Struct Cabac 

pub struct Cabac<'a> { /* private fields */ }

The CABAC decoder: arithmetic engine reading MSB-first from the RBSP plus the 460 adaptive context models.

Implementations

impl<'a> Cabac<'a>

pub fn new( data: &'a [u8], start_byte: usize, qp: i32, init_idc: u32, is_i: bool, ) -> Self

Initializes from the RBSP data at byte offset start_byte (the slice data, byte-aligned past the header), the QP of the slice (clamped 0..51), cabac_init_idc, and whether the slice is I/SI (spec 9.3.1).

pub fn dbg_state(&self) -> (u32, u32)

Engine state (codIRange, codIOffset) – for bring-up verification against symbol 0 of the oracle (Brick 1.1). At slice start this is (510, first-9-bits).

pub fn pcm_start_byte(&self) -> usize

I_PCM sample position (spec 7.3.5 + 9.3.3.2.5). The PCM marker is a terminate bin; after it decodes as 1, the flush output of the encoder is already inside the borrowed offset bits of the engine, so the raw pcm_sample_* bytes start at the consumed-bit position rounded up to the next byte boundary (pcm_alignment_zero_bits). byte_pos*8 - cnt is that consumed position (offset-field bits count as read, buffered bits do not). Valid only immediately after decode_terminate() returned true (no renormalization has run since).

pub fn reinit_at(&mut self, byte: usize)

Re-initializes the arithmetic engine at absolute byte (spec 9.3.1.2, invoked after the I_PCM samples), KEEPING the adaptive context models – only the engine registers restart. Mirrors the tail of Cabac::new.

pub fn view(&mut self) -> (&'a [u8], Engine, &mut [u8; 512])

Split into (data, engine copy, contexts) for a register-resident run over many bins; finish with Cabac::commit.

pub fn commit(&mut self, eng: Engine)

Adopt the engine registers a Cabac::view run ended with.

pub fn decode_decision(&mut self, ctx_idx: usize) -> u32

One context-coded bin. Single-bin convenience over [Engine::decode_decision]; multi-bin parsers take a Cabac::view instead.

pub fn decode_bypass(&mut self) -> u32

One bypass bin (see [Engine::decode_bypass]).

pub fn decode_terminate(&mut self) -> bool

The terminate bin (see [Engine::decode_terminate]).