Struct SymbolDecoder 

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

A range decoder over an AV1 tile’s symbol data.

Implementations

impl<'a> SymbolDecoder<'a>

pub fn new(data: &'a [u8], disable_cdf_update: bool) -> Result<Self>

Initialise the decoder over a tile’s sz-byte symbol partition (init_symbol, §8.2.2). The position must be byte-aligned, which the syntax guarantees at every call site.

pub fn read_symbol(&mut self, cdf: &mut [u16]) -> Result<usize>

Decode one symbol against cdf, adapting it unless updates are disabled (read_symbol, §8.2.6). cdf has N + 1 entries: N cumulative frequencies with cdf[N-1] == 1 << 15, then an adaptation counter.

pub fn read_bool(&mut self) -> Result<bool>

Decode one equiprobable bit (read_bool, §8.2.3). The transient CDF’s adaptation is never observed, so it is skipped.

pub fn read_literal(&mut self, n: u32) -> Result<u32>

Decode an n-bit literal, most-significant bit first (read_literal, §8.2.5).

pub fn read_ns(&mut self, n: u32) -> Result<u32>

Decode a non-symmetric NS(n) value in 0..n (read_ns, §8.2.4). Used for the palette colour-index map’s first sample, which is uniform over the palette size.

pub fn max_bits(&self) -> i64

The number of real bits still available (may be negative once the decoder is in the padding region). Exposed for the tile-exit checks.