/** The block profile a catalog `fec.blockProfile` may name: the one this library implements. */
export type FecBlockProfile = 'iso-ssbg1-v1';
/** Every accepted `fec.blockProfile` token. */
export declare const FEC_BLOCK_PROFILES: readonly FecBlockProfile[];
/** True for a block-profile token this library implements. */
export declare function isFecBlockProfile(value: unknown): value is FecBlockProfile;
/**
 * Read a required `fec.blockProfile`. Throws on an absent token and on any
 * token other than `iso-ssbg1-v1`: there is no default and nothing is
 * inferred from the wire (draft-ramadan-moq-fec §5.1).
 *
 * @param where the catalog path of the field, for the error message.
 */
export declare function parseFecBlockProfile(value: unknown, where: string): FecBlockProfile;
/** ISO/IEC 23008-1 C.3.3 ssbg_mode1: the two-octet packet length field. */
export declare const SSBG1_LENGTH_FIELD_BYTES = 2;
/** The largest protected packet an ssbg_mode1 symbol of size T can carry. */
export declare function ssbg1MaxPacketLength(symbolSize: number): number;
/** Whether a protected packet of `packetLength` bytes fits one T-byte ssbg_mode1 symbol. */
export declare function ssbg1FitsSymbol(packetLength: number, symbolSize: number): boolean;
/**
 * Build one ssbg_mode1 source symbol (C.3.3): the protected packet's length
 * in two octets, network byte order, then the packet, then zero octets up to
 * T. The protected packet is the MMTP packet before its Source FEC Payload ID
 * is appended (C.4.2).
 *
 * @throws when `length + 2 > T`: the packet cannot be protected under this
 * profile, and silently truncating it would corrupt every repair symbol.
 */
export declare function buildSsbg1SourceSymbol(packet: Uint8Array, symbolSize: number): Uint8Array;
/**
 * Recover the protected packet from one ssbg_mode1 source symbol: the bytes
 * the length field names. Returns null, never a guess, when the length field
 * points past the symbol or any padding octet is non-zero (C.3.3 padding is
 * all 00h), since either means the recovered symbol is not what was sent.
 */
export declare function trimSsbg1SourceSymbol(symbol: Uint8Array): Uint8Array | null;
/** The SS_ID after the last source symbol of `[ssStart, ssStart + ssbLength)`. */
export declare function isoBlockEnd(ssStart: number, ssbLength: number): number;
/**
 * Range membership (C.5.2, C.5.3): whether `ssId` is one of the
 * `ssbLength` consecutive SS_IDs starting at `ssStart`, modulo 2^32.
 */
export declare function isoBlockContains(ssStart: number, ssbLength: number, ssId: number): boolean;
/**
 * A lower bound on how many blocks the block starting at `a` lies behind the
 * one starting at `b` (0 when `a` does not precede `b`). An iso-ssbg1-v1
 * block holds at most `kMax` source symbols (the catalog `sourceSymbols`, the
 * AL-FEC maximum_k_for_repair_flow), so `n * kMax` SS_IDs always span at least
 * `n` blocks. Every interleave horizon in the receiver (decoder retention,
 * worker retirement, ordered-relay settlement) uses this one bound, so the
 * manager's horizon can never fall inside the decoder's.
 */
export declare function isoBlocksBehindLowerBound(a: number, b: number, kMax: number): number;
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