Company Confidential 12/21/2006

MP4/3GP/PSP file format

Company Confidential 22/21/2006

TopicsTopics

MP4 file Global Structure Various Box type introduction Detail Introduce Media Traks Box

3GP file introduction PSP file introduction

Company Confidential 32/21/2006

MP4 Global file StructureMP4 Global file Structure

I PTV MPEG4文件

moov

. . . otherboxes

trak(OD)

trak(BI FS)

trak(vi deo)

trak(audi o)

trak(vi deo hi nt)

trak(audi o hi nt)

I OD

f typ

mdat

I nterl eaved,t i me-ordered,BI FS, OD, vi deoand audi o accessuni ts, and hi nti nstructi ons

Company Confidential 42/21/2006

Object-Structured file formatObject-Structured file format

ISO base media file format---global container The basic objects in file is called BOX Box contain atoms

There’s lot’s kind of atoms,like trak atoms,mvhdr atoms Basically there’s 3 boxes in a MP4 file

1. ftyp box2. Moov box3. Mdat box

Company Confidential 52/21/2006

Moov Header/TraksMoov Header/Traks

Mvhd contains some global information for the file Creation time,mofification

time,timescale,duration,next_trak_id to allow new traks to be added or removed dynamically

Trak box has 2 functions contain media data (media tracks) contain packetization information for streaming protocols (hint tracks).

Company Confidential 62/21/2006

TraksTraks

Traks Describe a stream of Media Data OD---(iods)Optional BIFS---Optional Video tracks Audio tracks video hint tracks audio hint tracks

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TraksTraks

Traks has following atoms Tkhd----Trak header,contains the trak ID and

informations about the trak Tref----reference to related traks Mdia---Media Box,contains information about the

media data

Company Confidential 82/21/2006

Tipical Media TraksTipical Media Traks

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Mdhr boxMdhr box

Company Confidential 102/21/2006

Hdlr boxHdlr box

•declares the process by which the media-data in the track is presented•‘vide’ Video track•‘soun’ Audio track•‘hint’ Hint track

Company Confidential 112/21/2006

Minf boxMinf box

Vmhd:Video Media header Box Smhd:Sound Media header Box Hmhd:hint header box

Nmhd:Null Media Header Box,for media other tha Video and Audio

Company Confidential 122/21/2006

Minf Box--ContinuedMinf Box--Continued

Dinf Box---Defines the data URL,data reference Stbl Box---reference to Media Meta data has stts,ctts,stsd,stsz,stz2,stsc,stss boxes

Company Confidential 132/21/2006

stts Box Detailstts Box Detail

Stts---Time to sample box,defines every sample decoding time

DT(n+1) = DT(n) + STTS(n)

Company Confidential 142/21/2006

Ctts box detailCtts box detail

Ctts-provides the offset between decoding time and composition time.

CT(n) = DT(n) +CTTS(n)

Company Confidential 152/21/2006

Stsd box detailStsd box detail

Stsd The sample description table gives detailed information

about the coding type used, and any initialization information needed for that coding.

VisualSampleEntry:width/height,resolution etcAudioSampleEntry:sample size,sample rate etcContains mp4V and mp4A boxes,which contain esds box

which has decoder config information

Company Confidential 162/21/2006

Sample Size Boxes

Stsz contains the sample count and a table giving the

size in bytes of each sample.a entry_size of zero indicates that every sample has the sample_size

Company Confidential 172/21/2006

Mdat boxMdat box

Interleaved, time-ordered,BIFS, OD, video, and audio access units,to find the Audio/Video data to be decoded,use stbl/stsc box to get the data

Company Confidential 182/21/2006

3GP limitations to MP4 file format3GP limitations to MP4 file format

All 3GP file should have a “3GP” suffix name Ftyp box depending which profiles the 3GP files to

conforming to,the file type box should has Brand and compatible brands be set accordingly.

For example for a MPEG4 compatible 3GP file: Brand:3gp,3gp5 Compatible Brands:3gp5,3gp4, mp42, isom

Company Confidential 192/21/2006

3GP extentions to MP4 file format3GP extentions to MP4 file format

Streaming-server profile Branded ‘3gs6’ Add extention of RTP hint tracks to the file,defined in 3GPP TS

26.234 Progressive-download profile

branded ‘3gr6 ‘ the ‘moov’ box shall be placed right after the ‘ftyp’ box

in the beginning of the file; - all media tracks (if more than one) shall be

interleaved with an interleaving depth of one second or less.

Company Confidential 202/21/2006

3GP Codec3GP Codec

H.263 profile 0 Level 45 H.263 profile 3 Level 45 MPEG-4 Visual Simple Profile level Ob H.264(AVC)Baseline Profile Level 1b Enhanced aac Plus Extended AMR-WB MPEG-4 AAC Low Complexity (AAC-LC) MPEG4AACLongTermPrediction(AAC-LTP)

Company Confidential 212/21/2006

3GP Video Quality3GP Video Quality

QCIF （ 176x144 ） Mandatory SQCIF （ 128x96 ） Optional CIF （ 352x288 ） Optional

SQCIF （ 128x96 ） >=15FPS QCIF （ 176x144 ） >=10FPS CIF （ 352x288 ） >=3FPS

Company Confidential 222/21/2006

PSP file formatPSP file format

Ftyp box should have “MSNV” brand and compatible brand name

Added a UUID box which contain FPRF,VPRF,APRF,which contains codec_information,average/max frame rate,average/max bit rate,aspect ratio information

edts/stss is required Some other requiements such as time scale,fixed

vop rate etc,but seems not important

Company Confidential 232/21/2006

PSP codec limitationsPSP codec limitations

MPEG4 Simple Profile Support NTSC only,progressive encoding,only

support QVGA resolution Bitrate should not exceed 768Kbps

Company Confidential 242/21/2006

ReferencesReferences

ISO/IEC 14496-12:2004(E) ISO/IEC 14496-14:2003(E) 3GPP Standard 26244-6.3.0(2005.03) SONY PSP file/Memory Stick specification