Struct FileDemuxer 

pub struct FileDemuxer { /* private fields */ }

Demuxes a file, exposing one src pad per container stream (indexed the same way as StreamInfo::index). Linking a pad “selects” that stream; leaving it unlinked just drops its packets. Real demuxer I/O is blocking, so this is meant to be run as the pipeline’s source thread.

Fan-out (e.g. routing video and audio to separate branches) needs no separate “Tee” element here — it’s just a matter of linking more than one of these pads.

Set to loop through FileDemuxer::looping_handle and the end of the file rewinds to the start instead of ending the stream. Timestamps then keep climbing across the join rather than restarting: what a lap already reached is added to every later one, so a Pacer still paces, a muxer still sees its timestamps advance, and nothing downstream has to know a join happened. The consequence is that a looping source’s timestamps are no longer positions in the file — one second into the third lap is at twice the file’s length plus a second — and FileDemuxer::seek stays the way to speak in the file’s own timeline.

Implementations

impl FileDemuxer

pub fn open( name: impl Into<String>, path: impl AsRef<Path>, ) -> Result<(Self, Vec<StreamInfo>), FileDemuxError>

Opens the file and returns it alongside every stream it contains, so the caller can inspect them (count, media type, …) before deciding which of src_pads() to link.

pub fn looping_handle(&self) -> FileDemuxerHandle

The control endpoint for looping this file, valid for as long as the demuxer runs — take it here, before moving the demuxer into its pipeline, and keep it for as long as the loop is meant to be switchable. See FileDemuxerHandle::set_looping.

pub fn stream_parameters(&self, index: usize) -> Option<Parameters>

Codec parameters for one of this file’s streams — what you need to construct a matching crate::elements::SwDecoder for it.

pub fn stream_time_base(&self, index: usize) -> Option<Rational>

The unit decoded frame timestamps for this stream are expressed in — what you need to construct a matching crate::elements::Pacer for it.

Trait Implementations

impl Element for FileDemuxer

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.

fn attach_context(&mut self, _context: &Arc<Context>)

Hands this element the pipeline it is being wired into, at the moment and for the reason Element::pp_log_mut hands it the pipeline’s identity: the clock, the playback clock and the bus are the pipeline’s to give, not the caller’s to choose.

impl Source for FileDemuxer

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

Returns every output pad owned by this element.

impl SourceElement for FileDemuxer

fn is_live(&self) -> bool

Whether this source produces data from a live, externally advancing input rather than from a finite or application-controlled timeline.

fn is_seekable(&self) -> bool

Whether this source can reposition its own input timeline through Self::seek.

fn run(&mut self, control: &ControlReceiver, bus: &Bus) -> Result<()>

Drives this source until Eos (normal completion), crate::pipeline::Pipeline::finish, or Stop (see ControlMsg::Stop) — call crate::control::drain_control once per loop iteration to make control responsive between blocking reads.

fn on_control(&mut self, msg: &ControlMsg)

Reacts to one control message before it is forwarded to this source’s own pads — the same ordering Self::seek gets, and for the same reason: whatever this source holds must already reflect the message by the time downstream elements see it.

fn seek(&mut self, target: Duration) -> Result<Duration>

Repositions this source to target, an absolute position from the start of the media (e.g. av_seek_frame for crate::elements::FileDemuxer). Called by crate::control::drain_control as part of handling ControlMsg::Seek, before that message is forwarded to the source’s own pads — so whatever’s read next comes from the new position by the time downstream elements receive the new timeline announcement. Buffered and stateful old-timeline data is discarded by the preceding ControlMsg::Flush.