47 lines
1.4 KiB
Rust
47 lines
1.4 KiB
Rust
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use crate::constants::TILE_SZ;
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const ZIGZAG: [u8; TILE_SZ * TILE_SZ] = [
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0 , 1 , 5 , 6 , 14, 15, 27, 28,
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2 , 4 , 7 , 13, 16, 26, 29, 42,
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3 , 8 , 12, 17, 25, 30, 41, 43,
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9 , 11, 18, 24, 31, 40, 44, 53,
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10, 19, 23, 32, 39, 45, 52, 54,
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20, 22, 33, 38, 46, 51, 55, 60,
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21, 34, 37, 47, 50, 56, 59, 61,
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35, 36, 48, 49, 57, 58, 62, 63,
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];
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const DIVISORS: [u8; TILE_SZ * TILE_SZ] = [
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// source: https://en.wikipedia.org/wiki/Quantization_(image_processing)
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16, 11, 10, 16, 24, 40, 51, 61,
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12, 12, 14, 19, 26, 58, 60, 55,
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14, 13, 16, 24, 40, 57, 69, 56,
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14, 17, 22, 29, 51, 87, 80, 62,
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18, 22, 37, 56, 68, 109, 103, 77,
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24, 35, 55, 64, 81, 104, 113, 92,
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49, 64, 78, 87, 103, 121, 120, 101,
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72, 92, 95, 98, 112, 100, 103, 99,
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];
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pub fn to_quantized(
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coefs: [i32; TILE_SZ * TILE_SZ]
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) -> [i32; TILE_SZ * TILE_SZ] {
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let mut quant: [i32; TILE_SZ * TILE_SZ] = [0; TILE_SZ * TILE_SZ];
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for cf_ix in 0..TILE_SZ * TILE_SZ {
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quant[ZIGZAG[cf_ix] as usize] =
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coefs[cf_ix]
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// (coefs[cf_ix] + DIVISORS[cf_ix] as i32 / 2) /
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// (DIVISORS[cf_ix] as i32);
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}
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quant
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}
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pub fn from_quantized(
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quant: [i32; TILE_SZ* TILE_SZ]
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) -> [i32; TILE_SZ * TILE_SZ] {
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let mut coefs: [i32; TILE_SZ * TILE_SZ] = [0; TILE_SZ * TILE_SZ];
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for cf_ix in 0..TILE_SZ * TILE_SZ {
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coefs[cf_ix] = quant[ZIGZAG[cf_ix] as usize]; // * DIVISORS[cf_ix] as i32;
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}
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coefs
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}
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