//! Public option enum for audio sample export: the channel layout to negotiate.
/// The output channel layout for [`SampleExtractor`](super::SampleExtractor).
///
/// Selecting a value inserts a downmix into the resample stage
/// (`aformat=channel_layouts=…`, backed by swr); leaving it unset preserves the
/// source layout. ASR models such as whisper want [`Mono`](Channels::Mono).