Catalog

A Catalog represents an independent MSF catalog snapshot — the complete description of all tracks available in a broadcast.

Parse and Validate

    catalog, err := msf.ParseCatalog(rawJSON)
    if err != nil {
        // invalid JSON or wrong catalog shape
    }
    if err := catalog.Validate(); err != nil {
        // syntactically valid, but violates MSF rules
    }

ParseCatalog decodes an independent MSF catalog from JSON. Validate checks that the catalog satisfies draft-00 constraints (required fields, unique track identities, etc.).

`msf.Catalog`

type Catalog struct {
    DefaultNamespace string
    Version          int
    GeneratedAt      *int64
    IsComplete       bool
    Tracks           []Track
}

func ParseCatalog(data []byte) (Catalog, error)
func ParseCatalogString(s string) (Catalog, error)
func (c Catalog) Validate() error
func (c Catalog) Clone() Catalog
func (c Catalog) ApplyDelta(delta CatalogDelta) (Catalog, error)

Field	Type	Description
`DefaultNamespace`	`string`	Namespace implied by the catalog track (not serialized in JSON)
`Version`	`int`	MSF version number
`GeneratedAt`	`*int64`	Catalog generation timestamp (optional)
`IsComplete`	`bool`	Whether the catalog is marked as complete
`Tracks`	`[]Track`	Complete set of track descriptions

Track Description

Each track in the catalog is described by an msf.Track:

Field	Type	Description
`Namespace`	`string`	Track namespace (inherited from catalog if empty)
`Name`	`string`	Track name, unique within its namespace
`Packaging`	`Packaging`	Packaging mode (see below)
`Role`	`Role`	Content role: `video`, `audio`, `caption`, etc.
`Codec`	`string`	Codec string (e.g. `"avc1.64001f"`)
`MimeType`	`string`	MIME type for the track’s data payload
`Bitrate`	`*int64`	Bitrate in bps (optional)
`Width`	`*int64`	Video width (optional)
`Height`	`*int64`	Video height (optional)
`Framerate`	`*int64`	Frame rate (optional)
`SampleRate`	`*int64`	Audio sample rate (optional)
`ChannelConfig`	`string`	Audio channel configuration (optional)
`Label`	`string`	Human-readable label (optional)
`Language`	`string`	Language tag (optional)
`Depends`	`[]string`	Track names this track depends on (optional)
`IsLive`	`*bool`	Whether the track is live (optional)
`TargetLatency`	`*int64`	Target latency in milliseconds (optional)
`RenderGroup`	`*int64`	Render group for synchronized playback (optional)
`AltGroup`	`*int64`	Alternate group for quality switching (optional)
`InitData`	`string`	Base64-encoded initialization data (optional)
`TrackDuration`	`*int64`	Duration in milliseconds (optional, not for live)

Many optional fields use pointer types (*int64, *bool) to distinguish “absent” from “zero value”.

Packaging Modes

Constant	Value	Description
`msf.PackagingLOC`	`"loc"`	LOC-packaged media content
`msf.PackagingMediaTimeline`	`"mediatimeline"`	Media timeline track
`msf.PackagingEventTimeline`	`"eventtimeline"`	Event timeline track
`msf.PackagingCMAF`	`"cmaf"`	CMAF-packaged media content
`msf.PackagingLegacy`	`"legacy"`	Legacy timestamp+payload packaging

Roles

Constant	Value	Description
`msf.RoleVideo`	`"video"`	Video track
`msf.RoleAudio`	`"audio"`	Audio track
`msf.RoleAudioDescription`	`"audiodescription"`	Audio description track
`msf.RoleCaption`	`"caption"`	Caption track
`msf.RoleSubtitle`	`"subtitle"`	Subtitle track
`msf.RoleSignLanguage`	`"signlanguage"`	Sign language video track

Validation

Validate() returns *msf.ValidationError containing a list of problems:

    if err := catalog.Validate(); err != nil {
        var ve *msf.ValidationError
        if errors.As(err, &ve) {
            for _, problem := range ve.Problems {
                fmt.Println(problem)
            }
        }
    }

Catalog Delta