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Comment by tjoff | Hacker News Reader

Webapps limited by 4GiB memory?

Sounds about right. Guess 512 GiB menory is the minimum to read email nowadays.

I know you're in this for the satire, but it's less about the webapps needing the memory and more about the content - that's why I mentioned video editing webapps.

For video editing, 4GiB of completely uncompressed 1080p video in memory is only 86 frames, or about 3-4 seconds of video. You can certainly optimize this, and it's rare to handle fully uncompressed video, but there are situations where you do need to buffer this into memory. It's why most modern video editing machines are sold with 64-128GB of memory.

In the case of Figma, we have files with over a million layers. If each layer takes 4kb of memory, we're suddenly at the limit even if the webapp is infinitely optimal.

> 4GiB of completely uncompressed 1080p video in memory is only 86 frames

How is that data stored?

Because (2^32)÷(1920×1080×4) = 518 which is still low but not 86 so I'm curious what I'm missing?

Apparently with 24 bytes per pixel instead of bits :) Although to be fair, there's HDR+ and DV, so probably 4(RGBA/YUVA) floats per pixel, which is pretty close..

I would guess 3 colour channels at 16bit (i.e. 2 bytes)

(2^32)÷(1920×1080×4×3×2) = 86

Where does the 4 come from? I thought it was R+G+B+A, but you already have 3 colour channels in that calculation

Yep, my logic is faulty there. And even if we assume that it's 24bpp color, that's still a factor of 2 out.

> How is that data stored?

So glad you asked. It's stored poorly because I'm bad at maths and I'm mixing up bits and bytes.

That's what I get for posting on HN while in a meeting.

I'm strange to webdev, but can't you swap the remaining uncompressed frames that don't fit into memory to disk?

It doesn't actually allocate 4 GiB. Memory can be mapped without being physically occupied.

No, web apps can actually use 4GB of memory (now 16GB apparently).

In fairness, this is talking about Figma, not an email client

Finally a web browser capable of loading slack

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