dav1d has 240,000 lines of handwritten assembly — 79.9% assembly, 19.6% C, 0.5% other. Every cycle matters because we are talking about three billion devices decoding video nonstop.
The AV1 decoder dav1d is composed of 240,000 lines of handwritten assembly (79.9%), making it one of the largest assembly codebases, essential for software decoding on billions of devices lacking hardware decoders. ✦ AI generated
Jean-Baptiste Kempf · Lex Fridman · 2026-05-06 · original ↗
starts at this moment · 0:45
And just this one has two hundred and forty thousand. Every cycle matters. We are talking about probably three billion devices which are going to decode video nonstop because, for example, thirty percent of the video from Netflix is now in AV1, fifty percent of YouTube. — This is what peak video codecs should look like. — Seventy-nine point nine percent assembly, nineteen point six percent C, and zero point five percent other.
verbatim transcript · starts at 0:45
0:45- FFmpeg has one hundred thousand lines of assembly for all the codecs. - For all codecs. Mm-hmm. - And just this one has two hundred and forty thousand. Every cycle matters. We are talking about probably three billion devices which are going to decode video nonstop because, for example, thirty percent of the video from Netflix is now in AV1, fifty percent of YouTube. - This is what peak video codecs should look like.
1:11Seventy-nine point nine percent assembly, nineteen point six percent C, and zero point five percent other. - And what's incredible is with those tweets, which is factual, people get crazy. - For the last two years, they go crazy. No, intrinsics is fine. The compiler- - You can optimize your compiler. Auto-vectorization, it's your fault. You don't understand. And we've tried that forever, right? - For two years, and two years later, showing hundreds of examples
1:40of handwritten assembly. No, no, no, you're doing it wrong. The compiler can do this. The intelligence agencies tried to, like, say, "Can you put a backdoor in VLC?" - Yes. Two of them. - Well, what did you say? - No. Well, I was a lot less polite. - Basically saying, "Hell no." - Like, if we had to compromise our software, we would shut it down. This is clear.
2:00- Any tweets Kieran, you regret? - Tweets I regret? - Or is it like that, how does the French song go? Regret nothing. - Don't regret anything. No, it's because regrets are attacks on your mind. - The following is a conversation all about FFmpeg and VLC with Jean-Baptiste Kempf and Kieran Kunhya. FFmpeg is an open source software system that is the invisible backbone behind YouTube, Netflix, Chrome,
2:33VLC, Discord, and basically every platform that touches video or audio on the internet. It can decode, encode, transcode, stream, and play almost any video or audio format ever created. To me, it is one of the most incredible software systems ever developed, and it's all done by volunteers. VLC is also a legendary piece of software. It is an open source media player that plays basically anything you throw at