Struct Pacer 

pub struct Pacer { /* private fields */ }

Delays each buffer until its presentation time, so downstream sees frames (or, upstream of a decoder, compressed packets) at real playback speed instead of as fast as demux/decode can produce them. A Filter: receives via Sink, waits in short interruptible sleeps inside consume, then pushes the same buffer through its own (single) src pad. A pending pause/seek/stop interrupts that wait so the owning worker can process control: pause retains the in-flight buffer for resume, while seek and stop discard it.

Normally place a crate::queue::Queue upstream so the paced waits do not stall the demux/decoder feeding it and those stages can run ahead into the queue. The type does not enforce that placement; without the queue, pacing simply blocks the upstream caller on the same thread.

clock is shared across every Pacer in the pipeline (one per stream — video, audio, …) so they all agree on the same t=0 instead of each anchoring to its own first frame.

Implementations

impl Pacer

pub fn new( name: impl Into<String>, time_base: Rational, clock: Arc<Clock>, ) -> Result<Self, PacerError>

Trait Implementations

impl Element for Pacer

fn name(&self) -> Arc<str>

Returns a cheap clone (refcount bump, not a deep copy) of this element’s name — crate::bus::BusEvent stores names as Arc<str> for exactly this reason: a hot path like crate::queue::Queue posting BusEvent::Dropped once per overflowed buffer shouldn’t pay for a fresh heap allocation every time it wants to report which element it is.

fn element_type(&self) -> ElementType

See ElementType.

fn pp_log(&self) -> &PpLog

This element’s identity for crate::bus::Bus::post — same id/name as Element::name, just already wrapped as the crate::pp_log::PpLog its pp_info!/pp_warn!/pp_error! macros need. A stored private field, not built fresh per call, for the same reason name() returns a cheap Arc<str> clone instead of a fresh String — see its own docs.

fn pp_log_mut(&mut self) -> &mut PpLog

Mutable access to the same field Element::pp_log reads — used by crate::pipeline::ChainBuilder to stamp the owning crate::pipeline::Pipeline’s id onto every element that passes through it, via element_pp_log. Not meant to be called from anywhere else.

fn graph_id(&self) -> Option<ElementId>

A pre-reserved graph identity for elements that expose dynamic attachment handles. Most elements receive an ID from ChainBuilder and keep the default None implementation.

impl Sink for Pacer

fn consume(&mut self, buf: MediaBuffer) -> Result<()>

fn control(&mut self, msg: ControlMsg) -> Result<()>

Reacts to a ControlMsg (pause/resume/stop) and, for anything with a downstream of its own, forwards it on — same shape as consume, just a separate channel from MediaBuffer so it can reach every element (not just ones that already know how to interpret a data buffer) and, at a crate::queue::Queue, jump ahead of whatever data is backed up instead of waiting behind it. No default: every Sink has to consciously decide what this means for it, rather than silently dropping it.

impl Source for Pacer

fn src_pads(&mut self) -> &mut [SrcPad]