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

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

#101

Post by jeroenhd »

domoritz wrote: post #95
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…

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

Not OP, and I haven't done it myself yet, but it makes a lot of sense. It's basically free image hosting if you can get the file cached by Cloudflare.

Imgur these days is slow and riddled by ads. A page show will sometimes load many times the image size in Javascript, stylesheets and images. It also doesn't allow the user to just view the raw image, going as far as redirecting requests to the raw image to a web page if you directly access the URL.

The only downside I see is that the URL is less user friendly without the IPFS toolset installed. Sounds like a pretty good idea to me.

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

#102

Post by ryukafalz »

charlesdaniels wrote: post #72

This reminds me of a technology in Vernor Vinge's "zone of thought" series. I think they called it "evocations", where at the beginning of a call, a model is transmitted that allows the other end to re-construct what the sender would look/sound like from severely abridged data. It sure sounds plausible - the semantically meaningful parts of a conversation (video or audio) would appear to have significantly less entro…

It's been done, at least for video: https://www.youtube.com/watch?v=NqmMnjJ6GEg&feature=emb_titl...

Not for audio yet, I think?

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

#103

Post by tyingq »

lxgr wrote: post #63
tyingq wrote: post #47

Earlier quoted context omitted.

G.729 is 21-30kbps with transport overhead, depending on a few factors. So shaving off 5kbps would still be meaningful. Or better quality at the same bandwidth might enable in-band DTMF or fax, neither works on G.729 now.

In-band fax will certainly not work over a lossy voice codec, unless your fax modem is able to mimic human speech patterns.

I thought I remembered getting 2400 baud fax (unreliably) working on G.729. Though I guess, yes, if this codec is trained on voices that probably doesn't bode well for fax.

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

#104

Post by bscphil »

dkjaudyeqooe wrote: post #81
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…

Isn't that due to audio (frequency) compression coming out of the generative model? I guess that can be tweaked either way but they're going to tend towards that exactly because it sounds louder and thus clearer.

There are a couple of effects here:

1. Lossy codecs will use a low-pass filter to get rid of hard to compress higher frequencies. This is often inaudible, but even when it is, it should lower the volume, unless you're applying some kind of compensation for it.

2. It's true that lossy codecs compress different frequencies differently, but that's not usually done in such a way that amounts to applying EQ to the frequencies.

3. Even if the relative balance of frequencies did shift as a result of applying lossy compression, this is still done in a way that the overall loudness of the audio does not change. In this case the Lyra output has changed significantly and in an easily audible way (about +6 dB). You could easily get the same effect in Opus just by amplifying (or applying compression to) the result, but Opus is doing things correctly.

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

#106

Post by p1mrx »

kreetx wrote: post #59
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…

What are the current choices for "CD quality" speech compression (lossy but indiscernible) at the moment? Just had a discussion with a friend of keeping an always-on speech recorder on and wondered about disk space consumption.

Basically Opus (Vorbis successor) or AAC (MP3 successor).

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

#108

Post by perfmode »

bscphil wrote: post #88
rectang wrote: post #82

Earlier quoted context omitted.

Excellent catch. To be precise you need a measure of perceptual loudness rather than raw waveform excursion, but I would expect the results to be in line with what you've found. > 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 the other, people will say that the louder one was better, or came through more clearly, or whatever it is you're tryin…

Here's an EBU R 128 measure using r128gain: File 'reference.flac': loudness = -25.7 LUFS, sample peak = -9.2 dBFS File 'lyra.flac': loudness = -19.9 LUFS, sample peak = -4.1 dBFS File 'opus.flac': loudness = -25.9 LUFS, sample peak = -9.7 dBFS So that also matches pretty closely what my ears heard.

how do the samples compare when loudness is made constant/normalized?

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

#109

Post by superkuh »

domoritz wrote: post #95
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…

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

If you upload and then link to an image on Imgur and the person clicking the link has not run Imgur's javascript yet within $timeperiod, the image will not display. Instead you'll be given javascript to run.

Cloudflare as a gateway is distasteful and this won't last long, but for now at least when you click an ipfs image over cloudflare you get an image and not javascript code.

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

#110

Post by 0-_-0 »

perfmode wrote: post #108
bscphil wrote: post #88

Earlier quoted context omitted.

Here's an EBU R 128 measure using r128gain: File 'reference.flac': loudness = -25.7 LUFS, sample peak = -9.2 dBFS File 'lyra.flac': loudness = -19.9 LUFS, sample peak = -4.1 dBFS File 'opus.flac': loudness = -25.9 LUFS, sample peak = -9.7 dBFS So that also matches pretty closely what my ears heard.

how do the samples compare when loudness is made constant/normalized?

Just reduce the volume of the lyra one by hand. Doesn't change the fact that it sounds leagues above the others.
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