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Crate oxideav_evc

Crate oxideav_evc 

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Pure-Rust EVC — MPEG-5 Essential Video Coding (ISO/IEC 23094-1).

Round-10 status: a working Baseline-profile IDR + P + B decoder with residual coding (RLE + dequant + IDCT for nTbS up to 64), deblocking (§8.8.2 luma + chroma path), Main-profile CABAC init tables (Tables 40-90, §9.3.4.2 ctxInc helpers, eq. 1425/1426), full reference-picture-list parsing (§7.3.7 / §7.4.8) for non-IDR slices (sps_rpl_flag = 1), the HMVP candidate list (§8.5.2.7 / §8.5.2.4.4) wired through the inter pipeline, the round-9 multi-ref DPB + POC reordering, and the round-10 spatial-neighbour MV grid AMVP (§8.5.2.4) + LTRP RPL → DPB resolution (§8.3.2 / §8.3.5) + flush() drain of the output queue.

The crate decomposes into:

  • bitreader — MSB-first bit reader (§9.2 helpers).
  • nal — 2-byte NAL header (§7.3.1.2) + length-prefixed framing.
  • sps / pps / aps — parameter-set parsers (§7.3.2.x).
  • slice_header — slice_header() parse (§7.3.4).
  • cabac — full CABAC parsing process (§9.3): arithmetic decoding engine (regular + bypass + terminate) plus the FL / U / TR / EGk binarization helpers. The Baseline sps_cm_init_flag == 0 path uses a single ctxTable=0 / ctxIdx=0 context.
  • cabac_init — Main-profile (sps_cm_init_flag == 1) initValue tables (Tables 40-90 of §9.3.5) + the §9.3.2.2 init pipeline (cabac_init::init_main_profile_contexts) + the §9.3.4.2 per- syntax-element ctxInc helpers (btt_split_flag, last_sig_coeff_x/y_prefix, sig_coeff_flag, coeff_abs_level_greaterA/B_flag, etc.).
  • slice_data — slice_data() walker plus the round-3 IDR pixel pipeline (slice_data::decode_baseline_idr_slice) and the round-4 inter pipeline (slice_data::decode_baseline_inter_slice).
  • intra — intra prediction (§8.4.4) for the Baseline 5-mode set (DC, HOR, VER, UL, UR; sps_eipd_flag == 0 path).
  • inter — round-4 inter prediction (§8.5): MV resolution + 8-tap luma + 4-tap chroma sub-pel interpolation (Tables 25 / 27 — Baseline subset only) + AMVP candidate construction + default-weighted bipred.
  • transform — inverse DCT-II for nTbS ∈ {2, 4, 8, 16, 32, 64} (eq. 1062-1076). The 64-point matrix is built from the closed-form M[m][n] = round(64·√2·cos(π·m·(2n+1)/128)) (m≥1, M[0][n]=64), verified against every printed entry of eq. 1072 / 1074.
  • dequant — scaling + transform + final renorm (§8.7.2 / §8.7.3 / §8.7.4) for the sps_iqt_flag == 0 Baseline path.
  • picture — yuv420p 8-bit picture buffer + per-CU intra reconstruct glue (§8.7.5).
  • decoder — registered decoder factory returning a working Decoder for Baseline IDR + P/B bitstreams (8-bit 4:2:0, no residuals, single reference).
  • rpl — round-8 ref_pic_list_struct() parser (§7.3.7 / §7.4.8). Handles STRP + LTRP entries with the per-entry delta_poc_st / strp_entry_sign_flag / poc_lsb_lt shape.
  • hmvp — round-8 history-based MV prediction (§8.5.2.7 LRU update + §8.5.2.4.4 derive_default_mv walk). 23-entry list with per-CTU-row reset.

Round-8 deliberate omissions (pending follow-up rounds):

  • 10-bit support,
  • advanced deblocking (sps_addb_flag = 1 — round-6 supports the sps_addb_flag = 0 baseline filter only, now for both luma and chroma; addb is a Main-profile feature),
  • multi-reference DPB + reference list reordering (round 8 parses the RPL and the slice-side num_ref_idx_active_minus1[], but the inter pipeline still keys off the previous picture only),
  • Main-profile decode — round 7 lands the CABAC infrastructure (Tables 40-90 + ctxInc helpers); round 8 lands the RPL parse path and the HMVP candidate list. The actual Main-profile syntax decode (BTT / SUCO / ADMVP / EIPD / IBC / ATS / ADCC / ALF / DRA / AMVR / MMVD / affine / DMVR) still bubbles up Error::Unsupported.

All section / clause numbers refer to ISO/IEC 23094-1:2020(E) at docs/video/evc/ISO_IEC_23094-1-EVC-2020.pdf. Every module is spec-only — clauses, equations, and table numbers cite the Recommendation directly.

Modules§

alf
EVC Adaptive Loop Filter (ISO/IEC 23094-1 §8.9 / §7.3.5).
alf_tables
EVC ALF fixed filter tables (ISO/IEC 23094-1 §8.9.4 eq. 102 + 103).
aps
EVC adaptation parameter set parser (ISO/IEC 23094-1 §7.3.2.3).
bitreader
MSB-first bit reader plus 0-th-order Exp-Golomb helpers for EVC RBSPs.
cabac
EVC CABAC parsing process (ISO/IEC 23094-1 §9.3).
cabac_init
EVC Main-profile CABAC context initialization tables (ISO/IEC 23094-1 §9.3.2.2 + §9.3.4.2).
deblock
EVC deblocking filter (ISO/IEC 23094-1 §8.8.2).
decoder
Registry glue + minimal decode pipeline for the EVC crate.
dequant
EVC dequantization / scaling process (ISO/IEC 23094-1 §8.7.3 + §8.7.2 final renormalisation).
dra
EVC Dynamic Range Adjustment (ISO/IEC 23094-1 §8.10 / §7.3.6).
hmvp
History-based motion vector prediction (ISO/IEC 23094-1 §8.5.2.7, §8.5.2.4.4).
ibc
Intra Block Copy (IBC) primitives — ISO/IEC 23094-1 §8.6.
inter
EVC inter prediction (ISO/IEC 23094-1 §8.5).
intra
EVC intra prediction (ISO/IEC 23094-1 §8.4.4).
nal
EVC NAL unit framing (ISO/IEC 23094-1 §7.3.1, §7.4.2, Annex B).
neighbour
EVC neighbouring-block availability derivations (ISO/IEC 23094-1:2020 §6.4).
picture
EVC reconstructed picture buffer + per-CU pipeline glue (ISO/IEC 23094-1 §8.7.5).
pps
EVC picture parameter set parser (ISO/IEC 23094-1 §7.3.2.2).
rpl
Reference picture list parsing (ISO/IEC 23094-1 §7.3.7 / §7.4.8).
scan
EVC scanning processes (ISO/IEC 23094-1:2020 §6.5).
slice_data
EVC slice_data() walker (ISO/IEC 23094-1 §7.3.8).
slice_header
EVC slice header parser (ISO/IEC 23094-1 §7.3.4 / §7.4.5).
sps
EVC sequence parameter set parser (ISO/IEC 23094-1 §7.3.2.1, §7.4.3.1).
transform
EVC inverse transform (ISO/IEC 23094-1 §8.7.4).

Structs§

EvcFileInfo
Summary info recoverable from a bare EVC SPS — the public return type of probe.

Constants§

CODEC_ID_STR
Public codec id string. Matches the aggregator feature name evc.

Functions§

decode_idr_slice
Round-3 end-to-end decode of a Baseline-profile IDR slice.
probe
Probe a buffer for an EVC bitstream and return summary info from the first parseable SPS. Accepts either Annex B raw-bitstream framing (u(32) length prefix, the canonical case per ISO/IEC 23094-1 Annex B) or the tolerant 0x000001 / 0x00000001 start-code scanner.
register
Register the EVC implementation (currently parser-only) with a codec registry. The registered decoder factory returns an unsupported-error decoder per the round-1 deliverable.
walk_idr_slice
Walk an IDR slice’s slice_data() end-to-end given the active SPS and PPS. The slice’s RBSP is split into the slice header + the (byte-aligned) slice-data payload; this helper invokes the slice header parser then drives slice_data::walk_baseline_idr_slice across the rest of the RBSP. Returns the slice_data::SliceWalkStats once the engine terminates cleanly.