Module element

Structs§

Context: Everything a crate::pipeline::ChainBuilder/crate::elements::Tee needs to wire itself into a crate::pipeline::Pipeline — bundled into one Arc instead of threading bus/pipeline_id/graph/the wall and playback clocks through separately. Built once per source by crate::pipeline::PipelineBuilder::add_source (what crate::pipeline::Pipeline::new itself calls, for its own single-source case) and handed to that source’s own wire closure; a crate::elements::Tee keeps its own clone while it is alive, and its crate::elements::TeeHandle accesses that clone weakly so retaining the handle cannot keep the pipeline’s Bus open after the Tee itself is gone.

ElementType: Which kind of element posted a crate::bus::BusEvent — cheap to compare/match, unlike the accompanying name: Arc<str> (an instance-level identifier chosen by whoever constructed it, needed alongside this to tell apart e.g. two Queues in the same pipeline; see Element::element_type).

Element: A node in the pipeline graph with a name. Plain identity only — says nothing about whether the node has an input, an output, both, or neither.
Filter: An element with both an input and an output — decoder, encoder, filter, thumbnail extractor, … Just a name for “has a Sink to receive and a Source to push what it produces into”; nothing new to implement beyond those two.
Sink: Anything that can receive a buffer pushed from upstream — the input side of an element, or a plain terminal sink. Every Sink is named (via Element) so bus events (e.g. EOS) can identify which one they came from.
Source: An element with one or more output ports. It sends data downstream by pushing into its own src_pads() (e.g. self.src_pads()[0].push(buf)) — it’s never handed a downstream argument from the outside. See SrcPad.
SourceElement: A pure source: has output but no input. Its run method drives the production loop and pushes buffers into its own src pad(s) until EOS or an error. crate::pipeline::Pipeline::run normally invokes that loop on the pipeline’s background source thread; a caller may also invoke a concrete implementation directly. Sources typically wrap blocking I/O reads (demuxer, file/network source).

element_pp_log: Builds the PpLog every element constructs for its own Element::pp_log field, and that crate::pipeline::ChainBuilder/crate::pipeline::Pipeline rebuild once they know which pipeline an element belongs to. Keeps the element type, instance name, and pipeline id as separate fields, so a log reader does not need to parse a combined display string. The pipeline id is None for an element that isn’t wired into a Pipeline at all (e.g. most of this crate’s own tests). Public so a custom Element implemented outside this crate (see ElementType::Other) can build its own pp_log field the same way.