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AV2 video codec delivers 30% lower bitrate than AV1, final spec due in late 2025

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Re: AV2 video codec delivers 30% lower bitrate than AV1, final spec due in late 2025

#71

Post by JimDabell »

whycome wrote: post #65
lyu07282 wrote: post #38

Earlier quoted context omitted.

Yeah in the future we might use some sort of learned spatial+temporal representation to compress video, same for audio. Its easier to imagine for audio: Instead of storing the audio samples, we store text + some feature vectors that uses some model to "render" the audio samples.

It’s not absurd to think that you could send a model of your voice to a receiving party and then have your audio call just essentially be encoded text that gets thrown through the voice generator on the local machine. AI video could mean that essential elements are preserved (actors?) but other elements are generated locally. Hell, digital doubles for actors could also mean only their movements are transmitted. Essen…

Yeah, I brought that up here and got some interesting responses:

> It would be interesting to see how far you could get using deepfakes as a method for video call compression.

> Train a model locally ahead of time and upload it to a server, then whenever you have a call scheduled the model is downloaded in advance by the other participants.

> Now, instead of having to send video data, you only have to send a representation of the facial movements so that the recipients can render it on their end. When the tech is a little further along, it should be possible to get good quality video using only a fraction of the bandwidth.

— https://news.ycombinator.com/item?id=22907718

Specifically for voice, this was mentioned:

> A Real-Time Wideband Neural Vocoder at 1.6 Kb/S Using LPCNet

— https://news.ycombinator.com/item?id=19520194

Re: AV2 video codec delivers 30% lower bitrate than AV1, final spec due in late 2025

#72

Post by Avamander »

RamRodification wrote: post #52
alberth wrote: post #50

Will streaming services ever stop over-compressing their content? I have a top-of-the-line 4K TV and gigabit internet, yet the compression artifacts make everything look like putty. Honestly, the best picture quality I’ve ever seen was over 20 years ago using simple digital rabbit ears. You especially notice the compression on gradients and in dark movie scenes. And yes — my TV is fully calibrated, and I’m paying for…

It's a little surprising to me that there generally aren't more subscription tiers where you can pay more for higher quality. Seems like free money, from people like you (maybe) and me.

You can already pay for 4K or "enhanced bitrate" but it's still relatively low bitrate and what's worse, this service quality is not guaranteed. I've had Apple TV+ downgrade to 1080p and lower on a wired gigabit connection so many times.

Re: AV2 video codec delivers 30% lower bitrate than AV1, final spec due in late 2025

#73

Post by andrepd »

alberth wrote: post #50

Will streaming services ever stop over-compressing their content? I have a top-of-the-line 4K TV and gigabit internet, yet the compression artifacts make everything look like putty. Honestly, the best picture quality I’ve ever seen was over 20 years ago using simple digital rabbit ears. You especially notice the compression on gradients and in dark movie scenes. And yes — my TV is fully calibrated, and I’m paying for…

Ironically, piracy gives you yet again a better service. Thanks QxR.

Re: AV2 video codec delivers 30% lower bitrate than AV1, final spec due in late 2025

#74

Post by IshKebab »

RicoElectrico wrote: post #48
amiga386 wrote: post #40

Earlier quoted context omitted.

Hopefully that improves. The guy giving the presentation on AV2 made clear there was "rigorous scrutiny for hardware decoding complexity", and they were advised by Realtek and AMD on this. So it seems like they checked that all their ideas could be implemented efficiently in hardware as they went along, with advice from real hardware producers. Hopefully AV2-capable hardware will appear much quicker than AV1-capable…

Maybe not only reference software, but also reference RTL should be provided? Yes, this is more work, but should speed up adoption immensely.

There's no point having reference RTL. The point of reference software is to demonstrate the correct behaviour for people implementing production grade libraries and RTL. Having an RTL version of that wouldn't add anything - it should have identical behaviour.

Providing a production grade verified RTL implementation would obviously be useful but also entire companies exist to do that and they charge a lot of money for it.

Re: AV2 video codec delivers 30% lower bitrate than AV1, final spec due in late 2025

#75

Post by cogman10 »

PunchyHamster wrote: post #69
cogman10 wrote: post #57

Earlier quoted context omitted.

I think patents are quickly becoming less of a problem. A lot of the foundational encoding techniques have exited patent protection. H.264 and everything before it is patent free now. It's true you could still accidentally violate a patent but that minefield is clearing out as those patents simply have to become more esoteric in nature.

...till someone decides to patent one of the new techniques used

You can't patent something that's in use. Prior art is a defense to a patent claim/lawsuit.

But that's not my main point. My main point is that we are going down a fitting path with codecs which makes it hard to come up with general patents that someone might stumble over. That makes patents developed by the MPEG group far less likely to apply to AOM. A lot of those more generally applicable patents, like the DCT for example, have expired.

Re: AV2 video codec delivers 30% lower bitrate than AV1, final spec due in late 2025

#76

Post by nickthegreek »

alberth wrote: post #50

Will streaming services ever stop over-compressing their content? I have a top-of-the-line 4K TV and gigabit internet, yet the compression artifacts make everything look like putty. Honestly, the best picture quality I’ve ever seen was over 20 years ago using simple digital rabbit ears. You especially notice the compression on gradients and in dark movie scenes. And yes — my TV is fully calibrated, and I’m paying for…

for the super affluent, https://www.kaleidescape.com/compare/

Re: AV2 video codec delivers 30% lower bitrate than AV1, final spec due in late 2025

#77

Post by amiga386 »

DoctorOetker wrote: post #56
amiga386 wrote: post #16

Earlier quoted context omitted.

Yes, and it's allowing the format to change to allow more cleverness or apply more processing power. For example, changes from one frame to the next are encoded in rectangular areas called "superblocks" (similar to a https://en.wikipedia.org/wiki/Macroblock ). You can "move" the blocks (warp them), define their change in terms of other parts of the same frame (intra-frame prediction) or by referencing previous frames…

In general with movement through scenes it would seem that rectangular update windows seem like a poor match. Is there a reason codec's don't use the previous frame(s) as stored textures, and remap them on the screen? I can move a camera through room and a lot of the texture is just reprojectivetransformed.

> I can move a camera through room

That's what AV1 calls global motion and warped motion. Motion deltas (translation/rotation/scaling) can be applied to the whole frame, and blocks can be sheared vertically/horizontally as well as moved.

Re: AV2 video codec delivers 30% lower bitrate than AV1, final spec due in late 2025

#78

Post by cogman10 »

alberth wrote: post #50

Will streaming services ever stop over-compressing their content? I have a top-of-the-line 4K TV and gigabit internet, yet the compression artifacts make everything look like putty. Honestly, the best picture quality I’ve ever seen was over 20 years ago using simple digital rabbit ears. You especially notice the compression on gradients and in dark movie scenes. And yes — my TV is fully calibrated, and I’m paying for…

> You especially notice the compression on gradients and in dark movie scenes.

That's not a correctly calibrated TV. The contrast is tuned WAY up. People do that to see what's going on in the dark, but you aren't meant to really be able to see those colors. That's why it's a big dark blob. It's supposed to be barely visible on a well calibrated display.

A lot of video codecs will erase details in dark scenes because those details aren't supposed to be visible. Now, I will say that streaming services are tuning that too aggressively. But I'll also say that a lot of people have miscalibrated displays. People simply like to be able to make out every detail in the dark. Those two things come in conflict with one another causing the effect you see above.

Re: AV2 video codec delivers 30% lower bitrate than AV1, final spec due in late 2025

#79

Post by bee_rider »

dajonker wrote: post #4
jonplackett wrote: post #2

It’s pretty amazing people are still finding ways to make video smaller. Is this just people being clever or is it also more processing power being thrown at the problem when decoding / encoding?

I believe patents play a big role here as well. Anything new must be careful to not (accidentally) violate any active patent, so there might be some tricks that can't currently be used for AV1/AV2

It has always seemed very weird to me that compression algorithms were patentable.

1) it harms interoperability

2) I thought math wasn’t patentable?

Re: AV2 video codec delivers 30% lower bitrate than AV1, final spec due in late 2025

#80

Post by amiga386 »

cogman10 wrote: post #78
alberth wrote: post #50

Will streaming services ever stop over-compressing their content? I have a top-of-the-line 4K TV and gigabit internet, yet the compression artifacts make everything look like putty. Honestly, the best picture quality I’ve ever seen was over 20 years ago using simple digital rabbit ears. You especially notice the compression on gradients and in dark movie scenes. And yes — my TV is fully calibrated, and I’m paying for…

> You especially notice the compression on gradients and in dark movie scenes. That's not a correctly calibrated TV. The contrast is tuned WAY up. People do that to see what's going on in the dark, but you aren't meant to really be able to see those colors. That's why it's a big dark blob. It's supposed to be barely visible on a well calibrated display. A lot of video codecs will erase details in dark scenes because…

> but you aren't meant to really be able to see those colors

Someone needs to tell filmmakers. They shoot dark scenes because they can - https://www.youtube.com/watch?v=Qehsk_-Bjq4 - and it ends up looking like shit after compression that assumes normal lighting levels.

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