Struct StemLevels 

pub struct StemLevels<'a> { /* private fields */ }

The stem’s level in QUIET_FRAME frames at its own rate, with a quarter-frame hop, frame m centred at m hops. The quiet-note guard, the attack split and the split join read the same frames.

Implementations

impl<'a> StemLevels<'a>

pub fn new(mono: &'a [f64], rate: SampleRate) -> Self

Measures the RMS of every frame of mono at rate.

pub fn rms(&self) -> &[f64]

Returns the RMS of each frame.

pub fn envelope(&self, time: Seconds, window: Seconds) -> f64

Returns the RMS about its own mean of the window of samples centred at time: the envelope with any DC offset removed. Samples outside the stem count as silence.

pub fn frames_between(&self, from: Seconds, to: Seconds) -> Range<usize>

Returns the frames centred from from to to, both included.

pub fn harmonic_level(&self, frame: usize, pitch: MidiPitch) -> f64

Returns the level of frame frame at the first HARMONICS harmonics of pitch below the Nyquist frequency: the root of the summed power of each, from a Hann window over the frame with the frame’s mean removed. Samples outside the stem count as silence.

The window’s main lobe spans 160 Hz, so below about A2 (110 Hz) it cannot tell a note’s fundamental from a tone a fifth or a tritone away.

pub fn fundamental_level(&self, time: Seconds, pitch: MidiPitch) -> f64

Returns the level at the fundamental of pitch of the one period of samples centred at time, with their mean removed: one DFT bin over the period, unnormalised, so only ratios of two readings mean anything. The bin’s zeros fall on every harmonic of the note when the period is a whole number of samples. It is rounded to one, so at 22,050 Hz and at the worst phase a harmonic leaks about -70 dB at A1, -46 to -50 dB from A2 to A5, -23 dB at A6 and -17 dB at A7. The bin rejects only the note’s harmonics: a key 1 to 3 semitones up reads within 1 dB of the note, and a fifth up 2 to 6 dB under it. Samples outside the stem count as silence.

Trait Implementations

impl<'a> Clone for StemLevels<'a>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'a> Debug for StemLevels<'a>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.