Filtergraph IR Package (filtergraph)

The filtergraph package is the core Directed Acyclic Graph (DAG) intermediate representation.

Core Concepts

• Graph: Contains all filter nodes and tracks output pads.
• Node: Represents a single FFmpeg filter (e.g. scale, overlay, split, volume).
• Pad: Represents an input or output terminal. Pads are strictly typed as StreamTypeVideo or StreamTypeAudio.

import "github.com/farshidrezaei/vidonex/filtergraph"

graph := filtergraph.New()

nodeA := graph.AddNode("scale", map[string]string{"w": "1920", "h": "1080"})
nodeB := graph.AddNode("format", map[string]string{"pix_fmts": "yuv420p"})

// Type-safe connection
err := graph.Connect(nodeA.Outputs()[0], nodeB.Inputs()[0])

---

Compiler Passes

AutoSplitPass

Traverses the graph, counts consumers of each output pad, and automatically injects split or asplit filters if any output pad is connected to more than one downstream input pad.

pass := filtergraph.NewAutoSplitPass()
err := pass.Run(graph)

DeadCodeEliminationPass

Removes dangling nodes, orphan pads, and subgraphs that do not lead to the final output pads.

pass := filtergraph.NewDeadCodeEliminationPass()
err := pass.Run(graph)