Cobra Voice Activity Detection
iOS API

API Reference for the Cobra iOS SDK (Cocoapods).

Cobra

public class Cobra { }

Class for the Cobra VAD engine.

Cobra can be initialized using the class constructor. Resources should be cleaned when you are done using the delete() method.

Cobra.frameLength

public static let frameLength: UInt32

The number of audio samples per frame that Cobra accepts.

Cobra.sampleRate

public static let sampleRate: UInt32

The audio sample rate that Cobra accepts.

Cobra.version

public static let version: String

The Cobra library version string.

Cobra.init()

public init(
    accessKey: String,
    device: String? = nil) throws

init method for Cobra VAD engine.

Parameters

• accessKey String : AccessKey obtained from Picovoice Console.
• device String? : String representation of the device (e.g., CPU or GPU) to use. If set to best, the most suitable device is selected automatically. If set to gpu, the engine uses the first available GPU device. To select a specific GPU device, set this argument to gpu:${GPU_INDEX}, where ${GPU_INDEX} is the index of the target GPU. If set to cpu, the engine will run on the CPU with the default number of threads. To specify the number of threads, set this argument to cpu:${NUM_THREADS}, where ${NUM_THREADS} is the desired number of threads.

Returns

• Cobra : An instance of Cobra VAD engine.

Throws

• CobraError

Cobra.delete()

public func delete()

Releases resources acquired by Cobra.

Cobra.process()

public func process(pcm: [Int16]) throws -> Float32

Processes a frame of the incoming audio stream and emits the detection result. The required number of samples-per-frame can be obtained by calling .frameLength. The incoming audio needs to have a sample rate equal to .sampleRate and be 16-bit linearly-encoded. Cobra operates on single-channel audio.

Parameters

• pcm [Int16] : A frame of audio samples.

Returns

• Float32 : Probability of voice activity. It is a floating-point number within [0, 1].

Throws

• CobraError

Cobra.getAvailableDevices()

public static func getAvailableDevices() throws -> [String]

Retrieves a list of devices that can be specified when constructing Cobra.

Returns

• [String] : An array of available devices.

Throws

• CobraError: If an error occurs while retrieving the devices.

CobraError

public class CobraError : LocalizedError { }

Error thrown if an error occurs within Cobra VAD engine.

Exceptions

public class CobraMemoryError : CobraError {}
public class CobraIOError : CobraError {}
public class CobraInvalidArgumentError : CobraError {}
public class CobraStopIterationError : CobraError {}
public class CobraKeyError : CobraError {}
public class CobraInvalidStateError : CobraError {}
public class CobraRuntimeError : CobraError {}
public class CobraActivationError : CobraError {}
public class CobraActivationLimitError : CobraError {}
public class CobraActivationThrottledError : CobraError {}
public class CobraActivationRefusedError : CobraError {}