Rhino Speech-to-Intent
Rust API

Rust SDKs will no longer be maintained after July 15, 2025. If you plan to use the Rhino Speech-to-Intent Rust SDK for commercial purposes, please contact us.

API Reference for the Rhino Rust SDK (crates.io).

rhino::`Rhino`

pub struct Rhino

Struct for the Rhino Speech-to-Intent engine.

rhino::Rhino.`process()`

pub fn process(&self, pcm: &[i16]) -> Result<bool, RhinoError>

Process a frame of pcm audio with the Speech-to-Intent engine.

Parameters

pcm &[i16] : A frame of audio samples.

Returns

Result<bool, RhinoError> : If Ok, indicates whether Rhino has an inference ready or not. If Err, a RhinoError object describing the error that was encountered.

rhino::Rhino.`reset()`

pub fn reset() -> Result<(), RhinoError>

Resets the internal state of Rhino. It should be called before the engine can be used to infer intent from a new stream of audio.

Returns

Result<(), RhinoError> : If Ok, nothing is returned. If Err, a RhinoError object describing the error that was encountered.

rhino::Rhino.`get_inference()`

pub fn get_inference(&self) -> Result<RhinoInference, RhinoError>

Gets inference results from Rhino. If the spoken command was understood, it includes the specific intent name that was inferred, and (if applicable) slot keys and specific slot values. Should only be called after the process function returns true, otherwise Rhino has not yet reached an inference conclusion.

Returns

Result<RhinoInference, RhinoError> : If Ok, a RhinoInference containing the inference result data. If Err, a RhinoError object describing the error that was encountered.

rhino::Rhino.`context_info()`

pub fn context_info(&self) -> String

Gets the context information.

Returns

String : Once initialized, stores the source of the Rhino context in YAML format. Shows the list of intents, which expressions map to those intents, as well as slots and their possible values.

rhino::Rhino.`frame_length()`

pub fn frame_length(&self) -> u32

Gets the frame length.

Returns

u32 : Number of audio samples per frame.

rhino::Rhino.`sample_rate()`

pub fn sample_rate(&self) -> u32

Gets the sample rate.

Returns

u32 : Audio sample rate accepted by Rhino.

rhino::Rhino.`version()`

pub fn version(&self) -> String

Gets the Rhino version.

Returns

String : Rhino version string.

rhino::`RhinoBuilder`

pub struct RhinoBuilder

Builder struct for creating an instance of Rhino.

rhino::RhinoBuilder::`new()`

pub fn new<S: Into<String>, P: Into<PathBuf>>(
    access_key: S,
    context_path: P
) -> Self

Creates a new RhinoBuilder from required arguments.

Parameters

access_key S : AccessKey obtained from Picovoice Console.
context_path P : Absolute path to the Rhino context file (.rhn).

Returns

RhinoBuilder : A new Builder object.

rhino::RhinoBuilder.`access_key()`

pub fn access_key<'a, S: Into<String>>(
    &'a mut self,
    access_key: S
) -> &'a mut Self

Modifies the access_key of a RhinoBuilder object.

Parameters

access_key S : AccessKey obtained from Picovoice Console.

Returns

RhinoBuilder : The modified Builder object.

rhino::RhinoBuilder.`library_path()`

pub fn library_path<'a, P: Into<PathBuf>>(
    &'a mut self,
    library_path: P
) -> &'a mut Self

Overrides the default library_path of a RhinoBuilder object.

Parameters

library_path P : Path to the Rhino library file.

Returns

RhinoBuilder : The modified Builder object.

rhino::RhinoBuilder.`model_path()`

pub fn model_path<'a, P: Into<PathBuf>>(
    &'a mut self,
    model_path: P
) -> &'a mut Self

Overrides the default model_path of a RhinoBuilder object.

Parameters

model_path P : Path to the file containing model parameters (.pv).

Returns

RhinoBuilder : The modified Builder object.

rhino::RhinoBuilder.`context_path()`

pub fn context_path<'a, P: Into<PathBuf>>(
    &'a mut self,
    context_path: P
) -> &'a mut Self

Modifies the context_path of a RhinoBuilder object.

Parameters

context_path P : Absolute path to the Rhino context file (.rhn).

Returns

RhinoBuilder : The modified Builder object.

rhino::RhinoBuilder.`sensitivity()`

pub fn sensitivity<'a>(&'a mut self, sensitivity: f32) -> &'a mut Self

Overrides the default sensitivity of a RhinoBuilder object.

Parameters

sensitivity f32 : Inference sensitivity. A higher sensitivity value results in fewer misses at the cost of (potentially) increasing the erroneous inference rate. Sensitivity should be a floating-point number within 0 and 1.

Returns

RhinoBuilder : The modified Builder object.

rhino::RhinoBuilder.`endpoint_duration_sec()`

pub fn endpoint_duration_sec<'a>(&'a mut self, endpoint_duration_sec: f32) -> &'a mut Self

Overrides the default endpoint_duration_sec of a RhinoBuilder object.

Parameters

endpoint_duration_sec f32 : Endpoint duration in seconds. An endpoint is a chunk of silence at the end of an utterance that marks the end of spoken command. It should be a positive number within [0.5, 5]. A lower endpoint duration reduces delay and improves responsiveness. A higher endpoint duration assures Rhino doesn't return inference pre-emptively in case the user pauses before finishing the request.

Returns

RhinoBuilder : The modified Builder object.

rhino::RhinoBuilder.`require_endpoint()`

pub fn require_endpoint<'a>(
    &'a mut self,
    require_endpoint: bool
) -> &'a mut Self

Overrides the default value of require_endpoint for a RhinoBuilder object.

Parameters

require_endpoint bool : If set to true, Rhino requires an endpoint (a chunk of silence) after the spoken command. If set to false, Rhino tries to detect silence, but if it cannot, it still will provide inference regardless. Set to false only if operating in an environment with overlapping speech (e.g. people talking in the background).

Returns

RhinoBuilder : The modified Builder object.

rhino::RhinoBuilder.`init()`

pub fn init(&self) -> Result<Rhino, RhinoError>

Creates an instance of Rhino from the RhinoBuilder object.

Returns

Result<Rhino, RhinoError> : If Ok, an initialized instance of Rhino. If Err, and instance of RhinoError detailing the error that was encountered.

rhino::`RhinoInference`

pub struct RhinoInference

Represents an inference result returned from the Speech-to-Intent engine.

rhino::RhinoInference.`is_understood`

pub is_understood: bool

Indicates whether Rhino understood what it processed based on the context.

rhino::RhinoInference.`intent`

pub intent: Option<String>

If is_understood, name of intent that was inferred.

rhino::RhinoInference.`slots`

pub slots: HashMap<String, String>

If is_understood, dictionary of slot keys and values that were inferred.

rhino::`RhinoError`

pub struct RhinoError

An error type describing any errors encountered by the Rhino SDK.

rhino::RhinoError.`status`

pub status: RhinoErrorStatus

Type of error encountered.

rhino::RhinoError.`message`

pub status: Option<String>

Message detailing the cause of the error.

rhino::RhinoError.`new()`

pub fn new(status: RhinoErrorStatus, message: &str) -> Self

Creates a new instance of RhinoError.

Parameters

status RhinoErrorStatus : Type of error encountered.
message &str : Message detailing the cause of the error.

rhino::`RhinoErrorStatus`

pub enum RhinoErrorStatus {
    LibraryError(PvStatus),
    LibraryLoadError,
    FrameLengthError,
    ArgumentError,
}

Enum describing possible error types returned from the Rhino Rust SDK.

rhino::`PvStatus`

pub enum PvStatus {
    SUCCESS,
    OUT_OF_MEMORY,
    IO_ERROR,
    INVALID_ARGUMENT,
    STOP_ITERATION,
    KEY_ERROR,
    INVALID_STATE,
    RUNTIME_ERROR,
    ACTIVATION_ERROR,
    ACTIVATION_LIMIT_REACHED,
    ACTIVATION_THROTTLED,
    ACTIVATION_REFUSED,
}

Error codes returned from the Rhino library.

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Rhino Speech-to-Intent Rust API

Rhino Speech-to-Intent
Rust API