tf.signal.inverse_stft

TensorFlow 2 version View source on GitHub

Computes the inverse Short-time Fourier Transform of stfts.

tf.signal.inverse_stft(
    stfts, frame_length, frame_step, fft_length=None,
    window_fn=tf.signal.hann_window, name=None
)

To reconstruct an original waveform, a complimentary window function should be used in inverse_stft. Such a window function can be constructed with tf.signal.inverse_stft_window_fn.

Example:

frame_length = 400
frame_step = 160
waveform = tf.compat.v1.placeholder(dtype=tf.float32, shape=[1000])
stft = tf.signal.stft(waveform, frame_length, frame_step)
inverse_stft = tf.signal.inverse_stft(
    stft, frame_length, frame_step,
    window_fn=tf.signal.inverse_stft_window_fn(frame_step))

if a custom window_fn is used in stft, it must be passed to inverse_stft_window_fn:

frame_length = 400
frame_step = 160
window_fn = functools.partial(window_ops.hamming_window, periodic=True),
waveform = tf.compat.v1.placeholder(dtype=tf.float32, shape=[1000])
stft = tf.signal.stft(
    waveform, frame_length, frame_step, window_fn=window_fn)
inverse_stft = tf.signal.inverse_stft(
    stft, frame_length, frame_step,
    window_fn=tf.signal.inverse_stft_window_fn(
       frame_step, forward_window_fn=window_fn))

Implemented with GPU-compatible ops and supports gradients.

stfts A complex64 [..., frames, fft_unique_bins] Tensor of STFT bins representing a batch of fft_length-point STFTs where fft_unique_bins is fft_length // 2 + 1
frame_length An integer scalar Tensor. The window length in samples.
frame_step An integer scalar Tensor. The number of samples to step.
fft_length An integer scalar Tensor. The size of the FFT that produced stfts. If not provided, uses the smallest power of 2 enclosing frame_length.
window_fn A callable that takes a window length and a dtype keyword argument and returns a [window_length] Tensor of samples in the provided datatype. If set to None, no windowing is used.
name An optional name for the operation.

A [..., samples] Tensor of float32 signals representing the inverse STFT for each input STFT in stfts.

ValueError If stfts is not at least rank 2, frame_length is not scalar, frame_step is not scalar, or fft_length is not scalar.