/**
 * The Xing/Info header, and why an MP3 needs one.
 *
 * A Layer III stream has no container and no header describing the whole file.
 * Duration has to be guessed from the bitrate, seeking has to be guessed from
 * byte position, and — the part that is actually audible — there is no way to
 * say where the audio really starts and stops.
 *
 * That last one matters because MP3 cannot represent an arbitrary number of
 * samples. Frames hold exactly 1152 each, so any real recording gets padded to
 * the next frame boundary, and every encoder's filterbank prepends silence
 * before the first sample emerges. Decoded naively, a file gains silence at both
 * ends. Play two such files back to back and the join is audible: this is the
 * gap in "gapless".
 *
 * The fix is a convention rather than a standard: a first frame that codes no
 * audio and instead carries a tag with the frame count, the byte count, and the
 * exact number of samples to drop from each end. Decoders that recognise it skip
 * the frame entirely; decoders that do not simply decode 1152 samples of silence
 * and are none the worse.
 *
 * ## Naming the encoder honestly
 *
 * The delay and padding fields live in the "LAME tag" extension, and decoders
 * gate on the 9-byte encoder string that precedes them — many accept only
 * `LAME`, `Lavc` or `Lavf`. Writing one of those would buy wider gapless support
 * by claiming to be software this is not, so this writes `audiobox`. The cost is
 * real and worth stating plainly: decoders that check the name against a
 * whitelist will ignore our delay and padding and decode a fraction of a second
 * of extra silence at each end. The audio itself is unaffected, and audiobox
 * reads its own tag, so `decode(encode(x))` is sample-exact.
 */
import type { ChannelMode } from './frame.js';
/** The 9-byte encoder string. Exactly 9 bytes, space-padded. */
export declare const ENCODER_STRING = "audiobox ";
export interface InfoTagParameters {
    bitrateKbps: number;
    sampleRate: number;
    channels: number;
    mode: ChannelMode;
    modeExtension: number;
    /** Audio frames that follow, not counting this one. */
    frameCount: number;
    /** Total stream length in bytes, including this frame. */
    streamBytes: number;
    /** Samples of priming silence before the first real sample. */
    encoderDelay: number;
    /** Samples of silence after the last real sample. */
    encoderPadding: number;
    /** Variable bitrate: tag as `Xing` and carry a seek table. */
    vbr?: boolean;
    /** The assembled audio frames, needed to build the seek table. */
    frames?: Uint8Array;
    /** Size of this tag frame, since it precedes `frames` in the stream. */
    tagBytes?: number;
}
/**
 * Builds the complete leading frame, header and tag together.
 *
 * `Info` rather than `Xing` because the stream is constant-bitrate; the two are
 * the same structure, and the name is how a decoder tells CBR from VBR without
 * scanning. No seek table: it only helps VBR, where byte position and time are
 * not proportional.
 */
export declare function writeInfoTag(params: InfoTagParameters): Uint8Array;
/** Bytes the tag frame occupies, so the caller can size the stream first. */
export declare function infoTagFrameLength(bitrateKbps: number, sampleRate: number, channels: number, vbr?: boolean): number;