nx_vcodec_bitalloc_gate.nx source

1import "nx_gate_base.nx" 2// nx_vcodec_bitalloc_gate.nx -- DIAGNOSE where our bits go on standard akiyo (the +700% BD-rate gap): is it 3// the KEYFRAME (intra weakness) or the P-frames (inter/skip/entropy weakness)? Encodes a 48-frame GOP at a 4// mid qp with rct8 and reports keyframe bytes, total+mean P bytes, and their ratio. On near-static akiyo a 5// strong codec spends ~all bits on the 1 keyframe and near-zero on P (aggressive skip); if OUR P-frames are 6// expensive, the inter/skip/entropy path is the leak. Points the highest-leverage next fix. license: ORIGINAL 7import "nx_syscalls.nx" 8import "nx_video_codec_wasm.nx" 9 10const SW: i64 = 352 11const SH: i64 = 288 12const NF: i64 = 48 13 14func grow(name: *u8, ok: i64) -> i64 { if ok==1 { gw(" PASS " as *u8) } else { gw(" FAIL " as *u8) } gw(name); gw(" 15" as *u8); return ok } 16func gn(v: i64) -> i64 { 17 let b: *u8=sys_mmap(28); var m: i64=v; if m<0{sys_write(1,"-" as *u8,1);m=0-m} 18 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} 19 var i: i64=0; while i<k{b[i]=t[k-1-i];i=i+1} sys_write(1,b,k); return 0 } 20func cpb(d: *u8, s: *u8, n: i64) -> i64 { var i: i64=0; while i<n { d[i]=s[i]; i=i+1 } return 0 } 21 22func run(yuv: *u8, hi: i64, total: i64, qp: i64) -> i64 { 23 let N: i64=SW*SH; let C2: i64=(SW/2)*(SH/2); let fdata: i64=N+2*C2; let sz: i64=fdata 24 let fp: *i64 = sys_mmap(128*8) as *i64 25 var nf: i64=0; var p: i64=hi 26 while nf < NF { if p>=total { break } 27 var q: i64=p; while q<total { if (yuv[q]&0xff)==10 { break } q=q+1 } q=q+1 28 if q+fdata>total { break } fp[nf]=(yuv as i64)+q; nf=nf+1; p=q+fdata } 29 if nf < NF { gw("too few frames\n" as *u8); return 1 } 30 let prevE: *u8=sys_mmap(sz+64); let reconE: *u8=sys_mmap(sz+64) 31 let wire: *u8=sys_mmap(2097152); let blk: *i64=sys_mmap(512) as *i64; let mv: *i64=sys_mmap(128) as *i64 32 let est: *i64=sys_mmap(64) as *i64; let probs: *i64=sys_mmap(32*8) as *i64; let rcbuf: *u8=sys_mmap(2097152) 33 let t8c: *i64=sys_mmap(5120) as *i64; let rctx: *i64=sys_mmap(64) as *i64 34 vc_t8_init(t8c) 35 var z: i64=0; while z<sz { prevE[z]=0 as u8; z=z+1 } 36 rctx[0]=1; 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 37 var keyB: i64=0; var pB: i64=0; var pMax: i64=0 38 var f: i64=0 39 while f < NF { 40 let cur: *u8=fp[f] as *u8 41 var key: i64=0; if f==0 { key=1 } 42 rctx[0]=1 43 let nb: i64 = vv_enc_rct8(cur, prevE, reconE, SW, SH, qp, key, qp*188, wire, 2097152, blk, mv, rctx) 44 if nb<=0 { gw("enc fail\n" as *u8); return 1 } 45 if key==1 { keyB=nb } else { pB=pB+nb; if nb>pMax { pMax=nb } } 46 cpb(prevE, reconE, sz) 47 f=f+1 48 } 49 let meanP: i64 = pB/(NF-1) 50 gw(" qp=" as *u8); gn(qp) 51 gw(" KEYFRAME=" as *u8); gn(keyB); gw("B P-total=" as *u8); gn(pB) 52 gw("B meanP=" as *u8); gn(meanP); gw("B maxP=" as *u8); gn(pMax); gw("B\n" as *u8) 53 gw(" -> P-frames are " as *u8); gn(pB*100/(keyB+pB)); gw("% of the stream (near-static akiyo: SOTA codecs spend <20% on P via skip)\n" as *u8) 54 return 0 } 55 56func main() -> i64 { 57 gw("=== nx_vcodec_bitalloc_gate: WHERE our bits go on akiyo (intra keyframe vs inter P) ===\n" as *u8) 58 let box: *i64 = sys_mmap(16) as *i64 59 let yuv: *u8 = sys_read_file("/tmp/akiyo_cif.y4m" as *u8, box) 60 if (yuv as i64)==0 { gw("cannot read /tmp/akiyo_cif.y4m -> RED\n" as *u8); return 1 } 61 let total: i64=box[0] 62 var hi: i64=0; while hi<total { if (yuv[hi]&0xff)==10 { break } hi=hi+1 } hi=hi+1 63 run(yuv, hi, total, 8) 64 run(yuv, hi, total, 4) 65 gw("BITALLOC: DONE (diagnostic -- see the intra/inter split)\n" as *u8) 66 return 0 }