Time travelling recorder for Android. Always records in the background; go back in time and save any moment you missed.
Free/libre software under the GPL v3.
A fork of Echo by Marek Rogalski (mafik), with Opus encoding, compressed in-memory history, and UI refinements.
- Always-listening — a foreground microphone service continuously records audio, keeping a rolling history in memory
- Go back in time — use the scroll wheel to pick any moment within the buffered history and save it
- Compressed memory — audio is encoded to Opus (~60 B per 20 ms frame) before storage, giving you hours of history even on modest hardware
- Clean save — saved files are
.opusOgg containers, no re-encoding needed (frames are written directly to the file) - Configurable memory — set how much RAM to reserve for audio history in Settings
- No ads, no tracking, no Google Play — fully free software, ready for F-Droid distribution
SaidItFragment — the main view. Contains the scroll-wheel time picker, listen/stop/save buttons, and the memory-limit indicator. Displays the buffered duration and maximum capacity.
SaidItService — foreground service managing the audio pipeline. Runs a dedicated thread that reads PCM from AudioRecord, encodes it to Opus frames, stores them in the ring buffer, and writes them to the active save file if recording. Accessible via Handler (tasks sent to audioHandler).
OpusRingBuffer — pre-allocated circular array of byte[] frames. allocate(capacity) computes the number of frames from a byte budget using AVG_FRAME_BUDGET = 92 (60 B compressed frame + 32 B overhead). store() adds a compressed frame, read(skipFrames, consumer) passes frames sequentially to an OpusFileWriter.
OpusFileWriter — combines a Concentus OpusEncoder with Ogg container logic (page headers, CRC32, EOS). writeFrame() accepts pre-compressed Opus packets and wraps them in Ogg pages. On save, frames from OpusRingBuffer are fed directly to writeFrame() — zero re-encoding.
SettingsActivity — memory configuration via an EditText (value in MB, percentage shown relative to available heap). No quality selector (always 48 kHz).
| Area | Original Echo | good-echo |
|---|---|---|
| Codec | WAV (uncompressed PCM) | Opus in Ogg container |
| Memory storage | Raw PCM short[] chunks |
Compressed byte[] Opus frames (~60 B/frame) |
| Save path | Re-encodes from PCM to WAV | Writes compressed frames directly |
| Quality selector | 8/16/48 kHz radio buttons | Always 48 kHz (Opus handles quality internally) |
| Memory control | SeekBar (0–100 %) | EditText (MB input, shows percentage) |
| Time display | mm:ss | dd:hh:mm:ss (days/hours for long sessions) |
| Package | eu.mrogalski.saidit |
com.goodecho.app |
| Billing | Google Play in-app purchases | Removed entirely |
| Distributions | Google Play | F-Droid |
Requires JDK 17 and the Android SDK.
export ANDROID_HOME=/path/to/sdk
./gradlew assembleDebugThe APK will be at SaidIt/build/outputs/apk/debug/SaidIt-debug.apk.
Recording laws vary by jurisdiction. You are solely responsible for ensuring that your use of this app complies with all applicable laws in your area. The developers and contributors assume no liability for any misuse.
Copyright 2014 Marek Rogalski Copyright 2026 good-echo contributors
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.