MPEG2 vs MPEG4
MPEG sawv cev rau Moving Pictures Experts Group, ib lub koom haum koom tes nrog International Standards Organization (ISO) los tsim cov qauv tshiab rau digital audio thiab video. Nws thawj tus qauv MPEG-1 tau tso tawm hauv 5 qhov chaw thaum lub sijhawm xyoo 1993 txog 1999. Cov qauv no tau coj mus rau tag nrho cov qauv digital audio / video compression niaj hnub tau txais los ntawm ISO. MPEG-2 thiab MPEG-4 yog ob qhov loj tshaj tawm ntawm MPEG cov qauv.
MPEG-2
MPEG-2 tau tsim los kov yeej qhov tsis txaus ntawm MPEG-1 tus qauv. MPEG-1 muaj lub kaw lus compression txwv rau ob lub suab (lub tso suab) thiab, rau cov yeeb yaj kiab interlaced, muaj cov qauv kev txhawb nqa tsis zoo. Tsis tas li ntawd, nws tsuas muaj ib qho qauv "profile" (Constrained Parameters Bitstream), uas tsis haum rau cov yeeb yaj kiab uas muaj kev daws teeb meem siab dua. MPEG-1 tuaj yeem txhawb nqa 4k video, tab sis encoding video rau kev daws teeb meem siab dua yog qhov nyuaj. Muaj qhov tsis sib xws hauv kev txheeb xyuas cov khoom siv uas txhawb nqa qhov kev encoding. Tsis tas li ntawd, cov xim tsuas yog txwv rau 4: 2: 0 xim chaw.
MPEG-1 hloov mus rau MPEG-2 los ntawm kev txheeb cov teeb meem saum toj no. Kaum ib feem ntawm tus qauv raug tso tawm los ntawm 1996 txog 2004, thiab tseem cov qauv hloov tshiab. Ntu 8 raug tso tseg vim tsis muaj kev txaus siab rau kev lag luam. Tus qauv compression video yog H.263 thiab tau teev nyob rau hauv Part 2 thaum lub suab nce qib tau teev tseg hauv Part 3 thiab Part 7. Ntu 3 txhais tau hais tias ntau channel specification thiab Part 7 txhais cov Advance Audio Encoding. Cov ntu ntawm cov lus qhia tshwj xeeb uas txhais cov yam ntxwv sib txawv yog qhia hauv qab no;
• Part 1-Systems: piav qhia txog synchronization thiab multiplexing ntawm cov suab thiab video.
• Part 2-Video: compression coder-decoder (codec) for interlaced and non-interlaced video media signals
• Part 3-Audio: compression coder-decoder (codec) rau perceptual coding of audio media signals. Qhov no ua rau muaj ntau qhov txuas ntxiv thiab tus nqi me ntsis thiab cov qauv piv txwv rau MPEG-1 Suab Txheej I, II thiab III ntawm MPEG-1 suab kuj tau txuas ntxiv.
• Part 4: Methodology for testing compliance.
• Part 5: Piav txog cov tshuab rau Software simulation.
• Part 6: Piav txog kev txuas ntxiv rau Digital Storage Media Command thiab Control (DSM- CC).
• Part 7: Advanced Audio Coding (AAC).
• Part 9: Extension for real time interfaces.
• Part 10: Conformance extensions for Digital Storage Media Command and Control (DSM-CC).
• Part 11: Kev tswj cov cuab yeej cuab tam (IPMP)
MPEG-2 tus qauv yog siv hauv DVD's thiab Digital TV tshaj tawm txoj hauv kev (ISDB, DVB, ATSC). Nws yog tus qauv tsim rau MOD thiab TOD video tawm tswv yim. XDCAM kuj yog raws li MPEG-2.
MPEG-4
MPEG-4 yog tus qauv tshiab kawg uas tau hais los ntawm MPEG. Nws suav nrog cov yam ntxwv ntawm MPEG-1 thiab MPEG-2 nrog cov thev naus laus zis tshiab hauv kev lag luam thiab cov yam ntxwv xws li Virtual Reality Modeling Language (VRML), 3D rendering, object-oriented composite files thiab txhawb cov qauv rau kev tswj hwm cov cai sab nraud. Nws tau pib ua tus qauv rau kev sib txuas lus video me ntsis, tab sis tom qab ntawd tau hloov mus rau hauv cov txheej txheem multimedia coding. MPEG tseem yog tus qauv tsim.
MPEG-4 Ntu 2 piav qhia txog qhov pom kev thiab tsim lub hauv paus ntawm Advanced Simple Profile siv los ntawm codecs kev koom ua ke rau hauv software xws li DivX, Xvid, Nero Digital, thiab 3ivx thiab los ntawm QuickTime 6. MPEG-4 Part 10 piav qhia txog kev yees duab ntawm tus qauv. MPEG-4 AVC/H.264 lossis Advanced Video Coding siv nyob rau hauv x264 encoder, Nero Digital AVC, thiab HD video tawm zoo li Blu-duab tshav Disc yog raws li qhov no. Hauv qab no yog cov ntsiab lus ntawm Cov Khoom Uas Muaj nyob rau hauv specification ntawm cov qauv.
• Part 1: Systems
• Part 2: Visual
• Part 3: Audio
• Part 4: Kev ntsuam xyuas kev sib haum xeeb
• Part 5:
