Cobra Voice Activity Detection
Node.js API

API Reference for the Node.js Cobra SDK (npm)

Cobra

class Cobra { }

Class for the Cobra Voice Activity Detection engine.

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

Cobra.constructor()

Cobra.constructor(
  accessKey: string,
  options: CobraOptions = {}
)

Cobra constructor.

Parameters

• accessKey string : AccessKey obtained from Picovoice Console.
• options CobraOptions: Optional configuration arguments:
  • device string? : String representation of the device (e.g., CPU or GPU) to use for inference. If set to best, the engine picks the most suitable device. 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.
  • libraryPath string : Path to the Cobra dynamic library (.node).

Returns

• Cobra: An instance of Cobra platform.

Cobra.release()

Cobra.release()

Releases resources acquired by Cobra.

Cobra.frameLength

Cobra.frameLength

Getter for number of audio samples per frame.

Returns

• number: Number of audio samples per frame.

Cobra.sampleRate

Cobra.sampleRate()

Getter for audio sample rate accepted by Cobra.

Returns

• number: Audio sample rate accepted by Cobra.

Cobra.version

Cobra.version()

Getter for version.

Returns

• string: Current Cobra version.

Cobra.process()

Cobra.process(pcm)

Processes a frame of the incoming audio stream with the voice activity detection engine. The number of samples per frame can be attained 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 Array<number> : A frame of audio samples.

Returns

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

Cobra.listAvailableDevices()

Cobra.listAvailableDevices(options: CobraInputOptions = {}): string[]

Lists all available devices that Cobra can use for inference. Each entry in the list can be the device argument of the constructor.

Parameters

• options CobraInputOptions : Optional input configuration arguments.

Returns

• string[] : List of all available devices that Cobra can use for inference.

Errors

Exceptions thrown if an error occurs within Cobra Voice Activity Detection engine.

Exceptions:

class PvStatusOutOfMemoryError        extends Error {}
class PvStatusIoError                 extends Error {}
class PvStatusInvalidArgumentError    extends Error {}
class PvStatusStopIterationError      extends Error {}
class PvStatusKeyError                extends Error {}
class PvStatusInvalidStateError       extends Error {}
class PvStatusRuntimeError            extends Error {}
class PvStatusActivationError         extends Error {}
class PvStatusActivationLimitReached  extends Error {}
class PvStatusActivationThrottled     extends Error {}
class PvStatusActivationRefused       extends Error {}