Struct Scaler 

pub struct Scaler { /* private fields */ }

Converts/resizes decoded video frames — pixel format (e.g. the YUV a decoder produces -> the RGB most inference models expect) and resolution (source resolution -> a model’s fixed input size) in one pass via libswscale. A Filter: receives via Sink, pushes the converted frame on through its own (single) src pad.

Typical placement: right before something with a fixed input contract, e.g. an ONNX object-detection model — not a general-purpose pipeline stage, so most chains won’t need one at all.

Implementations

impl Scaler

pub fn new( name: impl Into<String>, dst_format: Pixel, dst_width: u32, dst_height: u32, flags: Flags, ) -> Self

dst_format/dst_width/dst_height describe what every output frame will be; the source side is learned automatically from whatever frames actually arrive (see context’s docs), so this doesn’t need decoder parameters up front the way crate::elements::SwDecoder::new does.

Trait Implementations

impl Element for Scaler

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 Send for Scaler

impl Sink for Scaler

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 Scaler

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