supervision-js
    Preparing search index...

    Interface MediaSessionMediaState

    Prepared media state visible to host applications.

    interface MediaSessionMediaState {
        inputMetadata: MediaNormalizationInputMetadata | null;
        normalizedMedia: NormalizedMedia | ProgressiveNormalizedMedia | null;
        objectUrl: string | null;
        preparation?: MediaSessionMediaPreparation | null;
    }
    Index
    inputMetadata: MediaNormalizationInputMetadata | null
    objectUrl: string | null
    preparation?: MediaSessionMediaPreparation | null

    Null until the session has prepared its media.

    Optional so a host holding a state it built before this field existed still satisfies the type.