nx_mdct.nx

buildroot/runtime/_hdl_build/nx_mdct.nx

6264 B120 linesdepth 3pulls 3 transitivereach 1 importersview sourcekind tool

docs dependencies structs consts functions

about

nx_mdct.nx -- R1 of the transform ladder: the Modified Discrete Cosine Transform (the lapped transform every perceptual audio codec uses -- MP3/AAC/Opus-CELT). Built on the SAME sine absorbed into nx_audio_osc (osc_sin_unit) -- one sine, no dup. Sine analysis+synthesis window (Princen-Bradley) -> Time-Domain Aliasing Cancellation: overlap-add of consecutive half-overlapped blocks PERFECTLY reconstructs the signal. That PR property is a pure math gate (verifiable without ears). No-float -> deterministic/bit-reproducible (the exceed). Unlocks R2 = psychoacoustic masking + quantization = perceptual audio toward Opus. license_tier: ORIGINAL expect_exit: 0

dependencies 2 imports · 1 importers

imports: nx_audio_osc.nxnx_syscalls.nx

imported by: nx_perceptual.nx

call flow from main pre-order; caps 40 nodes / depth 6 declared; ↻ = already shown

structs

none

consts

9	const K_MAGIC_1100: i64 = 1100
10	const K_MAGIC_2999: i64 = 2999
11	const K_MAGIC_65536: i64 = 65536
13	const OSCP: i64 = 65536
14	const QPI: i64 = 16384 // pi/2 in osc units; cos(x) = sin(x + pi/2)

functions

16	func mp(s: *u8) -> i64 { var n: i64=0; while s[n]!=(0 as u8){n=n+1} sys_write(1,s,n); return 0 } called by 1: main calls 1: sys_write
17	func mpn(v: i64) -> i64 called by 1: main calls 2: sys_mmap sys_write
25	func m_abs(v: i64) -> i64 { if v<0 { return 0-v } return v } called by 1: main
28	func mk_window(w: *i64, N: i64) -> i64 called by 2: main main calls 1: osc_sin_unit
35	func mbasis(n: i64, k: i64, N: i64) -> i64 called by 2: mdct imdct calls 1: osc_sin_unit
42	func mdct(x: i64, X: i64, w: *i64, N: i64) -> i64 called by 2: main main calls 1: mbasis
55	func imdct(X: i64, y: i64, w: *i64, N: i64) -> i64 called by 1: main calls 1: mbasis
69	func main() -> i64 calls 9: mp sys_mmap mk_window osc_sin_unit mdct imdct+3