Lyra audio codec enables high-quality voice calls at 3 kbps bitrate • Hacker News Board

Re: Lyra audio codec enables high-quality voice calls at 3 kbps bitrate

#121

Post by 908B64B197 » Tue, Mar 02, 2021, 1:06 AM UTC

colordrops wrote: post #75

rectang wrote: post #53

Earlier quoted context omitted.

Between miserable latency, not-so-great fidelity, and the fecklessness of phone companies in the face of the robocall epidemic, I have come to hate phone calls. I'm rooting for something to replace phone communications. Any chance that Matrix can do better on any of those fronts? Especially on fidelity and latency since they're germane to the high-level subject of this discussion.

One conspiracy theory is that tech companies have lobbied to prevent real action on robo-calls, in order to get people like you to hate calls and migrate to online services.

I don't think the FCC needed any lobbying to do nothing for the consumer these last few years.

Re: Lyra audio codec enables high-quality voice calls at 3 kbps bitrate

#122

Post by bentcorner » Tue, Mar 02, 2021, 1:09 AM UTC

kroltan wrote: post #116

bentcorner wrote: post #94

Earlier quoted context omitted.

I'm glad you bring up latency - I've experienced several second latency in discord and it's really terrible when it happens (diagnosed via side-channel). The worst thing is that the app does nothing to try to salvage the conversation and the app doesn't tell you it's in a degraded state, so you'd never know this was a problem.

It has a quality indicator on the bottom right, and if you click it there's a nice chart that shows the latency. https://i.imgur.com/vR7NSpG.png Or are you talking about something else?

Well, I stand corrected. I'll take a look at that chart next time I experience something like that happening. I haven't seen this UI before. Thanks!

Re: Lyra audio codec enables high-quality voice calls at 3 kbps bitrate

#123

Post by pabs3 » Tue, Mar 02, 2021, 1:11 AM UTC

motiejus wrote: post #8

Nothing about licensing or patents. I assume the worst (read: unusable for small businesses)? 10+ years ago I worked in a small voip shop, where we had very high quality (low jitter), but low bandwidth connection. I researched many codecs of the time (2010-ish). We liked speex, because it can be used "without strings attached". Also, I can choose the quality depending on the bandwidth. Although for low bandwidth g729…

The G.729 patents are now royalty-free btw:

https://web.archive.org/web/20170202062530/http://www.sipro.... https://en.wikipedia.org/wiki/G.729

Re: Lyra audio codec enables high-quality voice calls at 3 kbps bitrate

#124

Post by javajosh » Tue, Mar 02, 2021, 1:13 AM UTC

bscphil wrote: post #98

domoritz wrote: post #95

Earlier quoted context omitted.

Off topic but how do you put images on ipfs and what’s the advantage over e.g. Imgur?

Cloudflare are kindly hosting [1] a free HTTP gateway for the IPFS [2] network. So I can host an image myself on a server with IPFS, and Cloudflare will cache it for me. This is better than Imgur because the latter has been redirecting users to annoying "social" pages with ads instead of showing them the actual image, at least in some cases. I also can't be sure whether Imgur recompresses your uploads or not - I assu…

Is hosting the image yourself, on like a $5 Digital Ocean Droplet and a $10 personal domain, out of the question? This would seem to be the ideal situation in terms of simple, decentralized file hosting solution. What are the downsides of this approach?

(I can imagine a server package that can modify index.html sub-resource URLs depending on current server load, preferring private, locally hosted sub-resources but willing to use 3rd party solutions like Cloudflare, too, if required by a black swan event.)

Re: Lyra audio codec enables high-quality voice calls at 3 kbps bitrate

#125

Post by bscphil » Tue, Mar 02, 2021, 1:30 AM UTC

adrianmonk wrote: post #115

bscphil wrote: post #79

I've just taken a minute to confirm what my ears told me in Audacity. Please have a look at this screenshot: https://cloudflare-ipfs.com/ipfs/Qma41RMzieQ6ZGdGem9rLxnxEL1... The Lyra version is clearly much louder. This is a serious problem and it borders on being reasonable to call it "cheating". It's well known in the audio biz that if you ask people to compare two experiences, and one of them is a bit louder than t…

Definitely a real effect, but it seems like Google accounted for that in their listening tests. The Google blog post links to the Lyra paper[1], and Section 5.2 of the paper says: > To evaluate the absolute quality of the different systems on different SNRs a Mean Opinion Score (MOS) listening test was performed. Except for data collection, we followed the ITU-T P.800 (ACR) recommendation. You can download those ITU…

That's good information, thanks. My comment is mostly directed at the misleading blog post. I have no direct reason to believe that the study itself was compromised, though it would be great to have confirmation from the authors that it was not.

The part about matching volume levels in the ITU recommendation seems to be talking about making sure the source recordings were balanced. All their clips might well have been exactly at the ITU recommended level of -26 dB, but if Lyra introduced a level mismatch this would have to have been corrected at a later stage, and it's at least possible that it might not have been. The Lyra paper does explicitly say that they didn't follow the ITU rec for "data collection".

Interestingly, the Opus and Reference sources are almost exactly -26 dB relative to full scale (according to several measurements of loudness), but the Lyra clip is about 6 dB hotter. So the source (the reference clip) exactly follows the ITU rec. Did they remember to fix the levels on the Lyra clips? I hope so!

Re: Lyra audio codec enables high-quality voice calls at 3 kbps bitrate

#126

Post by bscphil » Tue, Mar 02, 2021, 1:47 AM UTC

javajosh wrote: post #124

bscphil wrote: post #98

Earlier quoted context omitted.

Cloudflare are kindly hosting [1] a free HTTP gateway for the IPFS [2] network. So I can host an image myself on a server with IPFS, and Cloudflare will cache it for me. This is better than Imgur because the latter has been redirecting users to annoying "social" pages with ads instead of showing them the actual image, at least in some cases. I also can't be sure whether Imgur recompresses your uploads or not - I assu…

Is hosting the image yourself, on like a $5 Digital Ocean Droplet and a $10 personal domain, out of the question? This would seem to be the ideal situation in terms of simple, decentralized file hosting solution. What are the downsides of this approach? (I can imagine a server package that can modify index.html sub-resource URLs depending on current server load, preferring private, locally hosted sub-resources but wi…

Out of the question? No. As convenient as running one command on a desktop computer? Also no.

> the ideal situation in terms of simple, decentralized file hosting solution

Not sure what you mean by "decentralized" if you are in fact hosting it yourself.

> What are the downsides of this approach?

Well, for the casual person it has the obvious downside that you have to have your own VPS. Most people don't have those. Even if you do, IPFS has a couple of advantages: you can host images anonymously, and anyone anywhere in the world can "pin" the image to make sure it stays live. If you're using a server and you forget to pay DO your $5 one month, all your images go poof into the ether.

Re: Lyra audio codec enables high-quality voice calls at 3 kbps bitrate

#127

Post by bscphil » Tue, Mar 02, 2021, 1:58 AM UTC

kixiQu wrote: post #52

rectang wrote: post #39

What I want to know is whether Lyra takes any longer to encode than the alternatives. Because as far as I can tell, nobody cares in the slightest about latency. Phone calls are getting to be like writing postcards to each other. Speak in a whole paragraph. Wait several seconds for the latency to clear. Then the other party responds with a whole paragraph, waits several seconds for the latency to clear... Improvements…

In the article, > This trick enables Lyra to not only run on cloud servers, but also on-device on mid-range phones in real time (with a processing latency of 90ms, which is in line with other traditional speech codecs). Does that not cover it?

Worth noting that the paper itself explicitly says 90ms algorithmic delay. Seems plausible to me that there might be additional processing required on top of that, and then you have to add network transit time... suffice it to say that the vast majority of use cases are going to be better served by Opus, for the time being.

> The overall algorithmic delay is 90 ms

https://arxiv.org/pdf/2102.09660.pdf

Re: Lyra audio codec enables high-quality voice calls at 3 kbps bitrate

#128

Post by lankalanka » Tue, Mar 02, 2021, 2:09 AM UTC

londons_explore wrote: post #74

walrus01 wrote: post #51

Earlier quoted context omitted.

They briefly mention the existence and current role of the webrtc codecs, but I don't see where they suggest they intend to contribute it or open it up as a library others can use.

If they don't release it as part of webrtc, they won't be able to use it in browser based videoconferencing. Google Meet/Hangouts on desktop rely on that. While it is theoretically possible to process audio with something compiled with webassembly, data can't be marshalled into/out of a webassembly worker without the main browser threads help, and that tends to be too janky to use for realtime audio on most platforms…

It would take some time to see how it goes. It's possible to run on browsers without being a member of WebRTC codec family. The codec can be deployed as a WebAssemble module and WebRTC acts as a data channel for it. Zoom used to deploy a similar approach while staying on its proprietary codec.

Re: Lyra audio codec enables high-quality voice calls at 3 kbps bitrate

#129

Post by robmsmt » Tue, Mar 02, 2021, 2:15 AM UTC

TheRealSteel wrote: post #90

rectang wrote: post #39

What I want to know is whether Lyra takes any longer to encode than the alternatives. Because as far as I can tell, nobody cares in the slightest about latency. Phone calls are getting to be like writing postcards to each other. Speak in a whole paragraph. Wait several seconds for the latency to clear. Then the other party responds with a whole paragraph, waits several seconds for the latency to clear... Improvements…

I spent the last year and a half living about as far from my home city as possible (Melbourne > Edinburgh) (Currently in quarantine) and the latency of phone calls drives me nuts . The huge gaps between people speaking, and the complete change in conversation flow since you have to speak in huge continuous paragraphs. The constant "go ahead" , "no you go" etc... Ugh. But I agree with you... nobody seems to care excep…

I also agree. Sometimes I speak to work colleagues who are on BT headsets and it must add what feels like 100ms to the call. I can sometimes hear the end of my sentence as I speak. Infuriating.

Re: Lyra audio codec enables high-quality voice calls at 3 kbps bitrate

#130

Post by neltnerb » Tue, Mar 02, 2021, 2:22 AM UTC

acdha wrote: post #73

Aloha wrote: post #55

Earlier quoted context omitted.

A cell phone tbh, is about the same latency as a landline in most end to end call circumstances. Latency only really is noticeable when better than 600ms. (And only a real problem over 1000)

Do you have a citation for that? I've heard 200ms as the key threshold and the ITU uses 100ms for their default delay sensitivity class[1]. One key concept is that this isn't fixed but situational: if you're watching a TV show, the threshold is higher than if you're trying to react to something which is higher than simply noticing a delay and speech is more forgiving than, say, music hitting a precise tempo (I believ…

I know that if the delay is constant, a good musician can compensate for it. I think it's a lot easier to hear that two things don't happen at exactly the same time than it is to tell whether two things happen 200ms or 300ms apart.

Musicians have that internal metronome to compare things with.