sdk/fidl/fuchsia.hardware.audio.signalprocessing/gain.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.hardware.audio.signalprocessing;

/// Hardware domain of the gain, e.g. ANALOG.
type GainDomain = flexible enum : uint8 {
    /// The processing element gain is applied in the digital domain.
    DIGITAL = 1;

    /// The processing element gain is applied in the analog domain.
    ANALOG = 2;

    /// The processing element gain is mixed using digital and analog hardware.
    MIXED = 3;
};

/// Gain type of representation.
type GainType = strict enum : uint8 {
    /// Gain specified in dB, for example -103.0dB or +3.2dB.
    DECIBELS = 1;

    /// Gain specified as a percentage, for example 10.0% or 80.5%.
    PERCENT = 2;
};

/// Parameters for an `Element` with `type` equal to `GAIN`.
type Gain = table {
    /// Specifies what the numbers for gain represent, e.g. a percentage.
    ///
    /// Required.
    1: type GainType;

    /// If included, the gain is applied in the specified `GainDomain`.
    /// If not included, the gain domain is unspecified.
    ///
    /// Optional.
    2: domain GainDomain;

    /// Minimum gain in `GainType` format.
    ///
    /// Required.
    3: min_gain float32;

    /// Maximum gain in `GainType` format.
    ///
    /// Required.
    4: max_gain float32;

    /// Minimum gain step in `GainType` format, this value must not be negative, but may be zero to
    /// convey an effectively continuous range of values. Must not exceed `max_gain` - `min_gain`.
    /// The actual gain set may be queried by the client with a `WatchElementState` call.
    ///
    /// Required.
    5: min_gain_step float32;
};

/// State for an `Element` with `type` equal to `GAIN`.
type GainElementState = table {
    /// Current gain in `GainType` format.
    ///
    /// Required.
    1: gain float32;
};