code wiki / _hdl_build / nx_vcodec_bitsplit_gate.nx
nx_vcodec_bitsplit_gate.nx source
↩ module page · 80 lines · 4313 B
1import "nx_gate_base.nx"
2// nx_vcodec_bitsplit_gate.nx -- WHERE do the coded-P-MB bits actually go: MV/headers (CAVLC section) vs residual
3// coefficients (range-coded section)? Decides the BIG entropy-vs-prediction question before building either.
4// The rct8 frame fn packs each luma plane as [cavlc_end:u16][CAVLC bits: skip+part+MV+qpel+t8][range bytes:
5// sig-map + levels]. yb (plane total) is in the vv header; cavlc_end is the plane's first 2 bytes -> range =
6// yb - cavlc_end. Accumulates the LUMA split over P-frames for baseline (emode 41) and partition (emode 169), on
7// /tmp/seq.y4m. If range >> cavlc, ENTROPY/residual is the lever; if cavlc is large, MV/prediction is. ORIGINAL
8import "nx_syscalls.nx"
9import "nx_video_codec_wasm.nx"
10
11const SW: i64 = 352
12const SH: i64 = 288
13const NF: i64 = 48
14
15func grow(name: *u8, ok: i64) -> i64 { if ok==1 { gw(" PASS " as *u8) } else { gw(" FAIL " as *u8) } gw(name); gw("
16" as *u8); return ok }
17func gn(v: i64) -> i64 {
18 let b: *u8=sys_mmap(28); var m: i64=v; if m<0{sys_write(1,"-" as *u8,1);m=0-m}
19 let t: *u8=sys_mmap(28); var k: i64=0; if m==0{t[0]=48 as u8;k=1} while m>0{t[k]=(48+(m%10)) as u8;m=m/10;k=k+1}
20 var i: i64=0; while i<k{b[i]=t[k-1-i];i=i+1} sys_write(1,b,k); return 0 }
21func cpb(d: *u8, s: *u8, n: i64) -> i64 { var i: i64=0; while i<n { d[i]=s[i]; i=i+1 } return 0 }
22
23func frames(yuv: *u8, hi: i64, total: i64, fp: *i64, fdata: i64) -> i64 {
24 var nf: i64=0; var p: i64=hi
25 while nf < NF { if p>=total { break }
26 var q: i64=p; while q<total { if (yuv[q]&0xff)==10 { break } q=q+1 } q=q+1
27 if q+fdata>total { break } fp[nf]=(yuv as i64)+q; nf=nf+1; p=q+fdata }
28 return nf }
29
30func run(fp: *i64, qp: i64, emode: i64, sz: i64) -> i64 {
31 let prevE: *u8=sys_mmap(sz+64); let reconE: *u8=sys_mmap(sz+64)
32 let wire: *u8=sys_mmap(4194304); let blk: *i64=sys_mmap(512) as *i64; let mv: *i64=sys_mmap(128) as *i64
33 let est: *i64=sys_mmap(64) as *i64; let probs: *i64=sys_mmap(32*8) as *i64; let rcbuf: *u8=sys_mmap(4194304)
34 let t8c: *i64=sys_mmap(5120) as *i64; let rctx: *i64=sys_mmap(64) as *i64
35 vc_t8_init(t8c)
36 var z: i64=0; while z<sz { prevE[z]=0 as u8; z=z+1 }
37 rctx[1]=est as i64; rctx[2]=probs as i64; rctx[3]=rcbuf as i64; rctx[4]=t8c as i64; rctx[5]=0; rctx[6]=0; rctx[7]=0
38 var cavlcB: i64=0; var rangeB: i64=0
39 var f: i64=0
40 while f < NF {
41 let cur: *u8=fp[f] as *u8
42 var key: i64=0; if f==0 { key=1 }
43 rctx[0]=emode
44 let nb: i64 = vv_enc_rct8(cur, prevE, reconE, SW, SH, qp, key, qp*30, wire, 4194304, blk, mv, rctx)
45 if nb<=0 { gw("enc fail\n" as *u8); return 1 }
46 if key==0 {
47 let yb: i64 = vv_rd_u32b(wire, 0) // luma plane byte count
48 let lo: i64 = wire[12] as i64
49 let hi2: i64 = wire[13] as i64
50 let ce: i64 = (lo & 0xff) | ((hi2 & 0xff) << 8) // luma cavlc_end (headers+MV bytes)
51 cavlcB = cavlcB + ce; rangeB = rangeB + (yb - ce)
52 }
53 cpb(prevE, reconE, sz)
54 f=f+1
55 }
56 let tot: i64 = cavlcB + rangeB
57 var pctc: i64 = 0; var pctr: i64 = 0
58 if tot > 0 { pctc = cavlcB*100/tot; pctr = rangeB*100/tot }
59 gw(" emode=" as *u8); gn(emode)
60 gw(" luma P: CAVLC(hdr+MV)=" as *u8); gn(cavlcB)
61 gw("B RANGE(residual)=" as *u8); gn(rangeB)
62 gw("B -> MV/hdr=" as *u8); gn(pctc); gw("% residual=" as *u8); gn(pctr); gw("%\n" as *u8)
63 return 0 }
64
65func main() -> i64 {
66 gw("=== nx_vcodec_bitsplit_gate: coded-P-MB bit split MV/hdr vs residual on /tmp/seq.y4m (qp=8) ===\n" as *u8)
67 let box: *i64 = sys_mmap(16) as *i64
68 let yuv: *u8 = sys_read_file("/tmp/seq.y4m" as *u8, box)
69 if (yuv as i64)==0 { gw("cannot read /tmp/seq.y4m -> RED\n" as *u8); return 1 }
70 let total: i64=box[0]
71 var hi: i64=0; while hi<total { if (yuv[hi]&0xff)==10 { break } hi=hi+1 } hi=hi+1
72 let C2: i64=(SW/2)*(SH/2); let fdata: i64=SW*SH+2*C2; let sz: i64=fdata
73 let fp: *i64=sys_mmap(128*8) as *i64
74 let nf: i64=frames(yuv, hi, total, fp, fdata)
75 if nf < NF { gw("too few frames -> RED\n" as *u8); return 1 }
76 gw(" (emode 41 = baseline no-partition; emode 169 = partition vcv-7)\n" as *u8)
77 run(fp, 8, 41, sz)
78 run(fp, 8, 41+128, sz)
79 gw("BITSPLIT: DONE\n" as *u8)
80 return 0 }