Recognition: no theorem link
High Fidelity Neural Audio Compression
Pith reviewed 2026-05-13 21:46 UTC · model grok-4.3
The pith
A neural network audio codec with streaming encoder-decoder and quantized latents delivers higher fidelity than baselines at real-time speeds.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
The authors present a real-time high-fidelity neural audio codec built from a streaming encoder-decoder with a quantized latent space trained end-to-end. Training is stabilized by a single multiscale spectrogram adversary that reduces artifacts and by a novel loss-balancer module in which each loss weight directly sets the fraction of the overall gradient it contributes. Lightweight Transformer models can be stacked on the quantized representation to achieve up to 40 percent additional compression while remaining faster than real time. MUSHRA subjective tests across multiple bandwidths and domains establish superiority over existing codecs for both 24 kHz monophonic and 48 kHz stereophonic音频
What carries the argument
Streaming encoder-decoder architecture with quantized latent space, trained using a single multiscale spectrogram adversary and a loss-balancer mechanism that decouples loss weights from gradient scale.
Load-bearing premise
The MUSHRA listening tests on the chosen audio domains and bandwidths are representative of real-world use and the model does not overfit to the training distribution in ways that degrade on unseen content.
What would settle it
A new MUSHRA test on audio outside the training domains (for example live concert recordings or rare speech accents) showing the neural codec no longer rated higher than the baselines at the same bitrate.
read the original abstract
We introduce a state-of-the-art real-time, high-fidelity, audio codec leveraging neural networks. It consists in a streaming encoder-decoder architecture with quantized latent space trained in an end-to-end fashion. We simplify and speed-up the training by using a single multiscale spectrogram adversary that efficiently reduces artifacts and produce high-quality samples. We introduce a novel loss balancer mechanism to stabilize training: the weight of a loss now defines the fraction of the overall gradient it should represent, thus decoupling the choice of this hyper-parameter from the typical scale of the loss. Finally, we study how lightweight Transformer models can be used to further compress the obtained representation by up to 40%, while staying faster than real time. We provide a detailed description of the key design choices of the proposed model including: training objective, architectural changes and a study of various perceptual loss functions. We present an extensive subjective evaluation (MUSHRA tests) together with an ablation study for a range of bandwidths and audio domains, including speech, noisy-reverberant speech, and music. Our approach is superior to the baselines methods across all evaluated settings, considering both 24 kHz monophonic and 48 kHz stereophonic audio. Code and models are available at github.com/facebookresearch/encodec.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper introduces EnCodec, a real-time neural audio codec using a streaming encoder-decoder with quantized latent representations trained end-to-end. Key contributions include a single multiscale spectrogram discriminator to reduce artifacts, a novel loss balancer that sets loss weights as target gradient fractions to stabilize training, and optional lightweight Transformer models for up to 40% further compression of the latent codes. The work reports extensive MUSHRA subjective evaluations across speech, noisy-reverberant speech, and music at multiple bandwidths for both 24 kHz mono and 48 kHz stereo audio, claiming consistent superiority over published baselines, with code and models released for reproducibility.
Significance. If the reported MUSHRA rankings hold, the work provides a practical advance in high-fidelity, low-latency neural audio compression with direct applicability to streaming and storage. Strengths include the public release of code and models, detailed ablation studies, and the loss-balancer formulation that decouples hyper-parameter choice from loss scale; these elements support replication and extension beyond the specific domains tested.
minor comments (3)
- [§3.3] §3.3: The single multiscale spectrogram discriminator is described at a high level; adding the exact frequency scales and window sizes used would aid exact replication.
- [Table 2] Table 2: The MUSHRA scores for the 48 kHz stereo music condition would benefit from reported confidence intervals or standard deviations to quantify variability across listeners.
- [§4.2] §4.2: The claim of 'parameter-free' behavior for certain loss terms is not fully supported by the listed free parameters (number of residual codebooks and balancer targets); a brief clarification on which quantities remain fixed would improve precision.
Simulated Author's Rebuttal
We thank the referee for the positive summary, recognition of the practical contributions (including the loss balancer, public code release, and MUSHRA evaluations), and the recommendation to accept. We are pleased that the work's applicability to streaming audio was noted.
Circularity Check
No significant circularity detected
full rationale
The paper presents an empirical neural audio codec (encoder-decoder with quantization, single multiscale spectrogram discriminator, and a proposed loss-balancer that normalizes gradient contributions by design). All central claims of superiority are grounded in external MUSHRA listening tests across speech, music, and stereo domains plus comparisons to published baselines, with code released for replication. No equation or training step reduces by construction to a fitted parameter renamed as a prediction, no self-citation chain is load-bearing for the architecture or results, and the loss-balancer is introduced as an explicit mechanism rather than derived from the target metric. The derivation chain is therefore self-contained against external benchmarks.
Axiom & Free-Parameter Ledger
free parameters (2)
- number of residual codebooks
- loss balancer target fractions
axioms (1)
- domain assumption Multiscale spectrogram discrimination is sufficient to suppress perceptual artifacts in audio reconstruction.
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Reference graph
Works this paper leans on
-
[1]
Pavel Andreev, Aibek Alanov, Oleg Ivanov, and Dmitry Vetrov. Hifi++: a unified framework for neural vocoding, bandwidth extension and speech enhancement.arXiv preprint arXiv:2203.13086 ,
-
[2]
Common voice: A massively-multilingual speech corpus,
Rosana Ardila, Megan Branson, Kelly Davis, Michael Henretty, Michael Kohler, Josh Meyer, Reuben Morais, Lindsay Saunders, Francis M Tyers, and Gregor Weber. Common voice: A massively-multilingual speech corpus. arXiv preprint arXiv:1912.06670 ,
-
[3]
Jimmy Lei Ba, Jamie Ryan Kiros, and Geoffrey E Hinton. Layer normalization. arXiv preprint arXiv:1607.06450,
work page internal anchor Pith review Pith/arXiv arXiv
-
[4]
Estimating or Propagating Gradients Through Stochastic Neurons for Conditional Computation
Yoshua Bengio, Nicholas Léonard, and Aaron Courville. Estimating or propagating gradients through stochastic neurons for conditional computation.arXiv preprint arXiv:1308.3432 ,
work page internal anchor Pith review Pith/arXiv arXiv
-
[5]
Shlomo E Chazan, Lior Wolf, Eliya Nachmani, and Yossi Adi
URL http: //hdl.handle.net/10230/42015. Shlomo E Chazan, Lior Wolf, Eliya Nachmani, and Yossi Adi. Single channel voice separation for unknown number of speakers under reverberant and noisy settings. InICASSP 2021-2021 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) , pp. 3730–3734. IEEE,
work page 2021
-
[6]
Global - 2021 forecast highlights - cisco
Cisco. Global - 2021 forecast highlights - cisco. https://www.cisco.com/c/dam/m/en_us/solutions/ service-provider/vni-forecast-highlights/pdf/Global_2021_Forecast_Highlights.pdf,
work page 2021
-
[7]
Fast and Accurate Deep Network Learning by Exponential Linear Units (ELUs)
Djork-Arné Clevert, Thomas Unterthiner, and Sepp Hochreiter. Fast and accurate deep network learning by exponential linear units (elus).arXiv preprint arXiv:1511.07289 ,
-
[8]
Music source separation in the waveform domain
Alexandre Défossez, Nicolas Usunier, Léon Bottou, and Francis Bach. Music source separation in the waveform domain. arXiv preprint arXiv:1911.13254 ,
-
[9]
Real time speech enhancement in the waveform domain
Alexandre Defossez, Gabriel Synnaeve, and Yossi Adi. Real time speech enhancement in the waveform domain. arXiv preprint arXiv:2006.12847 ,
-
[10]
Differentiable model compression via pseudo quantiza- tion noise
Alexandre Défossez, Yossi Adi, and Gabriel Synnaeve. Differentiable model compression via pseudo quantiza- tion noise. arXiv preprint arXiv:2104.09987 ,
-
[11]
Prafulla Dhariwal, Heewoo Jun, Christine Payne, Jong Wook Kim, Alec Radford, and Ilya Sutskever. Jukebox: A generative model for music.arXiv preprint arXiv:2005.00341 ,
-
[12]
Icassp 2022 deep noise suppression challenge
Harishchandra Dubey, Vishak Gopal, Ross Cutler, Sergiy Matusevych, Sebastian Braun, Emre Sefik Eskimez, Manthan Thakker, Takuya Yoshioka, Hannes Gamper, and Robert Aichner. Icassp 2022 deep noise suppression challenge. InICASSP,
work page 2022
-
[13]
Low bit-rate speech coding with vq-vae and a wavenet decoder
Cristina Gârbacea, Aäron van den Oord, Yazhe Li, Felicia SC Lim, Alejandro Luebs, Oriol Vinyals, and Thomas C Walters. Low bit-rate speech coding with vq-vae and a wavenet decoder. InICASSP 2019-2019 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) , pp. 735–739. IEEE,
work page 2019
-
[14]
Audio set: An ontology and human-labeled dataset for audio events
Jort F Gemmeke, Daniel PW Ellis, Dylan Freedman, Aren Jansen, Wade Lawrence, R Channing Moore, Manoj Plakal, and Marvin Ritter. Audio set: An ontology and human-labeled dataset for audio events. In 2017 IEEE international conference on acoustics, speech and signal processing (ICASSP) , pp. 776–780. IEEE,
work page 2017
-
[15]
It’s raw! audio generation with state-space models
Karan Goel, Albert Gu, Chris Donahue, and Christopher Ré. It’s raw! audio generation with state-space models. arXiv preprint arXiv:2202.09729 ,
-
[16]
Visqol: The virtual speech quality objective listener
Andrew Hines, Jan Skoglund, Anil Kokaram, and Naomi Harte. Visqol: The virtual speech quality objective listener. In IW AENC 2012; International Workshop on Acoustic Signal Enhancement , pp. 1–4. VDE,
work page 2012
-
[17]
Batch Normalization: Accelerating Deep Network Training by Reducing Internal Covariate Shift
Sergey Ioffe and Christian Szegedy. Batch normalization: Accelerating deep network training by reducing internal covariate shift. Technical Report 1502.03167, arXiv,
work page internal anchor Pith review Pith/arXiv arXiv
-
[18]
Architecture for variable bitrate neural speech codec with configurable computation complexity
Tejas Jayashankar, Thilo Koehler, Kaustubh Kalgaonkar, Zhiping Xiu, Jilong Wu, Ju Lin, Prabhav Agrawal, and Qing He. Architecture for variable bitrate neural speech codec with configurable computation complexity. In ICASSP 2022-2022 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) , pp. 861–865. IEEE,
work page 2022
-
[19]
End-to-end neural speech coding for real-time communications
Xue Jiang, Xiulian Peng, Chengyu Zheng, Huaying Xue, Yuan Zhang, and Yan Lu. End-to-end neural speech coding for real-time communications. InICASSP 2022-2022 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) , pp. 866–870. IEEE,
work page 2022
-
[20]
Text-free prosody-aware generative spoken language modeling
12 Eugene Kharitonov, Ann Lee, Adam Polyak, Yossi Adi, Jade Copet, Kushal Lakhotia, Tu-Anh Nguyen, Morgane Rivière, Abdelrahman Mohamed, Emmanuel Dupoux, et al. Text-free prosody-aware generative spoken language modeling. arXiv preprint arXiv:2109.03264 ,
-
[21]
Generative speech coding with predictive variance regularization
W Bastiaan Kleijn, Andrew Storus, Michael Chinen, Tom Denton, Felicia SC Lim, Alejandro Luebs, Jan Skoglund, and Hengchin Yeh. Generative speech coding with predictive variance regularization. InICASSP 2021-2021 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) , pp. 6478–6482. IEEE,
work page 2021
-
[22]
Felix Kreuk, Adam Polyak, Jade Copet, Eugene Kharitonov, Tu-Anh Nguyen, Morgane Rivière, Wei-Ning Hsu, Abdelrahman Mohamed, Emmanuel Dupoux, and Yossi Adi. Textless speech emotion conversion using decomposed and discrete representations.arXiv preprint arXiv:2111.07402 ,
-
[23]
Direct speech-to-speech translation with discrete units
Ann Lee, Peng-Jen Chen, Changhan Wang, Jiatao Gu, Xutai Ma, Adam Polyak, Yossi Adi, Qing He, Yun Tang, Juan Pino, et al. Direct speech-to-speech translation with discrete units. arXiv preprint arXiv:2107.05604, 2021a. Ann Lee, Hongyu Gong, Paul-Ambroise Duquenne, Holger Schwenk, Peng-Jen Chen, Changhan Wang, Sravya Popuri, Juan Pino, Jiatao Gu, and Wei-Ni...
-
[24]
Robust low rate speech coding based on cloned networks and wavenet
Felicia SC Lim, W Bastiaan Kleijn, Michael Chinen, and Jan Skoglund. Robust low rate speech coding based on cloned networks and wavenet. InICASSP 2020-2020 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) , pp. 6769–6773. IEEE,
work page 2020
-
[25]
Speech enhancement for low bit rate speech codec
Ju Lin, Kaustubh Kalgaonkar, Qing He, and Xin Lei. Speech enhancement for low bit rate speech codec. In ICASSP 2022-2022 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) , pp. 7777–7781. IEEE,
work page 2022
-
[26]
Generative spoken dialogue language modeling
Tu Anh Nguyen, Eugene Kharitonov, Jade Copet, Yossi Adi, Wei-Ning Hsu, Ali Elkahky, Paden Tomasello, Robin Algayres, Benoit Sagot, Abdelrahman Mohamed, et al. Generative spoken dialogue language modeling. arXiv preprint arXiv:2203.16502 ,
-
[27]
Disentangling speech from surroundings in a neural audio codec
Ahmed Omran, Neil Zeghidour, Zalán Borsos, Félix de Chaumont Quitry, Malcolm Slaney, and Marco Tagliasacchi. Disentangling speech from surroundings in a neural audio codec. arXiv preprint arXiv:2203.15578,
-
[28]
WaveNet: A Generative Model for Raw Audio
Aaron van den Oord, Sander Dieleman, Heiga Zen, Karen Simonyan, Oriol Vinyals, Alex Graves, Nal Kalchbrenner, Andrew Senior, and Koray Kavukcuoglu. Wavenet: A generative model for raw audio.arXiv preprint arXiv:1609.03499,
work page internal anchor Pith review Pith/arXiv arXiv
-
[29]
Speech resynthesis from discrete disentangled self-supervised representations
Adam Polyak, Yossi Adi, Jade Copet, Eugene Kharitonov, Kushal Lakhotia, Wei-Ning Hsu, Abdelrah- man Mohamed, and Emmanuel Dupoux. Speech resynthesis from discrete disentangled self-supervised representations. arXiv preprint arXiv:2104.00355 ,
-
[30]
Sravya Popuri, Peng-Jen Chen, Changhan Wang, Juan Pino, Yossi Adi, Jiatao Gu, Wei-Ning Hsu, and Ann Lee. Enhanced direct speech-to-speech translation using self-supervised pre-training and data augmentation. arXiv preprint arXiv:2204.02967 ,
-
[31]
Improving opus low bit rate quality with neural speech synthesis.arXiv preprint arXiv:1905.04628,
Jan Skoglund and Jean-Marc Valin. Improving opus low bit rate quality with neural speech synthesis.arXiv preprint arXiv:1905.04628,
-
[32]
Seanet: A multi-modal speech enhancement network
Marco Tagliasacchi, Yunpeng Li, Karolis Misiunas, and Dominik Roblek. Seanet: A multi-modal speech enhancement network. arXiv preprint arXiv:2009.02095 ,
-
[33]
Lpcnet: Improving neural speech synthesis through linear prediction
Jean-Marc Valin and Jan Skoglund. Lpcnet: Improving neural speech synthesis through linear prediction. In ICASSP 2019-2019 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) , pp. 5891–5895. IEEE, 2019a. Jean-Marc Valin and Jan Skoglund. A real-time wideband neural vocoder at 1.6 kb/s using lpcnet.arXiv preprint arXiv:1903.1...
-
[34]
Ryuichi Yamamoto, Eunwoo Song, and Jae-Min Kim. Parallel wavegan: A fast waveform generation model based on generative adversarial networks with multi-resolution spectrogram. InICASSP 2020-2020 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) , pp. 6199–6203. IEEE, 2020a. Ryuichi Yamamoto, Eunwoo Song, and Jae-Min Kim. Par...
-
[35]
15 Table A.1: Datasets description. License with asterisk annotation * imply that the specific license varies across the dataset and is specific to each sample. Dataset Audio domain Sampling rate Channels Duration License Common Voice 7.0 Speech 48 kHz 1 9,096 h CC-0 DNS Challenge 4 (speech) Speech 48 kHz 1 2,425 h Multiples* AudioSet General audio 48 kHz 2...
work page 2021
-
[36]
We used LeakyReLU as non-linear activation function
was the only one that prevented the discriminator from diverging. We used LeakyReLU as non-linear activation function. Finally, training hyper parameters are not shared either so we use the same parameters as for ourEnCodec model. A.2 Alternative quantizers A.2.1 DiffQ Quantizer Pseudo quantization noise.We perform scalar quantization of the latent represe...
work page 1996
-
[37]
with a differentiable bandwidth estimate. We extend the DiffQ approach for latent space quantization, adding support for streamable rescaling, proper sparsity, and improved prior coding. Formally, we introduce a learnt parameterB∈ RD (with D the dimension of the latent space) such that B(i) represents the number of bits to use of thei-th dimension. In pract...
work page 2015
-
[38]
with a temperatureτ = 0.5. This gives us a differentiable approximately 1-hot vector over the codebooks, i.e., notingGS the gumbel-softmax, zq,train = NC∑ i=1 GS(log(qi(z)),τ )T Ci. (8) At test time, we replace the gumbel-softmax with a sampling from the distributionqi. We define for alli, pi = softmax(li) the prior distribution over the codebooks entries w...
work page 2021
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