Soundify

Soundify 0.4.0

A free, offline, ad-free Android stem mixer and Clean Video music remover.

Clean Video

• Chunk scheduling fixed. Files whose final chunk was longer than the 5 s hop scheduled one more chunk without an overlap tail and failed with missing overlap tail. 5 of the 37 test clips hit it. The chunk plan is now built up front and stops at the final range, so every duration completes.
• Separation runs at the model's trained input level again. The MRX encoder's BatchNorm statistics come from audio normalised to -27 LUFS. Since 0.3.0 the app separated at native level, which put phone audio roughly 13 dB outside that range. Each file is now measured once, scaled to -27 LUFS for inference, and the stems are divided by the same gain afterwards. The clean mix is still matched to -16 LUFS / -1.5 dBTP.
• Measured effect: on the 33 completed clips of the test corpus, voice levels stayed within ±0.5 dB while the music stem became 2–4 dB more prominent on most music-heavy clips. The separation quality ceiling of the bundled model is unchanged; a checkpoint bake-off is still planned.
• Residual assignment is implemented (PASS / MUSIC / MUSIC_SFX) but left off until it is measured on real clips.
• History. Finished runs are stored under Soundify's Clean Video folder with a source fingerprint, name, duration, stems and size. Selecting a video that was already cleaned offers the existing result instead of separating it again. Results can be reopened, saved, deleted or cleared from the history screen.
• In-app storage. Settings and the history screen show a byte breakdown (projects, Clean Video results, temporary files, app and model) and a Free up space action. It removes temporary files and Clean Video results; projects and files saved through the system picker are kept.

Themes

Unchanged from 0.3.0: System, Light, Dark, AMOLED; Mint, Blue, Violet and Amber accents.

Tests

• 69 JVM tests.
• 21 instrumented tests on an API 35 emulator.
• 0 failures.

Assets

• Soundify-0.4.0.apk — debug-signed release APK, versionCode 4, versionName 0.4.0.
• mrx_mask.onnx — 117 MB MERL MRX separation model for source builds.
• SHA256SUMS.txt — checksums for both assets.

Known limitations

• Separation quality depends on the mix. Music with vocals, heavy compression or loud effects can still bleed between stems; the bundled MRX model is the limiting factor.
• A 20-minute video still takes roughly 25–30 minutes on the tested phone.
• The APK is debug-signed (personal build). Future releases must keep the same signing key to update in place.
• Stem Mixer requires all stems in a project to share the same sample rate.
• MP3/AAC stems may need a manual offset because of encoder delay.
• The source video is needed to save a video from a history entry. If the original URI is no longer readable, audio saving still works.