Trait Decoder 

pub trait Decoder: Send {
    // Required methods
    fn codec_id(&self) -> &CodecId;
    fn send_packet(&mut self, packet: &Packet) -> Result<()>;
    fn receive_frame(&mut self) -> Result<Frame>;
    fn flush(&mut self) -> Result<()>;

    // Provided methods
    fn reset(&mut self) -> Result<()> { ... }
    fn set_execution_context(&mut self, _ctx: &ExecutionContext) { ... }
}

A packet-to-frame decoder.

Required Methods

fn codec_id(&self) -> &CodecId

fn send_packet(&mut self, packet: &Packet) -> Result<()>

Feed one compressed packet. May or may not produce a frame immediately — call receive_frame in a loop afterwards.

fn receive_frame(&mut self) -> Result<Frame>

Pull the next decoded frame, if any. Returns Error::NeedMore when the decoder needs another packet.

fn flush(&mut self) -> Result<()>

Signal end-of-stream. After this, receive_frame will drain buffered frames and eventually return Error::Eof.

Provided Methods

fn reset(&mut self) -> Result<()>

Discard all carry-over state so the decoder can resume from a new bitstream position without producing stale output. Called by the player after a container seek.

Unlike flush (which signals end-of-stream and drains buffered frames), reset is expected to:

• drop every buffered input packet and pending output frame;
• zero any per-stream filter / predictor / overlap memory so the next send_packet decodes as if it were the first;
• leave the codec id and stream parameters untouched.

The default is a conservative “drain-then-forget”: call flush and ignore any remaining frames. Stateful codecs (LPC predictors, backward-adaptive gain, IMDCT overlap, reference pictures, …) should override this to wipe their internal state explicitly — otherwise the first ~N output samples after a seek will be glitchy until the state re-adapts.

fn set_execution_context(&mut self, _ctx: &ExecutionContext)

Advisory: announce the runtime environment (today: a thread budget for codec-internal parallelism). Called at most once, before the first send_packet. Default no-op; codecs that want to run slice-/GOP-/tile-parallel override this to capture the budget. Ignoring the hint is always safe — callers must still work with a decoder that runs serial.

Implementors