/** The catalog media roles that carry hang renditions. */
export type CatalogFecRole = 'video' | 'audio';
/** One media source's `fec` block, as `locateCatalogFecSource` found it. */
export type CatalogFecSource = {
    readonly dialect: 'hang';
    readonly role: CatalogFecRole;
    /** The rendition object. */
    readonly entry: Record<string, unknown>;
    /** The rendition's `fec` value, unvalidated (may be undefined). */
    readonly fec: unknown;
    /** JSON path of that `fec` block. */
    readonly fecPath: string;
} | {
    readonly dialect: 'msf';
    /** Index of the entry in `tracks[]`. */
    readonly index: number;
    /** The `tracks[]` entry (an empty object when the entry is not an object). */
    readonly entry: Record<string, unknown>;
    /** The entry's `fec` value, unvalidated (may be undefined). */
    readonly fec: unknown;
    /** JSON path of that `fec` block. */
    readonly fecPath: string;
};
/**
 * Locate the catalog entry that declares one media source's `fec` block, in
 * either catalog dialect.
 *
 * A hang `video`/`audio` rendition named `source` wins, in `roles` order, over
 * a `tracks[]` entry of the same name: when a catalog carries rendition blocks
 * beside a `tracks[]` switching-set index (the unified ABR ladder catalog),
 * the rendition blocks are authoritative, exactly as they are for hang's own
 * catalog decode. The precedence is keyed on the rendition EXISTING as an
 * object, not on it carrying `fec`: a rendition without `fec` locates with
 * `fec: undefined` and never falls through to `tracks[]`.
 *
 * Otherwise the first `tracks[]` entry named `source` locates. Returns
 * undefined when neither dialect names it, or when `catalog` is not an object.
 *
 * @param roles the hang roles to search, in order (both by default). A typed
 *   track reference passes its own role only.
 */
export declare function locateCatalogFecSource(catalog: unknown, source: string, roles?: readonly CatalogFecRole[]): CatalogFecSource | undefined;
/**
 * Whether an `iso-ssbg1-v1` block's optional `interleaveDepthMs` span is
 * usable: absent, or a non-negative safe integer. Zero or absence supplies no
 * elapsed deadline and still permits in-band FEC. True for every block that
 * names another profile (the span is not read) and for a non-object.
 */
export declare function isoBlockSpanUsable(fec: unknown): boolean;
/**
 * Whether one catalog `fec` block leaves its FEC available
 * (draft-ramadan-moq-fec §5.1): the decision the container's
 * `catalogFecUnavailable` explains with a typed reason.
 *
 * False when the block declares an FEC instance (any `algorithm` but `"none"`)
 * and names no implemented `blockProfile` (the retired `k-padded-v1`
 * included), or carries an `iso-ssbg1-v1` span it cannot use; and when a block
 * declaring no FEC instance carries a profile token that is not implemented.
 * True for a non-object and for every other block. It reads only the profile
 * and the span: malformed geometry (`sourceSymbols`, `symbolSize`) is
 * `catalogFecDeclaresUnconfigurableInstance`'s.
 *
 * A receiver applies no FEC to a source whose block is unavailable and joins
 * none of its repair tracks, without failing the session.
 */
export declare function catalogFecAvailable(fec: unknown): boolean;
/**
 * Whether a source's `fec` block declares an FEC instance (any `algorithm`
 * but `"none"`) whose `sourceSymbols` or `symbolSize` is not a positive
 * integer. Geometry a decoder cannot configure is a malformed catalog, not
 * "no FEC": the container's per-track resolver throws `track_fec` for exactly
 * this block, whatever its profile or span.
 */
export declare function catalogFecDeclaresUnconfigurableInstance(fec: unknown): boolean;
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