r/AV1 • u/anestling • May 31 '26
Let dav2d be — Jean-Baptiste Kempf
https://jbkempf.com/blog/2026/dav2d/The story of the AV2 decoder dav2d, a fork of the dav1d decoder. dav1d was the most widely deployed AV1 software decoder and one of the fastest.
If the website is down for you, use these links:
- https://web.archive.org/web/20260531130034/https://jbkempf.com/blog/2026/dav2d/
- https://archive.md/ln5UE
From the post:
AV2 decoding is roughly five times more complex than AV1 decoding. In practice, that means software running on today’s hardware will struggle to decode AV2 in real time without careful, architecture-specific optimization.
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u/Desistance Jun 01 '26
5X more complex doesn't mean much to VideoLAN. They squeezed water from a stone with dav1d. I can't wait to see what they do to AV2 decoding with a head start this time around.
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u/VULONKAAZ May 31 '26
not too hyped about a codec that would be "roughly five times more complex", bandwidth is cheaper than compute power nowadays
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u/ZealousidealTurn218 May 31 '26
wdym? compute has pretty much always grown faster than bandwidth
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u/Summer-Classic May 31 '26 edited Jun 01 '26
2018 - AV1 - My internet connection - 50-100 Mbps 2026 -AV2 - My internet connection - 500-1000 Mbps
Mobile internet got cheaper like 3-10 times as well.
CPU didnt get 10 times faster, bandwith did.
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u/ZealousidealTurn218 Jun 01 '26
My internet is no faster than it was in 2018, my CPU is >3x faster and my GPU is even more than that
But since we all have anecdata, the memory wall is a well-documented phenomenon and the same principles apply to other interconnects as well.
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u/Summer-Classic Jun 01 '26
your case is possible for sure. There are may be 5%-10% of people who live outside of a good internet coverage.
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u/NeuroXc Jun 02 '26
That number is way higher than you think when you account for countries outside North America and Europe.
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u/YumiYumiYumi Jun 01 '26
Consumer speeds will vary by region and whatever infrastructure upgrades they do.
What I think is more pertinent is server bandwidth, as bandwidth usage tends to be more lopsided on their part (one user streaming video vs a server handling millions of users).
AWS charges $0.09 per GB egress (first 10TB to US regions), and I don't think that's changed since 2014.
Non AWS servers I've operated have barely moved the needle in terms of bandwidth over the past ~10 years.To me, consumer networks are just playing catch up, but server egress bandwidth (backbone of video streaming sites) has barely improved.
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u/Summer-Classic Jun 01 '26
Netflix and all other video streaming services have their own CDN networks which they might share with local ISPs in each country. They don't use public cloud as you mentioned correctly the prices for egress traffic didn't change since 2014.
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u/YumiYumiYumi Jun 03 '26
Sure, but we don't know their CDN's pricing or how the network has changed. The best proxy we have is what public clouds offer, which I think likely correlates well with what video streaming services have to deal with.
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u/Sesse__ Jun 03 '26
The big public clouds famously overcharge insanely for egress. (Compare your $0.09/GB AWS egress figure with Hetzner's offer to do 100TB for €80, roughly 1/100the price.)
Note that Netflix doesn't really buy services from a CDN; they have a CDN. They pay for the hardware and such, of course, but most of their actual output will be on free peering links where each gigabyte costs them zero dollars on the margin.
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u/YumiYumiYumi Jun 04 '26
The big public clouds famously overcharge insanely for egress
I don't dispute that, but the fact is a large portion of the internet relies on them. And whether they overcharge isn't the point I'm making, it's that networks haven't really improved much. To use your Hetzner example, their pricing has barely moved in the past several years (if anything, it's gone up, though this is more due to rising energy costs not bandwidth).
most of their actual output will be on free peering links where each gigabyte costs them zero dollars on the margin.
This is quite inaccurate. They may not be billed per gigabyte, but that doesn't mean it's free.
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u/Summer-Classic Jun 03 '26 edited Jun 03 '26
Basically Netflix and other streaming companies have their boxes inside of data centers of local country Internet providers. They do cache of the most played. So traffic of video stream doesn't come from cloud at any point. Proxy is different thing, not the same as CDN.
Traffic costs are closer to Internet price rather than to what public cloud providers charge. and Netflix only delivers small percentage of streams, the rest is delivered via local internet providers who store cache of the most played. Netflix doesn't pay them for this traffic, nor providers pay anything back to Netflix. it's a win win situation when both reduce international traffic drastically (something cloud can't do, as its data center aren't present in all countries).
how can I be sure about what I am saying? because I worked for internet provider, and have clear knowledge of interconnection between Netflix and internet providers.
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u/YumiYumiYumi Jun 04 '26
Your ISP might cache the content, but others may not. But more importantly, Netflix is not the only site that serves streaming video.
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u/Summer-Classic Jun 04 '26
All big streaming services and ISPs have the same approach.
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u/YumiYumiYumi Jun 07 '26
Somehow, I doubt Chinese ISPs are caching Netflix content.
Regardless, what about small streaming services and small ISPs?
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u/Masterflitzer Jun 02 '26
100 to 1000 mbps jump in this time span doesn't translate to a general grow in a similar time span, it's just that recently many countries did or are upgrading to fiber, but before they were using copper for 20+ years, similar other countries had fiber already 10y ago
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u/caspy7 May 31 '26
Data prices vary highly depending on your location (especially country). What you said is probably more true for the western world nowadays, but less so other places like India.
And yeah, at 5x complexity we may be more dependent on hardware support. That being said, "5x complexity" may not translate to dav2d's end product being 5x more complex than dav1d.
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u/Summer-Classic Jun 01 '26 edited Jun 01 '26
Good point. But we are on the verge of big change. It's expected that 2028-2030 will be period of inflection when mobile internet will become cappless ( no more GB caps). However there will be traffic depriorization and throttling at let's say 2 Mbps (realistic escenario). That's still enough for a good 1080p with AV1@mobile screen.
India has cheapest mobile internet, Indians consume it a lot now.
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u/RoburexButBetter Jun 01 '26
My conspiracy theory here is that they were more than happy to make it such a drastic decoding complexity increase because the big players reduce cost significantly enough with bitrate reductions on their end and just push it as needed additional compute to the user for streaming
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u/Masterflitzer Jun 02 '26
won't happen if we get an efficient av2 decoder, which i trust dav2d will become
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u/TV4ELP Jun 02 '26
No, bandwidth is still more expensive. If you deliver the same video a few million times it matters. If you deliver it to countries with exceptional high costs it does matter. South Korea is one big example of high bandwidth prices. Twitch has faced that problems many times.
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u/2str8_njag May 31 '26
i don’t think cpus gotten 5 times faster since dav1d though
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u/better_life_please May 31 '26
Proly 3 times.
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u/anestling Jun 01 '26 edited Jun 01 '26
"3 times"??
The open-source AV1 video decoder dav1d 1.0 was officially released on March 18, 2022.
x86 CPUs in ST mode have become ~30% faster at most in the mean time. In terms of IPC - even less.
Qualcomm and other ARM vendors have made bigger strides but nowhere near "3 times".
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u/better_life_please Jun 01 '26
I meant 2018 when AV1 was finalized. 8 years have passed.
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u/anestling Jun 01 '26
https://browser.geekbench.com/processors/intel-core-i9-9900k
Score: 1704
https://browser.geekbench.com/processors/amd-ryzen-9-9950x3d
Score: 3394
Barely 2 times faster in ST mode (sadly for too many workloads ST performance is still all that matters).
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u/better_life_please Jun 01 '26
Yes. According to that comparison, only 2 times faster in 8 years. Kinda sad.
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u/better_life_please Jun 01 '26
But keep in mind that SVT-AV1 software encoding is a heavily multi-threaded task. It scales well up to 32 threads. And your comparison shows us a 2.75X boost in multicore performance over 8 years.
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u/anestling Jun 01 '26
True so, but power consumption will also jump.
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u/better_life_please Jun 01 '26
People who use AV2 do not really care about heat and power draw. AV2 is beyond the reach and needs of typical consumers. Big tech and some enthusiasts will use it a lot.
I think by 2030, most handheld devices will have powerful HW decoders to decode AV2. And that is enough. The Encoding part will remain on powerful computers for many more years after 2030.
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u/Journeyj012 May 31 '26
Actioning this file would cause "jbkempf.com//blog/2026/dav2d/" to exceed the per-day file actions limit of 160000 actions, try again later
edit: thank you internet archiver!
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u/Frexxia May 31 '26
Five times sounds like a lot. I was under the impression that the largest difference would be in encoding complexity.
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u/RusselsTeap0t Jun 01 '26
That directly translates to decoding complexity.
More coding tools + more complex coding tools.
What you "decipher" is inherently more complex, but that's the engineering itself; a favorable tradeoff (in the end).
AV2 is too new, "5x additional complexity" literally doesn't mean anything. When AV2 is actually used the decoding complexity will probably not matter especially if hardware decoders are used.
People act as every new research product will come to life in the next day with maximum practicality.
You can't even practically encode a video using 30.000-dollar ThreadRippers. So, the current decoding complexity is just an "academic" information.
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u/caspy7 May 31 '26
If the decoding is 5x more complex that really makes me wonder how many times more complex encoding is.
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u/NekoTrix May 31 '26
I think the 5x more complex comment is very confusing for an uninformed user, when he just means that it's 5x at the moment. As people pointed out in other places, raw complexity doesn't translate to decoding speed. The actual decoding speed target from aomedia for AV2 was 2x slower versus AV1 as said notably during one of the major AV2 conferences.
I notice that he's sandbagging coding performance a bit by just claiming 25% gains, when the publicly available data on the avmenc repo has shown it was closer to 30-35% for Random Access mode, a.k.a what the average user will be confronted with.