On native, importing anything but WAV failed with "Only WAV is supported
on native" — ffmpeg-kit-react-native was retired in 2025 and a real
decoder was left as a follow-up. Since in-app recording is web-only, the
native app's only way to add audio is importing a phone recording — which
is m4a/aac — so transcription was effectively broken on the APK.
Add react-native-audio-api (Software Mansion, maintained) and route
non-WAV files through its standalone decodeAudioData(ArrayBuffer), which
uses platform codecs + bundled FFmpeg. WAV keeps its pure-JS fast path.
The decoded channels go through the existing toMono16k, mirroring the web
AudioContext.decodeAudioData path exactly. Bytes are read locally and
passed as an ArrayBuffer, so it doesn't matter whether the picker yields
file:// or content://. WAV is now sniffed by RIFF/WAVE content, not just
the extension.
The lib's config plugin is intentionally NOT enabled: it only sets up
playback (background audio mode, a media-playback foreground service, mic
permission), none of which decoding needs — and adding those would
contradict the app's on-device/no-extra-permissions stance.
Validated locally (arm64 Docker build): react-native-audio-api compiles
and autolinks against RN 0.85 / new arch; the arm64-v8a APK ships
libreact-native-audio-api.so + libav{codec,format,util}/libswresample.so
+ liboboe.so (48MB -> 58MB). tsc clean, 279 tests pass, web export does
NOT bundle the native dep. Runtime decode still needs an on-device check.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
NilsBriggen
7aa8b05971