sdk/fidl/fuchsia.audio/format.fidl

// Copyright 2022 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
library fuchsia.audio;

/// Describes a format used for audio streams without reference to compression. Where
/// compression is supported, this type should be combined with `fuchsia.media2.Compression`.
/// An uncompressed audio stream uses LPCM encoding.
type Format = table {
    /// The type of individual samples.
    1: sample_type SampleType;

    /// The number of samples per frame.
    2: channel_count uint32;

    /// The number of frames per second.
    3: frames_per_second uint32;

    /// The spatial assignment of each channel.
    4: channel_layout ChannelLayout;
};

/// Expresses the type of individual audio samples.
type SampleType = flexible enum {
    UINT_8 = 1;
    INT_16 = 2;
    INT_32 = 3;
    FLOAT_32 = 4;
    FLOAT_64 = 5;
};

/// Expresses the intended assignment of channels in an audio elementary stream.
type ChannelLayout = flexible union {
    /// This value describes the assignment of every channel. Channel
    /// configuration must agree with `channel_count`.
    1: config ChannelConfig;
};

/// Spatial assignment of channels.
type ChannelConfig = flexible enum {
    /// Front.C (CENTER)
    MONO = 0x01;

    /// Front.L (LEFT) | Front.R (RIGHT)
    STEREO = 0x02;

    /// Front.L | Front.R | Back.L | Back.R, aka “Four corners”
    QUAD = 0x03;

    /// Front.L | Front.R | Back.C, aka “LRS”
    SURROUND_3 = 0x04;

    /// Front.L | Front.R | Front.C | Back.C, aka “LRCS”
    SURROUND_4 = 0x05;

    /// Front.L | Front.R | Front.C | LFE | Side.L | Side.R
    SURROUND_5_1 = 0x06;
};