# `FFix.Selection`
[🔗](https://github.com/akash-akya/ffix/blob/v0.2.0/lib/ffix/selection.ex#L1)

A query selecting input streams for an output.

Media helpers return selections for `:all` or `optional: true`.
`FFix.select/3` also returns them for string stream specifiers. Pass a
selection to `FFix.output/3`, `FFix.Encoder`, or `FFix.stream_copy/1`.

FFmpeg determines the matching tracks when the command runs. For a filter
input, select a required index such as `FFix.audio(source, 0)` instead.
See `FFix.Command.Input` for examples and `FFix.Command.Mapping` for
applying encoding settings to multiple selected tracks.

# `t`

```elixir
@opaque t()
```

# `media`

```elixir
@spec media(t()) :: FFix.Graph.StreamRef.media()
```

Returns the selected media type, or `:unknown` for whole-input and string queries.

---

*Consult [api-reference.md](api-reference.md) for complete listing*