binkaud: fix monaural RDFT decoding (and add a test while at it)

[nihav.git] / src / dsp / mdct.rs

diff --git a/src/dsp/mdct.rs b/src/dsp/mdct.rs
deleted file mode 100644 (file)
index 540ae45..0000000
--- a/src/dsp/mdct.rs
+++ /dev/null
@@ -1,57 +0,0 @@
-use std::f32::consts;
-use super::fft::*;
-
-pub struct IMDCT {
-    twiddle:    Vec<FFTComplex>,
-    fft:        FFT,
-    size:       usize,
-    z:          Vec<FFTComplex>,
-}
-
-/*
-fn imdct(src: &[f32], dst: &mut [f32], length: usize) {
-    for n in 0..length*2 {
-        dst[n] = 0.0;
-        for k in 0..length {
-            dst[n] += src[k] * (consts::PI / (length as f32) * ((n as f32) + 0.5 + ((length/2) as f32)) * ((k as f32) + 0.5)).cos();
-        }
-    }
-}*/
-
-impl IMDCT {
-    pub fn new(mode: FFTMode, size: usize, scaledown: bool) -> Self {
-        let mut twiddle: Vec<FFTComplex> = Vec::with_capacity(size / 4);
-        let factor = 2.0 * consts::PI / ((8 * size) as f32);
-        let scale = if scaledown { (1.0 / (size as f32)).sqrt() } else { 1.0 };
-        for k in 0..size/4 {
-            twiddle.push(FFTComplex::exp(factor * ((8 * k + 1) as f32)).scale(scale));
-        }
-        let fft = FFTBuilder::new_fft(mode, size/4);
-        let mut z: Vec<FFTComplex> = Vec::with_capacity(size / 2);
-        z.resize(size / 2, FFTC_ZERO);
-        IMDCT { twiddle, fft, size, z }
-    }
-    pub fn imdct(&mut self, src: &[f32], dst: &mut [f32]) {
-        let size2 = self.size / 2;
-        let size4 = self.size / 4;
-        let size8 = self.size / 8;
-        for k in 0..size4 {
-            let c = FFTComplex { re: src[size2 - 2 * k - 1], im: src[        2 * k] };
-            self.z[k] = c * self.twiddle[k];
-        }
-        self.fft.do_fft_inplace(&mut self.z, false);
-        for k in 0..size4 {
-            self.z[k] *= self.twiddle[k];
-        }
-        for n in 0..size8 {
-            dst[            2 * n]     = -self.z[size8 + n]    .im;
-            dst[            2 * n + 1] =  self.z[size8 - n - 1].re;
-            dst[    size4 + 2 * n]     = -self.z[        n]    .re;
-            dst[    size4 + 2 * n + 1] =  self.z[size4 - n - 1].im;
-            dst[    size2 + 2 * n]     = -self.z[size8 + n]    .re;
-            dst[    size2 + 2 * n + 1] =  self.z[size8 - n - 1].im;
-            dst[3 * size4 + 2 * n]     =  self.z[        n]    .im;
-            dst[3 * size4 + 2 * n + 1] = -self.z[size4 - n - 1].re;
-        }
-    }
-}