import { type AudioBufferLike } from '../asr/pcm-wav.js';
/** The payload shape returned by MediaRecorderSession. */
export interface RecordedAudioPayload {
    readonly base64: string;
    readonly mimeType: string;
}
export type MediaCaptureBackend = 'local-whisper' | 'cloud-openai';
interface LocalWhisperAudioContext {
    decodeAudioData(audioData: ArrayBuffer): Promise<AudioBufferLike>;
    close(): Promise<void>;
}
export interface LocalWhisperAudioOptions {
    readonly signal?: AbortSignal;
    /** Cloud provider selected for the cloud-openai backend. */
    readonly cloudProvider?: string;
    /** Injectable for tests; production uses AudioContext or webkitAudioContext. */
    readonly createAudioContext?: () => LocalWhisperAudioContext;
}
/**
 * Prepare the MediaRecorder payload for the selected ASR backend.
 * Local Whisper, Tencent Cloud standard recording, Xiaomi MiMo, and Volcano
 * Engine recording-file recognition get browser-decoded PCM WAV; other cloud
 * providers keep the original MediaRecorder codec.
 */
export declare function prepareRecordedAudioForBackend(backend: MediaCaptureBackend, audio: RecordedAudioPayload, options?: LocalWhisperAudioOptions): Promise<RecordedAudioPayload>;
/** Keep the final send guard in one small, directly testable place. */
export declare function isTranscriptionStillCurrent(options: {
    readonly mounted: boolean;
    readonly signal: AbortSignal;
    readonly captureIsCurrent: boolean;
}): boolean;
/**
 * Decode a browser MediaRecorder payload and convert it to mono 16 kHz
 * PCM16 WAV for the Host-side local Whisper runtime.
 */
export declare function normalizeRecordedAudioForLocalWhisper(audio: RecordedAudioPayload, options?: LocalWhisperAudioOptions): Promise<RecordedAudioPayload>;
export {};