Kusina Kurasika Kumanikidza: Chii Icho Uye Mashandisiro Acho

by kim Updated: June 28, 2022

Kurasikirwa kusingaperi ipfungwa yakakosha kana zvasvika kune digital media. Inoreva nzira iyo data inomanikidzwa pasina kurasikirwa kwe data. Kutsikirira kusina kurasikirwa inzira huru yekudzikisa saizi yefaira yedhijitari midhiya yako pasina kupira mhando.

Munyaya ino, tichaongorora

• chii chinonzi compression isina kurasikirwa,
• kuti inoshanda sei, uye
• mashandisiro aungaita kuti zvikubatsire.

Ngatitangei!

Tsanangudzo Yekurasikirwa Kusina Kudzvinyirira

Kurasikirwa kusingaperi imhando yekudzvanya data inochengetedza ese ekutanga data panguva yekukodha uye decoding process, zvekuti mhedzisiro yacho ndeye chaiyo replica yepakutanga faira kana data. Inoshanda nekutsvaga mapatani mune data uye kuichengeta zvakanyanya. Semuyenzaniso, kana faira riine mazwi mashanu anodzokororwa, pachinzvimbo chekuchengeta iwo mazwi mashanu akadzokororwa asina kurasikirwa anozochengeta chiitiko chimwe chete chezwi iro, pamwe nereferensi kwarinogona kuwana ruzivo nezve mashandisiro aro mufaira.

Kusiyana kurasikirwa kwekumanikidza (iyo inorasa rumwe ruzivo kusarudza kuderedza saizi) Kusarasikirwa Kudzvinyirira inokubvumira kuchengetedza resolution yemufananidzo, kujeka kwemavara uye kutendeseka kwefaira ne hapana kurasikirwa kwehutano. Izvi zvinoita kuti ive yakakodzera zvikumbiro apo imwe ruzivo rwakakosha uye haigone kubayirwa pakudzikisa saizi. Kushandiswa kwakajairika kwekumanikidza kusarasikirwa kunosanganisira:

• Kudzvanya mimhanzi mafaera (nekudaro mhando yekuteerera inofanira kuramba yakasimba)
• Kudzvanya mifananidzo yezvokurapa (sezvo zvidiki zvingave zvakakosha pakuongorora)
• Kudzvanya source code yesoftware application
• Kuchengeta magwaro ekuchengetedza kwenguva refu.

Mienzaniso yemacompressor anogona kushandisa iyi mhando yealgorithm ndeye ZIP uye PNG mafaira pamwe nemamwe mafomati emifananidzo akadai TIFF uye GIF.

Zvakanakira Kurasika Kudzvinyirira

Kurasikirwa kusingaperi tekinoroji inodzvanya data kuita diki saizi pasina kurasikirwa kwemhando. Izvi zvinogoneka kuburikidza nekushandiswa kwealgorithms inoona isingaite kana kudzokorora tambo yedata, uye wozoitsiva nemakodhi mapfupi. Kushandisa nzira iyi kunogona kubatsira kuderedza saizi yedata zvakanyanya, kazhinji ne hafu kana kupfuura, zvichiita kuti vashandisi vachengete uye vatumire ruzivo rwakakura zvakanyanya.

Kunze kwekuchengetedza nzvimbo yekuchengetera, kune akati wandei mamwe mabhenefiti ekushandisa kusarasikirwa kwekumanikidza. Izvi zvinosanganisira:

• Improved Performance: Kutsikirira kusina kurasikirwa kunogona kuvandudza kukurumidza iyo mafaira anotamiswa sezvo ari maduku uye anotora zvishoma bandwidth paunenge uchitumira kana kurodha.
• Data Kuvimbika: Nekuti hapana data rakarasika kana uchishandisa kusingarasikike compression, chero ruzivo rwakavharidzirwa rucharamba rusina kurongeka pakuora.
• kugarisana: Mafaira akadzvanywa anogona kazhinji kuvhurwa neakasiyana maapplication pamapuratifomu akasiyana nekuda kweakajairwa encoding algorithms.
• Yakaderedzwa Processing Nguva: Kuderedza saizi yefaira kunomhanyisa maitiro akadai sekudhinda, kutenderera uye kugadzirisa semafaira madiki anoda shoma simba rekombuta.

Mhando dzeKurasika Kudzvinyirira

Kune marudzi akasiyana-siyana e kudzvinyirira kusingarasikirwe matekiniki ayo anotendera iwe kudzvanya data pasina kurasikirwa chero ruzivo. Marudzi akajairika ekumanikidza kusingarasikirwe ndeaya ZIP, gzip, uye LZW. Aya matatu, pamwe chete nemamwe marudzi akasiyana-siyana, ose ane zvawo zvakanakira nezvaanokanganisa.

Muchikamu chino, tichakurukura mhando dzakasiyana dzekusarasikirwa nzira dzekumanikidza uye mashandisiro adzo:

• ZIP
• gzip
• LZW

Run Length Encoding

Run Length Encoding (RLE) ndeye data compression algorithm inoshandiswa kuderedza saizi yefaira pasina kurasikirwa chero data. Inoshanda nekuongorora data, kutsvaga mavara akatevedzana uye obva aamanikidza kuita diki, rakapfupikiswa fomu. Izvi zvinoita kuti mafaera ave nyore kuchengeta nekutamisa. Munguva ye decompression process, iyo yekutanga data inogona kuvakwazve zvachose.

Run Length Encoding inowanzo shandiswa kudzvanya mapikicha edhijitari sezvo ichinyatso dzikisa ruzivo rwedundancy muzvinhu zvakaita se. kudzokorora maitiro, kumhanya kwe pixels kana nzvimbo huru dzakazadzwa nemuvara mumwechete. Zvinyorwa zvinyorwa zvakare zvakakodzera vamiriri veRLE compression nekuti kazhinji vane mazwi anodzokororwa nemitsara.

Run Length Encoding inotora mukana wekuti akawanda anoteedzana masampula mukati meodhiyo mafaira ane zvakafanana tsika kuitira kudzideredza muhukuru asi chengetedza hunhu hwadzo hwepakutanga pakudonha. Izvi zvinogona kutungamira mukudzikiswa kwakakosha kwesaizi yefaira - kazhinji 50% kana kupfuura - nekurasikirwa kushoma maererano nemhando yekuteerera uye kuita.

Paunenge uchishandisa RLE encoding, zvakakosha kuyeuka kuti kunyangwe ichigona kuderedza masaizi efaira ane chekuita nekurira kana mufananidzo mafaera, zvinogona kunge zvisinganyatso batsira kune marudzi emafaira emafaira ayo anowanzo kunge asina zvakawanda redundancy nekuda kwemagadzirirwo aanoitwa zvakajairwa. . Naizvozvo kumwe kuyedza nemhando dzakasiyana dzemashandisirwo kungave kuri madikanwa usati waita sarudzo yekupedzisira yekuti rudzi urwu rwekumanikidza tekinoroji yakanyatsokodzera zvaunoda.

Huffman Coding

Huffman Coding is an adaptive, isingarasikike data compression algorithm. Iyi algorithm inoshandisa seti yezviratidzo zve data, kana mavara, pamwe neakawanda anoitika mufaira kuti ivake kodhi yeprefixing inoshanda. Kodhi iyi ine mazwi mapfupi ekodhedhi anomiririra mavara anowanzoitika uye mazwi ekodhedhi marefu anomiririra asingawanzo. Uchishandisa aya makodhi, Huffman Coding inogona kuderedza saizi yefaira ine zvishoma mhedzisiro pakuvimbika kwayo data.

Huffman Coding inoshanda mumatanho maviri: kugadzira seti yemakodhi echiratidzo akasarudzika uye kuishandisa kudzvanya dhata rwizi. Makodhi echiratidzo anowanzo kuvakwa kubva kune akasiyana faira kugoverwa kwemavara uye kubva kuruzivo rwunowanikwa nekuongorora ma frequency anoenderana nawo. mavara akasiyana anoitika mairi. Kazhinji, Huffman Coding inoshanda zvakanyanya kupfuura mamwe asingarasikike compression algorithms kana ichishandiswa pane data hova dzine zviratidzo zvine. kusaenzana mikana yekuitika - semuenzaniso, kuratidza chinyorwa chinyorwa mune mamwe mavara (sa "e") zvinoitika kakawanda kupfuura mamwe (se "z").

Arithmetic Coding

Imwe mhando yekumanikidza isingarasikike inogona kushandiswa inonzi Arithmetic Coding. Iyi nzira inotora mukana wekuti rukova rwe data runogona kuva nezvikamu zvisina basa zvinoshandisa nzvimbo, asi izvo zvisinga tauri ruzivo chairwo. Iyo inodzvanya iyo data nekubvisa izvi zvisingaite zvikamu uku ichichengetedza iyo yekutanga ruzivo zvemukati.

Kuti tinzwisise kuti Arithmetic Coding inoshanda sei, ngatitarisei muenzaniso wezvinyorwa. Ngatitii kune mavara mana mune yedu data rwizi - A, B, C, uye D. Kana iyo data yakasara isina kudzvanywa, hunhu hwega hwega hwaizotora mabhiti masere ehuwandu hwemabhiti makumi matatu nemaviri mhiri kwerukova rwese. NeArithmetic Coding, zvisinei, iyo inodzokororwa tsika senge A naB inogona kumiririrwa ine isingasviki mabits masere imwe neimwe.

Mumuenzaniso uyu tichashandisa mabhuroko mana-bit kumiririra hunhu hwega hwega zvinoreva kuti mavara mana anogona kurongedzerwa muchikamu chimwe chete chegumi nematanhatu. Iyo encoder inotarisa kuyerera kwedata uye inopa zvingangoitika kune yega yega hunhu zvichienderana nemukana wavo wekuonekwa mune dzinoteedzana tambo kuitira kuchengetedza nzvimbo uku uchinyatsoita chokwadi kana ichinge yadzikiswa kune imwe magumo. Panguva yekudzvanyirira saka mavara aya ane mukana wepamusoro anotora mabhiti mashoma nepo aya ane ma frequency epasi kana anoonekwa mashoma anozoda mamwe mabhiti pabhuroka remunhu asi anoramba akasungirirwa mukati me16-bit block senge asati achengeta akati wandei mabhayiti padhata rese. zvichienzaniswa neshanduro yayo isina kudzvanywa.

Mashandisiro Ekushandisa Kusina Kurasika Compression

Kurasikirwa kusingaperi inzira yekukodha uye kudzvanya data pasina kurasikirwa kweruzivo. Iyi nzira yekutsikirira inoshandiswa kuderedza saizi yemifananidzo yedhijitari, odhiyo, uye vhidhiyo mafaera. Kutsikirira kusina kurasikirwa kunoita kuti data ichengetwe pane chidimbu chehukuru hwayo hwepakutanga, zvichikonzera faira diki.

Saka, ngatipindei mune zvakadzama uye tiongorore sei kushandisa kusarasikirwa compression:

File Formats

Kurasikirwa kusingaperi imhando yekumanikidza data iyo inoderedza saizi yefaira pasina kupira chero data iri mukati meiyo yekutanga faira. Izvi zvinoita kuti ive nzira yakanaka yekumanikidza mafaera akakura senge mafoto edhijitari, maodhiyo mafaira, uye mavhidhiyo. Kuti ushandise rudzi urwu rwekumanikidza, unofanirwa kunzwisisa mhando dzemafaira anotsigirwa neasina kurasikirwa compressor uye maitiro ekuamisa nemazvo kuti awane mhedzisiro.

Paunenge uchimanikidza faira nekuda kwekurasikirwa, iwe une akati wandei sarudzo dzefaira mafomati. Zvingangodaro, iwe uchasarudza pakati JPEGs uye PNGs sezvo ivo vari vaviri vachipa zvakanakisa mhedzisiro ine yakanaka faira saizi. Iwe unogona zvakare kushandisa mafomati akafanana GIF kana TIFF kana software yako ichivatsigira. Kune zvakare mamwe mafomati akadzvanywa akagadzirirwa zvakananga kuodhiyo kana vhidhiyo. Izvi zvinosanganisira FLAC (inorasika odhiyo), AVI (yakarasikirwa vhidhiyo), uye QuickTime's Apple Lossless fomati (ALAC).

Zvakakosha kuziva kuti nepo mafomati aya achipa kudzvanya kuri nani pane avo asina-kumisikidzwa vamwe vavo, vanogona kuoma kushanda navo nekuda kwerutsigiro rwavo rushoma mune mamwe maapplication uye software zvirongwa. Zvichienderana nekugadzirisa kwako, kushandisa uncompressed formats inogona kunge iri nyore mukufamba kwenguva kunyangwe ikatora yakawanda dhisiki nzvimbo.

Compression Tools

Kune akasiyana maturusi ekumanikidza aripo ayo akagadzirirwa kudzikisa saizi yemafaira edata uchichengetedza kuvimbika kweiyo data yekutanga. Maturusi aya anoshandisa algorithms kuona dhata risingaverengeki uye oirasa kubva mufaira pasina kurasikirwa neruzivo.

Kutsikirira kusina kurasikirwa kunonyanya kubatsira pamifananidzo yemifananidzo, kana odhiyo nemavhidhiyo kurekodha. Zvishandiso zvakadai ZIP, RAR, Stuffit X, GZIP uye ARJ tsigira akasiyana mazinga ekusarasikirwa kwekumanikidza emhando dzakasiyana dzefaira dzinosanganisira maPDF uye akamanikidzwa executables (EXE). Semuenzaniso, kana iwe ukamanikidza mufananidzo neimwe yeaya mafomati pa hukuru hwekudzikisa saizi yekuisa, waizokwanisa kuvhura nekuona mufananidzo iwoyo pasina kurasikirwa chero ruzivo kana ruzivo rwemavara.

Iyo algorithm inoshandiswa ichakanganisa saizi yefaira inogona kuwanikwa pamwe chete nenguva yainotora kugadzirisa nekumanikidza faira. Izvi zvinogona kubva pamaminetsi kusvika kumaawa akati wandei zvichienderana nekuti mudziyo wawasarudza wakaita sei. Yakakurumbira compression maturusi akadai 7-zip (LZMA2) kupa mazinga epamusoro ekumanikidza asi zvinoda nguva yakareba yekugadzirisa. Yakanyanya optimized zvirongwa senge SQ=z (SQUASH) ndiwo maitiro akaderera anogona kudzvanya mamwe mabheti nekumhanya kwemheni zvichienzaniswa nemamwe maapplication akakurumbira senge. Winzip or WinRAR asi kuoma kwavo kwehunyanzvi kunoreva kuti havawanzo shandiswa nevashandisi veamateur PC.

Kuomesa Kwemifananidzo

Image compression inzira yekudzikisa huwandu hwe data inodiwa kumiririra mufananidzo wedhijitari. Izvi zvinoitwa neimwe kana mbiri nzira mbiri: nekubvisa kana kuderedza isingakoshi data yemufananidzo, inonzi kudzvinyirira kusingarasikirwe; kana nekunyatsobvisa data, kunonzi kurasikirwa kwekumanikidza.

ne kudzvinyirira kusingarasikirwe, mufananidzo wacho unooneka sezvawakaita usati watsikirirwa uye unoshandisa ndangariro shoma pakuchengetedza. With a kurasikirwa kwekumanikidza maitiro, imwe data inorasika kana faira yachengetwa uye kudzokororwa asi kana yaitwa nemazvo, hapana kukanganiswa kunooneka kunofanirwa kuoneka kubva kune yekutanga isina kudzvanywa faira.

Maitiro ekumanikidza asingarasikirwe anoshandiswa zvakanyanya mukutora mifananidzo yedhijitari, uye mune graphic dhizaini inoyerera. Maitiro asina kurasikirwa anobvumira kuti mafaera adzvanyirwe kuita madiki madiki pane kana akatsikirirwa nedzimwe nzira senge JPEG mifananidzo yakagadzirirwa kurasikirwa kwekumanikidza kwaunowana diki faira saizi nemutengo wekurasikirwa kwemhando kana ruzivo.

Mafomati emifananidzo asina kurasikirwa anosanganisira:

• Fireworks PNGs (ortf)
• GIFs (gif)
• uye inonyanya kushandiswa fomati TIFF (tiff).

Image processing software applications sePhotoshop inogona kuvhura mhando dzakasiyana dzemifananidzo uye ichishandura kuita imwe yeaya mafomati uchishandisa maficha akaita se "Save As" inova iyo kangani mafaera anoshandurwa pakati pemafomati pasina kudhawunirodha mamwe software.

Mamwe mamwe mafomati emifananidzo akadai JPEG 2000 (jp2) shandisawo rudzi urwu rwekumanikidza nzira asi ivo vanopa imwe bhenefiti sezvo vachigona kuchengetedza zvakanyatsojeka ruzivo kana zvichienzaniswa neJPEGs vachiri nediki faira saizi nekuda kwehurongwa hwavo hwekodhi.

mhedziso

Kurasikirwa kusingaperi chishandiso chine simba chinogona kukubatsira kuderedza saizi yefaira uye kuchengetedza nzvimbo yekuchengetera, ukuwo uchiita shuwa kuti haurasikirwe chero data mukuita. Inokugonesa kudzvanya mafaera pasina kurasikirwa chero ruzivo rwaainarwo, achiagadzira nyore kuchengeta, kuwana uye kugovera.

Mukupedzisa, kudzvinyirira kusingarasikirwe chishandiso chakakosha chemazuva ano kuchengetedza uye manejimendi.

Pfupiso yeKurasikirwa Kusina Kudzvinyirira

Kurasikirwa kusingaperi imhando yedhisiki yekumanikidza data iyo inoderedza saizi yemafaira pasina kupira chero data riri mukati. Yakanakira kudzvanya mameseji-akavakirwa mafaera senge zvinyorwa, maspredishiti, pamwe nemifananidzo nemaodhiyo mafaira.

Kubatsira kukuru kwekumanikidza kusingarasikike ndiko inokubvumira kuti uderedze saizi yefaira pasina kupira mhando yefaira. Izvi zvinoreva kuti iyo chaiyo faira inogona kudzvanywa kakawanda, zvichiita kuti zvive nyore kuchengeta uye kutamisa mafaira makuru nekukurumidza uye nyore. Inobvumirawo kushandiswa kwakanyatsochengetedzwa kwekuchengetedza nekubvisa data rakawandisa kubva mufaira uye kuchengetedza chete zvakakosha zveruzivo.

Kazhinji, kune marudzi maviri ekusarasikirwa kwekumanikidza algorithms - duramazwi-based algorithms senge Deflate/GZip kana Lempel-Ziv (iyo inomanikidza mafaera kuita rondedzero) kana nzira dzekubvisa redundancy senge arithmetic coding kana run length encoding (iyo inobvisa redundancy ne encoding kudzokorora mapatani). Rudzi rumwe norumwe rune zvinangwa zvarwo kana zvasvika kumhando dzemidhiya uye maapplication.

Kune mifananidzo, kunyanya, isingarasikike mafomati emifananidzo senge PNG anosarudzwa pane mamwe mafomati ekurasikirwa akadai JPEG nekuti ivo vanochengetedza zvemifananidzo zvirinani pane zvinoita JPEG ichiri kupa mwero unonzwisisika wekumanikidza pasina kushatisa kwakakosha kumhando yemufananidzo kana kuomerwa mukudhirodha kana kutora iyo yekutanga sosi data. Saizvozvowo, digital audio uncompressed waveform mafaira kuita zviri nani nazvo Vector quantization maitiro pane nzira dzakachena dzekudzikisa bitrate.

Mukupedzisa, kudzvinyirira kusingarasikirwe inzira inoshanda yekudzikisa hukuru hukuru hwefaira pasina chero chibayiro mumhando; izvi zvinovaita sarudzo dzakakura dzekuchengetedza data rakakosha uchichengetedza panzvimbo yekuchengetera uye mutengo. Sezvo maalgorithms akasiyana anoenderana nemhando dzakasiyana dzemidhiya zvinobudirira kupfuura mamwe, zvinogara zvakanaka kuita tsvakiridzo yekuti ndeipi fomati inonyatsoenderana nezvido zvako zvekuchengetedza kuvanzika uye kugona kwenzvimbo - sarudzo chaiyo inogona kuita mutsauko wese!

Zvakanakira Kurasika Kudzvinyirira

Kurasikirwa kusingaperi ndeye data encoding uye decoding process inobvumira mafaera kuchengetedza nzvimbo pasina kupira mhando. Kunyangwe mutengo wekuchengetedza uri kuramba uchidzikira, kuchengetedza zvemhando yepamusoro zvedhijitari kunogona kudhura uye kutora nguva. Inossless compression algorithms inofambisa kuchengetedza, network optimization, uye kufambisa faira kune akasiyana masisitimu. Pamusoro pezvo, yakakwenenzverwa yekumhanyisa data inogona kudzikisa mitengo yekushanda ine chekuita neI/O mashandiro uye kubatsira sainzi kana dhipatimendi rekuongorora data rezvokurapa kusimbisa mhedzisiro yavo nekukurumidza.

Zvakanakira kushandisa kusarasikirwa compression matekiniki zvinosanganisira:

• Kuderedzwa kwehukuru hwefaira pasina kuunza chero kukanganisa kana kuderedzwa kwemhando
• Yakavandudzwa kurodha peji nekudzikisa huwandu hwe data inofambiswa pawebhu
• Magedhi ekuvhura sosi maapplication anodzikisa mari yekutaurirana kuti uwane zvirimo pamaseva epamhepo
• Kuwedzera kwekuchengetedza kuchengetedza kwekugara kwenguva refu kwezvinyorwa zvedhijitari
• Yakavhura nzira dzekuridza chiridzwa uye Internet yekutepfenyura midhiya masevhisi nekugonesa vangangove vateereri vane hushoma bandwidth zviwanikwa.

Mhoroi, ndini Kim, amai uye munhu anofarira zvekumira-famba ane ruzivo mukugadzira midhiya nekuvandudzwa kwewebhu. Ndine chido chikuru chekudhirowa uye mifananidzo, uye ikozvino ndiri kunyura nemusoro munyika yekumira-kufamba. Neblog rangu, ndiri kugovera zvandinodzidza nemi varume.