Conditioning Deep Generative Raw Audio Models for Structured Automatic Music

Total Page:16

File Type:pdf, Size:1020Kb

Conditioning Deep Generative Raw Audio Models for Structured Automatic Music CONDITIONING DEEP GENERATIVE RAW AUDIO MODELS FOR STRUCTURED AUTOMATIC MUSIC Rachel Manzelli∗ Vijay Thakkar∗ Ali Siahkamari Brian Kulis ∗Equal contributions ECE Department, Boston University fmanzelli, thakkarv, siaa, [email protected] ABSTRACT In order to create sound, these methods often require an in- Existing automatic music generation approaches that fea- termediate step of interpretation of the output by humans, ture deep learning can be broadly classified into two types: where the symbolic representation transitions to an audio raw audio models and symbolic models. Symbolic mod- output in some way. els, which train and generate at the note level, are cur- An alternative is to train on and produce raw audio rently the more prevalent approach; these models can cap- waveforms directly by adapting speech synthesis models, ture long-range dependencies of melodic structure, but fail resulting in a richer palette of potential musical outputs, to grasp the nuances and richness of raw audio genera- albeit at a higher computational cost. WaveNet, a model tions. Raw audio models, such as DeepMind’s WaveNet, developed at DeepMind primarily targeted towards speech train directly on sampled audio waveforms, allowing them applications, has been applied directly to music; the model to produce realistic-sounding, albeit unstructured music. is trained to predict the next sample of 8-bit audio (typi- In this paper, we propose an automatic music generation cally sampled at 16 kHz) given the previous samples [25]. methodology combining both of these approaches to cre- Initially, this was shown to produce rich, unique piano ate structured, realistic-sounding compositions. We con- music when trained on raw piano samples. Follow-up sider a Long Short Term Memory network to learn the work has developed faster generation times [16], generated melodic structure of different styles of music, and then use synthetic vocals for music using WaveNet-based architec- the unique symbolic generations from this model as a con- tures [3], and has been used to generate novel sounds and ditioning input to a WaveNet-based raw audio generator, instruments [8]. This approach to music generation, while creating a model for automatic, novel music. We then eval- very new, shows tremendous potential for music genera- uate this approach by showcasing results of this work. tion tools. However, while WaveNet produces more real- istic sounds, the model does not handle medium or long- 1. INTRODUCTION range dependencies such as melody or global structure in music. The music is expressive and novel, yet sounds un- The ability of deep neural networks to generate novel mu- practiced in its lack of musical structure. sical content has recently become a popular area of re- search. Many variations of deep neural architectures have Nonetheless, raw audio models show great potential for generated pop ballads, 1 helped artists write melodies, 2 the future of automatic music. Despite the expressive na- and even have been integrated into commercial music gen- ture of some advanced symbolic models, those methods re- eration tools. 3 quire constraints such as mood and tempo to generate cor- Current music generation methods are largely focused responding symbolic output [22]. While these constraints on generating music at the note level, resulting in outputs can be desirable in some cases, we express interest in gen- consisting of symbolic representations of music such as se- erating structured raw audio directly due to the flexibility quences of note numbers or MIDI-like streams of events. and versatility that raw audio provides; with no specifica- These methods, such as those based on Long Short Term tion, these models are able to learn to generate expression Memory networks (LSTMs) and recurrent neural networks and mood directly from the waveforms they are trained on. (RNNs), are effective at capturing medium-scale effects We believe that raw audio models are a step towards less in music, can produce melodies with constraints such as guided, unsupervised music generation, since they are un- mood and tempo, and feature fast generation times [14,22]. constrained in this way. With such tools for generating raw audio, one can imagine a number of new applications, such 1 http://www.flow-machines.com/ as the ability to edit existing raw audio in various ways. 2 https://www.ampermusic.com/ 3 https://www.jukedeck.com/ Thus, we explore the combination of raw audio and symbolic approaches, opening the door to a host of new possibilities for music generation tools. In particular, c Rachel Manzelli, Vijay Thakkar, Ali Siahkamari, Brian we train a biaxial Long Short Term Memory network Kulis. Licensed under a Creative Commons Attribution 4.0 International to create novel symbolic melodies, and then treat these License (CC BY 4.0). Attribution: Rachel Manzelli, Vijay Thakkar, Ali Siahkamari, Brian Kulis. “Conditioning Deep Generative Raw Audio melodies as an extra conditioning input to a WaveNet- Models for Structured Automatic Music”, 19th International Society for based model. Consequently, the LSTM model allows us Music Information Retrieval Conference, Paris, France, 2018. to represent long-range melodic structure in the music, 182 Proceedings of the 19th ISMIR Conference, Paris, France, September 23-27, 2018 183 while the WaveNet-based component interprets and ex- pands upon the generated melodic structure in raw audio form. This serves to both eliminate the intermediate inter- pretation step of the symbolic representations and provide structure to the output of the raw audio model, while main- taining the aforementioned desirable properties of both models. We first discuss the tuning of the original unconditioned WaveNet model to produce music of different instruments, Figure 1: A stack of dilated causal convolutions as used styles, and genres. Once we have tuned this model appro- by WaveNet, reproduced from [25]. priately, we then discuss our extension to the conditioned case, where we add a local conditioning technique to the 256 possible values. The WaveNet model uses a deep raw audio model. This method is comparable to using a neural network to model the conditional probabilities text-to-speech method within a speech synthesis model. p(x jx ; :::; x ). The model is trained by predicting val- We first generate audio from the conditioned raw audio t 1 t−1 ues of the waveform at step t and comparing them to the model using well-known melodies (e.g., a C major scale true value x , using cross-entropy as a loss function; thus, and the Happy Birthday melody) after training on the Mu- t the problem simply becomes a multi-class classification sicNet dataset [24]. We also discuss an application of our problem (with 256 classes) for each timestep in the wave- technique to editing existing raw audio music by changing form. some of the underlying notes and re-generating selections The modeling of conditional probabilities in WaveNet of audio. Then, we incorporate the LSTM generations as a utilizes causal convolutions, similar to masked convolu- unique symbolic component. We demonstrate results of tions used in PixelRNN and similar image generation net- training both the LSTM and our conditioned WaveNet- works [7]. Causal convolutions ensure that the prediction based model on corresponding training data, as well as for time step t only depends on the predictions for previ- showcase and evaluate generations of realistic raw audio ous timesteps. Furthermore, the causal convolutions are melodies by using the output of the LSTM as a unique lo- dilated; these are convolutions where the filter is applied cal conditioning time series to the WaveNet model. over an area larger than its length by skipping particular This paper is an extension of an earlier work originally input values, as shown in Figure 1. In addition to dilated published as a workshop paper [19]. We augment that causal convolutions, each layer features gated activation work-in-progress model in many aspects, including more units and residual connections, as well as skip connections concrete results, stronger evaluation, and new applications. to the final output layers. 2. BACKGROUND 2.2 Symbolic Audio Models We elaborate on two prevalent deep learning models for music generation, namely raw audio models and symbolic Most deep learning approaches for automatic music gen- models. eration are based on symbolic representations of the mu- sic. MIDI (Musical Instrument Digital Interface), 4 for ex- 2.1 Raw Audio Models ample, is a ubiquitous standard for file format and proto- col specification for symbolic representation and transmis- Initial efforts to generate raw audio involved models used sion. Other representations that have been utilized include primarily for text generation, such as char-rnn [15] and the piano roll representation [13]—inspired by player pi- LSTMs. Raw audio generations from these networks are ano music rolls—text representations (e.g., ABC nota- often noisy and unstructured; they are limited in their ca- tion 5 ), chord representations (e.g., Chord2Vec [18]), and pacity to abstract higher level representations of raw audio, lead sheet representations. A typical scenario for produc- mainly due to problems with overfitting [21]. ing music in such models is to train and generate on the In 2016, DeepMind introduced WaveNet [25], a gen- same type of representation; for instance, one may train on erative model for general raw audio, designed mainly for a set of MIDI files that encode melodies, and then generate speech applications. At a high level, WaveNet is a deep new MIDI melodies from the learned model. These mod- learning architecture that operates directly on a raw audio els attempt to capture the aspect of long-range dependency waveform. In particular, for a waveform modeled by a vec- in music. tor x = fx1; :::; xT g (representing speech, music, etc.), the joint probability of the entire waveform is factorized as a A traditional approach to learning temporal dependen- product of conditional probabilities, namely cies in data is to use recurrent neural networks (RNNs).
Recommended publications
  • Self-Training Wavenet for TTS in Low-Data Regimes
    StrawNet: Self-Training WaveNet for TTS in Low-Data Regimes Manish Sharma, Tom Kenter, Rob Clark Google UK fskmanish, tomkenter, [email protected] Abstract is increased. However, it can be seen from their results that the quality degrades when the number of recordings is further Recently, WaveNet has become a popular choice of neural net- decreased. work to synthesize speech audio. Autoregressive WaveNet is To reduce the voice artefacts observed in WaveNet stu- capable of producing high-fidelity audio, but is too slow for dent models trained under a low-data regime, we aim to lever- real-time synthesis. As a remedy, Parallel WaveNet was pro- age both the high-fidelity audio produced by an autoregressive posed, which can produce audio faster than real time through WaveNet, and the faster-than-real-time synthesis capability of distillation of an autoregressive teacher into a feedforward stu- a Parallel WaveNet. We propose a training paradigm, called dent network. A shortcoming of this approach, however, is that StrawNet, which stands for “Self-Training WaveNet”. The key a large amount of recorded speech data is required to produce contribution lies in using high-fidelity speech samples produced high-quality student models, and this data is not always avail- by an autoregressive WaveNet to self-train first a new autore- able. In this paper, we propose StrawNet: a self-training ap- gressive WaveNet and then a Parallel WaveNet model. We refer proach to train a Parallel WaveNet. Self-training is performed to models distilled this way as StrawNet student models. using the synthetic examples generated by the autoregressive We evaluate StrawNet by comparing it to a baseline WaveNet teacher.
    [Show full text]
  • Unsupervised Speech Representation Learning Using Wavenet Autoencoders Jan Chorowski, Ron J
    1 Unsupervised speech representation learning using WaveNet autoencoders Jan Chorowski, Ron J. Weiss, Samy Bengio, Aaron¨ van den Oord Abstract—We consider the task of unsupervised extraction speaker gender and identity, from phonetic content, properties of meaningful latent representations of speech by applying which are consistent with internal representations learned autoencoding neural networks to speech waveforms. The goal by speech recognizers [13], [14]. Such representations are is to learn a representation able to capture high level semantic content from the signal, e.g. phoneme identities, while being desired in several tasks, such as low resource automatic speech invariant to confounding low level details in the signal such as recognition (ASR), where only a small amount of labeled the underlying pitch contour or background noise. Since the training data is available. In such scenario, limited amounts learned representation is tuned to contain only phonetic content, of data may be sufficient to learn an acoustic model on the we resort to using a high capacity WaveNet decoder to infer representation discovered without supervision, but insufficient information discarded by the encoder from previous samples. Moreover, the behavior of autoencoder models depends on the to learn the acoustic model and a data representation in a fully kind of constraint that is applied to the latent representation. supervised manner [15], [16]. We compare three variants: a simple dimensionality reduction We focus on representations learned with autoencoders bottleneck, a Gaussian Variational Autoencoder (VAE), and a applied to raw waveforms and spectrogram features and discrete Vector Quantized VAE (VQ-VAE). We analyze the quality investigate the quality of learned representations on LibriSpeech of learned representations in terms of speaker independence, the ability to predict phonetic content, and the ability to accurately re- [17].
    [Show full text]
  • Unsupervised Speech Representation Learning Using Wavenet Autoencoders
    Unsupervised speech representation learning using WaveNet autoencoders https://arxiv.org/abs/1901.08810 Jan Chorowski University of Wrocław 06.06.2019 Deep Model = Hierarchy of Concepts Cat Dog … Moon Banana M. Zieler, “Visualizing and Understanding Convolutional Networks” Deep Learning history: 2006 2006: Stacked RBMs Hinton, Salakhutdinov, “Reducing the Dimensionality of Data with Neural Networks” Deep Learning history: 2012 2012: Alexnet SOTA on Imagenet Fully supervised training Deep Learning Recipe 1. Get a massive, labeled dataset 퐷 = {(푥, 푦)}: – Comp. vision: Imagenet, 1M images – Machine translation: EuroParlamanet data, CommonCrawl, several million sent. pairs – Speech recognition: 1000h (LibriSpeech), 12000h (Google Voice Search) – Question answering: SQuAD, 150k questions with human answers – … 2. Train model to maximize log 푝(푦|푥) Value of Labeled Data • Labeled data is crucial for deep learning • But labels carry little information: – Example: An ImageNet model has 30M weights, but ImageNet is about 1M images from 1000 classes Labels: 1M * 10bit = 10Mbits Raw data: (128 x 128 images): ca 500 Gbits! Value of Unlabeled Data “The brain has about 1014 synapses and we only live for about 109 seconds. So we have a lot more parameters than data. This motivates the idea that we must do a lot of unsupervised learning since the perceptual input (including proprioception) is the only place we can get 105 dimensions of constraint per second.” Geoff Hinton https://www.reddit.com/r/MachineLearning/comments/2lmo0l/ama_geoffrey_hinton/ Unsupervised learning recipe 1. Get a massive labeled dataset 퐷 = 푥 Easy, unlabeled data is nearly free 2. Train model to…??? What is the task? What is the loss function? Unsupervised learning by modeling data distribution Train the model to minimize − log 푝(푥) E.g.
    [Show full text]
  • Real-Time Black-Box Modelling with Recurrent Neural Networks
    Proceedings of the 22nd International Conference on Digital Audio Effects (DAFx-19), Birmingham, UK, September 2–6, 2019 REAL-TIME BLACK-BOX MODELLING WITH RECURRENT NEURAL NETWORKS Alec Wright, Eero-Pekka Damskägg, and Vesa Välimäki∗ Acoustics Lab, Department of Signal Processing and Acoustics Aalto University Espoo, Finland [email protected] ABSTRACT tube amplifiers and distortion pedals. In [14] it was shown that the WaveNet model of several distortion effects was capable of This paper proposes to use a recurrent neural network for black- running in real time. The resulting deep neural network model, box modelling of nonlinear audio systems, such as tube amplifiers however, was still fairly computationally expensive to run. and distortion pedals. As a recurrent unit structure, we test both Long Short-Term Memory and a Gated Recurrent Unit. We com- In this paper, we propose an alternative black-box model based pare the proposed neural network with a WaveNet-style deep neu- on an RNN. We demonstrate that the trained RNN model is capa- ral network, which has been suggested previously for tube ampli- ble of achieving the accuracy of the WaveNet model, whilst re- fier modelling. The neural networks are trained with several min- quiring considerably less processing power to run. The proposed utes of guitar and bass recordings, which have been passed through neural network, which consists of a single recurrent layer and a the devices to be modelled. A real-time audio plugin implement- fully connected layer, is suitable for real-time emulation of tube ing the proposed networks has been developed in the JUCE frame- amplifiers and distortion pedals.
    [Show full text]
  • Linear Prediction-Based Wavenet Speech Synthesis
    LP-WaveNet: Linear Prediction-based WaveNet Speech Synthesis Min-Jae Hwang Frank Soong Eunwoo Song Search Solution Microsoft Naver Corporation Seongnam, South Korea Beijing, China Seongnam, South Korea [email protected] [email protected] [email protected] Xi Wang Hyeonjoo Kang Hong-Goo Kang Microsoft Yonsei University Yonsei University Beijing, China Seoul, South Korea Seoul, South Korea [email protected] [email protected] [email protected] Abstract—We propose a linear prediction (LP)-based wave- than the speech signal, the training and generation processes form generation method via WaveNet vocoding framework. A become more efficient. WaveNet-based neural vocoder has significantly improved the However, the synthesized speech is likely to be unnatural quality of parametric text-to-speech (TTS) systems. However, it is challenging to effectively train the neural vocoder when the target when the prediction errors in estimating the excitation are database contains massive amount of acoustical information propagated through the LP synthesis process. As the effect such as prosody, style or expressiveness. As a solution, the of LP synthesis is not considered in the training process, the approaches that only generate the vocal source component by synthesis output is vulnerable to the variation of LP synthesis a neural vocoder have been proposed. However, they tend to filter. generate synthetic noise because the vocal source component is independently handled without considering the entire speech To alleviate this problem, we propose an LP-WaveNet, production process; where it is inevitable to come up with a which enables to jointly train the complicated interactions mismatch between vocal source and vocal tract filter.
    [Show full text]
  • Anomaly Detection in Raw Audio Using Deep Autoregressive Networks
    ANOMALY DETECTION IN RAW AUDIO USING DEEP AUTOREGRESSIVE NETWORKS Ellen Rushe, Brian Mac Namee Insight Centre for Data Analytics, University College Dublin ABSTRACT difficulty to parallelize backpropagation though time, which Anomaly detection involves the recognition of patterns out- can slow training, especially over very long sequences. This side of what is considered normal, given a certain set of input drawback has given rise to convolutional autoregressive ar- data. This presents a unique set of challenges for machine chitectures [24]. These models are highly parallelizable in learning, particularly if we assume a semi-supervised sce- the training phase, meaning that larger receptive fields can nario in which anomalous patterns are unavailable at training be utilised and computation made more tractable due to ef- time meaning algorithms must rely on non-anomalous data fective resource utilization. In this paper we adapt WaveNet alone. Anomaly detection in time series adds an additional [24], a robust convolutional autoregressive model originally level of complexity given the contextual nature of anomalies. created for raw audio generation, for anomaly detection in For time series modelling, autoregressive deep learning archi- audio. In experiments using multiple datasets we find that we tectures such as WaveNet have proven to be powerful gener- obtain significant performance gains over deep convolutional ative models, specifically in the field of speech synthesis. In autoencoders. this paper, we propose to extend the use of this type of ar- The remainder of this paper proceeds as follows: Sec- chitecture to anomaly detection in raw audio. In experiments tion 2 surveys recent related work on the use of deep neu- using multiple audio datasets we compare the performance of ral networks for anomaly detection; Section 3 describes the this approach to a baseline autoencoder model and show su- WaveNet architecture and how it has been re-purposed for perior performance in almost all cases.
    [Show full text]
  • Predicting Uber Demand in NYC with Wavenet
    SMART ACCESSIBILITY 2019 : The Fourth International Conference on Universal Accessibility in the Internet of Things and Smart Environments Predicting Uber Demand in NYC with Wavenet Long Chen Konstantinos Ampountolas Piyushimita (Vonu) Thakuriah Urban Big Data Center School of Engineering Rutgers University Glasgow, UK University of Glasgow, UK New Brunswick, NJ, USA Email: [email protected] Email: [email protected] Email: [email protected] Abstract—Uber demand prediction is at the core of intelligent transportation systems when developing a smart city. However, exploiting uber real time data to facilitate the demand predic- tion is a thorny problem since user demand usually unevenly distributed over time and space. We develop a Wavenet-based model to predict Uber demand on an hourly basis. In this paper, we present a multi-level Wavenet framework which is a one-dimensional convolutional neural network that includes two sub-networks which encode the source series and decode the predicting series, respectively. The two sub-networks are combined by stacking the decoder on top of the encoder, which in turn, preserves the temporal patterns of the time series. Experiments on large-scale real Uber demand dataset of NYC demonstrate that our model is highly competitive to the existing ones. Figure 1. The structure of WaveNet, where different colours in embedding Keywords–Anything; Something; Everything else. input denote 2 × k, 3 × k, and 4 × k convolutional filter respectively. I. INTRODUCTION With the proliferation of Web 2.0, ride sharing applications, such as Uber, have become a popular way to search nearby at an hourly basis, which is a WaveNet-based neural network sharing rides.
    [Show full text]
  • Parallel Wave Generation in End-To-End Text-To-Speech
    Published as a conference paper at ICLR 2019 CLARINET:PARALLEL WAVE GENERATION IN END-TO-END TEXT-TO-SPEECH Wei Ping∗ Kainan Peng∗ Jitong Chen∗ {pingwei01, pengkainan, chenjitong01}@baidu.com Baidu Research 1195 Bordeaux Dr, Sunnyvale, CA 94089 ABSTRACT In this work, we propose a new solution for parallel wave generation by WaveNet. In contrast to parallel WaveNet (van den Oord et al., 2018), we distill a Gaussian inverse autoregressive flow from the autoregressive WaveNet by minimizing a regularized KL divergence between their highly-peaked output distributions. Our method computes the KL divergence in closed-form, which simplifies the training algorithm and provides very efficient distillation. In addition, we introduce the first text-to-wave neural architecture for speech synthesis, which is fully convolutional and enables fast end-to-end training from scratch. It significantly outperforms the previous pipeline that connects a text-to-spectrogram model to a separately trained WaveNet (Ping et al., 2018). We also successfully distill a parallel waveform synthesizer conditioned on the hidden representation in this end-to-end model. 1 1 INTRODUCTION Speech synthesis, also called text-to-speech (TTS), is traditionally done with complex multi-stage hand-engineered pipelines (Taylor, 2009). Recent successes of deep learning methods for TTS lead to high-fidelity speech synthesis (van den Oord et al., 2016a), much simpler “end-to-end” pipelines (Sotelo et al., 2017; Wang et al., 2017; Ping et al., 2018), and a single TTS model that reproduces thousands of different voices (Ping et al., 2018). WaveNet (van den Oord et al., 2016a) is an autoregressive generative model for waveform synthesis.
    [Show full text]
  • Unsupervised Learning of Cross-Modal Mappings Between
    Unsupervised Learning of Cross-Modal Mappings between Speech and Text by Yu-An Chung B.S., National Taiwan University (2016) Submitted to the Department of Electrical Engineering and Computer Science in partial fulfillment of the requirements for the degree of Master of Science in Electrical Engineering and Computer Science at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY June 2019 c Massachusetts Institute of Technology 2019. All rights reserved. Author.............................................................. Department of Electrical Engineering and Computer Science May 3, 2019 Certified by. James R. Glass Senior Research Scientist in Computer Science Thesis Supervisor Accepted by . Leslie A. Kolodziejski Professor of Electrical Engineering and Computer Science Chair, Department Committee on Graduate Students 2 Unsupervised Learning of Cross-Modal Mappings between Speech and Text by Yu-An Chung Submitted to the Department of Electrical Engineering and Computer Science on May 3, 2019, in partial fulfillment of the requirements for the degree of Master of Science in Electrical Engineering and Computer Science Abstract Deep learning is one of the most prominent machine learning techniques nowadays, being the state-of-the-art on a broad range of applications in computer vision, nat- ural language processing, and speech and audio processing. Current deep learning models, however, rely on significant amounts of supervision for training to achieve exceptional performance. For example, commercial speech recognition systems are usually trained on tens of thousands of hours of annotated data, which take the form of audio paired with transcriptions for training acoustic models, collections of text for training language models, and (possibly) linguist-crafted lexicons mapping words to their pronunciations. The immense cost of collecting these resources makes applying state-of-the-art speech recognition algorithm to under-resourced languages infeasible.
    [Show full text]
  • A Survey of Forex and Stock Price Prediction Using Deep Learning
    Review A Survey of Forex and Stock Price Prediction Using Deep Learning Zexin Hu †, Yiqi Zhao † and Matloob Khushi * School of Computer Science, The University of Sydney, Building J12/1 Cleveland St., Camperdown, NSW 2006, Australia; [email protected] (Z.H.); [email protected] (Y.Z.) * Correspondence: [email protected] † The authors contributed equally; both authors should be considered the first author. Abstract: Predictions of stock and foreign exchange (Forex) have always been a hot and profitable area of study. Deep learning applications have been proven to yield better accuracy and return in the field of financial prediction and forecasting. In this survey, we selected papers from the Digital Bibliography & Library Project (DBLP) database for comparison and analysis. We classified papers according to different deep learning methods, which included Convolutional neural network (CNN); Long Short-Term Memory (LSTM); Deep neural network (DNN); Recurrent Neural Network (RNN); Reinforcement Learning; and other deep learning methods such as Hybrid Attention Networks (HAN), self-paced learning mechanism (NLP), and Wavenet. Furthermore, this paper reviews the dataset, variable, model, and results of each article. The survey used presents the results through the most used performance metrics: Root Mean Square Error (RMSE), Mean Absolute Percentage Error (MAPE), Mean Absolute Error (MAE), Mean Square Error (MSE), accuracy, Sharpe ratio, and return rate. We identified that recent models combining LSTM with other methods, for example, DNN, are widely researched. Reinforcement learning and other deep learning methods yielded great returns and performances. We conclude that, in recent years, the trend of using deep-learning-based methods for financial modeling is rising exponentially.
    [Show full text]
  • Accent Transfer with Discrete Representation Learning and Latent Space Disentanglement
    Accent Transfer with Discrete Representation Learning and Latent Space Disentanglement Renee Li Paul Mure Dept. of Computer Science Dept. of Computer Science Stanford University Stanford University [email protected] [email protected] Abstract The task of accent transfer has recently become a field actively under research. In fact, several companies were established with the goal of tackling this challenging problem. We designed and implemented a model using WaveNet and a multitask learner to transfer accents within a paragraph of English speech. In contrast to the actual WaveNet, our architecture made several adaptations to compensate for the fact that WaveNet does not work well for drastic dimensionality reduction due to the use of residual and skip connections, and we added a multitask learner in order to learn the style of the accent. 1 Introduction In this paper, we explored the task of accent transfer in English speech. This is an interesting problem because it shows the ability of neural network to generate novel contents based on partial information, and this problem has not been explored as much as some of the other topics in style transfer. We believe that this task is very interesting and challenging because we will be developing the state-of-the-art model for our specific task: while there are some published papers about accent classification, so far, we have not been able to find a good pre-trained model to use for evaluating our results. Moreover, raw audio generative models are also a very active field of research, so there is not much literature or implementations for relevant tasks.
    [Show full text]
  • A Practical Guide to Ai in the Contact Center
    A PRACTICAL GUIDE TO AI IN THE CONTACT CENTER making your Business Brilliant Introduction Are you interested in how articial intelligence (AI) might impact your contact center? The hype cycle for AI is nearing its peak. But before you rush to deploy an AI tool, let’s separate fact from ction. What are the practical benets of AI today? What kind of chal- lenges arise from automation? What are the underlying technologies at play? In this e-book, we will answer these questions and more. We will examine AI from a prag- matic lens and offer suggestions to minimize costs and maximize returns. A Practical Guide to AI in the Contact Center 2 What is AI? People tend to generalize their discussions of AI with all the underlying technologies. The articial intelligence denition is open to interpretation. After all, there are several levels of “intelligent.” For EXAMPLES OF AI the purpose of business, we typically consider technologies that simulate or supplant human action as PLATFORMS: “AI.” • Microsoft Azure The ambiguity of AI makes it a difcult concept to invest in. The idea of advanced technology depos- Machine Learning ing human effort has overt appeal. However, without a directive, AI is wasted intelligence. • Google Cloud Machine Learning Engine • Amazon Lex WAVENET TIP: • Infosys Mana If you want to use AI successfully, ask yourself, “What problem am I trying to solve?” • WiPro Holmes • Rainbird • Ayasdi Do you want a chatbot that can take and place If you have a clear understanding of the problem • Vital A.I. orders in lieu of call center representatives? Do you are trying to solve, AI may benet your • Meya you want a program that analyzes customer data company.
    [Show full text]