【多媒体封装格式详解】---MP4【1】

MP4(MPEG-4 Part 14)是一种常见的多媒体容器格式，它是在“ISO/IEC 14496-14”标准文件中定义的。1.最小组成单元 BOX像FLV的tag、MKV的EBML、ASF文件中的 ASF object.mp4 是由一系列的box组成，他的最小组成单元就是box.size;指明了整个box所占用的大小，包括header部分.type;表示

tx3344

10782人浏览 · 2013-01-07 10:54:08

tx3344 · 2013-01-07 10:54:08 发布

MP4(MPEG-4 Part 14)是一种常见的多媒体容器格式，它是在“ISO/IEC 14496-14”标准文件中定义的。

1.最小组成单元 BOX

像FLV的tag、MKV的EBML、ASF文件中的 ASF object.mp4 是由一系列的box组成，他的最小组成单元就是box.

size;指明了整个box所占用的大小，包括header部分.

type;表示这个box的类型。(附表1)

largesize;如果box很大超过了uint32的最大数值，size就被设置为1，并用接下来的 largesize来存放大小。

2.mp4文件整体结构

mp4文件说白了就是一系列box组成，大box里面有小box。

接下来会深入到具体的box里面，来具体分析mp4格式

未完待续.....

附表1

Code	Abstract	Defined in/by
ainf	Asset information to identify, license and play	DECE
albm	Album title and track number (user-data)	3GPP
auth	Media author name (user-data)	3GPP
avcn	AVC NAL Unit Storage Box	DECE
bloc	Base location and purchase location for license acquisition	DECE
bpcc	Bits per component	JP2
buff	Buffering information	AVC
bxml	binary XML container	ISO
ccid	OMA DRM Content ID	OMA DRM 2.1
cdef	type and ordering of the components within the codestream	JP2
clsf	Media classification (user-data)	3GPP
cmap	mapping between a palette and codestream components	JP2
co64	64-bit chunk offset	ISO
colr	specifies the colourspace of the image	JP2
cprt	copyright etc. (user-data)	ISO
crhd	reserved for ClockReferenceStream header	MP4V1
cslg	composition to decode timeline mapping	ISO
ctts	(composition) time to sample	ISO
cvru	OMA DRM Cover URI	OMA DRM 2.1
dcfD	Marlin DCF Duration, user-data atom type	OMArlin
dinf	data information box, container	ISO
dref	data reference box, declares source(s) of media data in track	ISO
dscp	Media description (user-data)	3GPP
dsgd	DVB Sample Group Description Box	DVB
dstg	DVB Sample to Group Box	DVB
edts	edit list container	ISO
elst	an edit list	ISO
feci	FEC Informatiom	ISO
fecr	FEC Reservoir	ISO
fiin	FD Item Information	ISO
fire	File Reservoir	ISO
fpar	File Partition	ISO
free	free space	ISO
frma	original format box	ISO
ftyp	file type and compatibility	JP2, ISO
gitn	Group ID to name	ISO
gnre	Media genre (user-data)	3GPP
grpi	OMA DRM Group ID	OMA DRM 2.0
hdlr	handler, declares the media (handler) type	ISO
hmhd	hint media header, overall information (hint track only)	ISO
hpix	Hipix Rich Picture (user-data or meta-data)	HIPIX
icnu	OMA DRM Icon URI	OMA DRM 2.0
ID32	ID3 version 2 container	inline
idat	Item data	ISO
ihdr	Image Header	JP2
iinf	item information	ISO
iloc	item location	ISO
imif	IPMP Information box	ISO
infu	OMA DRM Info URL	OMA DRM 2.0
iods	Object Descriptor container box	MP4V1
iphd	reserved for IPMP Stream header	MP4V1
ipmc	IPMP Control Box	ISO
ipro	item protection	ISO
iref	Item reference	ISO
jP$20$20	JPEG 2000 Signature	JP2
jp2c	JPEG 2000 contiguous codestream	JP2
jp2h	Header	JP2
jp2i	intellectual property information	JP2
kywd	Media keywords (user-data)	3GPP
loci	Media location information (user-data)	3GPP
lrcu	OMA DRM Lyrics URI	OMA DRM 2.1
m7hd	reserved for MPEG7Stream header	MP4V1
mdat	media data container	ISO
mdhd	media header, overall information about the media	ISO
mdia	container for the media information in a track	ISO
mdri	Mutable DRM information	OMA DRM 2.0
meco	additional metadata container	ISO
mehd	movie extends header box	ISO
mere	metabox relation	ISO
meta	Metadata container	ISO
mfhd	movie fragment header	ISO
mfra	Movie fragment random access	ISO
mfro	Movie fragment random access offset	ISO
minf	media information container	ISO
mjhd	reserved for MPEG-J Stream header	MP4V1
moof	movie fragment	ISO
moov	container for all the meta-data	ISO
mvcg	Multiview group	AVC
mvci	Multiview Information	AVC
mvex	movie extends box	ISO
mvhd	movie header, overall declarations	ISO
mvra	Multiview Relation Attribute	AVC
nmhd	Null media header, overall information (some tracks only)	ISO
ochd	reserved for ObjectContentInfoStream header	MP4V1
odaf	OMA DRM Access Unit Format	OMA DRM 2.0
odda	OMA DRM Content Object	OMA DRM 2.0
odhd	reserved for ObjectDescriptorStream header	MP4V1
odhe	OMA DRM Discrete Media Headers	OMA DRM 2.0
odrb	OMA DRM Rights Object	OMA DRM 2.0
odrm	OMA DRM Container	OMA DRM 2.0
odtt	OMA DRM Transaction Tracking	OMA DRM 2.0
ohdr	OMA DRM Common headers	OMA DRM 2.0
padb	sample padding bits	ISO
paen	Partition Entry	ISO
pclr	palette which maps a single component in index space to a multiple- component image	JP2
pdin	Progressive download information	ISO
perf	Media performer name (user-data)	3GPP
pitm	primary item reference	ISO
res$20	grid resolution	JP2
resc	grid resolution at which the image was captured	JP2
resd	default grid resolution at which the image should be displayed	JP2
rtng	Media rating (user-data)	3GPP
sbgp	Sample to Group box	AVC, ISO
schi	scheme information box	ISO
schm	scheme type box	ISO
sdep	Sample dependency	AVC
sdhd	reserved for SceneDescriptionStream header	MP4V1
sdtp	Independent and Disposable Samples Box	AVC, ISO
sdvp	SD Profile Box	SDV
segr	file delivery session group	ISO
senc	Sample specific encryption data	DECE
sgpd	Sample group definition box	AVC, ISO
sidx	Segment Index Box	3GPP
sinf	protection scheme information box	ISO
skip	free space	ISO
smhd	sound media header, overall information (sound track only)	ISO
srmb	System Renewability Message	DVB
srmc	System Renewability Message container	DVB
srpp	STRP Process	ISO
stbl	sample table box, container for the time/space map	ISO
stco	chunk offset, partial data-offset information	ISO
stdp	sample degradation priority	ISO
sthd	Subtitle Media Header Box	DECE
stsc	sample-to-chunk, partial data-offset information	ISO
stsd	sample descriptions (codec types, initialization etc.)	ISO
stsh	shadow sync sample table	ISO
stss	sync sample table (random access points)	ISO
stsz	sample sizes (framing)	ISO
stts	(decoding) time-to-sample	ISO
styp	Segment Type Box	3GPP
stz2	compact sample sizes (framing)	ISO
subs	Sub-sample information	ISO
swtc	Multiview Group Relation	AVC
tfad	Track fragment adjustment box	3GPP
tfhd	Track fragment header	ISO
tfma	Track fragment media adjustment box	3GPP
tfra	Track fragment radom access	ISO
tibr	Tier Bit rate	AVC
tiri	Tier Information	AVC
titl	Media title (user-data)	3GPP
tkhd	Track header, overall information about the track	ISO
traf	Track fragment	ISO
trak	container for an individual track or stream	ISO
tref	track reference container	ISO
trex	track extends defaults	ISO
trgr	Track grouping information	ISO
trik	Facilitates random access and trick play modes	DECE
trun	track fragment run	ISO
tsel	Track selection (user-data)	3GPP
udta	user-data	ISO
uinf	a tool by which a vendor may provide access to additional information associated with a UUID	JP2
UITS	Unique Identifier Technology Solution	Universal Music
ulst	a list of UUID’s	JP2
url$20	a URL	JP2
uuid	user-extension box	ISO, JP2
vmhd	video media header, overall information (video track only)	ISO
vwdi	Multiview Scene Information	AVC
xml$20	a tool by which vendors can add XML formatted information	JP2
xml$20	XML container	ISO
yrrc	Year when media was recorded (user-data)	3GPP

QuickTime Codes

Code	Abstract	Defined in/by
clip	Visual clipping region container	QT
crgn	Visual clipping region definition	QT
ctab	Track color-table	QT
elng	Extended Language Tag	QT
imap	Track input map definition	QT
kmat	Compressed visual track matte	QT
load	Track pre-load definitions	QT
matt	Visual track matte for compositing	QT
pnot	Preview container	QT
wide	Expansion space reservation	QT