nx_rangecoder.nx

buildroot/runtime/nx_rangecoder.nx

9364 B158 linesdepth 2pulls 2 transitivereach 110 importersview sourcekind library

docs dependencies structs consts functions

about

nx_rangecoder.nx -- sovereign BINARY RANGE CODER (CABAC/VP8-class), the entropy-coding SOTA lever (task #31). The current nx_ventropy is CAVLC (fixed 4-bit run + 5-bit level-length) -> wasteful when the real symbol distribution is skewed (it almost always is). A range coder with ADAPTIVE per-context probabilities codes each binary decision at its true entropy (a p=0.97 flag costs ~0.04 bit, not 1). Design = the LZMA range coder (carry via a cache byte + a pending-0xFF counter -- exact, well-understood), 12-bit probabilities, adaptive update toward the observed bit. Bit-exact by construction; a divergence shows in the roundtrip gate. license_tier: ORIGINAL

dependencies 1 imports · 5 importers

imports: nx_ventropy.nx

imported by: nx_rangecoder_gain_gate.nxnx_rangecoder_sig.nxnx_vcodec.nxnx_vcodec_ffv1_entropy_gate.nxnx_vcodec_sigcoder_gate.nx

structs

none

consts

10	const RC_MAGIC_4096: i64 = 4096
11	const RC_MAGIC_4095: i64 = 4095
12	const RC_NCTX: i64 = 11 // contexts used by rc_block_encode/decode (probs array must be >= this, seeded 2048)
13	const RC_NCTX8: i64 = 24 // total contexts when 8x8 blocks are in the stream (11 for 4x4 + 13 for 8x8, below)

functions

20	func rc_enc_init(st: *i64) -> i64 { st[0]=0; st[1]=0xFFFFFFFF; st[2]=0; st[3]=1; st[4]=0; return 0 } called by 17: main vc_enc_frame_packed_rc vc_enc_frame_packed_rct8 vc_enc_frame_packed_rct8_region vc_enc_frame_packed_b vc_enc_frame_packed_rct9+11
22	func rc_shift_low(st: i64, out: u8) -> i64 called by 2: rc_enc_bit rc_enc_flush
40	func rc_enc_bit(st: i64, out: u8, p: i64, bit: i64) -> i64 called by 1: rc_enc_ctx calls 1: rc_shift_low
46	func rc_enc_flush(st: i64, out: u8) -> i64 { var i: i64=0; while i < 5 { rc_shift_low(st, out); i=i+1 } return st[4] } called by 19: main vc_rdskip_len vc_enc_frame_packed_rc vc_enc_frame_packed_rct8 vc_enc_frame_packed_rct8_region vc_enc_frame_packed_b+13 calls 1: rc_shift_low
49	func rc_dec_init(st: i64, in_: u8) -> i64 called by 9: main vc_dec_frame_packed_rc vc_dec_frame_packed_rct8_region vc_dec_frame_packed_rct8 vc_dec_frame_packed_b vc_dec_frame_packed_rct9+3
54	func rc_dec_bit(st: i64, in_: u8, p: i64) -> i64 called by 1: rc_dec_ctx
63	func rc_p_update(p: i64, bit: i64) -> i64 { if bit == 0 { return p + ((RC_MAGIC_4096 - p) >> 5) } return p - (p >> 5) } called by 2: rc_enc_ctx rc_dec_ctx
68	func rc_bits_q8(p: i64, bit: i64) -> i64 called by 2: rcs_level_cost_q8 rc_sig_cost_q8
81	func rc_enc_ctx(st: i64, out: u8, probs: *i64, ctx: i64, bit: i64) -> i64 called by 5: rc_block_encode rc_block64_encode rcs_enc_level rc_sig_encode vc_enc_frame_packed_rct9 calls 2: rc_enc_bit rc_p_update
83	func rc_dec_ctx(st: i64, in_: u8, probs: *i64, ctx: i64) -> i64 called by 5: rc_block_decode rc_block64_decode rcs_dec_level rc_sig_decode vc_dec_frame_packed_rct9 calls 2: rc_dec_bit rc_p_update
90	func rc_block_encode(coeffs: i64, st: i64, out: u8, probs: i64) -> i64 called by 3: main vc_enc_sub_rc enc_arm calls 4: ve_zz_idx rc_enc_ctx ve_zze ve_blen
105	func rc_block_decode(coeffs: i64, st: i64, in_: u8, probs: i64) -> i64 called by 2: main vc_dec_sub_rc calls 3: rc_dec_ctx ve_zz_idx ve_zzd
124	func rc_block64_encode(coeffs: i64, st: i64, out: u8, probs: i64, zz8: *i64) -> i64 called by 4: vc_enc_sub8_tail rlbytes_base enc_i16_dchad enc_frame calls 3: rc_enc_ctx ve_zze ve_blen
139	func rc_block64_decode(coeffs: i64, st: i64, in_: u8, probs: i64, zz8: *i64) -> i64 called by 1: vc_dec_sub8 calls 2: rc_dec_ctx ve_zzd