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Comment by 8K832d7tNmiQ | Hacker News Reader

The real news here is that They still use GPU to transcode their videos whilst other service such as search engine already use TPU for almost a decade now.

I thought they've already use custom chip for transcoding for decades.

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GPUs have specialized hardware for video transcoding, no? So this actually makes sense. The product was already made (although, perhaps not up to Youtube's standard) by GPU manufacturers.

The specialized hardware in GPUs is targeted at encoding content on the fly. While you could use this to encode a video for later playback it has a couple of drawbacks when it comes to size and quality, namely h264, keyframes, static frame allocations, no multipass encoding, etc. ... This is why video production software that supports GPU encoding usually marks this option as "create a preview, fast!". It's fast but that's it. If you want a good quality/size ratio you would use something like VP9 for example. Because of missing specialized hardware and internals of the codec itself currently this is very slow. Add multipass encoding, something like 4k at 60 frames, adaptive codec bitrates and suddenly encoding a second takes a over two minutes ... the result is the need for specialized hardware.

That is interesting, I didn't know that. I thought that doing computation on the GPU sped up encoding for even the high quality presets.

Is there any solid information about Google using TPU for the search engine, or is this an assumption you're making?

This[0] Google blog from 2017 states they were using TPU for RankBrain which is what powers the search engine

[0] - https://cloud.google.com/blog/products/ai-machine-learning/g...

All that power to show me recipes that hemhaw around and spend ten paragraphs to use all the right SEO words.

I feel like the Google results were better 20 years ago, what did they use back then before TPUs?

The web just got worse in a lot of ways, because everything needs to generate money.

I think search results 20 years ago were laughably worse than today.

They had to get special permission from the US government to export TPU's abroad to use in their datacenters. The TPU's fell under ITAR regulations (like many machine learning chips). The US government granted permission, but put some restriction like 'they must always be supervised by an american citizen', which I imagine leads to some very well paid foreign security guard positions for someone with the correct passport...

Read all that on some random government document portal, but can't seem to find it now...

They were actually transcoding on CPUs before, not GPUs

Are TPUs particularly useful for this kind of workload, compared to specialized encoders/decoders available on GPUs?

Yeah I was surprised that it's taken them this long to build custom hardware for encoding videos.

Right, at a competing video site we had vendors trying to sell us specialized encoding hardware most of a decade ago.

i think they do more general purpose things like downsampling, copyright detection etc which doesn't have globally available custom asics. i think gpus don't do encoding/decoding themselves, they have separate asics built in which do the standardised encodings

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