`nx_room_plc.nx` source

↩ module page · 108 lines · 5277 B
1// nx_room_plc.nx -- X-ROOM (overseas-grade): sovereign DETERMINISTIC audio PACKET-LOSS
2// CONCEALMENT. The last line of defense: when a frame is lost BEYOND what FEC recovers
3// (bursty overseas loss), synthesize a replacement instead of going silent. Pitch-repeat
4// the last good period with a gentle energy decay -> a smooth, click-free fill; the naive
5// alternative (zero-fill) drops a hole = an audible CLICK + silence gap.
6//
7// EXCEED axis (honest) vs zero/silence concealment: deterministic, audit-replayable
8// waveform extrapolation that (1) reconstructs far closer to the true signal, (2) keeps
9// energy up (not silent), (3) resumes more smoothly (smaller boundary jump). Sovereign,
10// integer-exact. HONEST SCOPE: periodic-extrapolation PLC on a known pitch period; true
11// pitch detection + LPC residual extrapolation (compose nx_nv1_lpc) = a deeper rung.
12//
13// main() is the SELF-VALIDATING GATE. Evidence -> knowledge/status/room_plc.log.
14// license_tier: ORIGINAL
15import "nx_syscalls.nx"
16
17const PLC_LOG: *u8 = "knowledge/status/room_plc.log"
18
19func pw(fd: i64, s: *u8) -> i64 { var n: i64 = 0; while s[n] != (0 as u8) { n = n + 1 } sys_write(fd, s, n); return 0 }
20func pwn(fd: i64, v: i64) -> i64 { let bb: *u8 = sys_mmap(28); var m: i64=v; if m<0 {m=0-m; sys_write(fd,"-" as *u8,1)}; let t: *u8 = sys_mmap(28); var k: i64=0; if m==0 {t[0]=48;k=1}; while m>0 {t[k]=(48+(m%10)) as u8; m=m/10; k=k+1}; var i: i64=0; while i<k {bb[i]=t[k-1-i]; i=i+1}; sys_write(fd, bb, k); return 0 }
21
22func pabs(x: i64) -> i64 { if x < 0 { return 0 - x } return x }
23
24// fill out[0..L) for a lost frame at `start`. mode 1 = ZERO-fill (naive). mode 0 = PLC:
25// repeat the last `P`-sample period with a linear energy decay (atten per sample).
26func plc_fill(sig: *i64, start: i64, L: i64, P: i64, atten: i64, mode: i64, out: *i64) -> i64 {
27    var j: i64 = 0
28    while j < L {
29        if mode == 1 { out[j] = 0 }
30        else {
31            let src: i64 = sig[start - P + (j % P)]
32            var a: i64 = 256 - j * atten
33            if a < 0 { a = 0 }
34            out[j] = src * a / 256
35        }
36        j = j + 1
37    }
38    return 0
39}
40// sum |out[j] - true[j]| over the concealed frame.
41func plc_err(out: *i64, sig: *i64, start: i64, L: i64) -> i64 {
42    var s: i64 = 0
43    var j: i64 = 0
44    while j < L { s = s + pabs(out[j] - sig[start + j]); j = j + 1 }
45    return s
46}
47func plc_energy(out: *i64, L: i64) -> i64 {
48    var s: i64 = 0
49    var j: i64 = 0
50    while j < L { s = s + pabs(out[j]); j = j + 1 }
51    return s
52}
53
54func main() -> i64 {
55    let NS: i64 = 64
56    let sig: *i64 = sys_mmap(8 * NS) as *i64
57    // periodic voiced-audio model: period P=8, smooth positive envelope, exactly repeating.
58    let base: *i64 = sys_mmap(8 * 8) as *i64
59    base[0]=40; base[1]=60; base[2]=75; base[3]=60; base[4]=40; base[5]=20; base[6]=10; base[7]=20
60    var i: i64 = 0
61    while i < NS { sig[i] = base[i % 8]; i = i + 1 }
62
63    let P: i64 = 8
64    let start: i64 = 40        // a period boundary; lose one full period [40,48)
65    let L: i64 = 8
66    let ATTEN: i64 = 4
67    let out: *i64 = sys_mmap(8 * 16) as *i64
68    var ok: i64 = 1
69
70    // PLC conceal
71    plc_fill(sig, start, L, P, ATTEN, 0, out)
72    let plc_e: i64 = plc_err(out, sig, start, L)
73    let plc_en: i64 = plc_energy(out, L)
74    let plc_resume: i64 = pabs(sig[start + L] - out[L - 1])   // jump at the resumption boundary
75
76    // ZERO-fill (naive control)
77    plc_fill(sig, start, L, P, ATTEN, 1, out)
78    let zero_e: i64 = plc_err(out, sig, start, L)
79    let zero_en: i64 = plc_energy(out, L)
80    let zero_resume: i64 = pabs(sig[start + L] - out[L - 1])
81
82    if plc_e >= zero_e { ok = 0 }          // PLC reconstructs far closer than silence
83    if plc_en <= zero_en { ok = 0 }        // PLC keeps energy up (not silent); zero_en==0
84    if plc_resume >= zero_resume { ok = 0 } // PLC resumes with a smaller boundary jump (less click)
85
86    // tamper: WRONG pitch period (P-1) -> the repeat is misaligned -> reconstruction error rises.
87    plc_fill(sig, start, L, P - 1, ATTEN, 0, out)
88    let tamper_e: i64 = plc_err(out, sig, start, L)
89    if tamper_e <= plc_e { ok = 0 }        // the correct pitch period is load-bearing
90
91    pw(1, "ROOMPLCGATE plc_err=" as *u8); pwn(1, plc_e); pw(1, " zero_err=" as *u8); pwn(1, zero_e)
92    pw(1, " plc_energy=" as *u8); pwn(1, plc_en); pw(1, " zero_energy=" as *u8); pwn(1, zero_en)
93    pw(1, " plc_resume=" as *u8); pwn(1, plc_resume); pw(1, " zero_resume=" as *u8); pwn(1, zero_resume)
94    pw(1, " wrongpitch_err=" as *u8); pwn(1, tamper_e)
95    if ok == 1 { pw(1, " verdict=GREEN\n" as *u8) } else { pw(1, " verdict=RED\n" as *u8) }
96
97    let lf: i64 = sys_openat_append(PLC_LOG, 420)
98    if lf >= 0 {
99        pw(lf, "ROOMPLCGATE plc_err=" as *u8); pwn(lf, plc_e); pw(lf, " zero_err=" as *u8); pwn(lf, zero_e)
100        pw(lf, " plc_energy=" as *u8); pwn(lf, plc_en); pw(lf, " zero_energy=" as *u8); pwn(lf, zero_en)
101        pw(lf, " plc_resume=" as *u8); pwn(lf, plc_resume); pw(lf, " zero_resume=" as *u8); pwn(lf, zero_resume)
102        pw(lf, " wrongpitch_err=" as *u8); pwn(lf, tamper_e)
103        if ok == 1 { pw(lf, " verdict=GREEN\n" as *u8) } else { pw(lf, " verdict=RED\n" as *u8) }
104        sys_close(lf)
105    }
106    if ok == 1 { sys_exit(0) } else { sys_exit(1) }
107    return 0
108}
nx_room_plc.nx source

`nx_room_plc.nx` source
