Jean-Baptiste Kempf

Kempf defined multimedia as a digital representation of streams for the human senses and said FFmpeg and VLC will eventually handle odour, haptics and brainwaves.

“multimedia is a digital representation of several streams for the human senses. And we will do that”

Lex Fridman Podcast: #496 – FFmpeg: The Incredible Technology Behind Video on the Internet (May 6, 2026) · Listen from 4:13:44

Kempf advised new open-source contributors to work on something they love, and said contributing to FFmpeg is the best programming education available.

“Work on something you love. I am working on VLC because I love movies”

Lex Fridman Podcast: #496 – FFmpeg: The Incredible Technology Behind Video on the Internet (May 6, 2026) · Listen from 1:35:07

Kempf said the core maintainer teams are tiny — about five people for VLC and ten to fifteen for FFmpeg — which is why code quality standards must be uncompromising.

“The core community of VLC is five people. The core community of FFmpeg is 10 to 15”

Lex Fridman Podcast: #496 – FFmpeg: The Incredible Technology Behind Video on the Internet (May 6, 2026) · Listen from 57:40

Kempf said two intelligence agencies asked for a backdoor in VLC and he refused, adding that VideoLAN would shut the software down rather than compromise it.

“If we had to compromise our software, we would shut it down. This is clear”

Lex Fridman Podcast: #496 – FFmpeg: The Incredible Technology Behind Video on the Internet (May 6, 2026) · Listen from 3:58:22

Kempf said he turned down tens of millions of dollars in toolbar, spyware and advertising offers because he considered them unethical and a betrayal of contributors.

“Yes, I could be a multimillionaire and be somewhere on the beach. But I did not do it because I thought it was not moral and it was not the right thing to do”

Lex Fridman Podcast: #496 – FFmpeg: The Incredible Technology Behind Video on the Internet (May 6, 2026) · Listen from 1:02:13

Kempf said VLC deliberately ignores file extensions and probes file contents because it was built to handle broken and untrusted input.

“we discard the file format, right? We look into the file to understand what's in it”

Lex Fridman Podcast: #496 – FFmpeg: The Incredible Technology Behind Video on the Internet (May 6, 2026) · Listen from 27:32

Kempf said HEVC licensing became unmanageable, with multiple patent pools and uncapped fees potentially costing large streamers hundreds of millions of dollars per year, which motivated the creation of AV1.

“for YouTube or Netflix, we could talk about hundreds of millions of dollars of licensing for patents per year”

Lex Fridman Podcast: #496 – FFmpeg: The Incredible Technology Behind Video on the Internet (May 6, 2026) · Listen from 3:52:09

Kempf said Kyber currently achieves seven milliseconds glass-to-glass latency between machines and is targeting four milliseconds.

“So far, we achieve seven milliseconds from Windows to Windows or Windows to Mac”

Lex Fridman Podcast: #496 – FFmpeg: The Incredible Technology Behind Video on the Internet (May 6, 2026) · Listen from 3:40:21

Kempf said he received a death threat containing powder after deciding to stop maintaining VLC's PowerPC port around 2009-2010.

“So I received a death threat with some powder in it, right?”

Lex Fridman Podcast: #496 – FFmpeg: The Incredible Technology Behind Video on the Internet (May 6, 2026) · Listen from 2:50:24

Kempf said Rust is excellent for new projects but advised against rewriting existing codebases, because reading code is far harder than writing it.

“It is an order of magnitude easier to write code than read code”

Lex Fridman Podcast: #496 – FFmpeg: The Incredible Technology Behind Video on the Internet (May 6, 2026) · Listen from 2:34:24

Kempf said roughly 30% of Netflix video and 50% of YouTube video is now delivered in AV1, often decoded in software because few devices have hardware decoders.

“30% of the video from Netflix are now in AV1. 50% of YouTube, right?”

Lex Fridman Podcast: #496 – FFmpeg: The Incredible Technology Behind Video on the Internet (May 6, 2026) · Listen from 2:13:53

Kempf said dav1d contains roughly 30,000 lines of C and 240,000 lines of handwritten assembly, more than all of FFmpeg's assembly combined.

“We are talking about 30,000 lines of C, but 240,000 lines of handwritten assembly, right? Handwritten assembly, 240,000 lines”

Lex Fridman Podcast: #496 – FFmpeg: The Incredible Technology Behind Video on the Internet (May 6, 2026) · Listen from 2:12:25

Kempf said VideoLAN's only effective leverage with large platform companies is public pressure on social media, citing a year-long inability to update VLC on the Android Play Store.

“The only way we got someone to answer was to put a very spicy, as you say, tweet saying that we were going to stop distributing VLC for Android”

Lex Fridman Podcast: #496 – FFmpeg: The Incredible Technology Behind Video on the Internet (May 6, 2026) · Listen from 1:26:23

Kempf said relicensing libVLC from GPL to LGPL required personally tracking down more than 350 individual contributors because copyright remains with each author.

“if you want to properly re-license, you need to find all the contributors. And at that time, I had to contact more than 350 people”

Lex Fridman Podcast: #496 – FFmpeg: The Incredible Technology Behind Video on the Internet (May 6, 2026) · Listen from 53:07

Kempf argued that video and audio compression is designed around human perception rather than lossless data reduction, which is why YUV is used instead of RGB.

“all the compressions that we do, and that's very important, people forget about that, is to be viewed by humans”

Lex Fridman Podcast: #496 – FFmpeg: The Incredible Technology Behind Video on the Internet (May 6, 2026) · Listen from 20:04