mp4

var (
	// Standard iTunes metadata atoms.
	AtomTitle     = [4]byte{0xA9, 'n', 'a', 'm'} // ©nam - Title
	AtomArtist    = [4]byte{0xA9, 'A', 'R', 'T'} // ©ART - Artist (author)
	AtomAlbum     = [4]byte{0xA9, 'a', 'l', 'b'} // ©alb - Album
	AtomComposer  = [4]byte{0xA9, 'c', 'm', 'p'} // ©cmp - Composer (narrator for audiobooks)
	AtomNarrator  = [4]byte{0xA9, 'n', 'r', 't'} // ©nrt - Narrator (dedicated audiobook narrator atom)
	AtomGenre     = [4]byte{0xA9, 'g', 'e', 'n'} // ©gen - Genre (custom text)
	AtomWriter    = [4]byte{0xA9, 'w', 'r', 't'} // ©wrt - Writer
	AtomComment   = [4]byte{0xA9, 'c', 'm', 't'} // ©cmt - Comment
	AtomYear      = [4]byte{0xA9, 'd', 'a', 'y'} // ©day - Year/Date
	AtomGrouping  = [4]byte{0xA9, 'g', 'r', 'p'} // ©grp - Grouping
	AtomCopyright = [4]byte{0xA9, 'c', 'p', 'y'} // ©cpy - Copyright
	AtomEncoder   = [4]byte{0xA9, 't', 'o', 'o'} // ©too - Encoder/Encoding tool
	AtomPublisher = [4]byte{0xA9, 'p', 'u', 'b'} // ©pub - Publisher

	// Non-copyright atoms (standard ASCII).
	AtomReleaseDate = [4]byte{'r', 'l', 'd', 't'} // rldt - Release date (Audible)
	AtomCover       = [4]byte{'c', 'o', 'v', 'r'} // covr - Cover artwork
	AtomGenreID     = [4]byte{'g', 'n', 'r', 'e'} // gnre - Genre ID (ID3v1 index)
	AtomMediaType   = [4]byte{'s', 't', 'i', 'k'} // stik - Media type (2 = audiobook)
	AtomDescription = [4]byte{'d', 'e', 's', 'c'} // desc - Description
	AtomFreeform    = [4]byte{'-', '-', '-', '-'} // ---- - Freeform/custom atom
)

var (
	BoxTypeMoov = gomp4.BoxTypeMoov()        // moov - Movie box
	BoxTypeUdta = gomp4.BoxTypeUdta()        // udta - User data box
	BoxTypeMeta = gomp4.BoxTypeMeta()        // meta - Metadata box
	BoxTypeIlst = gomp4.BoxTypeIlst()        // ilst - Item list box
	BoxTypeData = gomp4.BoxTypeData()        // data - Data box
	BoxTypeMvhd = gomp4.BoxTypeMvhd()        // mvhd - Movie header
	BoxTypeTrak = gomp4.BoxTypeTrak()        // trak - Track box
	BoxTypeHdlr = gomp4.BoxTypeHdlr()        // hdlr - Handler box
	BoxTypeMdia = gomp4.BoxTypeMdia()        // mdia - Media box
	BoxTypeMinf = gomp4.BoxTypeMinf()        // minf - Media information box
	BoxTypeStbl = gomp4.BoxTypeStbl()        // stbl - Sample table box
	BoxTypeStsd = gomp4.BoxTypeStsd()        // stsd - Sample description box
	BoxTypeMp4a = gomp4.BoxTypeMp4a()        // mp4a - MPEG-4 audio
	BoxTypeEsds = gomp4.BoxTypeEsds()        // esds - Elementary stream descriptor
	BoxTypeEc3  = gomp4.StrToBoxType("ec-3") // ec-3 - E-AC-3 (Dolby Digital Plus)
	BoxTypeDec3 = gomp4.StrToBoxType("dec3") // dec3 - E-AC-3 specific box
	BoxTypeAc3  = gomp4.StrToBoxType("ac-3") // ac-3 - AC-3 (Dolby Digital)
	BoxTypeDac3 = gomp4.StrToBoxType("dac3") // dac3 - AC-3 specific box
	BoxTypeAlac = gomp4.StrToBoxType("alac") // alac - Apple Lossless
	BoxTypeChpl = gomp4.StrToBoxType("chpl") // chpl - Chapter list (Nero)
	BoxTypeTref = gomp4.StrToBoxType("tref") // tref - Track reference
	BoxTypeChap = gomp4.StrToBoxType("chap") // chap - Chapter reference
)

var (
	// ErrNotMP4 is returned when the file is not a valid MP4/M4B file.
	ErrNotMP4 = errors.New("not a valid MP4/M4B file")

	// ErrNoMetadata is returned when the file has no metadata.
	ErrNoMetadata = errors.New("no metadata found")

	// ErrInvalidBox is returned when a box structure is invalid.
	ErrInvalidBox = errors.New("invalid box structure")
)