import type { WakeInferenceSession, WakeTensor } from './types.js';
/** Samples per detector frame: 80 ms at 16 kHz. */
export declare const WAKE_CHUNK_SAMPLES = 1280;
/** Milliseconds of audio per detector frame. */
export declare const WAKE_CHUNK_MS: number;
/** Mel frames the embedding backbone consumes per inference. */
export declare const WAKE_EMBED_WINDOW_FRAMES = 76;
/** Dimensions the embedding backbone emits per inference. */
export declare const WAKE_EMBED_DIM = 96;
/** Embedding frames the classifier consumes. */
export declare const WAKE_CLASSIFIER_FRAMES = 16;
/**
 * Extra trailing samples handed to the front end with each chunk, so framing
 * yields exactly `chunk / hop` new mel frames. Three hops.
 */
export declare const WAKE_MEL_CONTEXT_SAMPLES: number;
/** How much raw audio the pipeline keeps for pre-roll, in seconds. */
export declare const WAKE_RAW_TAIL_SECONDS = 4;
export interface FeaturePipelineOptions {
    /** The speech-embedding backbone session. */
    readonly embedding: WakeInferenceSession;
    /** Chunk size in samples. Must be a whole number of 160-sample hops. */
    readonly chunkSamples?: number | undefined;
}
/**
 * Streaming front end. One instance per audio stream; not safe to share across
 * concurrent streams because every buffer in it is stateful.
 */
export declare class WakeFeaturePipeline {
    #private;
    constructor(options: FeaturePipelineOptions);
    /** Samples this pipeline expects per {@link pushChunk} call. */
    get chunkSamples(): number;
    /** True once enough frames have accumulated to produce classifier features. */
    get ready(): boolean;
    /**
     * Return to the cold-start state: mel buffer primed with ones, no features,
     * no raw tail. Called on construction and whenever a stream restarts, so a
     * restarted detector cannot inherit half a phrase from before the crash.
     */
    reset(): void;
    /**
     * Feed exactly {@link chunkSamples} samples of 16 kHz mono audio, as raw int16
     * magnitudes expressed as floats (NOT normalised to [-1, 1], see
     * melspectrogram.ts).
     *
     * Returns the trailing 16 x 96 feature window as a flat tensor, or null while
     * the pipeline is still filling. Callers must not retain the returned tensor's
     * data across calls; it is reused.
     */
    pushChunk(samples: Float32Array): Promise<WakeTensor | null>;
    /**
     * The most recent `ms` milliseconds of raw audio, for a detection's pre-roll.
     * Returns whatever is available when less has been seen, never pads.
     */
    recentAudio(ms: number): Float32Array;
}
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