Lossless Compression ke eng?<\/h3>\n
Khatello e se nang tahlehelo e fokotsa boholo ba faele ka ho tsebahatsa le ho felisa boteng ba lipalo ntle le ho tlosa tlhahisoleseling. Ha e fokotsehile, faele e batla e t\u0161oana le ea pele, ‘me ha e na tahlehelo ea boleng kapa bot\u0161epehi ba data.<\/p>\n <\/div>\n <\/div>\n \n
Kamoo Khatello e sa Lahleheng e Sebetsang Kateng<\/h3>\n
Li-algorithms tse se nang tahlehelo tsa compression li sebelisa mekhoa e fapaneng ho fokotsa boholo ba faele ha li ntse li netefatsa ntlafatso e phethahetseng ea data ea mantlha. Mekhoa ena e sekaseka lipaterone, maqhubu le meaho ka har’a data ho e kenyelletsa ka mokhoa o atlehileng ntle le ho lahleheloa ke tlhahisoleseling.<\/p>\n \n
Khouto ea Length-Length (RLE)<\/h4>\n
RLE e nkela sebaka sa tatellano ea likarolo tse ts’oanang tsa data (e matha) ka boleng bo le bong le palo. Mohlala, “AAAAAABBBCCCCC” e fetoha “6A3B5C”, e fokotsa haholo boholo ba data ka tatellano e pheta-phetoang.<\/p>\n
Original: WWWWWWWWWWBBBWWWWWWWWWWWWBBBWWWWWWWWWW\nCompressed: 10W3B12W3B10W<\/pre>\n <\/div>\n <\/div>\n \n\n\n <\/i>\n <\/div>\nHuffman Coding<\/h4>\n
Mokhoa ona o fana ka likhoutu tsa bolelele bo feto-fetohang ho litlhaku tse kentsoeng, ka likhoutu tse khuts’oane bakeng sa litlhaku tse khafetsa. Mokhoa ona oa lipalo-palo o ntlafatsa khouto ho ipapisitsoe le phetisetso ea makhetlo a litlhaku.<\/p>\n
\n Mohlala:<\/strong>\nFrequent character 'e': 101\nLess frequent 'z': 1010101011<\/pre>\n <\/div>\n <\/div>\n \n\n\n <\/i>\n <\/div>\nLZ77 & LZ78 Algorithms<\/h4>\n
Mekhoa ena e thehiloeng ho dikishinari e nka sebaka sa ho hlaha khafetsa ha data ka lit\u0161upiso tsa kopi e le ‘ngoe e seng e ntse e le teng molatsoaneng o sa hatelloang. Ba theha motheo oa lifomate tse tsebahalang joalo ka ZIP le GIF.<\/p>\n
\n Mohlala:<\/strong>\nInstead of storing \"compression compression\"\nStore \"compression [pointer to earlier instance]\"<\/pre>\n <\/div>\n <\/div>\n \n\n\n <\/i>\n <\/div>\nFetola algorithm<\/h4>\n
Ho kopanya LZ77 le Huffman coding, Deflate e fana ka compression e babatsehang ka lebelo le letle. E sebelisoa ho compression ea ZIP, PNG, le HTTP (gzip), e e etsa e ‘ngoe ea li-algorithms tse sebelisoang haholo.<\/p>\n
\n Lisebelisoa:<\/strong>\n\n
- Li-archives tsa ZIP<\/li>\n
- Lit\u0161oant\u0161o tsa PNG<\/li>\n
- Khatello ea HTTP (gzip)<\/li>\n <\/ul>\n <\/div>\n <\/div>\n \n
\n\n <\/i>\n <\/div>\nLikhoutu tsa Arithmetic<\/h4>\n
Mokhoa ona o emela molaetsa e le palo ea linomoro pakeng tsa 0 le 1. E ka finyella litekanyetso tsa compression haufi le moeli oa theoretical entropy, e leng se etsang hore e sebetse haholo bakeng sa mefuta e itseng ea data.<\/p>\n
\n Molemo:<\/strong>\nE ka kenyelletsa likaroloana tsa likaroloana ka let\u0161oao, e fana ka compression e betere ho feta Huffman bakeng sa mehloli e mengata.<\/p>\n <\/div>\n <\/div>\n \n
\n\n <\/i>\n <\/div>\nDelta Encoding<\/h4>\n
Sebakeng sa ho boloka boleng bo felletseng, khouto ea delta e boloka liphapang lipakeng tsa litekanyetso tse latellanang. Sena se sebetsa haholo bakeng sa data moo boleng ba haufi bo ts’oanang, joalo ka lisampole tsa molumo kapa ‘malo oa sensor.<\/p>\n
\n Mohlala:<\/strong>\nOriginal: 105, 107, 106, 110, 108\nDelta: 105, +2, -1, +4, -2<\/pre>\n <\/div>\n <\/div>\n <\/div>\n \nTloaelehileng Lossless File Formats<\/h3>\n
\n\n\n <\/i>\nArchives<\/h4>\n <\/div>\n
\nZIP<\/div>\nRAR<\/div>\n7Z<\/div>\nGZIP<\/div>\nBZIP2<\/div>\nTAR<\/div>\n <\/div>\n <\/div>\n \n\n\n <\/i>\nLit\u0161oant\u0161o<\/h4>\n <\/div>\n
\nPNG<\/div>\nTIFF<\/div>\nBMP<\/div>\nGIF<\/div>\nWebP (e sa lahleheloeng)<\/div>\n <\/div>\n <\/div>\n \n\n\n <\/i>\nAudio<\/h4>\n <\/div>\n
\nFLAC<\/div>\nALAC<\/div>\nWAV<\/div>\nAPE<\/div>\nWavPack<\/div>\n <\/div>\n <\/div>\n <\/div>\n <\/div>\n <\/section>\n \n \n\n Khatello e Lahlehileng e hlalositsoe<\/h2>\n \n
\n\n\n <\/i>\n <\/div>\n\nLossy Compression ke eng?<\/h3>\n
Khatello ea tahlehelo e fokotsa boholo ba faele ka ho tlosa tlhahisoleseling e itseng ka ho sa feleng, haholo-holo data e sa hlokahaleng kapa e sa bohlokoa haholo. Faele e senyehileng e fapane le ea pele, empa liphapang li etselitsoe ho ba thata kapa ho ke ke ha khoneha hore batho ba lemohe tlas’a maemo a tloaelehileng.<\/p>\n <\/div>\n <\/div>\n \n
Kamoo Lossy Compression e Sebetsang Kateng<\/h3>\n
Khatello ea tahlehelo e fihlella maemo a holimo haholo a khatello ka ho etsa liqeto tsa maano mabapi le hore na u lahle data efe. Litaolo tsena li phahamisa tsebo mabapi le maikutlo a batho – seo mahlo a rona le litsebe tsa rona li ka se khonang le tseo re ke keng ra li lemoha – ho tlosa tlhahisoleseling ka litsela tse fokotsang t\u0161usumetso e hlokomelehang boleng.<\/p>\n \n
\n\n\n <\/i>\n <\/div>\nFetola Coding<\/h4>\n
Mokhoa ona o fetola data ho tloha sebakeng se seng (joaloka sebaka) ho ea ho se seng (joaloka khafetsa) moo khatello e ka sebelisoang ka katleho. Discrete Cosine Transform (DCT) e sebelisitsoeng ho JPEG ke mohlala o ka sehloohong.<\/p>\n
\n Tshebetso:<\/strong>\n\n
- Fetolela li-block blocks ho likarolo tsa frequency<\/li>\n
- Fokotsa likarolo tsa maqhubu a holimo ka mokhoa o matla haholoanyane<\/li>\n
- Mahlo a batho ha a utloele maqhubu ana<\/li>\n <\/ul>\n <\/div>\n <\/div>\n \n
\n\n <\/i>\n <\/div>\nQuantization<\/h4>\n
Quantization e fokotsa ho nepahala ha boleng ba data. E etsa ‘mapa oa mefuta e mengata ea litekanyetso ho sehlopha se senyenyane sa boleng ba lihlahisoa, ka katleho e fokotsa palo ea li-bits tse hlokahalang ho emela lintlha.<\/p>\n
\n Mohlala:<\/strong>\nOriginal values: 4.13, 4.28, 4.97, 4.02\nQuantized to: 4, 4, 5, 4<\/pre>\n <\/div>\n <\/div>\n \n\n\n <\/i>\n <\/div>\nMohlala oa Psychoacoustic<\/h4>\n
E sebelisoa ha ho hatelloa ka molumo, mokhoa ona o sebelisa mefokolo ea kutlo ea batho. E supa hore na ke likarolo life tsa molumo tse ka tlosoang ntle le ho ama boleng ba molumo o lemohuoang.<\/p>\n
\n Mehopolo ea Bohlokoa:<\/strong>\n\n
- Masking ea kutlo: Melumo e phahameng e utloahala e khutsitse<\/li>\n
- Kutloisiso ea khafetsa: Batho ba utloa maqhubu a mahareng hantle ka ho fetesisa<\/li>\n
- Masking ea nakoana: Melumo e ka pata tse ling tse etsahalang nakoana pele \/ kamora<\/li>\n <\/ul>\n <\/div>\n <\/div>\n \n
\n\n <\/i>\n <\/div>\nPerceptual Coding<\/h4>\n
Joalo ka mohlala oa psychoacoustic empa bakeng sa data e bonoang, mokhoa ona o tlosa tlhahisoleseling eo mahlo a motho a ke keng a e hlokomela, haholo-holo ka lintlha tse phahameng tsa maqhubu le phapang ea mebala.<\/p>\n
\n Lisebelisoa:<\/strong>\nE sebelisoa ho JPEG, MPEG, le litekanyetso tse ling tsa khatello ea pono ho beha data ea bohlokoa pele.<\/p>\n <\/div>\n <\/div>\n \n
\n\n <\/i>\n <\/div>\nMat\u0161eliso a Motion<\/h4>\n
Mokhoa oa compression oa video o sebelisang bofokoli ba nakoana ka ho kenyelletsa liphapang lipakeng tsa liforeimi ho fapana le foreimi e ngoe le e ngoe e felletseng. Ke feela liphetoho ho tloha foreiming e ‘ngoe ho ea ho e ‘ngoe tse kentsoeng ka botlalo.<\/p>\n
\n Tshebetso:<\/strong>\n\n
- Boloka “li-keyframes” tse felletseng (I-frames) nako le nako<\/li>\n
- Bakeng sa liforeimi tse ling, boloka feela liphapang (P-frames) kapa liphapang tsa mahlakore a mabeli (B-frames)<\/li>\n
- Liphetho tsa phokotso ea boholo ba lifaele tsa video<\/li>\n <\/ul>\n <\/div>\n <\/div>\n \n
\n\n <\/i>\n <\/div>\nMohlala o monyenyane oa Chroma<\/h4>\n
Mokhoa ona o fokotsa tlhahisoleseding ea mebala ho feta boitsebiso bo khanyang, o nka monyetla oa ho utloisisa ha leihlo la motho ho khanya ho feta ho se t\u0161oane ha mebala.<\/p>\n
\n Mefuta e Tloaelehileng:<\/strong>\n\n
- 4:4:4 – Ha ho sampling (‘mala o felletseng)<\/li>\n
- 4:2:2 – Halofo e tshekaletseng ya mebala e nang le qeto<\/li>\n
- 4:2:0 – Halofo ka bobeli e t\u0161ekaletseng le e theohileng ka mebala e nang le qeto<\/li>\n <\/ul>\n <\/div>\n <\/div>\n <\/div>\n \n
Tloaelehileng Lossy File Formats<\/h3>\n
\n\n\n <\/i>\nLit\u0161oant\u0161o<\/h4>\n <\/div>\n
\nJPEG<\/div>\nWebP (e lahlehile)<\/div>\nJPEG 2000<\/div>\nHEIF<\/div>\nAVIF<\/div>\n <\/div>\n <\/div>\n \n\n\n <\/i>\nAudio<\/h4>\n <\/div>\n
\nMP3<\/div>\nAAC<\/div>\nVorbis<\/div>\nOpus<\/div>\nWMA<\/div>\n <\/div>\n <\/div>\n \n\n\n <\/i>\nVideo<\/h4>\n <\/div>\n
\nH.264<\/div>\nH.265<\/div>\nVP9<\/div>\nAV1<\/div>\nWebM<\/div>\n <\/div>\n <\/div>\n <\/div>\n <\/div>\n <\/section>\n \n \n\n Lisebelisoa tse Sebetsang le Maemo a T\u0161ebeliso<\/h2>\n \n
\n\n\n\n <\/i>\n <\/div>\nLit\u0161oant\u0161o tsa Dijithale<\/h3>\n <\/div>\n
\nKhatello e sa Lahleheng<\/h4>\n
\n
- Tlhokomelo ea sebopeho sa RAW bakeng sa lifoto tsa litsebi<\/li>\n
- Polokelo ea boleng ba polokelo ea linepe tsa bohlokoa<\/li>\n
- Lit\u0161oant\u0161o tse hlokang ho hlophisoa kapa ho hlophisoa ha nako e telele<\/li>\n
- Sebopeho sa PNG bakeng sa lit\u0161oant\u0161o tse nang le mongolo kapa mahlakore a bohale<\/li>\n <\/ul>\n \n
Khatello e Lahlehileng<\/h4>\n
\n
- JPEG bakeng sa linepe tsa letsatsi le letsatsi le ho arolelana marang-rang<\/li>\n
- Ho hlahisa li-thumbnail bakeng sa li-galleries le ponelo-pele<\/li>\n
- Li-social media tse kentsoeng moo ho nang le meeli ea boholo<\/li>\n
- Lihokelo tsa lengolo-tsoibila le lits’ebetso tsa melaetsa<\/li>\n <\/ul>\n \n
\n Mokhoa o Molemo ka ho Fetisisa:<\/strong> T\u0161oara ka sebopeho sa RAW kapa se sa lahleheloeng, theha mefuta e lahlehileng bakeng sa ho arolelana, boloka li-masters tse se nang tahlehelo bakeng sa ho boloka litlaleho.\n <\/div>\n <\/div>\n <\/div>\n \n\n\n\n <\/i>\n <\/div>\n