feat(transcribing): configurable transcription language (#9684)

* configurable transcription language

* merge conflict

* set default config value

* fix lint

config.js

@@ -230,6 +230,17 @@ var config = {
     // subtitles and buttons can be configured)
     // transcribingEnabled: false,
 
+    // If true transcriber will use the application language.
+    // The application language is either explicitly set by participants in their settings or automatically
+    // detected based on the environment, e.g. if the app is opened in a chrome instance which is using french as its
+    // default language then transcriptions for that participant will be in french.
+    // Defaults to true.
+    // transcribeWithAppLanguage: true,
+
+    // Transcriber language. This settings will only work if "transcribeWithAppLanguage" is explicitly set to false.
+    // Available languages can be found in lang/language.json.
+    // preferredTranscribeLanguage: 'en',
+
     // Enables automatic turning on captions when recording is started
     // autoCaptionOnRecord: false,
 

react/features/base/conference/functions.js

@@ -3,6 +3,7 @@
 import _ from 'lodash';
 
 import { getName } from '../../app/functions';
+import { determineTranscriptionLanguage } from '../../transcribing/functions';
 import { JitsiTrackErrors } from '../lib-jitsi-meet';
 import {
     getLocalParticipant,
@@ -231,6 +232,7 @@ export function getConferenceOptions(stateful: Function | Object) {
     }
 
     options.applicationName = getName();
+    options.transcriptionLanguage = determineTranscriptionLanguage(options);
 
     // Disable analytics, if requessted.
     if (options.disableThirdPartyRequests) {

react/features/transcribing/functions.js

@@ -0,0 +1,30 @@
+// @flow
+
+import i18next from 'i18next';
+
+import JITSI_TO_BCP47_MAP from './jitsiToBCP47LocaleMap.json';
+
+const DEFAULT_TRANSCRIBER_LANG = 'en-US';
+
+
+/**
+ * Determine which language to use for transcribing.
+ *
+ * @param {*} config - Application config.
+ * @returns {string}
+ */
+export function determineTranscriptionLanguage(config: Object) {
+
+    const { preferredTranscribeLanguage, transcribeWithAppLanguage = true } = config;
+
+    // Depending on the config either use the language that the app automatically detected or the hardcoded
+    // config value.
+    const jitsiLocale = transcribeWithAppLanguage ? i18next.language : preferredTranscribeLanguage;
+
+    // Jitsi uses custom language tags, but the transcriber expects BCP-47 compliant tags. We use a mapping file
+    // to convert them.
+    // Not all languages that the app might detect are supported by the transcriber in which case use the default.
+    const { [jitsiLocale]: bcp47Locale = DEFAULT_TRANSCRIBER_LANG } = JITSI_TO_BCP47_MAP;
+
+    return bcp47Locale;
+}

react/features/transcribing/jitsiToBCP47LocaleMap.json

@@ -0,0 +1,51 @@
+{
+    "en": "en-US",
+    "af": "af-ZA",
+    "ar": "ar-EG",
+    "bg": "bg-BG",
+    "ca": "ca-ES",
+    "cs": "cs-CZ",
+    "da": "da-DK",
+    "de": "de-DE",
+    "el": "el-GR",
+    "enGB": "en-GB",
+    "es": "es-ES",
+    "esUS": "es-US",
+    "et": "et-EE",
+    "eu": "eu-ES",
+    "fi": "fi-FI",
+    "fr": "fr-FR",
+    "frCA": "fr-CA",
+    "he": "iw-IL",
+    "hi": "hi-IN",
+    "mr": "mr-IN",
+    "hr": "hr-HR",
+    "hu": "hu-HU",
+    "hy": "hy-AM",
+    "id": "id-ID",
+    "it": "it-IT",
+    "ja": "ja-JP",
+    "ko": "ko-KR",
+    "lt": "lt-LT",
+    "ml": "ml-IN",
+    "lv": "lv-LV",
+    "nl": "nl-NL",
+    "fa": "fa-IR",
+    "pl": "pl-PL",
+    "pt": "pt-PT",
+    "ptBR": "pt-BR",
+    "ru": "ru-RU",
+    "ro": "ro-RO",
+    "sk": "sk-SK",
+    "sl": "sl-SL",
+    "sr": "sr-RS",
+    "sq": "sq-AL",
+    "sv": "sv-SE",
+    "te": "te-IN",
+    "th": "th-TH",
+    "tr": "tr-TR",
+    "uk": "uk-UA",
+    "vi": "vi-VN",
+    "zhCN": "zh (cmn-Hans-CN)",
+    "zhTW": "zh-TW (cmn-Hant-TW)"
+}