Phan Ticn Dong Truyen Tai Mpeg

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I HC QUC GIA H NI TRNG I HC CNG NGH

Trn Vn Hoan

PHN TCH DNG TRUYN TI MPEG (MPEG TRANSPORT STREAM)

KHO LUN TT NGHIP I HC H CHNH QUY Ngnh: Cng ngh in t vin thng

Cn b hng dn: TS Ng Thi Tr

H NI - 2008

Trn Vn Hoan K49

Kha lun tt nghip

Tm tt ni dungLun vn c trnh by trong 3 chng : Chng 1: Gii thiu tng qut nht v chun nn MPEG, l do cn phi nn d liu, cc nguyn tc c bn c s dng trong chun nn MPEG p dng cho d liu hnh nh cng nh m thanh, gii thiu nhng c im chung nht ca cc chun nn MPEG1, 2, 4 v 7, chng ny cng ch ra cch hnh thnh dng bit MPEG. Chng 2: M t cch thc hnh thnh, cu trc ca dng c s ES, l do cn thit phi chia dng c s thnh cc gi, cch thc to ra cc gi c s ng gi PES ng thi phn tch cu to ca mt gi PES. Chng 3: Phn tch cch to thnh dng truyn ti MPEG, hot ng ca dng truyn ti, phn tch chi tit cu to v nhim v ca tng trng trong gi truyn ti, cui cng l ch ra nhng c im u vit ca dng truyn ti MPEG lm cho chun nn ny c nhng ng dng rng ri trong thc t.

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Trn Vn Hoan K49

Kha lun tt nghip

Mc lcTrang ph ba..................................................................................................................... Tm tt ni dung...............................................................................................................i Mc lc............................................................................................................................ii Bng cc k hiu vit tt..................................................................................................iv M u.............................................................................................................................1 Chng 1 : Tng quan v MPEG.....................................................................................2 1.1. Gii thiu ................................................................................................................2 1.2. ng dng ca nn d liu:.......................................................................................4 1.3. M ha khng tn hao v m ha d on c......................................................5 1.4. Nguyn l c bn ca nn.........................................................................................7 1.5. Nn video.................................................................................................................9 1.5.1. Nn trong nh.....................................................................................................11 1.5.2. Nn lin nh.......................................................................................................11 1.5.3. Gii thiu v php b chuyn ng....................................................................12 1.6. Gii thiu v MPEG-1...........................................................................................13 1.7. MPEG-2 cng vi cc Profile v Level.................................................................14 1.8. Gii thiu v MPEG -4..........................................................................................16 1.9. Gii thiu v MPEG-7........................................................................................18 1.10. Nn m thanh......................................................................................................18 1.11. Dng bit MPEG..................................................................................................20 Chng 2: Dng c s (elementary stream) v dng c s ng gi (packetized elementary stream).........................................................................................................22 2.1. Dng c s (elementary stream)............................................................................22 2.2. Dng c s ng gi (packetized elementary stream)...........................................24 2.2.1....................................................................Gii thiu chung v dng c s ng gi 24 2.2.2........................................................................................C php dng c s ng gi 27

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Trn Vn Hoan K49

Kha lun tt nghip

2.2.3...............................................................................................................Cu trc chi tit

32 Chng 3: Dng truyn ti.............................................................................................38 3.1. Gii thiu chung v dng truyn ti:......................................................................38 3.2. Chun ng h (clock references)..........................................................................39 3.3. Gii m dng truyn ti.........................................................................................41 3.4. Phn tch c php dng truyn ti..........................................................................43 3.5. c im dng truyn ti MPEG...........................................................................60 3.6. Tnh linh hot ca dng truyn ti:........................................................................61 Kt lun..........................................................................................................................62 Ti liu tham kho.........................................................................................................63

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Trn Vn Hoan K49

Kha lun tt nghip

Bng cc k hiu vit tt ABU Asia-Pacific Broadcasting Union ANSI American National Standard Institute ATSC Advance Television System Committee CAT Conditional Access Table CRC Cyclical Redundancy Checking DCT Discrete Cosine Transform DTS Decoding Time Stamp DVB Digital Video Broadcasting EBU European Broadcasting Union ES Elementary Stream GOP Group of Picture HDTV High-definition Television IEC International Electrotechnical Commission ISO International Organization for Standardization ITU International Telecommunication Union MPEG Moving Pictures Experts Group NIT Network Information Table PAT Program Association Table PCR Program Clock Reference PES Packetized Elementary Stream PID Packet Identification PMT Program Map Table PSI Program Specific Information PTS Presentation Time Stamp RLC Run Length Coding SCR System Clock Reference SDTV Standard Definition Television TS Transport Stream

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Trn Vn Hoan K49

Kha lun tt nghip

M uCng ngh s t khi ra i ngy cng th hin tnh u vit v thay th dn cng ngh tng t vn khng hiu qu v li thi. Ngy nay vic s ha c thc hin trn mi dng thc ca d liu, t vn bn ti hnh nh v m thanh. Cc mch in t tch hp c nghin cu ch to ngy cng nhiu c hiu nng tnh ton ngy cng cao, tin cy ngy cng chnh xc lm cho cng ngh s ngy cng pht trin. Trong xu hng s ha mi dng d liu nh trn th vic s ha tn hiu video l mt s tt yu. Tuy nhin tn hiu video c s ha c dung lng qu ln dn n vic lu tr v truyn dn hu nh khng th thc hin c. Do ny sinh nhu cu nn tn hiu video. Nhiu chun nn c ra i l kt tinh cng sc ca cc chuyn gia, cc nh khoa hc hng u trn th gii. Trong s cc chun nn th chun MPEG l chun nn ph bin nht, c ng dng rng ri nht. Chun nn ny c nghin cu, pht trin trong nhiu nm v gii quyt tt bi ton nn tn hiu video, kt qu l c th p ng mt cch rt a dng cc yu cu trong thc t. Mt thnh phn quan trng bc nht trong chun nn MPEG l dng truyn ti MPEG (MPEG Transport Stream). Nh c dng truyn ti m d liu c th c a t ni pht ti ni thu mt cch d dng, chnh xc v an ton. Hn na dng truyn ti cn rt mm do v linh hot, va h tr tt cho cc ng dng hin ti va m bo d dng cho s pht trin trong tng lai. Nhm mc ch tm hiu mt cch su sc v cu to v hot ng ca dng truyn ti MPEG, em chn ti ny vi mong mun c c s hiu bit v mt chun nn c ng dng rng ri nht trong thc t. Em xin chn thnh cm n thy Ng Thi Tr, ngi tn tnh ch bo v gip em trong qu trnh lm lun vn, thy ch cho em phng php nghin cu v cch trnh by lun vn mt cch khoa hc. Em cng xin cm n cc thy c trong Khoa in t vin thng ch bo cho em trong sut qu trnh hc tp. Em xin cm n gia nh v bn b gip em c th hon thnh lun vn ny.

H Ni, 5/2008

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Chng 1: Gii thiu tng quan v MPEG

Chng 1: Gii thiu tng quan v MPEG1.1. Gii thiu: MPEG l vit tt ca cm t Moving Pictures Experts Group c thnh lp bi t chc ISO (International Standards Organization) nhm thit lp chun cho vic nn v truyn ti c d liu hnh nh v d liu m thanh.

Ngun d liu (a)

B nn

Knh truyn

B gii nn

D liu gii nn

D liu vo (b)

B m ha phc tp

Dng bit chun

B gii m n gin

Hnh 1.1: (a) tng quan ca mt h thng c nn, bn pha ngun s dng b nn gi l compressor hay coder, bn pha nhn s dng b gii nn l expander hay decoder, (b) minh ha s bt i xng trong h thng, b m ha lun phi phc tp hn b gii m.

Vic nn d liu l tt yu cn thit do hai l do chnh sau y. Th nht l do lu tr: d liu sau khi nn c dung lng nh hn, do vy cn t khng gian lu tr hn. Th hai l do bng thng: d liu sau khi nn c tc bit thp hn nn cn bng thng t hn. T l gia tc bit ca ngun so vi tc bit ca knh truyn gi l t l nn Compression factor hay l Coding gain. H thng truyn ti l bt i xng. B m ha cn phi thng minh thch ng linh hot vi phn d liu cn m ha, cn b gii m ch cn lm n gin c th hiu c thng tin ca knh truyn mang ti. iu ny thch hp cho hot ng qung b khi

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Chng 1: Gii thiu tng quan v MPEG

m s lng thit b m ha t cn s lng b gii m l rt nhiu. Vi nhng ng dng kiu im-im th hng thit k nh vy khng th hin c tnh u vit.

Tn hiu Video

B m ha B m ha khng c nh ngha bi MPEG tr vic phi to ra dng bit chun

Dng bit

Tn hiu Video B gii m

MPEG nh ngha phn ny

B gii m phi c kh nng hiu c tt c mi dng bit chun

Khng nh ngha (a) B m ha hin ti Dng bit chun B gii m hin ti B gii m hin ti vn c kh nng lm vic

B m ha trong tng lai (b) B m ha c cu trc b mt

Dng bit chun Dng bit chun

B gii m c th lm vic c

(c)

Hnh 1.2: (a) MPEG nh ngha giao thc gia b m ha v b gii m. (b) Hng thit k ca MPEG l cho php to ra b m ha tt hn trong tng lai nhng vn m bo tng thch vi b gii m hin c. (c) Chi tit thit k ca