/**
 * Cross-environment base64 helpers for `Uint8Array` payloads.
 *
 * @module
 *
 * @remarks
 * Used by {@link @nhtio/adk!Media}'s `asBase64()` and by the in-memory reader handle path
 * (`describe()`/resolver), which inlines its buffer as base64 because it owns no external locator. Both
 * directions prefer Node's `Buffer` when present and fall back to `btoa`/`atob` with a chunked window so
 * large buffers do not overflow the call stack.
 */
/**
 * Encode a `Uint8Array` as a base64 string.
 *
 * @remarks
 * Prefers `Buffer.from(bytes).toString('base64')` when `globalThis.Buffer` exists; otherwise
 * chunk-encodes through `btoa` with a `0x8000`-byte window to avoid `Maximum call stack size exceeded`
 * on large buffers.
 *
 * @param bytes - The buffer to encode.
 * @returns The base64 representation.
 */
export declare const encodeBase64: (bytes: Uint8Array) => string;
/**
 * Decode a base64 string back into a `Uint8Array`.
 *
 * @remarks
 * Inverse of {@link encodeBase64}. Prefers `Buffer.from(b64, 'base64')` when `globalThis.Buffer` exists;
 * otherwise decodes through `atob` byte-by-byte.
 *
 * @param b64 - The base64 string to decode.
 * @returns The decoded bytes.
 */
export declare const decodeBase64: (b64: string) => Uint8Array;