[DEV] I built an Android app that runs Whisper Base Q8 fully offline, handling long audio chunking on devices down to 2GB RAM. No data leaves your phone.

Hey everyone,

https://preview.redd.it/8614i1pfht7h1.jpg?width=1080&format=pjpg&auto=webp&s=cd314472f90beecc17b4cbe432af47ae6f4469e0

As an Android developer, I’ve always been frustrated by how speech-to-text apps rely heavily on cloud APIs, compromising privacy and requiring active internet connections. I wanted to build a solution that runs **100% locally on the device**.

However, running heavy models like OpenAI's Whisper and Silero VAD locally on budget Android hardware comes with massive memory bottlenecks and unexpected crashes.

To fix this, I built **Transcribe Offline**. Instead of defaulting to Whisper Tiny (which has terrible accuracy), I managed to optimize **Whisper Base Q8** to run smoothly even on **2GB RAM devices** using a few engineering workarounds:

* **Semantic Chunking via Silero VAD:** Instead of blindly cutting audio into fixed time slots (which cuts through words and ruins the context), the app uses local Silero VAD to detect natural human speech boundaries. I added a **negative 200ms offset** to ensure the start of sentences is never chopped off.
* **Flat Memory Footprint:** Audio chunks are processed sequentially and instantly cleared from memory, meaning the app handles a 2-hour recording with the same flat memory usage as a 2-minute clip. No Out-Of-Memory (OOM) crashes.
* **Native C++ Performance:** Core engines are compiled via Android NDK/JNI to leverage hardware acceleration and keep the main UI thread completely fluid.

The app is completely private, requires zero permissions other than reading your local files, and outputs clean text or standard `.srt` subtitles with precise timestamps.

If you are interested in the engineering details, I wrote a quick deep dive on Medium about how I overcame the memory and text-cutting limitations: 🔗[Read the Engineering Deep Dive on Medium](https://medium.com/@creazyheart92/how-i-optimized-on-device-ai-audio-transcription-for-low-end-android-devices-down-to-2gb-ram-49f1a3847337)

The app is live on the Play Store, and I would absolutely love your honest feedback, feature requests, or any questions about the on-device pipeline!

👉[**Get Transcribe Offline on Google Play**](https://play.google.com/store/apps/details?id=egyption.developer.transcribe)

https://redd.it/1u861fk
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