English | 中文说明

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DuoTimeFaker 是一个针对多邻国（Duolingo）Android 客户端的轻量级 Xposed 模块。主要用于解决在中国大陆等非支持区域使用多邻国 AI 语音/视频通话（如 Lily 通话）时受限的问题。

1. 应用内时区伪装：
   • 在应用进程内将时区相关 API 拦截并返回 Asia/Tokyo（东京时区）。
   • 手机系统保持原有北京时间不变，不影响系统闹钟、日历与第三方应用。
2. 连接质量判定放宽：
   • 拦截客户端网络质量评估类（ConnectionQuality），避免因国际公网偶发抖动（RTT > 500ms）触发看门狗（VCWatchdog）导致通话意外中断。
   • 改善对讲机（Push-To-Talk, PTT）模式下的异步语音交互稳定性。
3. 低侵入性与便携性：
   • 支持通过 LSPatch 进行免 Root 修补使用，亦可在已 Root 设备上的 LSPosed 中直接启用。
   • 无需后台常驻后台辅助进程。

• 时区拦截： 多邻国通话信令在建立连接时会检查设备时区。模块在进程初始化时 Hook 以下接口：
  • java.util.TimeZone.getDefault()
  • java.time.ZoneId.systemDefault()
  • android.icu.util.TimeZone.getDefault()
  • java.lang.System.getProperty("user.timezone")
  • 多邻国内部时钟接口 defpackage.luh.f()
• 看门狗调优： 多邻国客户端 video-call-lib 会根据 Ping/Pong 延迟将网络状态划分为 GREAT (<=100ms)、GOOD (<=250ms)、FAIR (<=500ms) 与 POOR (>500ms)。模块将 ConnectionQuality 构造参数中的 POOR 状态调整为 GOOD，降低看门狗在网络抖动时掐断会话的频率。

1. 网络连通性： 多邻国通话信令服务器与 WebRTC 节点部署在海外 CDN（如 CloudFront）。在部分地区或网络环境下，直连可能因国际链路丢包而无法建连；若遇到无法连接的情况，仍需配合网络代理工具进行分流。
2. 语音识别引擎： 对讲机模式下的录音转写依赖 Android 系统的语音识别服务，建议设备安装 Google 语音服务（Google Speech Services）并下载英语离线语言包。

1. 在设备上安装 LSPatch；
2. 安装本模块提供的 DuoTimeFaker.apk；
3. 在 LSPatch 中配置多邻国，将 DuoTimeFaker 勾选为加载模块；
4. 启动多邻国即可。

1. 安装并在 LSPosed 管理器中激活 DuoTimeFaker；
2. 将作用域勾选为 多邻国 (com.duolingo)；
3. 强制停止并重新打开多邻国。

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DuoTimeFaker is a lightweight Xposed module designed for the Duolingo Android application. It addresses regional restrictions on Duolingo's AI-powered video and voice calling features (such as Lily Call) when running in unsupported timezones.

1. In-App Timezone Spoofing:
   • Redirects timezone queries within the target application process to Asia/Tokyo.
   • Leaves device-wide system time and timezone settings untouched.
2. Connection Watchdog Relaxation:
   • Intercepts client-side connection quality evaluations (ConnectionQuality) to mitigate premature disconnections caused by transient network jitter (RTT > 500ms).
   • Improves stability during Push-To-Talk (PTT) audio interactions.
3. Lightweight & Portable:
   • Fully compatible with non-root patching via LSPatch, as well as root-based LSPosed environments.
   • Requires no persistent background services or helper daemons.

• Timezone Interception: Duolingo verifies the client device timezone during session negotiation. The module hooks the following entries upon process initialization:
  • java.util.TimeZone.getDefault()
  • java.time.ZoneId.systemDefault()
  • android.icu.util.TimeZone.getDefault()
  • java.lang.System.getProperty("user.timezone")
  • Internal time provider defpackage.luh.f()
• Watchdog Tuning: Duolingo's video-call-lib categorizes ping round-trip times into GREAT (<=100ms), GOOD (<=250ms), FAIR (<=500ms), and POOR (>500ms). The module remaps POOR states to GOOD during object instantiation, preventing the client-side watchdog from triggering session aborts under moderate latency.

1. Network Connectivity: Duolingo's voice and signaling endpoints reside on overseas CDN infrastructure. Depending on the local ISP, direct access may experience packet loss or high latency. If connection fails, a routing proxy may still be required.
2. Speech Recognition: Audio transcription in Push-To-Talk mode relies on the Android system's SpeechRecognizer. It is recommended to have Google Speech Services installed with the English offline speech pack enabled.

1. Install LSPatch;
2. Install DuoTimeFaker.apk;
3. Configure the patched Duolingo application in LSPatch and enable the DuoTimeFaker module;
4. Launch Duolingo.

1. Install and enable DuoTimeFaker in LSPosed;
2. Set the module scope to Duolingo (com.duolingo);
3. Force stop and restart Duolingo.

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This repository is published for technical research and educational purposes only. Duolingo is a registered trademark of Duolingo, Inc.