Dav2d

(jbkempf.com)

172 points | by captain_bender 2 hours ago

11 comments

  • jordand 1 hour ago
    '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'

    AV1 software decoding is already very intensive so AV2 decoding benchmarks are the next thing that would be really interesting (or mortifying) to see.

    • mrbluecoat 38 minutes ago
      I came to post this as well. Until widespread, inexpensive hardware catches up to a 2018 codec, AV# will remain a niche ideal.
      • breve 27 minutes ago
        Hardly niche. My laptop isn't new and it has hardware AV1 decoding and encoding. My 10 year old iPhone 7 can play 1080p AV1 video in software for over 200 minutes with VLC. The iPhone 7 was released in 2016, a year and a half before AV1. The dav1d decoder is mighty.

        Netflix uses AV1: https://netflixtechblog.com/av1-now-powering-30-of-netflix-s...

        YouTube uses AV1. It's tough to be more mainstream than that.

        Right click on a YouTube video and select Stats for Nerds. If your system is capable of it, chances are it will be playing back in AV1.

        Most of the YouTube videos I watch these days are AV1 encodes. Sometimes it's in VP9 and occasionally it's H.264.

        • sylware 7 minutes ago
          Same. Mostly AV1, sometimes VP9, and rarely h264.

          What's missing mostly: live streams which are h264.

          Currently, and I say currently, dav1d is so fast, no worries on that side.

    • jbk 1 hour ago
      > AV1 software decoding is already very intensive so AV2 decoding benchmarks are the next thing that would be really interesting (or mortifying) to see.

      Yes, this is going to be fun to watch.

  • remix2000 31 minutes ago
    > Make it fast on older desktop, by writing asm for SSSE3+ chips

    I guess 5 years ago (around the time when Intel stopped making SSE-only chips) is technically "older", but I wouldn't prioritize avx2 when devices intended for consuming media definitely experience much less pressure to upgrade than workstations…

  • Slurpee99 1 hour ago

      ... improvements around 25% compared to AV1
    
      AV2 decoding is roughly five times more complex than AV1 decoding
    
    I'm not sure what these two lines mean or if we can compare them, any help?
    • whynotmaybe 1 hour ago
      I understood it as compression is 25% better : a quality of 10mbps in av1 can be achieved with 8mbps in Av2. But, it needs 5 times more compute power for this 25% gain.
    • jbk 1 hour ago
      > I'm not sure what these two lines mean or if we can compare them, any help?

      AV2 saves 25% bandwidth at the cost of 5x more decoding complexity.

      • 0x1ceb00da 22 minutes ago
        What does "complexity" mean here? Computation required?
    • croes 1 hour ago
      Smaller files but harder to decode
  • husky8 55 minutes ago
    Is codex working on novel decoders 24/7? I hope
  • latexr 40 minutes ago
    When AV1 was first announced, I got the impression the name was chosen partly as a pun/reference/homage to AVI, the classic but outdated format with used to be popular. Then when I saw Dav1d, OK, good way to continue the pun.

    But now with AV2 and Dav2d, that completely breaks. Are we eventually going to get AV3/Dav3d and AV4/Dav4d, which will read like Ave/Daved and Ava/Davad? Seems a bit awkward. Was the idea from the start to have the 1 be the version number, and have it specifically be part of the name?

    • jl6 29 minutes ago
      1dav2codecs?

      2av2furious?

      • Hendrikto 8 minutes ago
        And then AV3: Tokyo Drift, and after that AV Episode 1.
    • Arubis 28 minutes ago
      Dav3d could potentially work as a Snow Crash reference.
    • WhrRTheBaboons 36 minutes ago
      > experience Dav... Now in 3D!
  • the__alchemist 16 minutes ago
    Not to be confused with Da4vid (world-class hacker and owner of the Black sun) or D4vd (rap artist and alleged murderer)
    • staindk 3 minutes ago
      Or Dave2D, popular tech youtuber
  • anoncow 47 minutes ago
    I thought this was about Dave2D
    • rob 38 minutes ago
      I was thinking "Dav1d really changed his appearance since the murder charge."
  • GaggiX 1 hour ago
    I would love to see comparisons with AV1 on very low bitrates.
  • poly2it 1 hour ago
    Sorry if this sounds naive, but does it make sense to write a codec library in C/ASM considering how well Rust is progressing, especially when, as the author puts it, AV2 decoding is roughly five times more complex than AV1 decoding?
    • Arodex 57 minutes ago
      The algorithms deployed in these kind of codecs take into account not only human vision and mathematical laws of information, but also nitty-gritty details of how computers work, which are optimally exploited by directly having humans write detailed assembly rather than a compiler make a best guess and effort.
    • jbk 1 hour ago
      Because it's 5 times more complex, you need to get the maximum performance available. Therefore more ASM than ever.

      Rust does not bring more performance. Just more safety.

    • cogman10 37 minutes ago
      Encoder and decoder writers frequently need extremely fine grain control over SIMD instructions in order to get good performance.

      The way they weave these instructions can be very hard to express with a high level language.

      Further, there's a ton of work with arrays and importantly parts of arrays. They can, for example, need to extract every other element up to 1/2 the array. Unfortunately, rust has runtime array bounds checks which make writing that sort of code slower. The compiler can elade those checks, but usually only in simple cases.

      The authors would be writing a bunch of unsafe rust to get the performance they want and rust makes that more painful on purpose.

      I like rust, but C/ASM really is the right choice here. This is one of the few cases where rust's safety is a major detriment.

    • muhbaasu 30 minutes ago
      The ffmpeg devs have said many times in public that they routinely get speedups of 10x or more over C code. I'm not a reputable source on this myself but I highly recommend looking into their channels, mails, or posts.
    • Telaneo 1 hour ago
      Go ask FFmpeg what they're writing their encoders and decoders in.
      • latexr 46 minutes ago
        That isn’t particularly helpful to someone asking a question in good faith. What others are using doesn’t clarify why they are using it. Plus, FFmpeg is itself a decade older than Rust. The OP is asking about starting a new project today.
        • Telaneo 17 minutes ago
          > What others are using doesn’t clarify why they are using it.

          It does if you ask them, or at least research the topic at hand.

    • MattRix 58 minutes ago
      Yes? There is 5x more code to optimize the ASM for.
  • aetherspawn 52 minutes ago
    Ok whose idea was ‘Wiener filtering’
  • Eldodi 1 hour ago
    How is AV2 expected to avoid the patent-pool issues AV1 ran into?

    AV1 was designed as royalty-free, but Sisvel’s pool and the recent Dolby/Snap proved the contrary.

    https://accessadvance.com/2026/03/24/access-advance-licensor...

    • UnlockedSecrets 1 hour ago
      They filed a suit, henceforth making a claim of an issue...... They haven't "proved" anything other then they have lawyers on staff that can file some paperwork until the suit is settled in court...
    • AndrewDucker 1 hour ago
      How does that prove anything?

      They're claiming that there are patents, but that doesn't mean there are.

      • Eldodi 1 hour ago
        Dolby is only the most recent case, Sisvel consorsium actually bills licences per device:

        Consumer Display Device: EUR 0.32

        Consumer Non-Display Device: EUR 0.11

        (source here: https://www.sisvel.com/licensing-programmes/audio-and-video-...)

        • zamadatix 36 minutes ago
          Sisvel allows you to pay them if you believe their claims, they haven't actually taken anyone not paying to court yet to prove that. The only court cases for VP9/AV1 from Sisvel so far have been their patents being found invalid/irrelevant.

          Dolby is somewhat more interesting in that rather than scare tactics, media hype, and attempting to form a pool about it they are actually taking a patent assertion claim to court.

        • UnlockedSecrets 1 hour ago
          How does how they bill for their product, matter in terms of if their lawsuit holds merit?
        • silotis 45 minutes ago
          Can you point to any other patent lawsuit over AV1? AFAIK the Dolby case is the first.
        • croes 1 hour ago
          That doesn’t prove their claims are valid.

          I can claim the same and offer licenses per device.

    • croes 1 hour ago
      No codec can ever avoid patent-pool claims.
    • Arodex 1 hour ago
      Every single AV2 news here in the last week has seen exactly the same question.

      Either go back read the answers there first, or I will assume you are part of a FUD campaign (yes, I know HN guidelines, but again every single AV2 news in the last week has seen the same rhetorical "questions" as top "comments").