Struct OpusHead 

pub struct OpusHead {
    pub channels: u8,
    pub pre_skip: u16,
    pub input_sample_rate: u32,
    pub output_gain: i16,
    pub channel_mapping_family: u8,
    pub stream_count: u8,
    pub coupled_count: u8,
    pub channel_mapping: Vec<u8>,
}

The Opus identification header: the decoder configuration of an Opus stream (RFC 7845 section 5.1).

MP4 carries it as the fields of a dOps box (Self::from_dops, Self::to_dops); Ogg, Matroska and WebM CodecPrivate, and a WebCodecs AudioDecoderConfig.description carry the OpusHead packet itself (Self::from_identification_header, Self::to_identification_header).

Fields

channels: u8

The number of output channels.

pre_skip: u16

Samples at 48 kHz to discard from the start of the decoded stream: the encoder’s delay.

input_sample_rate: u32

The sample rate of the audio before it was encoded, for information only; Opus decodes at OPUS_SAMPLE_RATE regardless. Zero when unknown.

output_gain: i16

Gain to apply to the decoded output, in Q7.8 decibels.

channel_mapping_family: u8

The channel mapping family: 0 for mono or stereo in one stream, 1 for the Vorbis channel orders of up to eight channels in several streams.

stream_count: u8

The number of Opus streams in each packet.

coupled_count: u8

How many of those streams are coupled stereo pairs.

channel_mapping: Vec<u8>

For each output channel, the decoded stream channel that feeds it, or 255 for silence.

Implementations

impl OpusHead

pub fn new( channels: u8, pre_skip: u16, input_sample_rate: u32, ) -> Result<OpusHead, Error>

A mapping-family-0 header for a mono or stereo stream.

pub fn from_dops(dops: &[u8]) -> Result<OpusHead, Error>

Parses a complete dOps box, size and type included, as the Opus sample entry of an MP4 carries it (“Encapsulation of Opus in ISO Base Media File Format”, section 4.3.2).

pub fn to_dops(&self) -> Vec<u8>

Writes this header as a complete dOps box, size and type included.

pub fn from_identification_header(packet: &[u8]) -> Result<OpusHead, Error>

Parses an RFC 7845 OpusHead identification header packet, the little-endian form Ogg pages and Matroska or WebM CodecPrivate carry.

pub fn to_identification_header(&self) -> Vec<u8>

Writes this header as an RFC 7845 OpusHead identification header packet (version 1).

pub fn output_gain_factor(&self) -> f32

The linear factor Self::output_gain scales decoded samples by.

Trait Implementations

impl Clone for OpusHead

fn clone(&self) -> OpusHead

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for OpusHead

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

Formats the value using the given formatter.

impl Eq for OpusHead

impl PartialEq for OpusHead

fn eq(&self, other: &OpusHead) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for OpusHead