Struct pvoc::PhaseVocoder

pub struct PhaseVocoder { /* fields omitted */ }

A phase vocoder.

Roughly translated from http://blogs.zynaptiq.com/bernsee/pitch-shifting-using-the-ft/

Implementations

impl PhaseVocoder

pub fn new(
    channels: usize,
    sample_rate: f64,
    frame_size: usize,
    time_res: usize
) -> PhaseVocoder

Constructs a new phase vocoder.

channels is the number of channels of audio.

sample_rate is the sample rate.

frame_size is the fourier transform size. It must be > 1. For optimal computation speed, this should be a power of 2. Will be rounded to a multiple of time_res.

time_res is the number of frames to overlap.

Panics

Panics if frame_size is <= 1 after rounding.

pub fn num_channels(&self) -> usize

pub fn num_bins(&self) -> usize

pub fn time_res(&self) -> usize

pub fn sample_rate(&self) -> f64

pub fn process<S, F>(
    &mut self,
    input: &[&[S]],
    output: &mut [&mut [S]],
    mut processor: F
) -> usize where
    S: Float + ToPrimitive + FromPrimitive,
    F: FnMut(usize, usize, &[Vec<Bin>], &mut [Vec<Bin>]), 

Reads samples from input, processes the samples, then resynthesizes as many samples as possible into output. Returns the number of frames written to output.

processor is a function to manipulate the spectrum before it is resynthesized. Its arguments are respectively num_channels, num_bins, analysis_output and synthesis_input.

Samples are expected to be normalized to the range [-1, 1].

This method can be called multiple times on the same PhaseVocoder. If this happens, in the analysis step, it will be assumed that the input is a continuation of the input that was passed during the previous call.

It is possible that not enough data is available yet to fill output completely. In that case, only the first frames of output will be written to. Conversely, if there is more data available than output can hold, the remaining output is kept in the PhaseVocoder and can be retrieved with another call to process when more input data is available.

Remark

The synthesis_input passed to the processor_function is currently initialised to empty bins. This behaviour may change in a future release, so make sure that your implementation does not rely on it.

pub fn phase_to_frequency(&self, bin: usize, phase: f64) -> f64

pub fn frequency_to_phase(&self, freq: f64) -> f64