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Dav2d

jbkempf.com

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Re: Dav2d

#101

Earlier quoted context omitted.

Is there a compelling reason encoding needs to be done locally? The point of encoding is to reduce downstream bandwidth for the viewer, and upstream bandwidth for the distribution network. The content creator only needs to upload it once.

Video calls & streaming.

this

for other cases, I can just wait more for my cpu/gpu/cloud to do the job

Re: Dav2d

#102
post #60

Earlier quoted context omitted.

Intel's Arc dGPUs were really compelling for dedicated AV1 encode and decode, especially the small form factor of some cards. You could even fit it as a secondary card in a PC dedicated to recording and encode workflows for OBS. Hope we get a similar option with future lineups that support AV2, especially given how popular video creation and streaming are now.

Is there a compelling reason encoding needs to be done locally? The point of encoding is to reduce downstream bandwidth for the viewer, and upstream bandwidth for the distribution network. The content creator only needs to upload it once.

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Re: Dav2d

#103

Earlier quoted context omitted.

I don't know if I'm underestimating HN's reach but I doubt we did that, probably traffic from a much bigger aggregator/forum

You are underestimating HN's reach, this happens all the time. As someone who has been on the front page of HN it's a pretty big rush in traffic!

I'd wager that the load is amplified by other sites that treat HN as a goldmine of tasty links.

Re: Dav2d

#104
post #7

Sorry if this sounds naive, but does it make sense to write a codec library in C/ASM considering how well Rust is progressing, especially when, as the author puts it, AV2 decoding is roughly five times more complex than AV1 decoding ?

I don't know why you've been down-voted. It definitely isn't an optimal decision. A video codec isn't all assembly. There's plenty of plain unsafe C code. E.g. this is the first random file I clicked. It has a ton of raw C pointer stuff just begging to be exploited. https://code.videolan.org/videolan/dav2d/-/blob/main/src/dat... There is a project to write an AV1 decoder in Rust: Rav1d (really stretching the name her…

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Re: Dav2d

#105
post #7

Sorry if this sounds naive, but does it make sense to write a codec library in C/ASM considering how well Rust is progressing, especially when, as the author puts it, AV2 decoding is roughly five times more complex than AV1 decoding ?

yes it makes sense to use C/ASM here, but if you're curious, there is a rust port of dav1d named rav1d: https://github.com/memorysafety/rav1d it's not much slower than the original C/ASM implementation (last i checked ~5%?) but that matters here

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Re: Dav2d

#106
post #7

Sorry if this sounds naive, but does it make sense to write a codec library in C/ASM considering how well Rust is progressing, especially when, as the author puts it, AV2 decoding is roughly five times more complex than AV1 decoding ?

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Re: Dav2d

#107
post #7

Sorry if this sounds naive, but does it make sense to write a codec library in C/ASM considering how well Rust is progressing, especially when, as the author puts it, AV2 decoding is roughly five times more complex than AV1 decoding ?

Encoder and decoder writers frequently need extremely fine grain control over SIMD instructions in order to get good performance. The way they weave these instructions can be very hard to express with a high level language. Further, there's a ton of work with arrays and importantly parts of arrays. They can, for example, need to extract every other element up to 1/2 the array. Unfortunately, rust has runtime array bo…

Performance should not be priority #1. Security should be. Why do we slow down all CPUs to prevent SPECTRE attacks yet continue to write in C? As rav1d shows, the perf loss is far less to migrate from C to Rust than it is to apply SPECTRE mitigations, and adding a sandbox around a memory-unsafe codec is going to be way more expensive again than using Rust code to start.

Re: Dav2d

#108
post #78

Earlier quoted context omitted.

And then AV3: Tokyo Drift, and after that AV Episode 1.

Or go the Apple Watch naming scheme route. Just “AV” Next, AV Series 1 and 2 (released simultaneously) Later, AV Edition but it costs $10,000

AV360. AV365. AV2030. AVXP. AV8. AV10. Perhaps some here will be around for AV95.

Young AV?

Re: Dav2d

#109
post #66

Earlier quoted context omitted.

Too much traffic from HN? ``` Too Many Requests The page you have tried to access is not available because the owner of the file you are trying to access has exceeded our short term bandwidth limits. Please try again shortly. Details: Actioning this file would cause "jbkempf.com//blog/2026/dav2d/" to exceed the per-day file actions limit of 160000 actions, try again later ```

I don't know if I'm underestimating HN's reach but I doubt we did that, probably traffic from a much bigger aggregator/forum

Hacker news doesn't generate much traffic, despite what people are saying.

The host here has a limit of 160000 files served each day. That is extremely low. If the site has an icon, css, a js file and a few images it's 10 files each visit. That's will limit it to 16k visits/day. If there are more files loaded it might just handle a few thousand visits, and they have received more than that from HN now.

Re: Dav2d

#110

Earlier quoted context omitted.

Is there a compelling reason encoding needs to be done locally? The point of encoding is to reduce downstream bandwidth for the viewer, and upstream bandwidth for the distribution network. The content creator only needs to upload it once.

Well yes? The platforms only accept certain resolution/bitrates and also most of America isnt running 1gig up. They're running 5-30 mbps up. So yeah they need to encode it.

> They're running 5-30 mbps up

Do you not have 98% high speed 5G coverage?

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