Struct ChannelLayout 

pub struct ChannelLayout {
    pub mapping_family: u8,
    pub nb_channels: usize,
    pub nb_streams: usize,
    pub nb_coupled_streams: usize,
    pub mapping: Vec<u8>,
}

How a set of Opus streams becomes a set of output channels.

A multistream packet is several ordinary Opus streams concatenated. Some are coded as coupled stereo pairs and carry two channels each, the rest carry one, and the mapping says which of the resulting channels goes where in the output. Coupled streams always come first, so the channels a decoder produces are the coupled pairs in order, then the mono streams in order.

surround builds the standard layout for a channel count and mapping family, which is how OpusMSEncoder and OpusMSDecoder obtain theirs. The fields are public so a caller can read what a given channel count works out to, which is what the OpusHead for such a stream has to declare.

Fields

mapping_family: u8

The mapping family this layout came from: 0 for mono/stereo, 1 for the Vorbis surround orders. Kept so the layout can describe itself to an OpusHead without being asked twice.

nb_channels: usize

Output channels this layout produces, which is what a caller interleaves.

nb_streams: usize

Opus streams in the packet, coupled and uncoupled together.

nb_coupled_streams: usize

How many of those streams are coupled stereo pairs. They are the first nb_coupled_streams of them, and each carries two channels, so the streams carry nb_coupled_streams + nb_streams channels in total.

mapping: Vec<u8>

For each output channel, which of the streams’ channels feeds it.

Indices 0..2 * nb_coupled_streams are the coupled pairs, left then right; the rest are the mono streams in order. The value 255 marks a channel that is left silent. Length is nb_channels.

Implementations

impl ChannelLayout

pub fn surround(channels: usize, mapping_family: u8) -> Result<Self>

Standard layout for a channel count + mapping family (0 = mono/stereo, 1 = Vorbis surround for 1..=8 channels).

Trait Implementations

impl Clone for ChannelLayout

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ChannelLayout

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.