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Inputs and Constants

Pipelines expose values in two places:

  • Pipeline boundary ports: inputs and outputs on the edge of the graph.
  • Node ports: per-node inputs (including constants/defaults and configuration ports).

Why this matters​

In Helios, "controls" come from two places:

  • Graph defaults: the values saved into the pipeline graph (edited in Graph tab).
  • Overrides: values applied on top of those defaults for a specific stream (edited in Tune tab).

If you change a value in Graph, you are changing the pipeline definition. If you change a value in Tune, you are tuning behavior (often without touching the wiring).

What you can do​

  • Add/remove pipeline input/output ports (graph boundary ports).
  • Add/remove host IO ports (graph boundary ports used by some graph types).
  • Set default values on ports (global defaults).
  • Override values per stream in the Tune tab.

Boundary ports vs node ports (how to decide)​

Make it a pipeline boundary port when:

  • You need to feed a value into the pipeline from the stream or device.
  • You want to expose an output for selection/preview/recording.
  • You want the value to be easy to override per stream and show up prominently in Tune.

Keep it as a node port when:

  • It is an internal implementation detail that you rarely touch.
  • It is only meaningful inside the graph.

Where you edit them​

  • Graph tab:
    • Create/edit pipeline inputs/outputs (boundary ports).
    • Set default values on boundary ports and node ports.
  • Tune tab:
    • Edit global defaults and per-stream overrides for the same ports (without changing wiring).

Notes​

  • Global defaults apply to every consumer of the pipeline.
  • Per-stream overrides are stored per stream and can diverge from the global defaults.