mx_remote/wire/

enums.rs

// Author: Lars Op den Kamp (lars@opdenkamp-it.nl)
// Copyright (c) 2026 Op den Kamp IT Solutions

//! Wire enumerations and bitmasks.
//!
//! Each type is a newtype over the integer that travels on the wire, with
//! named constants rather than a closed set of variants. A value this library
//! has no name for reaches the caller as it arrived: zero is a valid value for
//! most of these, so a confidently wrong reading is worse than an unrecognised
//! one.

use core::fmt;
use core::ops::{BitAnd, BitOr, BitOrAssign};

/// Declares a bitmask newtype with the given named bit constants.
///
/// The representation defaults to `u32`; give it explicitly as `Name: u64` for
/// a mask whose wire field is wider.
macro_rules! bitmask {
    (
        $(#[$meta:meta])*
        $name:ident { $( $(#[$cmeta:meta])* $cname:ident = $value:expr; )* }
    ) => {
        bitmask! {
            $(#[$meta])*
            $name: u32 { $( $(#[$cmeta])* $cname = $value; )* }
        }
    };
    (
        $(#[$meta:meta])*
        $name:ident: $repr:ty { $( $(#[$cmeta:meta])* $cname:ident = $value:expr; )* }
    ) => {
        $(#[$meta])*
        #[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
        pub struct $name($repr);

        impl $name {
            /// No bits set.
            pub const NONE: Self = Self(0);

            $( $(#[$cmeta])* pub const $cname: Self = Self($value); )*

            /// Wraps a raw wire value, including bits this library has no name for.
            pub const fn from_bits(bits: $repr) -> Self {
                Self(bits)
            }

            /// Returns the raw wire value.
            pub const fn bits(self) -> $repr {
                self.0
            }

            /// Reports whether every bit in `other` is set.
            pub const fn has(self, other: Self) -> bool {
                self.0 & other.0 == other.0
            }

            /// Reports whether no bit is set.
            pub const fn is_empty(self) -> bool {
                self.0 == 0
            }
        }

        impl BitOr for $name {
            type Output = Self;
            fn bitor(self, rhs: Self) -> Self {
                Self(self.0 | rhs.0)
            }
        }

        impl BitOrAssign for $name {
            fn bitor_assign(&mut self, rhs: Self) {
                self.0 |= rhs.0;
            }
        }

        impl BitAnd for $name {
            type Output = Self;
            fn bitand(self, rhs: Self) -> Self {
                Self(self.0 & rhs.0)
            }
        }

        impl fmt::Display for $name {
            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
                // Two hex digits per byte of the wire field, plus "0x".
                write!(
                    f,
                    "{:#0width$x}",
                    self.0,
                    width = core::mem::size_of::<$repr>() * 2 + 2
                )
            }
        }
    };
}

/// Declares an enumeration newtype over `$repr` with the given named constants.
macro_rules! wire_enum {
    (
        $(#[$meta:meta])*
        $name:ident: $repr:ty { $( $(#[$cmeta:meta])* $cname:ident = $value:expr; )* }
    ) => {
        $(#[$meta])*
        #[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
        pub struct $name($repr);

        impl $name {
            $( $(#[$cmeta])* pub const $cname: Self = Self($value); )*

            /// Wraps a raw wire value, including one this library has no name for.
            pub const fn from_wire(value: $repr) -> Self {
                Self(value)
            }

            /// Returns the raw wire value.
            pub const fn to_wire(self) -> $repr {
                self.0
            }
        }
    };
}

bitmask! {
    /// Capabilities a device reports in its hello frame.
    DeviceFeature {
        /// Receives infrared.
        IR_RX = 1 << 0;
        /// Transmits infrared.
        IR_TX = 1 << 1;
        /// Speaks CEC.
        CEC = 1 << 2;
        /// Acts as a OneIP stream source.
        V2IP_SOURCE = 1 << 3;
        /// Acts as a OneIP stream sink.
        V2IP_SINK = 1 << 4;
        /// Routes video.
        VIDEO_ROUTING = 1 << 5;
        /// Routes audio.
        AUDIO_ROUTING = 1 << 6;
        /// Controls volume.
        VOLUME_CONTROL = 1 << 7;
        /// Supports audio return.
        AUDIO_RETURN = 1 << 8;
        /// Passes remote-control commands through.
        REMOTE_CONTROL = 1 << 9;
        /// Installer setup has been completed.
        SETUP_COMPLETED = 1 << 10;
        /// Is the master of its mesh.
        MESH_MASTER = 1 << 11;
        /// Has a notification pending.
        STATUS_NOTIFY = 1 << 12;
        /// Has a warning pending.
        STATUS_WARNING = 1 << 13;
        /// Has an error pending.
        STATUS_ERROR = 1 << 14;
        /// Is about to reboot.
        STATUS_REBOOT = 1 << 15;
        /// Is a member of a mesh.
        MESH_MEMBER = 1 << 16;
        /// Is an audio amplifier.
        AUDIO_AMPLIFIER = 1 << 17;
        /// Is still booting.
        BOOTING = 1 << 18;
        /// Is a management client rather than a device.
        MANAGER = 1 << 19;
        /// Is in power-save mode.
        STATUS_POWER_SAVE = 1 << 20;
        /// Supports meshing.
        MESH = 1 << 21;
        /// Is a multiviewer.
        MULTIVIEWER = 1 << 22;
        /// Has crashed since it last booted.
        STATUS_CRASHED = 1 << 23;
        /// Supports video walls.
        VIDEO_WALL = 1 << 24;
        /// Initialises the configuration it broadcasts.
        ///
        /// Firmware without this bit sends a device configuration built over
        /// uninitialised memory, so fields it did not mean to write carry junk.
        CONFIG_INITIALISED = 1 << 25;
        /// Receives one or more peers only by broadcast, because its multicast
        /// receive path is faulty.
        STATUS_MCAST_FAULT = 1 << 26;
        /// Powers its video processor down in power save. A device without it
        /// refuses to enter power save.
        POWER_SAVE = 1 << 27;
        /// Tags its uplink by the VLAN configuration it reports, and takes one
        /// written to it.
        VLAN = 1 << 28;
        /// Copies the overlay settings and logos of another unit when asked.
        OSD_SYNC = 1 << 29;
        /// Is downloading or installing a firmware or video processor
        /// upgrade. [`STATUS_REBOOT`](Self::STATUS_REBOOT) follows when it
        /// reboots to complete it.
        STATUS_UPGRADING = 1 << 30;
        /// Flips on every reboot, so a peer that sees it change knows the device restarted.
        BOOT_BIT = 1 << 31;
    }
}

bitmask! {
    /// What a OneIP device's video processor supports, as the device reports it
    /// in its configuration.
    ///
    /// Read-only, and a device's own: it fills the field in only on the frame
    /// describing itself, and leaves it zero on one it sends to configure
    /// another device. There is no write path.
    ///
    /// Bits are assigned by the video processor and only ever appended, so a
    /// bit this library has no name for is a later capability rather than an
    /// error. A device reports no features at all until its processor answers,
    /// and an older processor answers with none of the optional commands, so an
    /// empty mask is never reported as a capability set - see
    /// [`crate::Remote::v2ip_features`], which reports it as unknown instead.
    V2ipFpgaFeature: u64 {
        /// Applies a DSCP marking to the streams it sources.
        SOURCE_DSCP = 1 << 0;
        /// Reports the audio format arriving at its sink.
        SINK_AUDIO_FORMAT = 1 << 1;
        /// Places a tiling window on its sink.
        SINK_TILING_WINDOW = 1 << 2;
        /// Reports the state of its sink's overlay.
        SINK_OVERLAY_STATE = 1 << 3;
        /// Reports its sink's state.
        SINK_STATE = 1 << 4;
        /// Reports information about the stream its sink receives.
        SINK_STREAM_INFO = 1 << 5;
        /// Draws a test pattern, tone and lip-sync flash on its sink's output.
        SINK_TEST_PATTERN = 1 << 8;
    }
}

bitmask! {
    /// The device settings a OneIP configuration can carry, each on its own bit.
    ///
    /// The same bits serve as the settings a frame carries and as the values
    /// of the on/off ones among them. `IR_PROFILE` to `POWER_SAVE_SCHEDULE`
    /// carry a value elsewhere in the block and have no on/off value of their
    /// own.
    ///
    /// A device reports every setting it has, so one it never reports is one
    /// it does not have.
    V2ipDeviceSetting {
        /// Disables the decoder while the display is off.
        SINK_CHECK_POWER = 1 << 0;
        /// Disables the HDMI output while there is no signal.
        SINK_OFF_NO_SIGNAL = 1 << 1;
        /// Sends infrared modulated.
        IR_TX_MODULATED = 1 << 2;
        /// Lights the status LED.
        STATUS_LED = 1 << 3;
        /// Lights the network port LEDs.
        NETWORK_LED = 1 << 4;
        /// Runs the fan in quiet mode.
        FAN_QUIET = 1 << 5;
        /// Accepts CEC combo keys.
        CEC_COMBO_KEYS = 1 << 6;
        /// Accepts CEC combo keys for the device's own input.
        CEC_COMBO_INPUT = 1 << 7;
        /// The infrared profile of the device's global infrared port.
        IR_PROFILE = 1 << 8;
        /// The infrared profile of the output's infrared port.
        IR_PROFILE_SINK = 1 << 9;
        /// The infrared profiles stored on the device. Reported by the device
        /// itself and never written.
        IR_PROFILES = 1 << 10;
        /// The minutes a device stays idle before it powers down by itself.
        AUTO_POWER_SAVE = 1 << 11;
        /// The daily windows in which the device powers down.
        POWER_SAVE_SCHEDULE = 1 << 12;
        /// The device's clock has been set, on/off. Reported by the device
        /// itself and never written.
        CLOCK_SET = 1 << 13;
        /// The PTP mode the device runs.
        PTP_MODE = 1 << 14;
        /// The PTP domain the device runs in.
        PTP_DOMAIN = 1 << 15;
        /// The priority1 the device announces as a PTP grandmaster.
        PTP_PRIORITY1 = 1 << 16;
        /// Sends the source's audio as an AES67 flow, where the source allows.
        AES67 = 1 << 17;
        /// The level the device powers down to in power save. A device picks
        /// it itself: the level that saves the most while its input and
        /// display can still wake it. Written without
        /// [`POWER_SAVE_DISABLED`](Self::POWER_SAVE_DISABLED), it switches
        /// power save on, and the level written is ignored, except by a
        /// device whose firmware predates picking it, which takes the level
        /// as its setting.
        POWER_SAVE_LEVEL = 1 << 18;
        /// The interval between the device's PTP announce messages.
        PTP_ANNOUNCE = 1 << 19;
        /// The interval between the device's PTP sync messages.
        PTP_SYNC = 1 << 20;
        /// The interval between the device's PTP delay requests.
        PTP_DELAY_REQ = 1 << 21;
        /// The announce intervals before the device drops a silent PTP master.
        PTP_ANNOUNCE_TIMEOUT = 1 << 22;
        /// The DSCP of the device's PTP messages.
        PTP_DSCP = 1 << 23;
        /// The minutes after which the device forgets a SAP announcement it
        /// heard.
        SAP_EXPIRE = 1 << 24;
        /// Listens for SAP announcements.
        SAP_LISTEN = 1 << 25;
        /// Sends SAP announcements.
        SAP_ANNOUNCE = 1 << 26;
        /// The seconds between the device's SAP announcements.
        SAP_INTERVAL = 1 << 27;
        /// Never powers down by itself: automatic power save and the power
        /// save schedule leave the device running, and switching this on
        /// wakes a device either has powered down. A power save request
        /// still powers it down. Writing
        /// [`POWER_SAVE_LEVEL`](Self::POWER_SAVE_LEVEL) switches it off.
        POWER_SAVE_DISABLED = 1 << 28;
        /// The TTL of the device's streams, video, audio and ancillary
        /// alike. Reported only by a device with an encoder.
        STREAM_TTL = 1 << 29;
        /// Connects to the cloud service. A device that does not report it
        /// connects regardless.
        CLOUD = 1 << 30;
        /// The angle the device's HDMI output is turned by. Reported only by
        /// a device with an HDMI output.
        SINK_ROTATION = 1 << 31;
    }
}

wire_enum! {
    /// When a OneIP output mixes 5.1 and 7.1 PCM down to stereo.
    V2ipDownmixMode: u8 {
        /// Never.
        OFF = 0;
        /// When the display's EDID lists two PCM channels or fewer.
        AUTO = 1;
        /// Always.
        ALWAYS = 2;
    }
}

wire_enum! {
    /// How loud a OneIP output's stereo downmix is.
    V2ipDownmixLevel: u8 {
        /// Scaled so the mix never clips.
        NORMALISED = 0;
        /// Unscaled, with dialogue at the level it has in stereo.
        UNSCALED = 1;
    }
}

wire_enum! {
    /// How far a OneIP device powers down in power save, each level saving more
    /// than the one before.
    V2ipPowerSaveLevel: u8 {
        /// No level.
        NONE = 0;
        /// Part of the video processing powers down.
        REDUCED = 1;
        /// All of the video processing powers down.
        LOW = 2;
        /// Everything but the network powers down.
        OFF = 3;
    }
}

bitmask! {
    /// What a unit offers at one power save level.
    UnitPowerSave: u8 {
        /// The unit can power down to this level.
        SUPPORTED = 1 << 0;
        /// A signal on the HDMI input wakes the unit.
        INPUT_WAKE = 1 << 1;
        /// The display powering on wakes the unit, and the unit can power it
        /// on.
        OUTPUT_WAKE = 1 << 2;
    }
}

wire_enum! {
    /// How a OneIP device takes part in PTP.
    V2ipPtpMode: u8 {
        /// No PTP.
        OFF = 0;
        /// Follows a grandmaster, and never becomes one.
        FOLLOWER = 1;
        /// Follows a grandmaster, or becomes one when there is none.
        AUTO = 2;
    }
}

wire_enum! {
    /// The test pattern a OneIP sink draws on its output.
    V2ipTestPattern: u8 {
        /// No pattern.
        OFF = 0;
        /// Colour bars.
        BARS = 1;
        /// One flat colour, the one the test card carries.
        FLAT = 2;
        /// A ramp.
        RAMP = 3;
        /// A grid.
        GRID = 4;
        /// A strip.
        STRIP = 5;
        /// A test card.
        CARD = 6;
    }
}

wire_enum! {
    /// The test tone a OneIP sink plays on its output.
    V2ipToneMode: u8 {
        /// No tone.
        OFF = 0;
        /// A continuous tone.
        CONTINUOUS = 1;
        /// A channel ident.
        IDENT = 2;
        /// A line-up tone, which needs two channels or more.
        LINEUP = 3;
        /// A beep on each lip-sync mark.
        BEEP = 4;
    }
}

bitmask! {
    /// What a OneIP sink reports about its test card.
    V2ipTestcardFlag: u8 {
        /// The sink can draw the test card.
        SUPPORTED = 1 << 0;
        /// The output shows the pattern.
        SHOWING = 1 << 1;
        /// The tone plays on the output.
        PLAYING = 1 << 2;
        /// A pattern change has yet to reach the video processor.
        PATTERN_PENDING = 1 << 3;
        /// A tone change has yet to reach the video processor.
        TONE_PENDING = 1 << 4;
        /// A lip-sync change has yet to reach the video processor.
        SYNC_PENDING = 1 << 5;
    }
}

bitmask! {
    /// The flags of what a OneIP output plays from a session description.
    V2ipSdpFlag: u8 {
        /// The output plays a stream from a description.
        ACTIVE = 1 << 0;
        /// And nothing else, as no video is routed to it.
        AUDIO_ONLY = 1 << 1;
        /// The clock mode and state hold the video processor's answer.
        CLOCK = 1 << 2;
    }
}

wire_enum! {
    /// The sample encoding of a stream a OneIP output plays from a description.
    V2ipSdpEncoding: u8 {
        /// None.
        NONE = 0;
        /// 16-bit linear PCM.
        L16 = 1;
        /// 24-bit linear PCM.
        L24 = 2;
        /// AM824.
        AM824 = 3;
    }
}

wire_enum! {
    /// Where a described stream's media clock comes from.
    V2ipSdpMediaClock: u8 {
        /// None given.
        NONE = 0;
        /// Direct, at an offset from the reference clock.
        DIRECT = 1;
        /// The sender's.
        SENDER = 2;
    }
}

wire_enum! {
    /// The reference clock a described stream names.
    V2ipSdpRefClock: u8 {
        /// None given.
        NONE = 0;
        /// PTP.
        PTP = 1;
        /// A traceable clock.
        TRACEABLE = 2;
        /// The sender's local MAC.
        LOCAL_MAC = 3;
    }
}

wire_enum! {
    /// What a OneIP output's video processor times a described stream by.
    V2ipSdpClockMode: u8 {
        /// Arrival.
        ARRIVAL = 0;
        /// PTP.
        PTP = 1;
        /// The sender.
        SENDER = 2;
    }
}

wire_enum! {
    /// How far a OneIP output's video processor has got with a described
    /// stream's timing.
    V2ipSdpClockState: u8 {
        /// Idle.
        IDLE = 0;
        /// Running its servo.
        SERVO = 1;
        /// Aligning.
        ALIGNING = 2;
        /// Timed.
        TIMED = 3;
        /// Parked.
        PARKED = 4;
        /// Playing untimed.
        UNTIMED = 5;
        /// The timing is not supported.
        UNSUPPORTED = 6;
    }
}

bitmask! {
    /// The flags of a unit's status report.
    UnitFlag {
        /// A changed setting takes effect after a reboot.
        REBOOT_REQUIRED = 1 << 0;
        /// A newer video processor image is available.
        FPGA_UPGRADE = 1 << 1;
        /// The IP configuration comes from DHCP.
        DHCP = 1 << 2;
        /// The IP configuration was changed through the mesh, and is reverted
        /// unless the mesh controller confirms it in time.
        NET_PENDING = 1 << 3;
        /// The fan runs in quiet mode.
        FAN_QUIET = 1 << 4;
        /// Powered by an external supply rather than PoE.
        EXTERNAL_PSU = 1 << 5;
        /// The video processor runs with its IP configured. Without it the
        /// encoder and decoder health carry nothing.
        FPGA_CONFIGURED = 1 << 6;
        /// The encoder is enabled.
        ENCODER_ACTIVE = 1 << 7;
        /// The decoder is enabled.
        DECODER_ACTIVE = 1 << 8;
        /// The decoder disables itself without a display.
        AUTO_DISABLE = 1 << 9;
        /// The decoder disabled itself without a display.
        AUTO_DISABLE_ACTIVE = 1 << 10;
        /// The HDMI output switches off without a signal.
        OFF_NO_SIGNAL = 1 << 11;
        /// The HDMI output switched off without a signal.
        OFF_NO_SIGNAL_ACTIVE = 1 << 12;
        /// Display power is checked before the decoder is enabled.
        POWER_CHECK = 1 << 13;
        /// The boot count is reported.
        BOOT_COUNT = 1 << 14;
        /// The fan speed is reported.
        FAN_SPEED = 1 << 15;
    }
}

wire_enum! {
    /// What a unit command asks of its unit.
    UnitCommandKind: u8 {
        /// Clear the current system status.
        CLEAR_STATUS = 0;
        /// Upgrade the video processor to the latest image.
        FPGA_UPGRADE = 1;
        /// Change the IP configuration.
        NET_CONFIG = 2;
        /// Keep a pending IP configuration.
        NET_CONFIRM = 3;
    }
}

bitmask! {
    /// The flags of a unit command.
    UnitCommandFlag: u8 {
        /// With [`UnitCommandKind::FPGA_UPGRADE`]: flash the image even if it
        /// is running already.
        FORCE = 1 << 0;
        /// With [`UnitCommandKind::NET_CONFIG`]: use DHCP, ignoring the
        /// addresses.
        DHCP = 1 << 1;
    }
}

bitmask! {
    /// The flags of a OneIP device's PTP state.
    V2ipPtpFlag: u8 {
        /// The device runs PTP and the block holds its state. A block without
        /// it holds nothing: the device has no PTP, or is in power save.
        VALID = 1 << 0;
        /// The device locked to a master since its PTP started, so its mesh
        /// holds a time.
        FOLLOWED = 1 << 1;
    }
}

wire_enum! {
    /// How far a OneIP device's PTP clock has locked to its master.
    V2ipPtpLock: u8 {
        /// Not locked.
        UNLOCKED = 0;
        /// Locking.
        LOCKING = 1;
        /// Locked.
        LOCKED = 2;
    }
}

bitmask! {
    /// The flags of a OneIP device's VLAN configuration.
    V2ipVlanFlag: u16 {
        /// The block carries a configuration. A block without it carries
        /// nothing, whatever its other bytes hold.
        VALID = 1 << 0;
        /// Untagged frames arriving on the uplink are dropped instead of
        /// reaching the device.
        TRUNK = 1 << 1;
        /// Reported by the device: the configuration is applied, and reverted
        /// unless the mesh controller confirms it. Never written.
        PENDING = 1 << 2;
        /// Sent by the mesh controller: a pending configuration it heard, which
        /// the device then keeps.
        CONFIRM = 1 << 3;
        /// Reported by the device: it has an SFP port. Never written.
        HAS_SFP = 1 << 4;
    }
}

impl V2ipDeviceSetting {
    /// The settings that are on or off, as opposed to carrying a value, and
    /// that can be written.
    pub const SWITCHES: Self = Self(
        0xFF | Self::AES67.0
            | Self::SAP_LISTEN.0
            | Self::SAP_ANNOUNCE.0
            | Self::POWER_SAVE_DISABLED.0
            | Self::CLOUD.0,
    );

    /// The settings only a device reports about itself, which no write
    /// carries.
    pub const REPORTED_ONLY: Self = Self(Self::IR_PROFILES.0 | Self::CLOCK_SET.0);

    /// The PTP settings.
    pub const PTP_SETTINGS: Self =
        Self(Self::PTP_MODE.0 | Self::PTP_DOMAIN.0 | Self::PTP_PRIORITY1.0);

    /// The PTP message settings.
    pub const PTP_MESSAGES: Self = Self(
        Self::PTP_ANNOUNCE.0
            | Self::PTP_SYNC.0
            | Self::PTP_DELAY_REQ.0
            | Self::PTP_ANNOUNCE_TIMEOUT.0
            | Self::PTP_DSCP.0,
    );

    /// The settings whose values a frame carries in a block of their own
    /// behind the rest, [`V2ipPtpMessages`](crate::V2ipPtpMessages): the PTP
    /// message settings, the two SAP values, the stream TTL and the output's
    /// rotation.
    pub const SETTINGS_BLOCK: Self = Self(
        Self::PTP_MESSAGES.0
            | Self::SAP_EXPIRE.0
            | Self::SAP_INTERVAL.0
            | Self::STREAM_TTL.0
            | Self::SINK_ROTATION.0,
    );

    /// These bits with every bit of `other` cleared.
    pub(crate) const fn without(self, other: Self) -> Self {
        Self(self.0 & !other.0)
    }
}

bitmask! {
    /// Capabilities of a single bay.
    BayFeatures {
        /// HDMI output.
        HDMI_OUT = 1 << 0;
        /// HDMI input.
        HDMI_IN = 1 << 1;
        /// Digital audio output.
        AUDIO_DIG_OUT = 1 << 2;
        /// Digital audio input.
        AUDIO_DIG_IN = 1 << 3;
        /// Analogue audio output.
        AUDIO_ANA_OUT = 1 << 4;
        /// Analogue audio input.
        AUDIO_ANA_IN = 1 << 5;
        /// Infrared input.
        IR_IN = 1 << 6;
        /// Infrared output.
        IR_OUT = 1 << 7;
        /// Amplified audio output.
        AUDIO_AMP_OUT = 1 << 8;
        /// Remote-control output.
        RC_OUT = 1 << 9;
        /// Remote-control input.
        RC_IN = 1 << 10;
        /// Dolby decoding.
        DOLBY = 1 << 11;
        /// Switches itself off when idle.
        AUTO_OFF = 1 << 12;
        /// Is a remote OneIP source.
        V2IP_SOURCE_REMOTE = 1 << 13;
        /// Is a remote OneIP sink.
        V2IP_SINK_REMOTE = 1 << 14;
        /// Is a local OneIP source.
        V2IP_SOURCE_LOCAL = 1 << 15;
        /// Is a local OneIP sink.
        V2IP_SINK_LOCAL = 1 << 16;
    }
}

bitmask! {
    /// Live status flags of a single bay.
    ///
    /// Bits 16-19 and 22-23 are bit-fields rather than flags; read them with
    /// [`BayStatus::rc_type`] and [`BayStatus::hdcp`].
    BayStatus {
        /// The bay reports a fault.
        FAULT = 1 << 0;
        /// The bay is hidden from the user interface.
        HIDDEN = 1 << 1;
        /// The amplifier zone the bay drives is powered on.
        POWERED = 1 << 2;
        /// A signal is present.
        SIGNAL_DETECTED = 1 << 3;
        /// Hot-plug detect is asserted.
        HPD_DETECTED = 1 << 4;
        /// The signal is scrambled.
        SIGNAL_SCRAMBLE = 1 << 5;
        /// An HDBaseT link is up.
        HDBT_CONNECTED = 1 << 6;
        /// A CEC device answered.
        CEC_DETECTED = 1 << 7;
        /// The attached device was powered on.
        POWERED_ON = 1 << 8;
        /// The attached device was powered off.
        POWERED_OFF = 1 << 9;
        /// Audio return over HDMI is active.
        AUDIO_ARC_HDMI = 1 << 10;
        /// Audio return over optical is active.
        AUDIO_ARC_OPTIC = 1 << 11;
        /// Audio return over analogue is active.
        AUDIO_ARC_ANALOG = 1 << 12;
        /// The bay is offline.
        OFFLINE = 1 << 13;
        /// The OneIP decoder is disabled.
        DECODER_DISABLE = 1 << 14;
        /// The OneIP encoder is disabled.
        ENCODER_DISABLE = 1 << 15;
        /// CEC is switched off for this bay.
        CEC_DISABLED = 1 << 20;
        /// The OneIP encoder reports an error.
        ENCODER_ERROR = 1 << 21;
        /// The bay's name was generated - a default, or taken from CEC or the
        /// EDID - rather than set by a user. A device that predates this bit
        /// never sets it, so a clear bit does not prove a user set the name.
        AUTO_NAME = 1 << 24;
    }
}

impl BayStatus {
    const RC_TYPE_SHIFT: u32 = 16;
    const RC_TYPE_MASK: u32 = 0xF << Self::RC_TYPE_SHIFT;
    const HDCP_SHIFT: u32 = 22;
    const HDCP_MASK: u32 = 0x3 << Self::HDCP_SHIFT;

    /// Extracts the remote-control type carried in bits 16-19.
    pub const fn rc_type(self) -> RcType {
        RcType(((self.0 & Self::RC_TYPE_MASK) >> Self::RC_TYPE_SHIFT) as u8)
    }

    /// Extracts the HDCP version carried in bits 22-23.
    pub const fn hdcp(self) -> u8 {
        ((self.0 & Self::HDCP_MASK) >> Self::HDCP_SHIFT) as u8
    }
}

bitmask! {
    /// Media carried by a virtual link.
    LinkFeature {
        /// Video over HDMI.
        VIDEO_HDMI = 1 << 0;
        /// Audio over optical.
        AUDIO_OPTICAL = 1 << 1;
        /// Audio over analogue.
        AUDIO_ANALOG = 1 << 2;
        /// Infrared.
        IR = 1 << 3;
        /// Remote control.
        RC = 1 << 4;
    }
}

wire_enum! {
    /// A remote-control action.
    RcAction: u16 {
        /// Toggle power.
        POWER_TOGGLE = 0;
        /// Power on.
        POWER_ON = 1;
        /// Power off.
        POWER_OFF = 2;
        /// Volume up.
        VOLUME_UP = 3;
        /// Volume down.
        VOLUME_DOWN = 4;
        /// Toggle mute.
        VOLUME_MUTE = 5;
    }
}

wire_enum! {
    /// A remote-control key code (CEC or IR).
    RcKey: u16 {
        /// Digit 0.
        NUM0 = 0;
        /// Digit 1.
        NUM1 = 1;
        /// Digit 2.
        NUM2 = 2;
        /// Digit 3.
        NUM3 = 3;
        /// Digit 4.
        NUM4 = 4;
        /// Digit 5.
        NUM5 = 5;
        /// Digit 6.
        NUM6 = 6;
        /// Digit 7.
        NUM7 = 7;
        /// Digit 8.
        NUM8 = 8;
        /// Digit 9.
        NUM9 = 9;
        /// Confirm the highlighted item.
        SELECT = 10;
        /// Go back one step.
        BACK = 11;
        /// Navigate up.
        UP = 12;
        /// Navigate down.
        DOWN = 13;
        /// Navigate left.
        LEFT = 14;
        /// Navigate right.
        RIGHT = 15;
        /// Open the main menu.
        MENU = 16;
        /// Open the content menu.
        CONTENT_MENU = 17;
        /// Next channel.
        CHANNEL_UP = 18;
        /// Previous channel.
        CHANNEL_DOWN = 19;
        /// Start playback.
        PLAY = 20;
        /// Pause playback.
        PAUSE = 21;
        /// Stop playback.
        STOP = 22;
        /// Start recording.
        RECORD = 23;
        /// Fast forward.
        FAST_FORWARD = 24;
        /// Rewind.
        REWIND = 25;
        /// Red colour key.
        RED = 26;
        /// Green colour key.
        GREEN = 27;
        /// Yellow colour key.
        YELLOW = 28;
        /// Blue colour key.
        BLUE = 29;
        /// Open help.
        HELP = 30;
        /// Show information.
        INFORMATION = 31;
        /// Open teletext.
        TEXT = 32;
        /// Open the programme guide.
        GUIDE = 33;
        /// Open video on demand.
        VIDEO_ON_DEMAND = 34;
        /// Return to the previous channel.
        PREVIOUS_CHANNEL = 80;
        /// Toggle 3D mode.
        MODE_3D = 81;
        /// Toggle subtitles.
        SUBTITLE = 82;
        /// Select an audio track.
        SOUND_SELECT = 83;
        /// Select an input.
        INPUT_SELECT = 84;
        /// Eject the medium.
        EJECT = 85;
        /// Next chapter.
        NEXT_CHAPTER = 86;
        /// Previous chapter.
        PREV_CHAPTER = 87;
        /// Open interactive services.
        INTERACTIVE = 128;
        /// Open search.
        SEARCH = 129;
        /// Sky home key.
        SKY = 130;
        /// Base of the range carrying a raw CEC user-control code.
        CUSTOM_CEC = 1280;
        /// Base of the range carrying a raw Sky key code.
        CUSTOM_SKY = 2048;
    }
}

wire_enum! {
    /// The remote-control protocol of a connected sink or source.
    RcType: u8 {
        /// Infrared.
        IR = 0;
        /// HDMI CEC.
        CEC = 1;
        /// Sky UK over IP.
        SKY_UK = 2;
        /// TiVo.
        TIVO = 3;
        /// Kodi.
        KODI = 4;
        /// Dish.
        DISH = 5;
        /// DirecTV.
        DIRECTV = 6;
        /// Another MX Remote device.
        MX_REMOTE = 7;
        /// Routed inside the device itself.
        INTERNAL = 8;
    }
}

impl fmt::Display for RcType {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let name = match *self {
            Self::IR => "IR",
            Self::CEC => "CEC",
            Self::SKY_UK => "Sky",
            Self::TIVO => "TiVo",
            Self::KODI => "Kodi",
            Self::DISH => "Dish",
            Self::DIRECTV => "DirecTV",
            Self::MX_REMOTE => "MX-Remote",
            Self::INTERNAL => "Internal",
            _ => "Unknown",
        };
        f.write_str(name)
    }
}

wire_enum! {
    /// An EDID preset selectable on an HDMI input.
    EdidProfile: u16 {
        /// 1080p with stereo audio.
        STEREO_1080P = 0;
        /// A fixed EDID stored on the device.
        FIXED = 1;
        /// 4K.
        UHD_4K = 2;
        /// 1080p with 5.1 audio.
        SURROUND51_1080P = 3;
        /// 720p.
        HD_720P = 4;
        /// 1080p with 7.1 audio.
        SURROUND71_1080P = 5;
        /// 4K with 7.1 audio.
        SURROUND71_4K = 6;
        /// 4K HDR with stereo audio.
        HDR_STEREO_4K = 7;
        /// 4K HDR with 7.1 audio.
        HDR_SURROUND71_4K = 8;
        /// 4K HDR, audio to the AVR only.
        HDR_AVR_ONLY_4K = 9;
        /// The lowest common denominator of the connected sinks.
        LOWEST_COMMON = 10;
        /// The lowest common denominator of every sink, connected or not.
        LOWEST_COMMON_ALL = 11;
        /// 4K HDR with Dolby Atmos.
        HDR_ATMOS_4K = 12;
        /// Copy the EDID of sink 1; the range runs to [`EdidProfile::SINK_32`].
        SINK_1 = 101;
        /// Copy the EDID of sink 32; the range starts at [`EdidProfile::SINK_1`].
        SINK_32 = 132;
        /// Base of the range carrying a user-supplied EDID.
        CUSTOM_0 = 500;
        /// The device reports no profile.
        UNKNOWN = 0xFFF;
    }
}

impl fmt::Display for EdidProfile {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let name = match *self {
            Self::STEREO_1080P => "1080p stereo",
            Self::FIXED => "fixed",
            Self::UHD_4K => "4K",
            Self::SURROUND51_1080P => "1080p 5.1",
            Self::HD_720P => "720p",
            Self::SURROUND71_1080P => "1080p 7.1",
            Self::SURROUND71_4K => "4K 7.1",
            Self::HDR_STEREO_4K => "4K HDR Stereo",
            Self::HDR_SURROUND71_4K => "4K HDR 7.1",
            Self::HDR_AVR_ONLY_4K => "4K HDR AVR",
            Self::LOWEST_COMMON => "lowest common denominator",
            Self::LOWEST_COMMON_ALL => "lowest common denominator (all sinks)",
            Self::HDR_ATMOS_4K => "4K HDR Dolby Atmos",
            _ => {
                if self.0 >= Self::SINK_1.0 && self.0 <= Self::SINK_32.0 {
                    return write!(f, "copy from sink #{}", self.0 - Self::SINK_1.0 + 1);
                }
                return write!(f, "custom #{}", self.0);
            }
        };
        f.write_str(name)
    }
}

wire_enum! {
    /// A firmware component.
    FirmwareType: u8 {
        /// The unit's own firmware.
        MCU = 0;
        /// The video processor's FPGA image.
        FPGA = 1;
        /// The video processor's RTOS image.
        RTOS = 2;
        /// The video processor's loader image.
        LOADER = 3;
        /// The unit's bootloader.
        BOOTLOADER = 4;
    }
}

impl fmt::Display for FirmwareType {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let name = match *self {
            Self::MCU => "MCU",
            Self::FPGA => "FPGA",
            Self::RTOS => "RTOS",
            Self::LOADER => "Loader",
            Self::BOOTLOADER => "Bootloader",
            _ => return write!(f, "firmware #{}", self.0),
        };
        f.write_str(name)
    }
}

wire_enum! {
    /// The negotiated speed of a network port.
    UtpLinkSpeed: u8 {
        /// The device reports no speed.
        UNKNOWN = 0;
        /// 10Mbit/s.
        SPEED_10M = 1;
        /// 100Mbit/s.
        SPEED_100M = 2;
        /// 200Mbit/s.
        SPEED_200M = 3;
        /// 1Gbit/s.
        SPEED_1G = 4;
    }
}

impl fmt::Display for UtpLinkSpeed {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let name = match *self {
            Self::SPEED_10M => "10Mbit/s",
            Self::SPEED_100M => "100Mbit/s",
            Self::SPEED_200M => "200Mbit/s",
            Self::SPEED_1G => "1Gbit/s",
            _ => "Unknown",
        };
        f.write_str(name)
    }
}

wire_enum! {
    /// The window layout of a multiviewer.
    MultiviewerViewMode: u8 {
        /// The device reports no layout.
        UNKNOWN = 0;
        /// One full-screen window.
        SINGLE = 1;
        /// Picture in picture.
        PIP = 2;
        /// Two windows, large.
        TWO_SCREEN_LARGE = 3;
        /// Two windows, small.
        TWO_SCREEN_SMALL = 4;
        /// Three windows, large.
        THREE_SCREEN_LARGE = 5;
        /// Three windows, small.
        THREE_SCREEN_SMALL = 6;
        /// Four windows, equal size.
        FOUR_SCREEN_EQUAL = 7;
        /// Four windows, small.
        FOUR_SCREEN_SMALL = 8;
    }
}

wire_enum! {
    /// The corner a multiviewer places its picture-in-picture window in.
    MultiviewerPipPosition: u8 {
        /// The device reports no position.
        UNKNOWN = 0;
        /// Top left.
        LEFT_TOP = 1;
        /// Bottom left.
        LEFT_BOTTOM = 2;
        /// Top right.
        RIGHT_TOP = 3;
        /// Bottom right.
        RIGHT_BOTTOM = 4;
    }
}

wire_enum! {
    /// The size of a multiviewer's picture-in-picture window.
    MultiviewerPipSize: u8 {
        /// The device reports no size.
        UNKNOWN = 0;
        /// Small.
        SMALL = 1;
        /// Medium.
        MEDIUM = 2;
        /// Large.
        LARGE = 3;
    }
}

wire_enum! {
    /// The resolution and refresh rate a multiviewer drives its output at.
    MultiviewerOutputMode: u8 {
        /// The device reports no output mode.
        UNKNOWN = 0;
        /// 4096x2160p60.
        DCI4K_P60 = 1;
        /// 4096x2160p50.
        DCI4K_P50 = 2;
        /// 3840x2160p60.
        UHD_P60 = 3;
        /// 3840x2160p50.
        UHD_P50 = 4;
        /// 3840x2160p30.
        UHD_P30 = 5;
        /// 3840x2160p25.
        UHD_P25 = 6;
        /// 1920x1200p60, reduced blanking.
        WUXGA_P60_RB = 7;
        /// 1920x1080p60.
        HD1080_P60 = 8;
        /// 1920x1080p50.
        HD1080_P50 = 9;
        /// 1360x768p60.
        WXGA_P60 = 10;
        /// 1280x800p60.
        WXGA800_P60 = 11;
        /// 1280x720p60.
        HD720_P60 = 12;
        /// 1280x720p50.
        HD720_P50 = 13;
        /// 1024x768p60.
        XGA_P60 = 14;
    }
}

wire_enum! {
    /// The HDCP version a multiviewer output negotiates.
    MultiviewerHdcpMode: u8 {
        /// The device reports no HDCP mode.
        UNKNOWN = 0;
        /// HDCP 1.4.
        V14 = 1;
        /// HDCP 2.2.
        V22 = 2;
        /// Content protection off.
        OFF = 3;
    }
}

wire_enum! {
    /// The IT-content flag a multiviewer sets on its output.
    MultiviewerItcMode: u8 {
        /// The device reports no IT-content mode.
        UNKNOWN = 0;
        /// Video content.
        VIDEO = 1;
        /// PC content.
        PC = 2;
    }
}

wire_enum! {
    /// The EDID template a multiviewer presents to its sources.
    ///
    /// A template's name is the largest resolution it advertises and the audio
    /// format it declares support for.
    MultiviewerEdidTemplate: u8 {
        /// The device reports no template.
        EDID_UNKNOWN = 0;
        /// 4K2K60 4:4:4, stereo 2.0.
        EDID_4K2K60_444_STEREO = 1;
        /// 4K2K60 4:4:4, Dolby/DTS 5.1.
        EDID_4K2K60_444_DOLBY_DTS_51 = 2;
        /// 4K2K60 4:4:4, HD audio 7.1.
        EDID_4K2K60_444_HD_AUDIO_71 = 3;
        /// 4K2K30 4:4:4, stereo 2.0.
        EDID_4K2K30_444_STEREO = 4;
        /// 4K2K30 4:4:4, Dolby/DTS 5.1.
        EDID_4K2K30_444_DOLBY_DTS_51 = 5;
        /// 4K2K30 4:4:4, HD audio 7.1.
        EDID_4K2K30_444_HD_AUDIO_71 = 6;
        /// 1080p, stereo 2.0.
        EDID_1080P_STEREO = 7;
        /// 1080p, Dolby/DTS 5.1.
        EDID_1080P_DOLBY_DTS_51 = 8;
        /// 1080p, HD audio 7.1.
        EDID_1080P_HD_AUDIO_71 = 9;
        /// 1920x1200, stereo 2.0.
        EDID_1920X1200_STEREO = 10;
        /// 1680x1050, stereo 2.0.
        EDID_1680X1050_STEREO = 11;
        /// 1600x1200, stereo 2.0.
        EDID_1600X1200_STEREO = 12;
        /// 1440x900, stereo 2.0.
        EDID_1440X900_STEREO = 13;
        /// 1360x768, stereo 2.0.
        EDID_1360X768_STEREO = 14;
        /// 1280x1024, stereo 2.0.
        EDID_1280X1024_STEREO = 15;
        /// 1024x768, stereo 2.0.
        EDID_1024X768_STEREO = 16;
        /// 720p, stereo 2.0.
        EDID_720P_STEREO = 17;
        /// Whatever the display connected to the HDMI output presents. The
        /// template a multiviewer leaves the factory with.
        EDID_COPY_OUTPUT = 18;
        /// The EDID loaded onto the device.
        EDID_CUSTOM = 19;
    }
}

wire_enum! {
    /// The aspect ratio a multiviewer scales its windows to.
    MultiviewerAspectRatio: u8 {
        /// The device reports no aspect ratio.
        UNKNOWN = 0;
        /// Fill the window.
        FULL = 1;
        /// 16:9.
        RATIO_16_9 = 2;
    }
}

wire_enum! {
    /// A multiviewer setting that is on, off, or not reported.
    MultiviewerBool: u8 {
        /// Off.
        OFF = 0;
        /// On.
        ON = 1;
        /// The device reports no value.
        UNKNOWN = 0xFF;
    }
}

wire_enum! {
    /// One of a multiviewer's four inputs.
    ///
    /// The wire numbers the inputs from zero and this type from one, so that
    /// zero can mean "not reported" the way it does for every other
    /// multiviewer setting. So `to_wire` and `from_wire` carry this type's
    /// numbering rather than the wire's, and neither is the conversion to
    /// reach for when a raw multiviewer byte is what is in hand.
    MultiviewerSource: u8 {
        /// The device reports no source.
        UNKNOWN = 0;
        /// Input 1.
        INPUT_1 = 1;
        /// Input 2.
        INPUT_2 = 2;
        /// Input 3.
        INPUT_3 = 3;
        /// Input 4.
        INPUT_4 = 4;
    }
}

impl MultiviewerSource {
    /// Reads a zero-based wire value, mapping anything past input 4 to
    /// [`MultiviewerSource::UNKNOWN`].
    ///
    /// The firmware spells "not known" as 0xFF, which lands past input 4 and
    /// so needs no case of its own.
    pub(crate) const fn from_zero_based(value: u8) -> Self {
        if value > 3 {
            Self::UNKNOWN
        } else {
            Self(value + 1)
        }
    }

    /// The zero-based value the wire carries, or `None` for a source naming no
    /// input.
    ///
    /// A multiviewer reads zero as its first input, so there is no value that
    /// says "leave this alone": a request that cannot name an input has to be
    /// refused rather than sent.
    pub(crate) const fn to_zero_based(self) -> Option<u8> {
        match self.0 {
            1..=4 => Some(self.0 - 1),
            _ => None,
        }
    }
}

impl MultiviewerBool {
    /// Reads a wire value, mapping anything but 0 and 1 to
    /// [`MultiviewerBool::UNKNOWN`].
    pub(crate) const fn from_wire_tristate(value: u8) -> Self {
        if value > 1 {
            Self::UNKNOWN
        } else {
            Self(value)
        }
    }
}

wire_enum! {
    /// The colour space a OneIP output scales to.
    ///
    /// The field is four bits wide and only these four values are defined. A
    /// receiver passes the whole nibble to its validator, so a fifth value is
    /// dropped without a word rather than clamped to one of these.
    V2ipColourSpace: u8 {
        /// RGB.
        RGB = 0;
        /// YCbCr 4:4:4.
        YCBCR444 = 1;
        /// YCbCr 4:2:2.
        YCBCR422 = 2;
        /// YCbCr 4:2:0.
        YCBCR420 = 3;
    }
}

wire_enum! {
    /// The 2-byte `mxr_signal_type` carried in scaling configs and bay signal
    /// reports.
    ///
    /// Byte 0 is the CTA-861 short video descriptor, 0 when the signal is not
    /// HDMI. Byte 1 packs `color:4` in the low nibble, then `non_int:1` and
    /// `bpp:3` above it.
    MxrSignalType: u16 {
        /// No signal format was reported.
        NONE = 0;
    }
}

/// The bpp index a sender writes when it has no bit depth to report.
///
/// It sits outside the four indices that name a real depth, so an unset
/// format reads differently from every genuine one.
const SIG_BPP_UNSET: u16 = 5;

impl MxrSignalType {
    /// The CTA-861 short video descriptor, 0 when the signal is not HDMI.
    pub const fn svd(self) -> u8 {
        (self.0 & 0xFF) as u8
    }

    /// The colour space.
    pub const fn colour_space(self) -> u8 {
        ((self.0 >> 8) & 0xF) as u8
    }

    /// Whether the frame rate carries a 1000/1001 clock.
    pub const fn is_non_integer(self) -> bool {
        self.0 & (1 << 12) != 0
    }

    /// The raw bpp index as carried on the wire. The field is an index, not a
    /// bit depth; [`MxrSignalType::bpp`] converts it.
    pub const fn bpp_index(self) -> u8 {
        ((self.0 >> 13) & 0x7) as u8
    }

    /// The bit depth the bpp index stands for, `None` when unknown or unset.
    pub const fn bpp(self) -> Option<u8> {
        match self.bpp_index() {
            1 => Some(8),
            2 => Some(10),
            3 => Some(12),
            4 => Some(16),
            _ => None,
        }
    }

    /// Reports whether the word carries a signal format at all.
    ///
    /// A bay with nothing configured says so two ways. A sender that zeroes
    /// the word and stamps the unset bpp index leaves an index no real depth
    /// uses, and one that writes a plain zero leaves nothing at all. Neither
    /// is a format, and the svd and colour space beside them are not answers
    /// either: both read as zero, which is what this word says for "not HDMI"
    /// and "RGB" when it *is* set.
    pub const fn is_set(self) -> bool {
        self.0 != 0 && self.bpp_index() as u16 != SIG_BPP_UNSET
    }

    /// Builds the word from the fields a scaling write consumes.
    ///
    /// `non_int` is left clear: the receiving struct carries the bit, and the
    /// apply path does not read it.
    ///
    /// Building rather than editing is the point. A sink with no mode
    /// configured reports the word with the unset bpp index in it, so a caller
    /// that read that word back and filled in an svd would send an index no
    /// depth uses - which the receiver decodes to zero and rejects without
    /// answering.
    pub(crate) const fn from_parts(svd: u8, colour: u8, bpp_index: u8) -> Self {
        Self((svd as u16) | (((colour & 0xF) as u16) << 8) | (((bpp_index & 0x7) as u16) << 13))
    }

    /// The bpp index that stands for a bit depth, `None` for a depth no index
    /// names.
    ///
    /// Only the three depths a OneIP output stage accepts are here. Index 4
    /// names 16bpp, which [`MxrSignalType::bpp`] reads back from a device, but
    /// the output stage refuses it - so offering it as something to write would
    /// send a frame that is decoded cleanly and then dropped in silence.
    pub(crate) const fn bpp_index_for_depth(depth: u8) -> Option<u8> {
        match depth {
            8 => Some(1),
            10 => Some(2),
            12 => Some(3),
            _ => None,
        }
    }
}

impl fmt::Display for MxrSignalType {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        if !self.is_set() {
            return f.write_str("unset");
        }
        match self.bpp() {
            Some(bpp) => write!(
                f,
                "svd {}, color {}, {}bpp",
                self.svd(),
                self.colour_space(),
                bpp
            ),
            None => write!(f, "svd {}, color {}", self.svd(), self.colour_space()),
        }
    }
}

bitmask! {
    /// The kinds of overlay setting an overlay sync copies.
    OsdSyncWhat: u8 {
        /// Captions.
        CAPTIONS = 1 << 0;
        /// Which logo is shown, and where.
        LOGO = 1 << 1;
        /// Background colours.
        BACKGROUNDS = 1 << 2;
        /// The logo images in the four slots.
        LOGO_SLOTS = 1 << 3;
    }
}

bitmask! {
    /// What a unit says of the message on its output.
    OsdMessageFlag: u8 {
        /// A message is set. In a write: show it, rather than take it down.
        SET = 1 << 0;
        /// The output shows it, rather than another message ahead of it.
        SHOWN = 1 << 1;
        /// The unit's video processor composes the message layer.
        SUPPORTED = 1 << 2;
        /// The unit did not take the write it answers, and reports the
        /// message it kept.
        REFUSED = 1 << 3;
    }
}

wire_enum! {
    /// Where a message stands against the unit's own messages: its upgrade,
    /// Locate Device and encrypted source messages.
    OsdMessagePriority: u8 {
        /// After them.
        LOW = 0;
        /// Between them.
        NORMAL = 1;
        /// Before them.
        TOP = 2;
    }
}

wire_enum! {
    /// How far a unit has got with taking an overlay sync.
    OsdSyncState: u8 {
        /// Taking it.
        TAKING = 0;
        /// Every setting written and committed.
        DONE = 1;
        /// Failed, for the reason the report gives.
        FAILED = 2;
        /// Kept for later, as the unit's video processor is off in power
        /// save.
        DEFERRED = 3;
    }
}

wire_enum! {
    /// The output size an overlay setting applies at.
    OsdSyncSize: u8 {
        /// Large outputs, which every value but `SMALL` also means.
        LARGE = 1;
        /// Small outputs.
        SMALL = 2;
    }
}

wire_enum! {
    /// How a caption's lines are aligned.
    OsdCaptionAlign: u8 {
        /// To the left.
        LEFT = 0;
        /// Centred.
        CENTRE = 1;
        /// To the right.
        RIGHT = 2;
        /// The layout's default.
        DEFAULT = 0xFF;
    }
}

wire_enum! {
    /// How a caption's text is read.
    OsdCaptionFormat: u8 {
        /// As plain text.
        PLAIN = 0;
        /// As Markdown.
        MARKDOWN = 1;
        /// The layout's default.
        DEFAULT = 0xFF;
    }
}

bitmask! {
    /// The caption fields an overlay setting gives. A field left out keeps
    /// what the unit has.
    OsdCaptionField: u16 {
        /// The font.
        FONT = 1 << 0;
        /// The size.
        SIZE = 1 << 1;
        /// The horizontal position.
        X = 1 << 2;
        /// The vertical position.
        Y = 1 << 3;
        /// The alignment.
        ALIGN = 1 << 4;
        /// The format.
        FORMAT = 1 << 5;
        /// The colour.
        COLOUR = 1 << 6;
        /// The wrap width.
        WRAP = 1 << 7;
        /// The text.
        TEXT = 1 << 8;
    }
}

bitmask! {
    /// The logo fields an overlay setting gives. A field left out keeps what
    /// the unit has.
    OsdLogoField: u16 {
        /// Which logo.
        LOGO = 1 << 0;
        /// The horizontal position.
        X = 1 << 1;
        /// The vertical position.
        Y = 1 << 2;
    }
}

bitmask! {
    /// The first byte of a third-party vendor id, ahead of its three
    /// identifying bytes.
    ///
    /// Bits without a name are passed through as they arrived.
    ThirdPartyVendorFlag: u8 {
        /// The three bytes are an identifier the vendor chose, rather than its
        /// IEEE OUI.
        NOT_OUI = 1 << 0;
    }
}