel in the video (e. g. as a separate channel encoded with video).
- kristopolous 4y ago
  No that's in the decoder step which is up to the shared library that's used for it on your system - likely doing a hardware call to your graphics card which is the perfect place to do this stuff. The solution is a drop in decoder replacement. Heck it might already exist, it's a pretty obvious, easy and direct application.

deleted 4y ago

[deleted]

berkut 4y ago

Moving to higher bit depths than 8-bit will also help a bit - it's not helped by agressive compression, but even with lossless compression (PNG) 8-bit gradients like skies still suffer from the problem...

Gigachad 4y ago

Netflix has the originals though. They would sooner just start streaming better quality.

rgovostes 4y ago

Even the Apple TV 4K’s UI suffers from banding, such as when they generate blurred backgrounds in the Music app to match album artwork. They need to bring back their 1980s dithering algorithms or something.

CharlesW 4y ago
Interesting. I don't see this with my Dolby Vision-capable setup, presumably because it stays in 10-bit mode for both UI rendering and video playback.

deleted 4y ago

[deleted]

njharman 4y ago

AI based compression is under current research https://www.youtube.com/watch?v=dVa1xRaHTA0 https://www.youtube.com/watch?v=dVa1xRaHTA0 Netflix has strong history of optimizing their streams. I bet they will be first to deploy.

astrange 4y ago
You don’t need AI for this. The problem is that dark areas are fundamentally harder to code (they need more bits), and how much the artifacts are visible depends strongly on how your TV and viewing environment are set up. It’s possible they’re viewing in a too bright setup and are seeing things they weren’t supposed to.

pornel 4y ago

This may be due to how Netflix’s VMAF metric judges frame quality and prefers images with more edges, even when these are false edges caused by banding: https://mobile.twitter.com/jonsneyers/status/1573371624132419585 https://mobile.twitter.com/jonsneyers/status/157337162413241...