Wiring & DAG

AVFlow builds a directed acyclic graph (DAG) from each component’s inputs array.

Basic rules

1. Sources have no inputs — they produce media.
2. Nodes consume one or more upstream components and produce processed media.
3. Sinks consume upstream components and write output (stream, file, room, etc.).
4. Every inputs entry must reference an existing component by name.
5. The graph must be acyclic.

Media types

Components exchange video, audio, and optionally captions (from ASR). AVFlow infers which streams to pass when you connect components — you rarely need manual split nodes.

Use select to filter by participant identity, track type, or media type. On RTC sources it lives inside config; on nodes and sinks it is a top-level field.

Common patterns

Source → sink (relay)

A relay has no processing nodes: the source connects straight to the sink. This works for pull sources (rtmp_pull, whep_pull, srt_pull, file_pull) and 1:1 sinks such as rtmp_push.

rtmp_pull ──► rtmp_push

Source → mixers → sink (mix)

RTC room sources (livekit, jitsi, daily, agora) are multi-stream (1:n) and need a mix — video_mixer and audio_mixer — before rtmp_push or similar 1:1 sinks, even for a single participant.

Composite recording

Same mix pattern as above, often with a segment sink:

livekit ──► video_mixer ──► rtmp_push
        └──► audio_mixer ──┘

ASR captions

Wire the ASR node into sinks that support subtitles (segment, rtmp_push, RTC sinks, etc.).

livekit ──► audio_mixer ──► segment
        └──► asr ──────────┘

Validation errors

Jobs are rejected at submit time if:

• A 1:1 RTC sink (e.g. rtmp_push) is wired directly to a multi-participant RTC source without a mixer
• segment is connected directly to a multi-track RTC source (use mixers first)
• Input limits are exceeded

Fix the topology and resubmit — AVFlow does not partially run invalid graphs.