Crate rusty_h264_common 

Shared primitives for the rusty_h264 pure-Rust H.264 codec.

This crate is the foundation both the encoder and decoder sit on. It is #![forbid(unsafe_code)]: the bit-twiddling core of an H.264 codec is exactly where memory-safety bugs hide in the C implementations, so we keep it provably safe.

Modules mirror the concerns shared across codec/common in Cisco’s openh264:

• bit_writer / bit_reader — MSB-first bit packing + Exp-Golomb.
• nal — NAL units, Annex-B framing, RBSP emulation prevention.
• types — shared enums and the raw YUV frame container.

The shipped build is #![forbid(unsafe_code)]. The profile feature (a measurement-only dev build, never shipped) relaxes this to unlock the rdtsc timer in prof; that is the only unsafe in the crate and only under profile.

Re-exports

pub use bit_reader::BitReader;

pub use bit_writer::BitWriter;

pub use nal::NalUnit;

pub use nal::NalUnitType;

pub use types::ChromaFormat;

pub use types::Profile;

pub use types::YuvFrame;

Modules

aligned

A 16-byte-aligned heap byte buffer for the openh264 spatial asm kernels.

bit_reader

MSB-first bit reader with H.264 Exp-Golomb decoding.

bit_writer

MSB-first bit writer with H.264 Exp-Golomb coding.

cabac_tables

CABAC tables ported verbatim from openh264 common_tables.cpp (spec Tables 9-44/9-45 and 9-12..9-33). 460 contexts, 4 init models [I,idc0,idc1,idc2]. CTX_NA sentinels (I-slice-unused contexts) are 0 as in openh264.

cavlc

CAVLC — Context-Adaptive Variable-Length Coding of residual blocks.

deblock

In-loop deblocking filter (spec §8.7), all-intra case.

inter

Inter prediction primitives: motion compensation and motion-vector prediction. Shared by the encoder (reconstruction) and decoder so the two agree bit-for-bit. Motion vectors are in quarter-pel units; phase 4b uses the integer part only (full-pel), with the 6-tap/bilinear sub-pel filters arriving in 4c.

nal

NAL units, Annex-B framing, and RBSP emulation-prevention.

predict

Intra prediction + shared block reconstruction for I_16x16 macroblocks.

prof

Feature-gated decode/encode stage profiler — the instrument for perf work.

transform

H.264 4×4 residual transform and quantization (spec §8.5 / §8.6).

types

Shared codec types: profiles, chroma format, and the raw YUV frame container.

Constants

ACCEL

Whether the vendored SIMD kernels are compiled in (asm feature on x86-64). Exposed so benchmarks can state which path they measured — a harness that silently falls back to the scalar twin reports numbers that look like a regression in the fast path.