Struct AnalysisEngine 

pub struct AnalysisEngine {
    fft_size: usize,
    smoothing_constant: f64,
    min_decibels: f64,
    max_decibels: f64,
    data: Box<[f32; 32768]>,
    current_block: usize,
    fft_computed: bool,
    blackman_windows: Vec<f32>,
    smoothed_fft_data: Vec<f32>,
    computed_fft_data: Vec<f32>,
    windowed: Vec<f32>,
}

The actual analysis is done on the DOM side. We provide the actual base functionality in this struct, so the DOM just has to do basic shimming

Fields

fft_size: usize

The number of past sample-frames to consider in the FFT

smoothing_constant: f64

min_decibels: f64

max_decibels: f64

data: Box<[f32; 32768]>

This is a ring buffer containing the last MAX_FFT_SIZE sample-frames

current_block: usize

The index of the current block

fft_computed: bool

Have we computed the FFT already?

blackman_windows: Vec<f32>

Cached blackman window data

smoothed_fft_data: Vec<f32>

The smoothed FFT data (in frequency domain)

computed_fft_data: Vec<f32>

The computed FFT data, in decibels

windowed: Vec<f32>

The windowed time domain data Used during FFT computation

Implementations

impl AnalysisEngine

pub fn new( fft_size: usize, smoothing_constant: f64, min_decibels: f64, max_decibels: f64, ) -> Self

pub fn set_fft_size(&mut self, fft_size: usize)

pub fn get_fft_size(&self) -> usize

pub fn set_smoothing_constant(&mut self, smoothing_constant: f64)

pub fn get_smoothing_constant(&self) -> f64

pub fn set_min_decibels(&mut self, min_decibels: f64)

pub fn get_min_decibels(&self) -> f64

pub fn set_max_decibels(&mut self, max_decibels: f64)

pub fn get_max_decibels(&self) -> f64

fn advance(&mut self)

fn curent_block_mut(&mut self) -> &mut [f32]

Get the data of the current block

fn convert_index(&self, index: usize) -> usize

Given an index from 0 to fft_size, convert it into an index into the backing array

fn advance_index(&self, index: &mut usize)

Given an index into the backing array, increment it

pub fn push(&mut self, block: Block)

fn compute_blackman_windows(&mut self)

https://webaudio.github.io/web-audio-api/#blackman-window

fn apply_blackman_window(&mut self)

fn compute_fft(&mut self)

pub fn fill_time_domain_data(&self, dest: &mut [f32])

pub fn fill_byte_time_domain_data(&self, dest: &mut [u8])

pub fn fill_frequency_data(&mut self, dest: &mut [f32])

pub fn fill_byte_frequency_data(&mut self, dest: &mut [u8])

Trait Implementations

impl MallocSizeOf for AnalysisEngine

fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize

Measure the heap usage of all descendant heap-allocated structures, but not the space taken up by the value itself.