Errors using maxAlternatives with recognizeUsingWebSocket on SpeechToTextV1

[jkelvie]

Overview

In the last week, when calling recognizeUsingWebSocket on the SpeechToTextV1 API, we suddenly we get the error: "No active exception to reraise"

This happens when maxAlternatives is set to anything higher than 1.

This error does NOT occur with the non-WebSocket recognition calls.

Expected behavior The SDK should return several alternatives.

Actual behavior We get an exception - passed as an event of type error on the SpeechToTextV1.RecognizeStream.

The exception has only the message: "No active exception to reraise"

This is obviously not a very helpful error message.

How to reproduce We are using the 7.0.0 version of the ibm-watson Node.js SDK. This also, though, occurs with the previous version (6.2.2).

Complete sample code to replicate is below. If it is run with maxAlternatives set to 1 instead, the ASR will work.

const IamAuthenticator = require('ibm-watson/auth').IamAuthenticator
const SpeechToTextV1 = require('ibm-watson/speech-to-text/v1')

require('dotenv').config()

// const model = 'en-US_Multimedia'
const speechToText = new SpeechToTextV1({
  authenticator: new IamAuthenticator({
    apikey: process.env.WATSON_STT_KEY
  }),
  serviceUrl: process.env.WATSON_STT_URL
})

const recognizeParams = {
  backgroundAudioSuppression: 0.5,
  contentType: 'audio/l16;rate=16000;channels=1;',
  endOfPhraseSilenceTime: 1.0,
  interimResults: true,
  lowLatency: false,
  maxAlternatives: 3, // recently started getting errors on 5/5/2022 with this
  model: 'en-US_Multimedia',
  objectMode: true,
  speechDetectorSensitivity: 0.2
}

const recognizeStream = speechToText.recognizeUsingWebSocket(recognizeParams)

// Pipe in the audio from our audio object
require('fs').createReadStream('test/data/AudioWithSilence-16000.raw').pipe(recognizeStream)

recognizeStream.on('data', (event) => {
  // Ignore results that come in after the recognize stream is destroyed
  if (!recognizeStream) {
    return
  }

  console.info('Results returned: ' + JSON.stringify(event, null, 2))
})

recognizeStream.on('error', (event) => {
  /** @type {any} */
  const eventAny = event
  console.error('recognizeStream error: ' + eventAny.raw.data)
  if (recognizeStream) recognizeStream.stop()
})

recognizeStream.on('close', () => {
  console.info('recognizeStream stopped')
})

recognizeStream.on('end', () => {
  console.info('recognizedStream ended')
})

Screenshots If applicable, add screenshots to help explain your problem.

SDK Version 7.0.0 - also tested with 6.2.2

Additional information: Node.js 16.9.1

Additional context This is a critical error - this is harming the quality of our ASR, as well as leading to errors in our production systems.

A zipped version of the raw audio file we tested with is attached: AudioWithSilence-16000.zip