Leopard Speech-to-Text
Java API

API Reference for the Java Leopard SDK (leopard-java)

package: ai.picovoice.leopard

Leopard

public class Leopard { }

Class for the Leopard Speech-to-Text engine.

Leopard must be initialized using the Leopard.Builder() Class. Resources should be cleaned when you are done using the delete() function.

Leopard.delete()

public void delete()

Releases resources acquired by Leopard.

Leopard.getSampleRate()

public int getSampleRate()

Getter for required audio sample rate for PCM data.

Returns

• int: Required audio sample rate for PCM data.

Leopard.getVersion()

public String getVersion()

Getter for version.

Returns

• String: Current Leopard version.

Leopard.process()

public LeopardTranscript process(short[] pcm) throws LeopardException

Processes given audio data and returns its transcription. The incoming audio needs to have a sample rate equal to .getSampleRate() and be 16-bit linearly-encoded. Furthermore, Leopard operates on single channel audio. If you wish to process data in a different sample rate or format consider using .processFile().

Parameters

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

Returns

• LeopardTranscript: Inferred transcription and word metadata.

Throws

• LeopardException: if there is an error while processing the audio frame.

Leopard.processFile()

public LeopardTranscript processFile(String path) throws LeopardException

Processes a given audio file and returns its transcription.

Parameters

• path String : Absolute path to the audio file. The supported audio file formats are: 3gp (AMR), FLAC, MP3 , MP4/m4a (AAC), Ogg, WAV and WebM.

Returns

• LeopardTranscript: Inferred transcription and word metadata.

Throws

• LeopardException: if there is an error while processing the audio file.

Leopard.getAvailableDevices()

public static String[] getAvailableDevices(String libraryPath) throws LeopardException

Retrieves a list of available hardware devices that Leopard can use to run inference.

Parameters

• libraryPath String : Path to a native Leopard library. Set to null to use default library.

Returns

• String[]: List of available hardware devices that Leopard can use to run inference.

Throws

• LeopardException: If the library file cannot be loaded.

Leopard.getAvailableDevices()

public static String[] getAvailableDevices() throws LeopardException

Retrieves a list of available hardware devices that Leopard can use to run inference.

Returns

• String[]: List of available hardware devices that Leopard can use to run inference.

Throws

• LeopardException: If the default library file cannot be loaded.

Leopard.Builder

public static class Builder {
    public Builder(String accessKey) { }
}

Builder for creating an instance of Leopard with a mixture of default arguments.

Parameters

• accessKey String : AccessKey obtained from Picovoice Console.

Leopard.Builder.build()

public Leopard build() throws LeopardException

Creates an instance of Leopard Speech-to-Text engine.

Returns

• Leopard: An instance of Leopard Speech-to-Text engine.

Throws

• LeopardException: If an error occurs while creating an instance of Leopard Speech-to-Text engine.

Leopard.Builder.setAccessKey()

public Leopard.Builder setAccessKey(String accessKey)

Sets the AccessKey of the builder.

Parameters

• accessKey String : AccessKey obtained from Picovoice Console.

Returns

• Leopard.Builder: Modified Leopard.Builder object.

Leopard.Builder.setModelPath()

public Leopard.Builder setModelPath(String modelPath)

Sets the model path of the builder.

Parameters

• modelPath String : Absolute path to the file containing model parameters (.pv).

Returns

• Leopard.Builder: Modified Leopard.Builder object.

Leopard.Builder.setDevice()

public Leopard.Builder setDevice(String modelPath)

Sets the device of the builder. If not set it will be set to the default device.

Parameters

• 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

• Leopard.Builder: The instance of Leopard.Builder object.

Leopard.Builder.setLibraryPath()

public Builder setLibraryPath(String libraryPath)

Sets the library path of the builder.

Parameters

• libraryPath String : Absolute path to the native Leopard library.

Returns

• Leopard.Builder: Modified Leopard.Builder object.

Leopard.Builder.setEnableAutomaticPunctuation()

public Leopard.Builder setEnableAutomaticPunctuation(boolean enableAutomaticPunctuation)

Setter for enabling automatic punctuation insertion.

Parameters

• enableAutomaticPunctuation boolean : Set to true to enable automatic punctuation insertion.

Returns

• Leopard.Builder: Modified Leopard.Builder object.

Leopard.Builder.setEnableDiarization()

public Leopard.Builder setEnableDiarization(boolean enableDiarization)

Setter for enabling speaker diarization.

Parameters

• enableDiarization boolean : Set to true to enable speaker diarization, which allows Leopard to differentiate speakers as part of the transcription process. Word metadata will include a speakerTag to identify unique speakers.

Returns

• Leopard.Builder: Modified Leopard.Builder object.

LeopardTranscript

public class LeopardTranscript {
    public LeopardTranscript(String transcriptString, Word[] wordArray) { }
}

Class that contains transcription results returned from Leopard.process() and Leopard.processFile().

Parameters

• transcriptString String : Inferred transcription.
• wordArray LeopardTranscript.Word[] : Transcribed words and their associated metadata.

LeopardTranscript.getTranscriptString()

public String getTranscriptString()

Getter for the inferred transcription.

Returns

• String: Inferred transcription.

LeopardTranscript.getWordArray()

public Word[] getWordArray()

Getter for transcribed words and their associated metadata.

Returns

• LeopardTranscript.Word[]: Transcribed words and their associated metadata.

LeopardTranscript.Word

public static class Word {
    public Word(String word, float confidence, float startSec, float endSec, int speakerTag) { }
}

Class for storing word metadata from a LeopardTranscript.

Parameters

• word String : Transcribed word.
• confidence float : Transcription confidence. It is a number within [0, 1].
• startSec float : Start of word in seconds.
• endSec float : End of word in seconds.
• speakerTag int : The speaker tag is -1 if diarization is not enabled during initialization; otherwise, it's a non-negative integer identifying unique speakers, with 0 reserved for unknown speakers.

LeopardTranscript.Word.getWord()

public String getWord()

Getter for the transcribed word.

Returns

• String: Transcribed word.

LeopardTranscript.Word.getConfidence()

public float getConfidence()

Getter for the transcription confidence.

Returns

• float: Transcription confidence. It is a number within [0, 1].

LeopardTranscript.Word.getStartSec()

public float getStartSec()

Getter for the start of word in seconds.

Returns

• float: Start of word in seconds.

LeopardTranscript.Word.getEndSec()

public float getEndSec()

Getter for the end of word in seconds.

Returns

• float: End of word in seconds.

LeopardTranscript.Word.getSpeakerTag()

public int getSpeakerTag()

Getter for the speaker tag.

Returns

• int: Speaker tag associated with speaker.

LeopardException

public class LeopardException extends Exception { }

Exception thrown if an error occurs within Leopard Speech-to-Text engine.

Exceptions:

public class LeopardActivationException           extends LeopardException { }
public class LeopardActivationLimitException      extends LeopardException { }
public class LeopardActivationRefusedException    extends LeopardException { }
public class LeopardActivationThrottledException  extends LeopardException { }
public class LeopardIOException                   extends LeopardException { }
public class LeopardInvalidArgumentException      extends LeopardException { }
public class LeopardInvalidStateException         extends LeopardException { }
public class LeopardKeyException                  extends LeopardException { }
public class LeopardMemoryException               extends LeopardException { }
public class LeopardRuntimeException              extends LeopardException { }
public class LeopardStopIterationException        extends LeopardException { }