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A Real-Time Wideband Neural Vocoder at 1.6 Kb/S Using LPCNet

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61–70 of 76 posts

Re: A Real-Time Wideband Neural Vocoder at 1.6 Kb/S Using LPCNet

#61
post #30

Earlier quoted context omitted.

Can you try it with Tom's Diner by Suzanne Vega? It's sung without any instruments, and an early version of MP3 reportedly was a disaster on that song.

Here you go: http://no.gd/vega2.wav It holds up ridiculously well considering the entire song compresses down to 25392 bytes.

Compare it with this now: https://youtu.be/lHjn8ffnEKU :-)

Re: A Real-Time Wideband Neural Vocoder at 1.6 Kb/S Using LPCNet

#62
post #18

OK, so... Would it be possible to do something similar for video?

Similar as in the same approach, or as in "apply neural networks to all the things"? Because if it's the former, this approach was very specifically tailored to human speech, taking into account how much it can compress/interpolate qualities like pitch and the spectral envelope. That's far too specific to apply to video. As for the latter, you'd have to perhaps feed Google Scholar the right incantations or ask someon…

I should have been more specific. I meant that instead of compressing video to minimise pixel difference, minimise feature difference instead.

Re: A Real-Time Wideband Neural Vocoder at 1.6 Kb/S Using LPCNet

#63
post #53
post #52

Earlier quoted context omitted.

So can you do domain adaptation and get it to vocode my voice into Johnny Cash's? Larynx adaptation.

In theory, it wouldn't be too hard to implement with an neural network. In theory. In practice, the problem is figuring out how to do the training because I don't have 2 hours of your voice saying the same thing as the target voice and with perfect alignment. I suspect it's still possible, but it's not a simple thing either.

Perfect alignment, or any alignment for that matter, is not necessary. Check out adversarial networks. CycleGAN can be trained to do similar feats in image domain without aligned inputs. Shouldn't be hard to adopt it to audio.

Re: A Real-Time Wideband Neural Vocoder at 1.6 Kb/S Using LPCNet

#64
post #30

Earlier quoted context omitted.

Can you try it with Tom's Diner by Suzanne Vega? It's sung without any instruments, and an early version of MP3 reportedly was a disaster on that song.

Here you go: http://no.gd/vega2.wav It holds up ridiculously well considering the entire song compresses down to 25392 bytes.

Could you also try "I Feel Love" by Donna Summer?

I am curious how it sounds when there is a really active bassline and lead synth.

Re: A Real-Time Wideband Neural Vocoder at 1.6 Kb/S Using LPCNet

#65
post #60

Just to put this in perspective, a traditional phone line encodes 56 Kb/s of data, which was believed to be the size channel to send the human voice with a reasonable quality. They are doing it in 1.6 Kb/s!

Aren't "traditional" aka POTS lines analog, and therefore not doing any encoding whatsoever?

There are band filters and such on legacy, fully analog systems.

G.711 (which is standard now for non-cellular call audio) is a step down, but Opus at 16Kbps sounds better to me than a classic, full analog system due to the lack of band cutoff & smarter encoding.

Re: A Real-Time Wideband Neural Vocoder at 1.6 Kb/S Using LPCNet

#66
post #38

For comparison, your standard police/fire/medical digital radio in the US sends voice at 4.4Kb/s. So this is a approximately a third of that.

So maybe this line of work will mean more spectrum available in the future.

Only if Motorola gets out of the way and supports modern codecs and standards. Current public safety radio networks are using ancient TDMA tech that Motorola has cobbled together, along with audio codecs that shred voice quality. The only good part is the durability of the pricey radio, some are even intrinsically safe.

Re: A Real-Time Wideband Neural Vocoder at 1.6 Kb/S Using LPCNet

#67

The examples sound excellent. Top (equal or better) of any text-to-speech synthesizer I've ever heard. I would love to start using it for audio books and for VoIP to save space and traffic as soon as possible. And a Linux-native text-to-speech synthesizer capable of producing speech of this quality is a thing I dream of (now the only option I know is booting to Windows and using Ivona voices)

Mozilla Deepspeech (Speech tp Text) and Mozilla TTS are both useful at this point: https://research.mozilla.org/machine-learning/

Re: A Real-Time Wideband Neural Vocoder at 1.6 Kb/S Using LPCNet

#68
post #14
post #5

3 Gflops, we are deep beyond diminishing returns here. Opus seems good enough.

Opus is awesome and covers a previously unmatched spectrum of use cases... but that isn't everything. Opus isn't good enough to be a replacement for AMBE for use over radio. Opus doesn't make it easier to make very high quality speech synthesis, etc. Opus loss robustness could be much better using tools from this toolbox-- and we're a long way from not wanting better performance in the face of packet loss.

Opus is still improving, v1.1 to v1.2 then onto v1.3 (current in FFMpeg) saw huge reductions in compute for encoding, and the minimum bitrate for stereo wideband fall year after year.

The limiting factor for Opus's penetration has been compute, FEC is still rarely supported on VOIP deskphones due to this, ditto for handling multiple Opus calls at once.

Re: A Real-Time Wideband Neural Vocoder at 1.6 Kb/S Using LPCNet

#70
post #14
post #5

3 Gflops, we are deep beyond diminishing returns here. Opus seems good enough.

Opus is awesome and covers a previously unmatched spectrum of use cases... but that isn't everything. Opus isn't good enough to be a replacement for AMBE for use over radio. Opus doesn't make it easier to make very high quality speech synthesis, etc. Opus loss robustness could be much better using tools from this toolbox-- and we're a long way from not wanting better performance in the face of packet loss.

This is roughly 2x improvement over AMBE+2, except AMBE peaks at maybe couple hundred MIPS, and there are better less computationally intensive alternative, like 20-70 MIPS https://dspini.com/vocoders/lowrate/twelp-lowrate/twelp2400
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