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Kieran Kunhya

๐Ÿ‘ค Speaker
1922 total appearances

Appearances Over Time

Podcast Appearances

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

Here, we are degrading the signal, right?

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

And so we need to degrade both the audio and the video signal in the best way possible.

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

And we can do that, but it involves

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

first, a lot of theoretical knowledge about how it works, the eye works, but a lot of mathematical change, a lot of mathematical tricks, right?

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

For example, when you move to RGB and you go to YUV, for example, what we do very often is that we scale down the resolution of the color compared to the brightness.

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

And most of the time, and just this without compression, it divides the size by two.

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

But most people don't see it, right?

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

And so on and so on, right?

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

And then you go to very complex mathematical change.

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

So of course, Fourier's transform, which de facto are not Fourier transform, they are like

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

discrete continuous transform, but that's the same idea.

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

So frequency domain, we split the video by blocks, right?

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

So that's why when it's wrongly decoded, you see those blocks and badly encoded, you see those blocks and so on to arrive to compression states that are insanely high, right?

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

And each generation of the codec is like 30% less for the same quality, right?

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

And this requires amount of power, of computational power that are huge.

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

So what happens is globally is that you have an address, right, which gives you, with the operating system, a stream of bytes, a stream of data, right?

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

And this is the first step.

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

And the second step arises with demuxing, where you're going to separate audio, video, subtitle in type of different tracks.

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

And then on each of those tracks, you're going to decompress them, decode them, either audio with an audio codec, video to video codec, and subtitle to subtitle codec.

Lex Fridman Podcast
#496 โ€“ FFmpeg: The Incredible Technology Behind Video on the Internet

And once you've decompressed those type of things, you have raw images, raw, and then you're going to talk with your graphic card in your screen and display that.