Subly (“the app”, “we”) turns speech in your videos into subtitles directly on your device. This policy explains what data the app processes, what never leaves your phone, and the limited technical data shared with third-party services (Google Firebase and Google AdMob).
Contact: andrei.bialiauski@gmail.com
1Summary
Your videos, audio, and subtitle text never leave your device through the app. Speech recognition runs entirely on-device using the open-source whisper.cpp engine. There is no cloud processing, no account, and no sign-in.
- No third-party AI service is used. Every AI feature — speech recognition (the open-source Whisper model, run by whisper.cpp), translation, and the generated title, description, hashtags, summary and “best moment” suggestion — runs on your device. Your video, audio and subtitle text are never sent to OpenAI, Google, Apple or any other AI provider.
- The app connects to the internet only to download speech-recognition models (at your request), to send anonymous usage statistics and crash reports to Google Firebase, and to show ads via Google AdMob. The version from HUAWEI AppGallery uses Huawei services instead and shows no ads (section 6).
- In the European Economic Area and the UK, ads are shown only after you give consent through the Google consent form. If you decline, the app works fully without ads.
2Data processed only on your device
- Videos you pick. Selection happens through the system photo picker, so the app sees only the videos you choose — it has no blanket access to your library.
- Audio extracted from a video for transcription, and the resulting subtitles (text, timings, waveform data, caption style). Transcripts are stored as files in the app’s private storage.
- Downloaded speech-recognition models and your model and language preferences.
- Exported videos with burned-in subtitles — saved to your gallery only when you choose to save them. Subtitle files (SRT/VTT) are created temporarily and only when you share them.
On-device AI features. The app does not use any third-party or cloud AI service. Every AI feature runs locally on your device, and its input (the audio of your video, or the subtitle text) and its output stay there:
- Speech recognition — the open-source Whisper model, run by the whisper.cpp engine inside the app. “Whisper” is only the name of the model; the app does not use OpenAI’s service.
- Translation of subtitles — Apple’s on-device Translation framework on iOS, Google ML Kit on-device translation on Android. Language packs are downloaded by the operating system or ML Kit; the text you translate is not sent anywhere.
- Post text and “best moment” (title, description, hashtags, summary, suggested excerpt) — Apple Intelligence’s on-device Foundation Models on iOS, Gemini Nano via Android AICore on supported Android phones, and a built-in text heuristic everywhere else.
None of this is uploaded anywhere by the app. Deleting the app removes its private data; videos you saved to your gallery remain yours and stay there.
3Model downloads (Hugging Face)
When you download a speech-recognition model, the app fetches it over HTTPS from huggingface.co (Hugging Face, Inc.). As with any internet connection, that service can see standard connection data such as your IP address. The app adds no personal information to these requests. See the Hugging Face privacy policy.
4Usage statistics, crash reports, and performance (Google Firebase)
The app uses Google Analytics for Firebase, Firebase Crashlytics, and Firebase Performance Monitoring, operated by Google LLC. These services collect:
- device model, operating system version, app version, language and country;
- anonymous, app-scoped identifiers generated by Firebase (not your name, email, or phone number — the app never asks for those);
- usage events: which screens are opened, the duration of a picked video, model downloads completing or failing, transcription completing, failing, or being cancelled (with the model name, recognition language, audio length, processing time, and subtitle count), and whether an ad was skipped;
- crash reports and performance traces (app start time, processing durations), including a technical log of the app’s recent steps.
These events and logs contain no video content, no subtitle text, and no file names or paths. Data is processed by Google and may be transferred to servers in the United States. See Google’s privacy policy and Firebase privacy and security. Google retains analytics data for limited periods (user-level Analytics data typically up to 14 months).
5Advertising (Google AdMob)
The app shows banner and interstitial ads through Google AdMob. To serve and measure ads, Google may process your device’s advertising identifier, IP address, and coarse ad-interaction data.
- EEA/UK: before any ad is requested, the app shows Google’s consent form (User Messaging Platform). Ads — personalized or not — are requested only in line with your choices. Without the required consent no ads are shown at all, and every feature of the app keeps working.
- iOS: the App Tracking Transparency prompt is shown when the app first starts, before any ad is requested; Google’s consent form (EEA/UK) follows later, after your first finished video. Apple’s SKAdNetwork is used for privacy-preserving, aggregate ad measurement.
See how Google uses information from apps that use its services and the list of AdMob ad technology providers.
6The AppGallery version (Huawei services)
The version of the app distributed through HUAWEI AppGallery does not use Google Firebase or Google AdMob and shows no ads. Instead of section 4 it uses services operated by Huawei:
- HUAWEI Analytics Kit, AppGallery Connect Crash and APM (performance monitoring) — collect the same kinds of data as described in section 4: device model, operating system version, app version, language and country, an anonymous app-scoped identifier, the same usage events, crash reports and performance traces. As in section 4, these contain no video content, no subtitle text, and no file names or paths.
- HUAWEI Push Kit — a push token is generated so the app can receive occasional notifications about the app (you can mute them per notification channel in system settings).
- HMS Core app update check — the app asks AppGallery whether a newer version is available.
This data is processed in the data center Huawei assigns to your region (Germany, Russia or Singapore). See the HUAWEI Consumer privacy statement.
7Permissions the app requests
Android: internet (model downloads, statistics, ads); notifications (to show transcription progress); foreground service (to finish a transcription if you switch away from the app). The app requests no storage or media permissions — it uses the system photo picker.
iOS: photo library access (to pick a video and to save the result); the tracking permission (used only for ad relevance, governed by the consent flow above).
8Sharing
The app sends your files to other apps only when you explicitly tap share, using the system share sheet. What happens to a file after you hand it to another app is governed by that app’s policy.
9Data retention and deletion
Data on your device stays until you delete it or uninstall the app. Data collected by Google (Firebase, AdMob) is retained under Google’s policies, and data collected by Huawei (section 6) under Huawei’s. To request deletion of analytics or crash data associated with your device, contact us at the address above.
10Children
Subly is not directed at children under 13 (or the equivalent minimum age in your jurisdiction), and we do not knowingly collect personal data from children.
11Your rights
If you are in the EEA, the UK, or another jurisdiction with similar laws, you have the right to access, correct, delete, or object to the processing of your personal data, and to withdraw ad consent at any time. You may also lodge a complaint with your supervisory authority. Legal bases: your consent (personalized advertising); legitimate interest (crash diagnostics, aggregate usage statistics, and app security).
12Changes to this policy
We may update this policy as the app evolves. Material changes will be reflected in a new effective date on this page.
13Contact
Questions about this policy or your data: andrei.bialiauski@gmail.com