mp4檔案的基本組成單元是box，也就是說mp4檔案是由各種各樣的box組成的，有parent box，還有children box。因此，這些boxes之間存在一定的層次關係，總結如下表所示，表中標記出了各個box必選或可選特性，√代表box必選。
ftyp
√ file type and compatibility
pdin
progressive download information
moov
√ container for all the metadata
mvhd
√ movie header, overall declarations
trak
√ container for an individual track or stream
tkhd
√ track header, overall information about the track
tref
track reference container
edts
edit list container
elst
an edit list
mdia
√ container for the media information in a track
mdhd
√ media header, overall information about the media
hdlr
√ handler, declares the media (handler) type
minf
√ media information container
vmhd
video media header, overall information (video track only)
smhd
sound media header, overall information (sound track only)
hmhd
hint media header, overall information (hint track only)
nmhd
null media header, overall information (some tracks only)
dinf
√ data information box, container
dref
√ data reference box, declares source(s) of media data in track
stbl
√ sample table box, container for the time/space map
stsd
√ sample descriptions (codec types, initialization etc.)
stts
√ (decoding) time-to-sample
ctts
(composition) time to sample
stsc
√ sample-to-chunk, partial data-offset
information
stsz
sample sizes (framing)
stz2
compact sample sizes (framing)
stco
√ chunk offset, partial data-offset information
co64
64-bit chunk offset
stss
sync sample table (random access points)
stsh
shadow sync sample table
padb
sample padding bits
stdp
sample degradation priority
sdtp
independent and disposable samples
sbgp
sample-to-group
sgpd
sample group description
subs
sub-sample information
mvex
movie extends box
mehd
movie extends header box
trex
√ track extends defaults
ipmc
ipmp control box
moof
movie fragment
mfhd
√ movie fragment header
traf
track fragment
tfhd
√ track fragment header
trun
track fragment run
sdtp
independent and disposable samples
sbgp
sample-to-group
subs
sub-sample information
mfra
movie fragment random access
tfra
track fragment random access
mfro
√ movie fragment random access offset
mdat
media data container
free
free space
skip
free space
udta
user-data
cprt
meta
metadata
hdlr
√ handler, declares the metadata (handler) type
dinf
data information box, container
dref
data reference box, declares source(s) of metadata items
ipmc
ipmp control box
iloc
item location
ipro
item protection
sinf
protection scheme information box
frma
original format box
imif
ipmp information box
schm
scheme type box
schi
scheme information box
iinf
item information
xmlxml container
bxml
binary xml container
pitm
primary item reference
fiin
file delivery item information
paen
partition entry
fpar
file partition
fecr
fec reservoir
segr
file delivery session group
gitn
group id to name
tsel
track selection
meco
additional metadata container
mere
metabox relation
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