Struct sample::rate::Converter

pub struct Converter<I> where I: Iterator, I::Item: Frame {
    // some fields omitted
}

An iterator that converts the rate at which frames are yielded from some given frame Iterator via some given ratio.

Other names for sample::rate::Converter might include:

• Sample rate converter
• {Up/Down}sampler
• Sample interpolater
• Sample decimator

At the moment, Converter only supports basic linear amplitude interpolation between frames and is far from the most precise algorithm available. The current form of interpolation also requires that samples are either in f64 format or can be converted to and from f64 format. In terms of audio quality, it is not recommended for use in pro-audio applications or professional sound design. However if you are simply reading audio files and need to do a single conversion from their sample rate to your own domain for basic playback, Converter might be sufficient and fast at the very least.

That said, the aim is to provide higher quality interpolation types soon and change Converters interface to a generic API compatible with a range of interpolation types.

Methods

impl<I> Converter<I> where I: Iterator, I::Item: Frame

fn from_hz_to_hz(source_frames: I, source_hz: f64, target_hz: f64) -> Self

Construct a new Converter from the source frames and the source and target sample rates (in Hz).

fn scale_playback_hz(source_frames: I, scale: f64) -> Self

Construct a new Converter from the source frames and the amount by which the current playback rate (not sample rate) should be multiplied to reach the new playback rate.

For example, if our source_frames is a sine wave oscillating at a frequency of 2hz and we wanted to convert it to a frequency of 3hz, the given scale should be 1.5.

fn scale_sample_hz(source_frames: I, scale: f64) -> Self

Construct a new Converter from the source frames and the amount by which the current sample rate (not playback rate) should be multiplied to reach the new sample rate.

If our source_frames are being sampled at a rate of 44_100hz and we want to convert to a sample rate of 96_000hz, the given scale should be 96_000.0 / 44_100.0.

This is the same as calling Converter::scale_playback_hz(source_frames, 1.0 / scale).

fn set_hz_to_hz(&mut self, source_hz: f64, target_hz: f64)

Update the source_to_target_ratio internally given the source and target hz.

This method might be useful for changing the sample rate during playback.

fn set_playback_hz_scale(&mut self, scale: f64)

Update the source_to_target_ratio internally given a new playback rate multiplier.

This method is useful for dynamically changing rates.

fn set_sample_hz_scale(&mut self, scale: f64)

Update the source_to_target_ratio internally given a new sample rate multiplier.

This method is useful for dynamically changing rates.

fn source(&self) -> &I

Borrow the source_frames Iterator from the Converter.

fn source_mut(&mut self) -> &I

Mutably borrow the source_frames Iterator from the Converter.

fn into_source(self) -> I

Drop self and return the internal source_frames Iterator.

fn next_frame(&mut self) -> Option<I::Item> where I::Item::Sample: Duplex<f64>

Yields the next interpolated target frame.

Trait Implementations

impl<I> Iterator for Converter<I> where I: Iterator, I::Item: Frame, I::Item::Sample: Duplex<f64>

type Item = I::Item

The type of the elements being iterated over.

fn next(&mut self) -> Option<Self::Item>

Advances the iterator and returns the next value.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator.

fn count(self) -> usize

Consumes the iterator, counting the number of iterations and returning it.

fn last(self) -> Option<Self::Item>

Consumes the iterator, returning the last element.

fn nth(&mut self, n: usize) -> Option<Self::Item>

Consumes the n first elements of the iterator, then returns the next() one.

fn chain<U>(self, other: U) -> Chain<Self, U::IntoIter> where U: IntoIterator<Item=Self::Item>

Takes two iterators and creates a new iterator over both in sequence.

fn zip<U>(self, other: U) -> Zip<Self, U::IntoIter> where U: IntoIterator

'Zips up' two iterators into a single iterator of pairs.

fn map<B, F>(self, f: F) -> Map<Self, F> where F: FnMut(Self::Item) -> B

Takes a closure and creates an iterator which calls that closure on each element.

fn filter<P>(self, predicate: P) -> Filter<Self, P> where P: FnMut(&Self::Item) -> bool

Creates an iterator which uses a closure to determine if an element should be yielded.

fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F> where F: FnMut(Self::Item) -> Option<B>

Creates an iterator that both filters and maps.

fn enumerate(self) -> Enumerate<Self>

Creates an iterator which gives the current iteration count as well as the next value.

fn peekable(self) -> Peekable<Self>

Creates an iterator which can use peek to look at the next element of the iterator without consuming it.

fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where P: FnMut(&Self::Item) -> bool

Creates an iterator that [skip()]s elements based on a predicate.

fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where P: FnMut(&Self::Item) -> bool

Creates an iterator that yields elements based on a predicate.

fn skip(self, n: usize) -> Skip<Self>

Creates an iterator that skips the first n elements.

fn take(self, n: usize) -> Take<Self>

Creates an iterator that yields its first n elements.

fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where F: FnMut(&mut St, Self::Item) -> Option<B>

An iterator adaptor similar to [fold()] that holds internal state and produces a new iterator.

fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where F: FnMut(Self::Item) -> U, U: IntoIterator

Creates an iterator that works like map, but flattens nested structure.

fn fuse(self) -> Fuse<Self>

Creates an iterator which ends after the first None.

fn inspect<F>(self, f: F) -> Inspect<Self, F> where F: FnMut(&Self::Item) -> ()

Do something with each element of an iterator, passing the value on.

fn by_ref(&mut self) -> &mut Self

Borrows an iterator, rather than consuming it.

fn collect<B>(self) -> B where B: FromIterator<Self::Item>

Transforms an iterator into a collection.

fn partition<B, F>(self, f: F) -> (B, B) where B: Default + Extend<Self::Item>, F: FnMut(&Self::Item) -> bool

Consumes an iterator, creating two collections from it.

fn fold<B, F>(self, init: B, f: F) -> B where F: FnMut(B, Self::Item) -> B

An iterator adaptor that applies a function, producing a single, final value.

fn all<F>(&mut self, f: F) -> bool where F: FnMut(Self::Item) -> bool

Tests if every element of the iterator matches a predicate.

fn any<F>(&mut self, f: F) -> bool where F: FnMut(Self::Item) -> bool

Tests if any element of the iterator matches a predicate.

fn find<P>(&mut self, predicate: P) -> Option<Self::Item> where P: FnMut(&Self::Item) -> bool

Searches for an element of an iterator that satisfies a predicate.

fn position<P>(&mut self, predicate: P) -> Option<usize> where P: FnMut(Self::Item) -> bool

Searches for an element in an iterator, returning its index.

fn rposition<P>(&mut self, predicate: P) -> Option<usize> where P: FnMut(Self::Item) -> bool, Self: ExactSizeIterator + DoubleEndedIterator

Searches for an element in an iterator from the right, returning its index.

fn max(self) -> Option<Self::Item> where Self::Item: Ord

Returns the maximum element of an iterator.

fn min(self) -> Option<Self::Item> where Self::Item: Ord

Returns the minimum element of an iterator.

fn max_by_key<B, F>(self, f: F) -> Option<Self::Item> where B: Ord, F: FnMut(&Self::Item) -> B

Returns the element that gives the maximum value from the specified function.

fn min_by_key<B, F>(self, f: F) -> Option<Self::Item> where B: Ord, F: FnMut(&Self::Item) -> B

Returns the element that gives the minimum value from the specified function.

fn rev(self) -> Rev<Self> where Self: DoubleEndedIterator

Reverses an iterator's direction.

fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB) where FromA: Default + Extend<A>, FromB: Default + Extend<B>, Self: Iterator<Item=(A, B)>

Converts an iterator of pairs into a pair of containers.

fn cloned<'a, T>(self) -> Cloned<Self> where Self: Iterator<Item=&'a T>, T: 'a + Clone

Creates an iterator which clone()s all of its elements.

fn cycle(self) -> Cycle<Self> where Self: Clone

Repeats an iterator endlessly.

fn sum<S>(self) -> S where S: Add<Self::Item, Output=S> + Zero

Sums the elements of an iterator.

fn product<P>(self) -> P where P: Mul<Self::Item, Output=P> + One

Iterates over the entire iterator, multiplying all the elements

fn cmp<I>(self, other: I) -> Ordering where I: IntoIterator<Item=Self::Item>, Self::Item: Ord

Lexicographically compares the elements of this Iterator with those of another.

fn partial_cmp<I>(self, other: I) -> Option<Ordering> where I: IntoIterator, Self::Item: PartialOrd<I::Item>

Lexicographically compares the elements of this Iterator with those of another.

fn eq<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialEq<I::Item>

Determines if the elements of this Iterator are equal to those of another.

fn ne<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialEq<I::Item>

Determines if the elements of this Iterator are unequal to those of another.

fn lt<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>

Determines if the elements of this Iterator are lexicographically less than those of another.

fn le<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>

Determines if the elements of this Iterator are lexicographically less or equal to those of another.

fn gt<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>

Determines if the elements of this Iterator are lexicographically greater than those of another.

fn ge<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>

Determines if the elements of this Iterator are lexicographically greater than or equal to those of another.

Derived Implementations

impl<I: Clone> Clone for Converter<I> where I: Iterator, I::Item: Frame, I::Item: Clone

fn clone(&self) -> Converter<I>

Returns a copy of the value.

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

Performs copy-assignment from source.