1. 2/21/2006 Company Confidential 1 MP4/3GP/PSP file format

2. 2/21/2006 Company Confidential 2Topics MP4 file Global Structure Various Box type introduction Detail Introduce Media Traks Box 3GP file introduction PSP file introduction

3. 2/21/2006 Company Confidential 3 MP4 Global file Structure

4. 2/21/2006 Company Confidential 4 Object-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 box 2. Moov box 3. Mdat box

5. 2/21/2006 Company Confidential 5 Moov 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).

6. 2/21/2006 Company Confidential 6Traks Traks Describe a stream of Media Data OD---(iods)Optional BIFS---Optional Video tracks Audio tracks video hint tracks audio hint tracks

7. 2/21/2006 Company Confidential 7Traks 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

8. 2/21/2006 Company Confidential 8 Tipical Media Traks

9. 2/21/2006 Company Confidential 9 Mdhr box

10. 2/21/2006 Company Confidential 10 Hdlr box declares the process by which the media-data in the track is presented ‘vide’ Video track ‘soun’ Audio track ‘hint’ Hint track

11. 2/21/2006 Company Confidential 11 Minf 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

12. 2/21/2006 Company Confidential 12 Minf 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

13. 2/21/2006 Company Confidential 13 stts Box Detail Stts---Time to sample box,defines every sample decoding time DT(n+1) = DT(n) + STTS(n)

14. 2/21/2006 Company Confidential 14 Ctts box detail Ctts-provides the offset between decoding time and composition time. CT(n) = DT(n) +CTTS(n)

15. 2/21/2006 Company Confidential 15 Stsd 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 etc AudioSampleEntry:sample size,sample rate etc Contains mp4V and mp4A boxes,which contain esds box which has decoder config information

16. 2/21/2006 Company Confidential 16 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

17. 2/21/2006 Company Confidential 17 Mdat 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

18. 2/21/2006 Company Confidential 18 3GP 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

19. 2/21/2006 Company Confidential 19 3GP 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.

20. 2/21/2006 Company Confidential 20 3GP 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)

21. 2/21/2006 Company Confidential 21 3GP Video Quality QCIF （ 176x144 ） Mandatory SQCIF （ 128x96 ） Optional CIF （ 352x288 ） Optional SQCIF （ 128x96 ） >=15FPS QCIF （ 176x144 ） >=10FPS CIF （ 352x288 ） >=3FPS

22. 2/21/2006 Company Confidential 22 PSP 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

23. 2/21/2006 Company Confidential 23 PSP codec limitations MPEG4 Simple Profile Support NTSC only,progressive encoding,only support QVGA resolution Bitrate should not exceed 768Kbps

24. 2/21/2006 Company Confidential 24References 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