如何让AVAudioEngine从Mic输出PCM-16？

Question

我正在使用return realm.where(Conversation.class) .equalTo("id",conversationId) .findFirstAsync() // maybe use findAllAsync instead? .asFlowable() .filter(RealmResults::isLoaded) .switchMap(conversation -> conversation.getMessages().where().findAllSortedAsync("receivedDate", Sort.DESCENDING) .asFlowable() .filter(RealmResults::isLoaded)); 而我正试图以16000Hz输出AVAudioEngine，但我似乎无法让它工作。这就是我正在做的事情：

.pcmFormatInt16

如上所述，当我访问缓冲区时，它总是全0，静默。

Answer 1

AVAudioEngine不支持更改采样率。 您可以使用AVAudioConverter来更改样本率

let inputFormat = input.outputFormat(forBus: 0)
let recordingFormat = AVAudioFormat(commonFormat: .pcmFormatInt16, sampleRate: 16000.0, channels: 1, interleaved: true)
converter = AVAudioConverter(from: inputFormat, to: recordingFormat)

mixer.installTap(onBus: 0, bufferSize: 2048, format: inputFormat) { [weak self] (buffer, _) in
    let convertedBuffer = self?.converter.convertBuffer(additionalBuffer: buffer)
}