fix: downmix multi-channel audio to mono for SFSpeechRecognizer#32
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chrishutchins wants to merge 1 commit intof:masterfrom
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fix: downmix multi-channel audio to mono for SFSpeechRecognizer#32chrishutchins wants to merge 1 commit intof:masterfrom
chrishutchins wants to merge 1 commit intof:masterfrom
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SFSpeechRecognizer silently returns no results when receiving multi-channel audio buffers. USB audio interfaces like the RODECaster Pro II send 2-channel 48kHz audio, and the previous `format: nil` tap delivered these buffers unchanged to the recognition request. Create a mono AVAudioFormat at the hardware sample rate when the device has more than one channel and pass it to installTap, letting AVAudioEngine handle the downmix automatically. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Summary
Problem:
SFSpeechRecognizersilently returns no results when receiving multi-channel audio buffers. USB audio interfaces like the RODECaster Pro II send 2-channel 48kHz audio, and the previousformat: niltap delivered these buffers unchanged to the recognition request. The waveform visualization works fine (it only reads channel 0), but the recognizer never fires its result callback.Fix: When the input device has more than one channel, create a mono
AVAudioFormatat the hardware sample rate and pass it toinstallTap.AVAudioEnginehandles the downmix automatically. Single-channel devices (e.g. built-in mic) are unaffected.Test plan
🤖 Generated with Claude Code