maroontree 0.1.1

AV1 & AV2 tiny still-image (AVIF) encoder
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99

/*
 * // Copyright (c) Radzivon Bartoshyk 6/2026. All rights reserved.
 * //
 * // Redistribution and use in source and binary forms, with or without modification,
 * // are permitted provided that the following conditions are met:
 * //
 * // 1.  Redistributions of source code must retain the above copyright notice, this
 * // list of conditions and the following disclaimer.
 * //
 * // 2.  Redistributions in binary form must reproduce the above copyright notice,
 * // this list of conditions and the following disclaimer in the documentation
 * // and/or other materials provided with the distribution.
 * //
 * // 3.  Neither the name of the copyright holder nor the names of its
 * // contributors may be used to endorse or promote products derived from
 * // this software without specific prior written permission.
 * //
 * // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

use std::sync::{Arc, OnceLock};

#[allow(unused)]
fn fwht_raw(input: &mut [i32; 16]) {
    let mut mid = [0i32; 16];
    for i in 0..4 {
        let (a0, b0, c0, d0) = (input[i], input[4 + i], input[8 + i], input[12 + i]);
        let mut a1 = a0 + b0;
        let mut d1 = d0 - c0;
        let e1 = (a1 - d1) >> 1;
        let b1 = e1 - b0;
        let c1 = e1 - c0;
        a1 -= c1;
        d1 += b1;
        mid[i] = a1;
        mid[4 + i] = c1;
        mid[8 + i] = d1;
        mid[12 + i] = b1;
    }
    for i in 0..4 {
        let base = i * 4;
        let (a0, b0, c0, d0) = (mid[base], mid[base + 1], mid[base + 2], mid[base + 3]);
        let mut a1 = a0 + b0;
        let mut d1 = d0 - c0;
        let e1 = (a1 - d1) >> 1;
        let b1 = e1 - b0;
        let c1 = e1 - c0;
        a1 -= c1;
        d1 += b1;
        input[base] = a1;
        input[base + 1] = c1;
        input[base + 2] = d1;
        input[base + 3] = b1;
    }
}

#[allow(unused)]
fn transpose(m: &[i32; 16]) -> [i32; 16] {
    let mut o = [0i32; 16];
    for r in 0..4 {
        for c in 0..4 {
            o[c * 4 + r] = m[r * 4 + c];
        }
    }
    o
}

#[allow(unused)]
fn wht_scalar(resid: &mut [i32; 16]) {
    fwht_raw(resid);
    let t = transpose(resid);
    resid.copy_from_slice(&t)
}

pub(crate) fn levels_from_resid(resid: &mut [i32; 16]) {
    type Wht = dyn Fn(&mut [i32; 16]) + Send + Sync;
    static WHT: OnceLock<Arc<Wht>> = OnceLock::new();
    let f = WHT.get_or_init(|| {
        #[cfg(all(target_arch = "aarch64", feature = "neon"))]
        {
            use crate::neon::fwht_raw_neon;
            Arc::new(fwht_raw_neon)
        }
        #[cfg(not(all(target_arch = "aarch64", feature = "neon")))]
        {
            Arc::new(wht_scalar)
        }
    });
    f(resid);
}