Filtergraph data model.

A graph is a pure Elixir value containing input references, filter nodes, exported streams, terminal sinks, and graph-level settings. It is serialized to ffmpeg syntax only at FFix.to_filtergraph/1, FFix.to_argv/1, or FFix.run/1.

Most users build filter pipelines inside FFix.command/3 callbacks:

FFix.command(
  "input.mp4",
  fn src ->
    src[:video] |> FFix.Filter.scale(w: 1280, h: -1)
  end,
  fn video, src ->
    FFix.output("out.mp4", video: video, audio: src[:audio])
  end
)

Use input/2 when building a reusable graph outside a command callback:

video = FFix.Graph.input(0, :video)

graph =
  FFix.graph(
    outputs: [
      preview: video |> FFix.Filter.scale(w: 320, h: -1)
    ]
  )

graph[:name] and graph[index] return exported streams from a %FFix.Graph{} value. In FFix.command/3, callback input and graph output shapes are preserved, so use normal Elixir access for the shape you return.

Selectors

• :input maps the whole input, like -map 0
• :video maps/selects the video stream class, like 0:v
• :audio maps/selects the audio stream class, like 0:a
• {:video, 1} or {:audio, 1} selects a stream-class index
• {:raw, "s?"} keeps an ffmpeg selector escape hatch