STT/native_client/javascript/index.ts
2021-05-18 13:45:52 +02:00

363 lines
12 KiB
TypeScript

import binary from 'node-pre-gyp';
import path from 'path';
// 'lib', 'binding', 'v0.1.1', ['node', 'v' + process.versions.modules, process.platform, process.arch].join('-'), 'stt-bindings.node')
const binding_path = binary.find(path.resolve(path.join(__dirname, 'package.json')));
// On Windows, we can't rely on RPATH being set to $ORIGIN/../ or on
// @loader_path/../ but we can change the PATH to include the proper directory
// for the dynamic linker
if (process.platform === 'win32') {
var dslib_path = path.resolve(path.join(binding_path, '../..'));
// electron-builder does weird magic hand-in-hand with electronjs,
// and messes with the path where we expect things to be for the Windows
// linker.
if ('electron' in process.versions) {
dslib_path = dslib_path.replace("app.asar", "app.asar.unpacked");
}
var oldPath = process.env.PATH;
process.env['PATH'] = `${dslib_path};${process.env.PATH}`;
}
const binding = require(binding_path);
if (process.platform === 'win32') {
process.env['PATH'] = oldPath;
}
/**
* Stores text of an individual token, along with its timing information
*/
export interface TokenMetadata {
/** The text corresponding to this token */
text: string;
/** Position of the token in units of 20ms */
timestep: number;
/** Position of the token in seconds */
start_time: number;
}
/**
* A single transcript computed by the model, including a confidence value and
* the metadata for its constituent tokens.
*/
export interface CandidateTranscript {
tokens: TokenMetadata[];
/**
* Approximated confidence value for this transcription. This is roughly the
* sum of the acoustic model logit values for each timestep/token that
* contributed to the creation of this transcription.
*/
confidence: number;
}
/**
* An array of CandidateTranscript objects computed by the model.
*/
export interface Metadata {
transcripts: CandidateTranscript[];
}
/**
* Provides an interface to a Coqui STT stream. The constructor cannot be called
* directly, use :js:func:`Model.createStream`.
*/
class StreamImpl {
/** @internal */
_impl: any;
/**
* @param nativeStream SWIG wrapper for native StreamingState object.
*/
constructor(nativeStream: object) {
this._impl = nativeStream;
}
/**
* Feed audio samples to an ongoing streaming inference.
*
* @param aBuffer An array of 16-bit, mono raw audio samples at the
* appropriate sample rate (matching what the model was trained on).
*/
feedAudioContent(aBuffer: Buffer): void {
binding.FeedAudioContent(this._impl, aBuffer);
}
/**
* Compute the intermediate decoding of an ongoing streaming inference.
*
* @return The STT intermediate result.
*/
intermediateDecode(): string {
return binding.IntermediateDecode(this._impl);
}
/**
* Compute the intermediate decoding of an ongoing streaming inference, return results including metadata.
*
* @param aNumResults Maximum number of candidate transcripts to return. Returned list might be smaller than this. Default value is 1 if not specified.
*
* @return :js:func:`Metadata` object containing multiple candidate transcripts. Each transcript has per-token metadata including timing information. The user is responsible for freeing Metadata by calling :js:func:`FreeMetadata`. Returns undefined on error.
*/
intermediateDecodeWithMetadata(aNumResults: number = 1): Metadata {
return binding.IntermediateDecodeWithMetadata(this._impl, aNumResults);
}
/**
* Compute the final decoding of an ongoing streaming inference and return the result. Signals the end of an ongoing streaming inference.
*
* @return The STT result.
*
* This method will free the stream, it must not be used after this method is called.
*/
finishStream(): string {
const result = binding.FinishStream(this._impl);
this._impl = null;
return result;
}
/**
* Compute the final decoding of an ongoing streaming inference and return the results including metadata. Signals the end of an ongoing streaming inference.
*
* @param aNumResults Maximum number of candidate transcripts to return. Returned list might be smaller than this. Default value is 1 if not specified.
*
* @return Outputs a :js:func:`Metadata` struct of individual letters along with their timing information. The user is responsible for freeing Metadata by calling :js:func:`FreeMetadata`.
*
* This method will free the stream, it must not be used after this method is called.
*/
finishStreamWithMetadata(aNumResults: number = 1): Metadata {
const result = binding.FinishStreamWithMetadata(this._impl, aNumResults);
this._impl = null;
return result;
}
}
/**
* Exposes the type of Stream without actually exposing the class.
* Because the Stream class should not be instantiated directly,
* but instead be created via :js:func:`Model.createStream`.
*/
export type Stream = StreamImpl;
/**
* An object providing an interface to a trained Coqui STT model.
*/
export class Model {
/** @internal */
_impl: any;
/**
* @param aModelPath The path to the frozen model graph.
*
* @throws on error
*/
constructor(aModelPath: string) {
this._impl = null;
const [status, impl] = binding.CreateModel(aModelPath);
if (status !== 0) {
throw `CreateModel failed: ${binding.ErrorCodeToErrorMessage(status)} (0x${status.toString(16)})`;
}
this._impl = impl;
}
/**
* Get beam width value used by the model. If :js:func:`Model.setBeamWidth` was
* not called before, will return the default value loaded from the model file.
*
* @return Beam width value used by the model.
*/
beamWidth(): number {
return binding.GetModelBeamWidth(this._impl);
}
/**
* Set beam width value used by the model.
*
* @param aBeamWidth The beam width used by the model. A larger beam width value generates better results at the cost of decoding time.
*
* @throws on error
*/
setBeamWidth(aBeamWidth: number): void {
const status = binding.SetModelBeamWidth(this._impl, aBeamWidth);
if (status !== 0) {
throw `SetModelBeamWidth failed: ${binding.ErrorCodeToErrorMessage(status)} (0x${status.toString(16)})`;
}
}
/**
* Add a hot-word and its boost.
*
* Words that don't occur in the scorer (e.g. proper nouns) or strings that contain spaces won't be taken into account.
*
* @param aWord word
* @param aBoost boost Positive value increases and negative reduces chance of a word occuring in a transcription. Excessive positive boost might lead to splitting up of letters of the word following the hot-word.
*
* @throws on error
*/
addHotWord(aWord: string, aBoost: number): void {
const status = binding.AddHotWord(this._impl, aWord, aBoost);
if (status !== 0) {
throw `addHotWord failed: ${binding.ErrorCodeToErrorMessage(status)} (0x${status.toString(16)})`;
}
}
/**
* Erase entry for hot-word
*
* @param aWord word
*
* @throws on error
*/
eraseHotWord(aWord: string): void {
const status = binding.EraseHotWord(this._impl, aWord);
if (status !== 0) {
throw `eraseHotWord failed: ${binding.ErrorCodeToErrorMessage(status)} (0x${status.toString(16)})`;
}
}
/**
* Clear all hot-word entries
*
* @throws on error
*/
clearHotWords(): void {
const status = binding.ClearHotWords(this._impl);
if (status !== 0) {
throw `clearHotWord failed: ${binding.ErrorCodeToErrorMessage(status)} (0x${status.toString(16)})`;
}
}
/**
* Return the sample rate expected by the model.
*
* @return Sample rate.
*/
sampleRate(): number {
return binding.GetModelSampleRate(this._impl);
}
/**
* Enable decoding using an external scorer.
*
* @param aScorerPath The path to the external scorer file.
*
* @throws on error
*/
enableExternalScorer(aScorerPath: string): void {
const status = binding.EnableExternalScorer(this._impl, aScorerPath);
if (status !== 0) {
throw `EnableExternalScorer failed: ${binding.ErrorCodeToErrorMessage(status)} (0x${status.toString(16)})`;
}
}
/**
* Disable decoding using an external scorer.
*
* @throws on error
*/
disableExternalScorer(): void {
const status = binding.DisableExternalScorer(this._impl);
if (status !== 0) {
throw `DisableExternalScorer failed: ${binding.ErrorCodeToErrorMessage(status)} (0x${status.toString(16)})`;
}
}
/**
* Set hyperparameters alpha and beta of the external scorer.
*
* @param aLMAlpha The alpha hyperparameter of the CTC decoder. Language Model weight.
* @param aLMBeta The beta hyperparameter of the CTC decoder. Word insertion weight.
*
* @throws on error
*/
setScorerAlphaBeta(aLMAlpha: number, aLMBeta: number): void {
const status = binding.SetScorerAlphaBeta(this._impl, aLMAlpha, aLMBeta);
if (status !== 0) {
throw `SetScorerAlphaBeta failed: ${binding.ErrorCodeToErrorMessage(status)} (0x${status.toString(16)})`;
}
}
/**
* Use the Coqui STT model to perform Speech-To-Text.
*
* @param aBuffer A 16-bit, mono raw audio signal at the appropriate sample rate (matching what the model was trained on).
*
* @return The STT result. Returns undefined on error.
*/
stt(aBuffer: Buffer): string {
return binding.SpeechToText(this._impl, aBuffer);
}
/**
* Use the Coqui STT model to perform Speech-To-Text and output metadata
* about the results.
*
* @param aBuffer A 16-bit, mono raw audio signal at the appropriate sample rate (matching what the model was trained on).
* @param aNumResults Maximum number of candidate transcripts to return. Returned list might be smaller than this.
* Default value is 1 if not specified.
*
* @return :js:func:`Metadata` object containing multiple candidate transcripts. Each transcript has per-token metadata including timing information.
* The user is responsible for freeing Metadata by calling :js:func:`FreeMetadata`. Returns undefined on error.
*/
sttWithMetadata(aBuffer: Buffer, aNumResults: number = 1): Metadata {
return binding.SpeechToTextWithMetadata(this._impl, aBuffer, aNumResults);
}
/**
* Create a new streaming inference state. One can then call :js:func:`StreamImpl.feedAudioContent` and :js:func:`StreamImpl.finishStream` on the returned stream object.
*
* @return a :js:func:`StreamImpl` object that represents the streaming state.
*
* @throws on error
*/
createStream(): StreamImpl {
const [status, ctx] = binding.CreateStream(this._impl);
if (status !== 0) {
throw `CreateStream failed: ${binding.ErrorCodeToErrorMessage(status)} (0x${status.toString(16)})`;
}
return new StreamImpl(ctx);
}
}
/**
* Frees associated resources and destroys model object.
*
* @param model A model pointer returned by :js:func:`Model`
*
*/
export function FreeModel(model: Model): void {
binding.FreeModel(model._impl);
}
/**
* Free memory allocated for metadata information.
*
* @param metadata Object containing metadata as returned by :js:func:`Model.sttWithMetadata` or :js:func:`StreamImpl.finishStreamWithMetadata`
*/
export function FreeMetadata(metadata: Metadata): void {
binding.FreeMetadata(metadata);
}
/**
* Destroy a streaming state without decoding the computed logits. This
* can be used if you no longer need the result of an ongoing streaming
* inference and don't want to perform a costly decode operation.
*
* @param stream A streaming state pointer returned by :js:func:`Model.createStream`.
*/
export function FreeStream(stream: StreamImpl): void {
binding.FreeStream(stream._impl);
}
/**
* Returns the version of this library. The returned version is a semantic
* version (SemVer 2.0.0).
*/
export function Version(): string {
return binding.Version();
}