echogarden/dist/recognition/AmazonTranscribeSTT.js

An easy-to-use speech toolset. Includes tools for synthesis, recognition, alignment, speech translation, language detection, source separation and more.

import { LanguageCode } from '@aws-sdk/client-transcribe-streaming';
import { wordCharacterRegExp } from '../nlp/Segmentation.js';
import * as FFMpegTranscoder from '../codecs/FFMpegTranscoder.js';
import { Logger } from '../utilities/Logger.js';
export async function recgonize(rawAudio, languageCode, region, accessKeyId, secretAccessKey) {
    const flac16Khz16bitMonoAudio = await FFMpegTranscoder.encodeFromChannels(rawAudio, { format: 'flac', sampleRate: 16000, sampleFormat: 's16', channelCount: 1 });
    const logger = new Logger();
    if (!(languageCode in LanguageCode)) {
        let matchingLanguageCode = undefined;
        if (languageCode.length === 2) {
            matchingLanguageCode = languageCodeDefaultDialects.find(value => value.startsWith(languageCode));
        }
        if (matchingLanguageCode) {
            logger.log(`Short language code '${languageCode}' has been extended to the default dialect '${matchingLanguageCode}'`);
            languageCode = matchingLanguageCode;
        }
        else {
            throw new Error(`Language code ${languageCode} is not supported by Amazon Transcribe`);
        }
    }
    logger.start('Initialize Amazon Transcribe streaming client module');
    const streamingTranscribeSdk = await import('@aws-sdk/client-transcribe-streaming');
    const streamingTranscribeClient = new streamingTranscribeSdk.TranscribeStreamingClient({
        region,
        credentials: {
            accessKeyId,
            secretAccessKey
        }
    });
    const audioStream = async function* () {
        const chunkSize = 2 ** 12;
        for (let i = 0; i < flac16Khz16bitMonoAudio.length; i += chunkSize) {
            const chunk = flac16Khz16bitMonoAudio.subarray(i, i + chunkSize);
            yield { AudioEvent: { AudioChunk: chunk } };
        }
    };
    const params = {
        LanguageCode: languageCode,
        MediaSampleRateHertz: rawAudio.sampleRate,
        MediaEncoding: 'flac',
        AudioStream: audioStream(),
    };
    logger.start('Request recognition from Amazon Transcribe');
    const command = new streamingTranscribeSdk.StartStreamTranscriptionCommand(params);
    const response = await streamingTranscribeClient.send(command);
    let transcript = '';
    let events = [];
    for await (const event of response.TranscriptResultStream) {
        if (!event.TranscriptEvent) {
            continue;
        }
        const transcriptEvent = event.TranscriptEvent;
        const results = transcriptEvent.Transcript.Results;
        if (results.length == 0) {
            continue;
        }
        const firstResult = results[0];
        const alternatives = firstResult.Alternatives;
        if (!alternatives || alternatives.length == 0) {
            continue;
        }
        const firstAlternative = alternatives[0];
        //logger.log(firstAlternative.Transcript!)
        if (firstResult.IsPartial === false) {
            events = [...events, ...firstAlternative.Items];
            transcript += ' ' + firstAlternative.Transcript;
        }
    }
    logger.start('Process result');
    transcript = transcript.replace(/ +/g, ' ').trim();
    const timeline = [];
    for (const event of events) {
        const text = event.Content;
        if (!wordCharacterRegExp.test(text)) {
            continue;
        }
        const startTime = event.StartTime;
        const endTime = event.EndTime;
        const confidence = event.Confidence;
        timeline[timeline.length - 1].endTime = startTime;
        timeline.push({
            type: 'word',
            text,
            startTime,
            endTime,
            confidence
        });
    }
    logger.end();
    return { transcript, timeline };
}
export const languageCodeDefaultDialects = [
    'af-ZA',
    'ar-SA',
    'ca-ES',
    'cs-CZ',
    'da-DK',
    'de-DE',
    'el-GR',
    'en-US',
    'es-ES',
    'eu-ES',
    'fa-IR',
    'fi-FI',
    'fr-FR',
    'gl-ES',
    'he-IL',
    'hi-IN',
    'hr-HR',
    'id-ID',
    'it-IT',
    'ja-JP',
    'ko-KR',
    'lv-LV',
    'ms-MY',
    'nl-NL',
    'no-NO',
    'pl-PL',
    'pt-BR',
    'ro-RO',
    'ru-RU',
    'sk-SK',
    'so-SO',
    'sr-RS',
    'sv-SE',
    'th-TH',
    'tl-PH',
    'uk-UA',
    'vi-VN',
    'zh-CN',
];
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