Engines sub-package

Dragonfly supports multiple speech recognition engines as its backend. The engines sub-package implements the interface code for each supported engine.

Also contained within this sub-package are a number of text-to-speech implementations. These can be used independently of the speech recognition engines via the get_speaker() function.

Main SR engine back-end interface

get_current_engine()[source]

Get the currently initialized SR engine object.

If an SR engine has not been initialized yet, None will be returned instead.

Return type:

EngineBase | None

Returns:

engine object or None

Usage example:

# Print the name of the current engine if one has been
# initialized.
from dragonfly import get_current_engine
engine = get_current_engine()
if engine:
    print("Engine name: %r" % engine.name)
else:
    print("No engine has been initialized.")
get_engine(name=None, **kwargs)[source]

Get the engine implementation.

This function will initialize an engine instance using the get_engine and is_engine_available functions in the engine packages and return an instance of the first available engine. If one has already been initialized, it will be returned instead.

If no specific engine is requested and no engine has already been initialized, this function will initialize and return an instance of the first available engine in the following order:

SR engine back-end

Engine name string(s)

  1. Dragon/Natlink

"natlink"

  1. Kaldi

"kaldi"

  1. WSR/SAPI 5

"sapi5", "sapi5inproc", "sapi5shared"

  1. CMU Pocket Sphinx

"sphinx"

The Text-input engine can be initialized by specifying "text" as the engine name. This back-end will not be initialized if no specific engine is requested because the back-end is not a real SR engine and is used mostly for testing.

Arguments:

Parameters:
  • name (str) – optional human-readable name of the engine to return.

  • **kwargs – optional keyword arguments passed through to the engine for engine-specific configuration.

Return type:

EngineBase

Returns:

engine instance

Raises:

EngineError

get_speaker(name=None)[source]

Get the text-to-speech (speaker) implementation.

This function will initialize and return a speaker instance instance of the available speaker back-end. If one has already been initialized, it will be returned instead.

If no specific speaker back-end is requested and no speaker has already been initialized, this function will initialize and return an instance of the first available back-end in the following order:

TTS speaker back-end

Speaker name string(s)

  1. SAPI 5

"sapi5"

  1. Dragon/Natlink

"natlink"

  1. eSpeak

"espeak"

  1. CMU Flite

"flite"

  1. Text (stdout)

"text"

The first two speaker back-ends are only available on Microsoft Windows. The second requires that Dragon NaturallySpeaking and Natlink are installed on the system.

The third and fourth back-ends, eSpeak and CMU Flite, may be used on most platforms. These require that the appropriate command-line programs are installed on the system.

The last back-end (text) is used as a fallback when no real speaker implementation is available. This back-end writes input text to stdout, i.e., prints text to the console.

Arguments:

Parameters:

name (str) – optional human-readable name of the speaker to return.

Return type:

SpeakerBase

Returns:

speaker instance

Raises:

EngineError

register_engine_init(engine)[source]

Register initialization of an engine.

This function sets the default engine to the first engine initialized.

register_speaker_init(speaker)[source]

Register initialization of a speaker.

This function sets the default speaker to the first speaker initialized.

Engine back-ends

Text-to-speech (speaker) back-ends

For more information on the available text-to-speech implementations, see the following sections: