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

cnx-software.com

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

#21

Post by ddevault »

hatsunearu wrote: post #9

http://www.rowetel.com/wordpress/?page_id=452 Take a look at this too. Also runnable on low power devices. And there was some work of using AI to enhance the codec2 encoded bits too.

Yeah, with Codec 2 setting the gold standard, I don't find this very impressive. I find this more intelligible at one-third of the Lyra bitrate:

http://www.rowetel.com/downloads/codec2/hts2a_1300.wav

Codec 2 does a better job of isolating the parts of sound which are most necessary to intelligible speech, without necessarily caring too much about preserving the original qualities of the speaker's voice or environment.

Fun fact: Codec 2 can be used to transmit voice over IRC:

https://github.com/asiekierka/voirc

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

#22

Post by BugsJustFindMe »

temp-dude-87844 wrote: post #10

When Google's announcement [1] was posted a few days ago, I listened to their samples and heard an odd effect in the "chocolate bread" sample (the video chat example) [1], which is not mirrored in this article. On that sample, I felt [2] that the Lyra version exaggerates the pronunciation of the phrase 'with chocolate' in a way that meaningfully differs from the speaker's original. It weakens the voiced 'th' to nothi…

> 'with chocolate' in a way that meaningfully differs from the speaker's original. It weakens the voiced 'th' to nothingness

I honestly don't hear a 'th' in the original.

> It was surprising, given that the speaker doesn't sound like that in the original.

I disagree. Note that the speaker says "these bread". The three possibilities for those two words—"these bread", "thiiiis bread", and "these breads" with a dropped "s"—would all be weird things for a native english speaker to say for different reasons relating to either wrong pronunciation of "this" or "breads" or the fact that bread is its own collective noun and therefore we typically require separate qualifiers like "these buns" or "these loaves" when separating multiple individual "pieces" (another) into a non-collective. We ask for "some bread" or "a piece of bread", but we don't say "a bread" or "some breads" unless we are discussing categorical types of bread ("ciabatta and rye are breads") rather than instances of such, and only one type of bread is represented in the video.

The Lyra reproduction has a band-pass filtered quality to it, but I find it still remarkably representative of the reference.

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

#23

Post by boneitis »

I found the Lyra codecs in both examples easily the most difficult to comprehend, even compared against the scratchy Speex.

Am I the only one? It is a little odd to me to see the praise here and on the previous discussion.

To be fair, I am convinced I have APD (and, to be fair again, I have never got it checked out).

E: Just realized there is a third example. Perhaps it is not as strong a statement due to Opus' doubled bitrate, but it is still far scratchier. Yet, it is more decipherable than the Lyra codec to me.

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

#24

Post by scotty79 »

temp-dude-87844 wrote: post #10

When Google's announcement [1] was posted a few days ago, I listened to their samples and heard an odd effect in the "chocolate bread" sample (the video chat example) [1], which is not mirrored in this article. On that sample, I felt [2] that the Lyra version exaggerates the pronunciation of the phrase 'with chocolate' in a way that meaningfully differs from the speaker's original. It weakens the voiced 'th' to nothi…

"When a man looks for something beyond his reach ..."

The word "looks" sounds completely wrong for me with Lyra. To the point of completely not understanding what this word is supposed to be (first example with your [1] link).

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

#25

Post by viraptor »

faebi wrote: post #2

Maybe in the future, all we need is a speech example, some AI and the continious transmission of text for low data voice transmission?

Only if you're ready to kill all the intonation nuance. If you're ok with that, why not stick to just reading text? At least we can use emotes in there.

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

#27

Post by cbdumas »

BugsJustFindMe wrote: post #22
temp-dude-87844 wrote: post #10

When Google's announcement [1] was posted a few days ago, I listened to their samples and heard an odd effect in the "chocolate bread" sample (the video chat example) [1], which is not mirrored in this article. On that sample, I felt [2] that the Lyra version exaggerates the pronunciation of the phrase 'with chocolate' in a way that meaningfully differs from the speaker's original. It weakens the voiced 'th' to nothi…

> 'with chocolate' in a way that meaningfully differs from the speaker's original. It weakens the voiced 'th' to nothingness I honestly don't hear a 'th' in the original. > It was surprising, given that the speaker doesn't sound like that in the original. I disagree. Note that the speaker says "these bread". The three possibilities for those two words—"these bread", "thiiiis bread", and "these breads" with a dropped…

I agree completely, I've listened to the reference sample probably ten times now and I can only hear /wɪ/

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

#28

Post by zamadatix »

nousermane wrote: post #19
lxgr wrote: post #14

Earlier quoted context omitted.

Isn‘t VoIP at such low data rates already dominated by the overhead of UDP, IP and whatever lower layer? Multiplexing it with a low-bandwidth video stream would be possible, though. I was thinking this could be most relevant for something like digital wireless transmissions.

To say the least, yeah. At 3kbps and 20ms framing, it's only 7.5 bytes of payload per frame. RTP, UDP, IP, and Ethernet overhead are what - 60-ish bytes?

60ish sounds right, though with Ethernet it's going to be padded to a minimum 64 bytes regardless. Might not matter depending what your bottleneck link actually uses though.

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

#30

Post by walrus01 »

the 3kbps example here with the 'bread with chocolate filling inside' video is frankly amazing, how good it is compared to the original.

https://ai.googleblog.com/2021/02/lyra-new-very-low-bitrate-...

It is unfortunate that for now this appears to be proprietary, closed source and being treated as a google competitive advantage over others, unlike opus which is fully open.

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