Crate rustdct [−] [src]

RustDCT is a pure-Rust signal processing library that computes the most common Discrete Cosine Transforms

DCT Type 1
DCT Type 2 (Often called "the" DCT - by far the most common algorithm, used by JPEG image compression and others)
DCT Type 3 (the inverse of the DCT type 2, also used in JPEG)
DCT Type 4
MDCT (Used in audio and video compression such as Ogg and MP3)

The recommended way to use RustDCT is to create a DCTplanner instance, then call its plan_dct1 or plan_dct2 or etc methods. Each DCT type has its own method which will choose the best algorithm for the given size.

// Compute a DCT Type 2 of size 1234
use std::sync::Arc;
use rustdct::DCTplanner;

let mut input:  Vec<f32> = vec![0f32; 1234];
let mut output: Vec<f32> = vec![0f32; 1234];

let mut planner = DCTplanner::new();
let dct = planner.plan_dct2(1234);
dct.process(&mut input, &mut output);

// The DCT instance returned by the planner is stored behind an `Arc`, so it's cheap to clone
let dct_clone = Arc::clone(&dct);

RustDCT also exposes individual DCT algorithms. For example, if you're writing a JPEG compression library, it's safe to assume you want a DCT2 and DCT3 of size 8. Instead of going through the planner, you can directly create hardcoded DCT instances of size 8.

// Compute a DCT type 2 of size 8, and then compute a DCT type 3 of size 8 on the output.
use rustdct::dct2::DCT2;
use rustdct::dct2::dct2_butterflies::DCT2Butterfly8;
use rustdct::dct3::DCT3;
use rustdct::dct3::dct3_butterflies::DCT3Butterfly8;
 
let mut input = [0f32; 8];
let mut intermediate = [0f32; 8];
let mut output = [0f32; 8];
 
let dct2 = DCT2Butterfly8::new();
let dct3 = DCT3Butterfly8::new();
 
dct2.process(&mut input, &mut intermediate);
dct3.process(&mut intermediate, &mut output);

Re-exports

pub extern crate rustfft;

Modules

dct1	Algorithms for computing the Discrete Cosine Transform Type 1
dct2	Algorithms for computing the Discrete Cosine Transform Type 2
dct3	Algorithms for computing the Discrete Cosine Transform Type 3
dct4	Algorithms for computing the Discrete Cosine Transform Type 4
mdct	Algorithms for computing the Modified Discrete Cosine Transform
num_complex	Complex numbers.
num_traits	Numeric traits for generic mathematics

Structs

DCTplanner

The DCT planner is used to make new DCT algorithm instances.

Traits

DCTnum

Generic floating point number, implemented for f32 and f64