38,350 research outputs found
A Phase Vocoder based on Nonstationary Gabor Frames
We propose a new algorithm for time stretching music signals based on the
theory of nonstationary Gabor frames (NSGFs). The algorithm extends the
techniques of the classical phase vocoder (PV) by incorporating adaptive
time-frequency (TF) representations and adaptive phase locking. The adaptive TF
representations imply good time resolution for the onsets of attack transients
and good frequency resolution for the sinusoidal components. We estimate the
phase values only at peak channels and the remaining phases are then locked to
the values of the peaks in an adaptive manner. During attack transients we keep
the stretch factor equal to one and we propose a new strategy for determining
which channels are relevant for reinitializing the corresponding phase values.
In contrast to previously published algorithms we use a non-uniform NSGF to
obtain a low redundancy of the corresponding TF representation. We show that
with just three times as many TF coefficients as signal samples, artifacts such
as phasiness and transient smearing can be greatly reduced compared to the
classical PV. The proposed algorithm is tested on both synthetic and real world
signals and compared with state of the art algorithms in a reproducible manner.Comment: 10 pages, 6 figure
Expediting TTS Synthesis with Adversarial Vocoding
Recent approaches in text-to-speech (TTS) synthesis employ neural network
strategies to vocode perceptually-informed spectrogram representations directly
into listenable waveforms. Such vocoding procedures create a computational
bottleneck in modern TTS pipelines. We propose an alternative approach which
utilizes generative adversarial networks (GANs) to learn mappings from
perceptually-informed spectrograms to simple magnitude spectrograms which can
be heuristically vocoded. Through a user study, we show that our approach
significantly outperforms na\"ive vocoding strategies while being hundreds of
times faster than neural network vocoders used in state-of-the-art TTS systems.
We also show that our method can be used to achieve state-of-the-art results in
unsupervised synthesis of individual words of speech.Comment: Published as a conference paper at INTERSPEECH 201
A High Quality Text-To-Speech System Composed of Multiple Neural Networks
While neural networks have been employed to handle several different
text-to-speech tasks, ours is the first system to use neural networks
throughout, for both linguistic and acoustic processing. We divide the
text-to-speech task into three subtasks, a linguistic module mapping from text
to a linguistic representation, an acoustic module mapping from the linguistic
representation to speech, and a video module mapping from the linguistic
representation to animated images. The linguistic module employs a
letter-to-sound neural network and a postlexical neural network. The acoustic
module employs a duration neural network and a phonetic neural network. The
visual neural network is employed in parallel to the acoustic module to drive a
talking head. The use of neural networks that can be retrained on the
characteristics of different voices and languages affords our system a degree
of adaptability and naturalness heretofore unavailable.Comment: Source link (9812006.tar.gz) contains: 1 PostScript file (4 pages)
and 3 WAV audio files. If your system does not support Windows WAV files, try
a tool like "sox" to translate the audio into a format of your choic
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