Introduce optional Apple account-backed credits with scoped gateway access while preserving local and BYOK paths. Refresh assistant behavior, tests, privacy disclosures, docs, and the website for the 2.0 experience.
The keyboard preview crashed on first record with a
`__abort_with_payload` deep inside Speech's
`DictationTranscriber`. The disassembly surfaced three
preconditions checked before a `brk #0x1`:
+620 "Audio sample data must be 16-bit signed integers"
+848 "Multi-channel audio is not supported"
+1072 "Client info not fully initialized"
We hit the first one. `DictationTranscriber` (iOS 26's new
`SpeechAnalyzer`-backed engine) is strict about its input
format: only Int16 PCM, not the Float32 PCM that the iOS 18
`SFSpeechRecognizer` path accepted. Our audio-tap and
`AudioBufferSnapshot.samples: [Float]` are Float32 all the
way down — that was the SFSpeech shape, and the previous
`AppleSpeechASR` adapted internally. With iOS 26 as the
deployment target, the only ASR backend is
`SpeechAnalyzerASR`, and the conversion needed to happen at
the `AnalyzerInput` boundary.
Fix:
- `transcribe` builds the `AVAudioFormat` as
`.pcmFormatInt16, 16 kHz, 1 ch, interleaved: true` (the
canonical layout for Int16 Speech input).
- `makeInputStream` runs the per-sample conversion
`Int16(round(clamp(s * 32767, -32768, 32767)))` into the
`AVAudioPCMBuffer`'s `int16ChannelData[0]`. The explicit
clip is required (a `s == 1.5` from a gain-overflow at the
audio-engine boundary would otherwise wrap to a negative
Int16 after the implicit truncation). `round()` (not
truncate) preserves DC balance — `0.5` quantises to
`+16384`, not `+16383`, matching what audio DAWs expect.
- The conversion helper is exposed as
`ASRServiceFactory.convertFloat32ToInt16` so unit tests
can lock the math without instantiating the full pipeline.
Why not change `AudioBufferSnapshot` to `[Int16]` instead
(see earlier first-principles discussion): the snapshot is a
transport format that both `AudioCaptureService` (in the
ext) and `PreviewASRController` (in the main app) produce.
Float32 is the natural shape coming out of `AVAudioEngine`,
and pushing the conversion to the ASR service keeps the
transport contract platform-agnostic — a future second
backend with different format needs can have its own
adaptation without dragging everyone else.
Tests:
- `testFloat32ToInt16EdgeCases` — 0, ±1, ±0.5, ±1.5
(gain-overflow case).
- `testFloat32ToInt16RoundTrip` — quantisation step is
1/32767 (so the asymmetric Int16 range is honoured: -32768
has no exact Float source).
- `testFloat32ToInt16Empty` — `sourceCount == 0` with nil
pointers is a no-op (function guards on count before
dereferencing).
- All 25 tests pass (22 existing + 3 new).
- BUILD SUCCEEDED.
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