Lossless vs Lossy Compression Wɔakyerɛkyerɛ mu: Akwankyerɛ a Edi Mu
Te nsonsonoe titiriw a ɛda compression ahorow ntam, wɔn algorithms, applications, ne sɛnea wobɛpaw nea ɛfata ama w’ahiade pɔtee no ase.
Data Compression ho ntease
Data compression yɛ ɔkwan titiriw a wɔfa so yɛ dijitaal mfiridwuma mu a ɛtew fael akɛse so denam redundancy a woyi fi hɔ ne nsɛm a wɔsan hyehyɛ no foforo so. Bere a yɛn dijitaal wiase no trɛw denam mfonini ahorow a ɛyɛ fɛ, 4K video ahorow, ne application ahorow a ɛyɛ den so no, nhyɛso a etu mpɔn no bɛyɛ nea ɛho hia kɛse ma nneɛma a wɔkora so yiye, data a wɔde mena ntɛmntɛm, ne bandwidth a wɔde di dwuma no so tew.
Compression algorithms no hyɛ akuw atitiriw abien mu: a enni adehwere ne adehwere. Nsonsonoeɛ a ɛda saa akwan yi ntam no nteaseɛ ho hia na ama yɛasi gyinaeɛ a ɛwɔ nimdeɛ a ɛfa sɛdeɛ wɔbɛkora, de akɔma, na wɔde digyital data ayɛ adwuma wɔ dwumadie ne nnwuma ahodoɔ mu.
Nea Enti a Nhyɛso Ho Hia
Digitals nneɛma a ɛrepae no ama nhyɛso ho hia sen bere biara. Efi streaming services a ɛde 4K video kɔ telefon a wokura kyin so, kosi cloud storage platforms a fael ɔpepepem pii gu mu, kosi wɛb brawsa ahorow a ɛde nkratafa a ɛyɛ den gu milisekɔn mu so —compression mfiridwuma ne tumi a aniwa nhu a ɛma yɛn dijitaal wiase no yɛ adwuma yiye.
Lossless vs Lossy: Nsonsonoe atitiriw a ɛwɔ mu
Nhyɛso a Ɛnyɛ Adehwere
Mfitiase data a wɔasan ayɛ no pɛpɛɛpɛ
Nneɛma a Wɔhwere
Data a wɔtew so a wɔhwere su a wogye tom
Nneɛma a wɔkora so 100% a ɛyɛ mfitiaseɛ data. Sɛ wɔpopa a, nea efi mu ba no ne fibea no yɛ pɛ bit-for-bit.
Yi data a wobu no sɛ ɛho nhia pii no fi hɔ daa. No mfitiase fael no ntumi nnya bio pɛpɛɛpɛ bere a wɔahyɛ no den akyi.
Mpɛn pii no, otumi du ho 2:1 kosi 5:1 compression ratios a egyina data su so. Ahwehwɛde a ɛne sɛ wɔbɛkora nsɛm nyinaa so no anohyeto.
Ebetumi anya ratios a ɛkorɔn kɛse, mpɛn pii 10:1 kosi 100:1 anaa nea ɛboro saa, denam nsɛm a “perceptually redundant” a wɔtow gu so.
Nsɛm, nhyehyɛe ahorow a wotumi di dwuma, database ahorow, aduruyɛ mfonini ahorow, nneɛma a wɔkora so, adwumayɛfo adwumayɛ nhyehyɛe, biribiara a ɛhwehwɛ sɛ wɔsan si no pɛpɛɛpɛ.
Mfonini, nnwom, video a wɔde fa so, wɛb mfonini, ne application afoforo a data bi a wɔhwere no yɛ nea wogye tom wɔ atirimpɔw ahorow a mfaso wɔ so.
Ebetumi ayɛ compress na decompress mpɛn pii a ɛnsɛee. Decompression a ɛto so 100 no ne nea ɛto so 1 no yɛ pɛ.
Recompression biara de ba su foforo a wɔhwere. Saa “awo ntoatoaso mu adehwere” yi boaboa ano wɔ kyinhyia biara mu.
Mpɛn pii no, ɛhwehwɛ sɛ kɔmputa tumi a ɛba fam ma encoding/decoding sɛ wɔde toto advanced lossy algorithms ho a.
Mpɛn pii no, ɛho hia kɔmputa so nneɛma pii, titiriw ma algorithms a ɛyɛ nwonwa te sɛ video codecs.
Wɔakyerɛkyerɛ Nhyɛso a Ɛnyɛ Adehwere mu
Dɛn ne Lossless Compression?
Lossless compression tew fael kɛse so denam akontaabu a ɛho nhia a wohu na woyi fi hɔ a ennyi nsɛm biara mfi hɔ no so. Sɛ wɔpopa a, fael no ne mfitiase de no yɛ pɛ bit-for-bit, na ɛnhwere ne su anaa data mudi mu kura koraa.
Sɛnea Lossless Compression Yɛ Adwuma
Lossless compression algorithms de akwan horow di dwuma de tew fael kɛse so bere a wɔhwɛ hu sɛ wɔbɛsan ayɛ mfitiase data no pɛpɛɛpɛ. Saa akwan yi hwehwɛ nhwɛso, mpɛn dodow, ne nhyehyɛe ahorow a ɛwɔ data no mu mu de kyerɛw no yiye a nsɛm nhwere.
Mmirikatu-Length Encoding (RLE) .
RLE de botae ne akontaabu biako si data nneɛma a ɛyɛ pɛ (runs) a ɛtoatoa so ananmu. Sɛ nhwɛso no, “AAAAAABBBCCCCC” bɛyɛ “6A3B5C”, a ɛtew kɛse so kɛse ma data a ɛwɔ ntoatoaso pii a wɔsan yɛ no.
Original: WWWWWWWWWWBBBWWWWWWWWWWWWBBBWWWWWWWWWW Compressed: 10W3B12W3B10W
Huffman Mmarahyɛ Bagua
Saa kwan yi de koodu a ne tenten sesa ma nkyerɛwde a wɔde hyɛ mu, a mmara ntiantiaa wom ma nkyerɛwde a ɛtaa ba. Saa akontabuo kwan yi ma encoding a egyina character frequency distribution so no yɛ papa.
Frequent character 'e': 101 Less frequent 'z': 1010101011
LZ77 & LZ78 Nneɛma a Wɔde Yɛ Adwuma
Saa akwan a egyina nsɛm asekyerɛ nhoma so yi de nsɛm a ɛfa mfonini biako a ɛwɔ asuten a wɔanhyɛ no den no mu dedaw ho si data a ɛba mpɛn pii ananmu. Wɔn na wɔyɛ nnyinaso ma format ahorow a agye din te sɛ ZIP ne GIF.
Instead of storing "compression compression" Store "compression [pointer to earlier instance]"
Deflate Algorithm no mu na ɛyɛ adwuma
Sɛ wɔka LZ77 ne Huffman coding bom a, Deflate ma compression a ɛkyɛn so a ahoɔhare pa wom. Wɔde di dwuma wɔ ZIP, PNG, ne HTTP nhyɛsoɔ (gzip) mu, na ɛma ɛyɛ algorithms a wɔde di dwuma kɛseɛ no mu baako.
- ZIP nneɛma a wɔkora so
- PNG mfonini ahorow
- HTTP nhyɛso (gzip) .
Nkontaabu mu Nkontaabu
Saa kwan yi gyina hɔ ma nkrasɛm bi sɛ akontaahyɛde ahorow a ɛwɔ 0 ne 1. Ebetumi anya nhyɛso nsusuwii a ɛbɛn nsusuwii mu entropy anohyeto no, na ɛma ɛyɛ adwuma yiye kɛse ma data ahorow bi.
Ebetumi de encode fractional bits wɔ symbol biara mu, de compression a eye sen Huffman ama ma sources pii.
Delta Encoding a Wɔde Di Dwuma
Sɛ anka ɛbɛkora botaeɛ a ɛyɛ pɛpɛɛpɛ so no, delta encoding sie nsonsonoeɛ a ɛwɔ botaeɛ a ɛtoatoa soɔ ntam. Eyi tu mpɔn titiriw ma data a ɛwɔ baabi a gyinapɛn ahorow a ɛbɛn ho no yɛ pɛ, te sɛ ɔdio nhwɛsode anaa sensor akenkan.
Original: 105, 107, 106, 110, 108 Delta: 105, +2, -1, +4, -2
Fael Formats a Wɔtaa Yɛ a Ɛnyɛ Adehwere
Nneɛma a Wɔakora So
Mfonini ahorow
Ɔdio a wɔde tie
Wɔakyerɛkyerɛ Lossy Compression mu
Dɛn ne Lossy Compression?
Lossy compression tew fael kɛse so denam nsɛm bi a eyi fi hɔ daa so, titiriw data a ɛho nhia anaasɛ ɛho nhia pii wɔ nkate mu. Fael a wɔayi afi mu no yɛ soronko wɔ mfitiase de no ho, nanso wɔayɛ nsonsonoe no sɛnea ɛbɛyɛ a ɛbɛyɛ den anaasɛ ɛrentumi nyɛ yiye sɛ nnipa behu wɔ tebea horow a ɛfata mu.
Sɛnea Lossy Compression Yɛ Adwuma
Lossy compression nya compression ratios a ɛkorɔn kɛse denam gyinaesi a ɛfa ɔkwan a wɔfa so si data a ɛsɛ sɛ wɔtow gu ho no so. Saa algorithms yi de nimdeɛ a ɛfa nnipa nkate ho—nea yɛn aniwa ne yɛn aso betumi ahu ne nea entumi nhu—di dwuma de yi nsɛm fi hɔ wɔ akwan horow so a ɛmma nkɛntɛnso a ɛda adi wɔ su pa so no nyɛ kɛse.
Nsakrae Coding
Saa kwan yi dane data fi domain biako (te sɛ spatial) kɔ foforo (te sɛ frequency) baabi a wobetumi de compression adi dwuma yiye. Discrete Cosine Transform (DCT) a wɔde di dwuma wɔ JPEG mu no yɛ nhwɛso titiriw.
- Dane mfonini blocks kɔ frequency components mu
- Quantize high-frequency components no denneennen
- Nnipa aniwa ntumi nte saa mpɛn dodow yi nka kɛse
Nneɛma dodow a wɔde kyerɛ
Quantization brɛ data botae ahorow no pɛpɛɛpɛyɛ ase. Ɛde input value ahodoɔ bi map kɔ output values ketewa bi so, na ɛtew bit dodoɔ a ɛhia na wɔde gyina hɔ ma data no so yie.
Original values: 4.13, 4.28, 4.97, 4.02 Quantized to: 4, 4, 5, 4
Adwene ne Nneyɛe Ho Nhwɛso
Wɔde saa ɔkwan yi di dwuma wɔ ɔdio a wɔde mia so mu no, ɛde anohyeto ahorow a ɛwɔ nnipa aso mu no di dwuma. Ɛkyerɛ ɔdio afã horow a wobetumi ayi afi hɔ a ennya nnyigyei a wosusuw sɛ ɛyɛ papa no so nkɛntɛnso.
- Nnyigyei a wɔde kata aso so: Nnyigyei a ano yɛ den kata nnyigyei a ɛyɛ komm so
- Mpɛn dodow a wɔte nka: Nnipa te mpɛn dodow a ɛwɔ mfinimfini yiye
- Bere mu akataso: Nnyigyei betumi akata afoforo a ɛba bere tiaa bi ansa na aba/akyi
Nkate mu Nsɛm a Wɔde Di Dwuma
Te sɛ adwene mu nnyigyei ho nhwɛso nanso wɔ aniwa so nsɛm ho no, saa kwan yi yi nsɛm a nnipa aniwa ntaa nhu, titiriw wɔ nsɛm a ɛkɔ so mpɛn pii ne kɔla ahorow mu.
Wɔde di dwuma wɔ JPEG, MPEG, ne aniwa so nhyɛso gyinapɛn afoforo mu de di data a ɛho hia wɔ nkate mu di kan.
Motion Akatua a Wɔde Ma
Video compression technique a ɛde temporal redundancy di dwuma denam encoding nsonsonoe a ɛda frame ahorow ntam sen frame biara a edi mũ so. Nsakrae a efi frame biako so kɔ foforo so nkutoo na wɔde encode ahyɛ mu koraa.
- Fa “keyframes” (I-frames) a edi mũ sie bere ne bere mu
- Wɔ frame afoforo ho no, sie nsonsonoe nkutoo (P-frames) anaa nsonsonoe a ɛwɔ akwan abien so (B-frames) .
- Ɛde fael kɛse so tew kɛse ma video
Chroma Subsampling a Wɔde Di Dwuma
Saa kwan yi brɛ kɔla ho nsɛm ase sen hann ho nsɛm, na ɛde sɛnea onipa aniwa tumi te hann nka kɛse sen kɔla ahorow a ɛsono emu biara no di dwuma.
- 4:4:4 – Subsampling biara nni hɔ (kɔla a ɛyɛ pɛpɛɛpɛ) .
- 4:2:2 – Ɛma kɔla a ɛkɔ soro no yɛ fã
- 4:2:0 – Ɛma kɔla nsusuwii a ɛkɔ soro ne nea ɛda fam nyinaa yɛ fã
Fael Formats a Ɛtaa Yɛ Lossy
Mfonini ahorow
Ɔdio a wɔde tie
Video
Nneɛma a Wɔde Di Dwuma a Ɛyɛ Mfaso ne Nsɛm a Wɔde Di Dwuma
Digitals Mfoninitwa
Nhyɛso a Ɛnyɛ Adehwere
- RAW format a wɔkora so ma mfoninitwafo a wɔyɛ adwumaden
- Mfonini ahorow a ɛho hia a wɔkora so yiye wɔ baabi a wɔkora nneɛma so
- Mfonini ahorow a ɛhwehwɛ sɛ wɔyɛ ho adwuma kɛse wɔ akyi anaasɛ wɔyɛ mu nsakrae
- PNG format a wɔde yɛ mfonini a ɛwɔ nkyerɛwee anaa anoano a ɛyɛ nnam
Nneɛma a Wɔhwere
- JPEG ma da biara da mfonini ne wɛb kyɛfa
- Thumbnail awo ntoatoaso ma galleries ne previews
- Social media uploads wɔ baabi a size anohyeto ahorow wɔ hɔ
- Email attachments ne nkrasɛm application ahorow
Audio a Wɔyɛ
Nhyɛso a Ɛnyɛ Adehwere
- Nneɛma a wɔkyere gu kasɛt so yiye wɔ studio ahorow (WAV, FLAC) .
- Audiophile nnwom a wɔaboaboa ano
- Audio engineering ne adwumayɛfo a wɔyɛ adwumaden
- Nsɛm a wɔakyere agu hama so a ɛho hia a wɔkora so
Nneɛma a Wɔhwere
- Nnwuma a wɔde fa nsɛm so (Spotify, Apple Music) .
- Nnwom afiri a wotumi fa so a nneɛma a wɔkora so kakraa bi
- Intanɛt so radio ne podcast ahorow
- Nnwom a wɔde yɛ video ne nsɛm a wɔka kyerɛ wɔ akyi
Video a Wɔyɛ
Nhyɛso a Ɛnyɛ Adehwere
- Sini ne TV so dwumadi ho abenfo
- Nneɛma a wonya fi aniwa so
- Aguadi adwuma a wɔbɔ ka kɛse
- Aduruyɛ ne nyansahu mu video ho nkrataa
Nneɛma a Wɔhwere
- Nneɛma a wɔde fa nsɛm so (Netflix, YouTube) .
- Television a wɔbɔ ho dawuru
- Video nhyiam ne webinar ahorow
- Social media video ahorow a wɔde twitwiw nneɛma
Wɛb Nkɔsoɔ
Nhyɛso a Ɛnyɛ Adehwere
- PNG ma logos, icons, ne mfonini ahorow a ɛda adi pefee
- SVG ma interface elements a wotumi sesa
- WebP lossless ma mfonini a ɛyɛ den a ɛhwehwɛ sɛ ɛyɛ pɛpɛɛpɛ
- Agyapade a egyina nsɛm so a wɔde hyɛ (HTML, CSS, JavaScript) .
Nneɛma a Wɔhwere
- JPEG anaa WebP ma mfonini ne mfonini a ɛyɛ den
- MP4 video a codecs a ɛfata wom
- Nnwom a ɛwɔ akyi ne nnyigyei a wɔde yɛ nneɛma
- Mfonini a wɔde hyɛ mu a ɛkɔ so ma ɛyɛ adwuma a wosusuw sɛ ɛyɛ ntɛmntɛm
Data a Wɔkora So & Nneɛma a Wɔde Sie
Nhyɛso a Ɛnyɛ Adehwere
- Database backups ne nneɛma a wɔde kɔ amannɔne
- Source code akorae ahorow
- Nwoma a wɔde asie (PDF, Office fael ahorow) .
- Adwumayɛ ho kyerɛwtohɔ a ɛho hia ne mmara kwan so nkrataa
Nneɛma a Wɔhwere
- Video a wɔde hwɛ nneɛma so a ɛwɔ ahwehwɛde ahorow a ɛyɛ papa a wogye tom
- Nsɛm ho amanneɛbɔfo akorae a ɛnyɛ nea ɛho hia kɛse a wogye tom sɛ wɔhwere su pa bi
- Automated backups a ɛfa nneɛma a ɔdefo no ayɛ ho
- Data akɛse a ɛho nhia sɛ wonya nokwaredi a edi mũ
Mobile so Nnwuma a Wɔde Di Dwuma
Nhyɛso a Ɛnyɛ Adehwere
- Application executable fael ne koodu
- UI elements a ɛhwehwɛ sɛ ɛyɛ pɛpɛɛpɛ
- Nsɛm a wɔakyerɛw ne nhyehyɛe ho data
- Data a wɔde sie a ɛho hia a wɔde di dwuma
Nneɛma a Wɔhwere
- Mfonini ne mfonini ahorow a ɛwɔ app no mu
- Video so nkyerɛkyerɛ ne ɔyɛkyerɛ ahorow
- Audio amanneɛbɔ ne nnyigyei a wɔde bɔ nnwom
- Cached content ama offline hwɛ
Compression Types denam Fael Format so
Fael ahorow ahorow de nhyɛso akwan pɔtee bi a wɔayɛ no yiye ama wɔn nsɛm no su di dwuma. Sɛ wote format ahorow a wɔde compression akwan bɛn na edi dwuma ase a, ɛboa wo ma wusi gyinae pa wɔ wo dijitaal nsɛm a wode besie na wode akyɛ ho.
| Ɔkwan a wɔfa so yɛ no | Korɔ | Ɔkwan a Wɔfa so Yɛ Nhyɛso | Nea Wɔde Di Dwuma Yiye Ma | Nhyɛso Nkyɛmu |
|---|---|---|---|---|
| Mfonini ahorow | ||||
| PNG | Ɛnyɛ adehwere | Nneɛma a wɔde yi mframa fi mu (LZ77 + Huffman) . | Mfonini, screenshots, mfonini a nsɛm anaa nea ɛda adi pefee wom | 1.5:1 kosi 3:1 |
| JPEG | Ɔhweree ade | DCT, dodow a wɔde kyerɛ | Mfonini ahorow, mfonini ahorow a ɛyɛ den a kɔla ahorow a ɛsakra ntɛmntɛm wom | 10:1 kosi 20:1 |
| WebP | Hybrid a wɔde afrafra | Nkɔmhyɛ coding (a ɛyera), VP8 intra-frame (a ɛyera) . | Wɛbsaet mfonini ahorow, mfonini ahorow a ɛyɛ mmuae | Lossy: 25-35% ketewaa bi sen JPEG Lossless: 26% sua sen PNG |
| TIFF | Ɛnyɛ adehwere | Nneɛma ahorow (LZW, ZIP, ne nea ɛkeka ho) . | Mfoninitwa a ɛyɛ adwumaden, nhoma tintim, nneɛma a wɔkora so | 1.5:1 kosi 3:1 |
| AVIF | Ɔhweree ade | AV1 intra-frame coding a wɔde kyerɛw nsɛm | Next-gen wɛb mfonini, application ahorow a ɛkɔ akyiri | Ɛkɔ 50% a ɛyɛ ketewaa sen JPEG |
| Audio Formats a Wɔde Di Dwuma | ||||
| MP3 | Ɔhweree ade | Adwene mu nnyigyei ho nhwɛso, MDCT | Nnwom, podcast, atie a wɔde di dwuma wɔ ɔkwan a ɛkɔ akyiri so | 10:1 kosi 12:1 |
| FLAC na ɛyɛ | Ɛnyɛ adehwere | Linear nkɔmhyɛ, Aburow coding | Audiophile nnwom a wɔaboaboa ano, archiving | 2:1 kosi 3:1 |
| AAC | Ɔhweree ade | Adwene mu nnyigyei ho nhwɛso a ɛkɔ akyiri | Digitals broadcasting, nnwuma a wɔde fa nsɛm so | Ɛyɛ papa sen MP3 wɔ bitrate koro no ara mu |
| Opus a wɔde yɛ adwuma | Ɔhweree ade | SILK + CELT codec ahorow a wɔde kyerɛw nsɛm | Ɛnne nkitahodi, bere ankasa mu dwumadie | Ɛkorɔn sen codec afoforo wɔ bitrates a ɛba fam mu |
| WAV | Wɔanhyɛ no den | Obiara nni hɔ (mpɛn pii no, ɛwom sɛ nhyɛso bi betumi aba de) . | Studio a wɔkyere gu kasɛt so, master audio fael ahorow | 1:1 (nhyɛso biara nni hɔ default so) . |
| Video Nneɛma a Wɔde Yɛ Adwuma | ||||
| H.264/AVC na ɛwɔ hɔ | Ɔhweree ade | Kankyee ho akatua, DCT, CABAC/CAVLC | Streaming, broadcast, dijitaal video a wɔde di dwuma | 50:1 kosi 100:1 |
| H.265/HEVC na ɛkyerɛkyerɛ mu | Ɔhweree ade | Advanced motion prediction, coding blocks akɛse | 4K / 8K nsɛm, a ɛkorɔn-efficiency streaming | 25-50% ye sen H.264 |
| AV1 | Ɔhweree ade | Nkɔmhyɛ ne nsakrae coding a ɛyɛ nwonwa | Awo ntoatoaso a edi hɔ streaming, application ahorow a wontua hwee | 30% ye sen HEVC |
| ProRes | Ɔhweree ade (wɔhwɛ so a ɛnyɛ nea ɛyera) . | DCT a egyina intraframe so | Video a wɔsesa, nea wɔyɛ wɔ akyi | 5:1 kosi 10:1 (egyina variant so) . |
| FFV1 | Ɛnyɛ adehwere | Golomb-Rice mmara ahorow, nsɛm a ɛfa ho nhwɛso | Video a wɔkora so, nea wɔkora so | 2:1 kosi 3:1 |
| Nwoma a Wɔahyehyɛ | ||||
| Hybrid a wɔde afrafra | Deflate (nsɛm), JPEG/JBIG2 (mfonini ahorow) . | Nwoma a wɔkyekyɛ, nkrataa, nwoma ahodoɔ | Ɛsono emu nsɛm kɛse | |
| DOCX/XLSX na ɛwɔ hɔ | Ɛnyɛ adehwere | ZIP (core), ahorow ahorow ma nneɛma a wɔde ahyɛ mu | Ɔfese nkrataa, nkrataa a wɔde kyerɛw nsɛm | 1.5:1 kosi 3:1 |
| EPUB | Hybrid a wɔde afrafra | ZIP (container), ahorow ahorow ma emu nsɛm | E-nhoma, dijitaal nhoma ahorow | Egyina emu nsɛm no su so |
| Nneɛma a Wɔde Sie | ||||
| ZIP | Ɛnyɛ adehwere | Nneɛma a wɔde yi mframa fi mu (LZ77 + Huffman) . | Fael a wɔkora so wɔ ɔkwan a ɛkɔ akyiri so, cross-platform a ɛne ne ho hyia | 2:1 kosi 10:1 (egyina emu nsɛm so) . |
| 7Z | Ɛnyɛ adehwere | LZMA, LZMA2, PPMd, ne nea ɛkeka ho. | High-ratio compression hia | 30-70% ye sen ZIP |
| RAR | Ɛnyɛ adehwere | Algorithm a ɛyɛ ne dea | Maximum compression ne nnwinnade a ɛyɛ wɔn de | 10-30% ye sen ZIP |
Sɛnea Wobɛpaw Compression Type a Ɛfata
So mfitiase data no a wɔbɛsan ayɛ no pɛpɛɛpɛ ho hia?
So nneɛma a wɔkora so anohyeto anaa bandwidth anohyeto yɛ nneɛma a ɛhaw adwene kɛse?
So wɔbɛsan asiesie emu nsɛm no anaasɛ wɔbɛyɛ ho adwuma?
Nneyɛe Pa a Wɔde Yɛ Compression Strategy
- Fa mfitiase masters no sie a compression a enni adehwere anaasɛ wɔ ɔkwan a wɔanhyɛ so bere biara a ɛbɛyɛ yiye. Eyinom yɛ wo dijitaal “negatives.”
- Yɛ lossy versions ma nkyekyɛmu ne kyɛfa sɛnea ɛbɛyɛ a ɛbɛkari pɛ ne fael kɛse a egyina sɛnea wɔpɛ sɛ wɔde bedi dwuma no so.
- Susuw ɔkwan a wɔfa so yɛ no nnidiso nnidiso ho a ɛsono compression levels ma atirimpɔw ahorow (archive, adwumayɛ fael, kyekyɛ).
- Sɔ compression nhyehyɛe ahorow hwɛ sɛnea ɛbɛyɛ a wubehu kari pɛ a eye sen biara wɔ fael kɛse ne ne su ntam ma wo nsɛm pɔtee no.
- Kɔ so nya nsɛm a ɛfa compression mfiridwuma foforo ho efisɛ wobetumi ama nkɔso kɛse aba wɔ adwumayɛ ne nea ɛyɛ papa mu.
- Kyerɛw wo compression adwumayɛ nhyehyɛe no sɛnea ɛbɛyɛ a ɛbɛyɛ pɛpɛɛpɛ na ama daakye fael sohwɛ ayɛ mmerɛw.
Nsɛm a Wɔtaa Bisa
So wubetumi adan akɔ nhyɛso a enni adehwere ne nhyɛso a wɔhwere ntam?
Wubetumi adan afi ɔkwan a ɛnyɛ adehwere so akɔ nea wɔhwere so bere nyinaa, nanso nea ɛne no bɔ abira no ntumi nyɛ yiye ankasa. Sɛ wɔtow nsɛm gu wɔ lossy compression mu pɛ a, wontumi nnya bio. Sɛ wodane fi lossy format mu kɔ losless format mu a, ɛbɛkora fael no so wɔ ne mprempren tebea mu (a quality loss biara ka ho), nanso ɛrensan nsan mfa mfitiase data a woyii fii hɔ wɔ lossy compression a edi kan no mu no mma.
So compression sɛe fael ahorow anaasɛ ɛmma ɛnyɛ den?
Lossless compression nsɛe fael ahorow da —sɛnea wɔkyerɛ ase no, fael a wɔayi afi mu no ne mfitiase de no yɛ pɛ. Lossy compression yi data fi hɔ daa, nanso eyi nam nhyehyɛe so na ɛtaa de n’ani si nsɛm a enni nkate mu nkɛntɛnso ketewaa bi so. Ɛdefa sɛnea ɛyɛ den ho no, fael ahorow a wɔahyɛ no den yiye no nyɛ nea entumi nnyina pintinn kɛse fi awosu mu te sɛ nea wɔanhyɛ no den no. Nanso, ebia fael ahorow bi a wɔahyɛ no den kɛse no betumi asɛe kɛse, efisɛ mfomso ketewaa bi betumi aka data pii bere a nsɛm ahyɛ mu ma kɛse no.
Dɛn nti na obi bɛpaw lossy compression sɛ eyi data fi hɔ a?
Lossy compression ma compression ratios a eye kɛse sen akwan a lossless, mpɛn pii no ɛyɛ nketewa mpɛn 10-100. Wei ma ɛyɛ nea mfaso wɔ so ma application ahorow a fael kɛse, bandwidth, anaa storage anohyeto ahorow yɛ nneɛma a ɛho hia a ɛsɛ sɛ wosusuw ho. Nhumu titiriw ne sɛ wɔayɛ lossy compression sɛ ebeyi nsɛm a nnipa ntaa nhu anaasɛ ennya nkɛntɛnso kɛse biara wɔ su a wosusuw sɛ ɛyɛ so no afi hɔ. Wɔ application pii fam—te sɛ nnwom a wɔde fa streaming, mfonini a wɔkyɛ, anaa video a wɔhwɛ—no, mfaso kɛse wɔ aguadi a ɛda mfiridwuma mu su a wɔatew so ketewaa bi ne fael kɛse a wɔatew so kɛse ntam no so.
Ɔkwan bɛn so na compression nya SEO so nkɛntɛnso ma mfonini ahorow a ɛwɔ wɛbsaet ahorow so?
Mfonini a wɔde hyɛ mu no nya SEO so nkɛntɛnso kɛse denam ahoɔhare a wɔde hyɛ krataafa so, a ɛyɛ ade titiriw a ɛde dibea a ɛwɔ hɔ ma nhwehwɛmu engine ahorow no so. Mfonini a wɔabɔ no yiye no tew kratafa no mu duru so na ɛma bere a wɔde gu mu no tu mpɔn, na ɛde osuahu a wɔde di dwuma no metrics a eye ne nhwehwɛmu dodow a ɛkorɔn ba. Bere a mpɛn pii no, nhyɛso a wɔhwere no ma wɔtew kɛse so yiye no, ade titiriw ne sɛ wobehu sɛnea ɛkari pɛ—ɛsɛ sɛ wɔmia mfonini ahorow no sɛnea ɛbɛyɛ a ɛbɛhyɛ ntɛmntɛm nanso ɛkura ne su a ɛdɔɔso a ɛbɛma wɔn a wɔde di dwuma no anya kyɛfa na wɔde nsɛm ama yiye. Nnɛyi formats te sɛ WebP ma compression a ɛkyɛn so a ɛyɛ papa, na mfonini ahorow a ɛyɛ mmuae a wɔde bedi dwuma no hwɛ hu sɛ wɔde bɛma yiye wɔ mfiri ahorow nyinaa so.
So compression kwan bi wɔ hɔ a ɛyɛ adwuma yiye ma data ahorow nyinaa?
Compression kwan biako biara nni hɔ a ɛyɛ adwuma yiye ma data ahorow nyinaa. Nsɛm ahorow ahorow wɔ akontaabu mu su ahorow ne redundancies ahorow a wobetumi de adi dwuma. Ɛsono sɛnea nsɛm no mia so wɔ mfonini ahorow ho, a ɛsono sɛnea ɛte wɔ ɔdio anaa video ho no. Wɔ ɔfã bi te sɛ mfonini mu mpo no, mfonini a kɔla ahorow a ɛsakra ntɛmntɛm no mia so wɔ ɔkwan soronko so sen mfonini a ano yɛ nnam a kɔla kakraa bi na ɛwom. Eyi nti na nhyehyɛe soronko wɔ hɔ ma nsɛm ahorow ahorow, ne nea enti a nnɛyi nhyɛso nnwinnade taa hwehwɛ nsɛm mu de di dwuma de algorithm a etu mpɔn sen biara ma data nhyehyɛe pɔtee biara di dwuma.
Mɛyɛ dɛn ahu sɛ mede compression level a ɛfata redi dwuma?
Sɛ wobɛhwehwɛ compression level a ɛfata a, ɛhwehwɛ sɛ wokari pɛ wɔ nneɛma abiɛsa mu: fael kɛse, ne su, ne bere a wɔde yɛ adwuma. Sɛ wopɛ sɛ wobɔ wo ho ban a, yɛ aniwa anaa aso mu sɔhwɛ ahorow de hu baabi a su a ɛso tew no bɛyɛ nea ɛda adi wɔ wo nsɛm pɔtee ne atiefo no ho. Sɛ wopɛ lossless compression a, fa toto algorithms ahorow ho na woahu size reduction a eye sen biara ma wo data type. Application pii de compression levels a wɔahyɛ ato hɔ (e.g., low, medium, high) ma, a ɛma mfiase pa. Sɔ nea wɔahyɛ da ayɛ no hwɛ bere nyinaa wɔ baabi a wopɛ sɛ woyɛ no —ebia nhyɛso nhyehyɛe a ɛte sɛ nea eye wɔ wo nkɔso afiri no so no renyɛ papa wɔ mfiri ahorow so anaasɛ wɔ tebea horow a ɛsono sɛnea wobɛhwɛ mu.
So fael ahorow a wɔde mia no mpɛn pii no ma wɔhwere ne su foforo?
Wɔ compression a enni adehwere ho no, compression ne decompression cycles a wɔtaa yɛ no nni nkɛntɛnso biara wɔ quality so —fael no da so ara te sɛ nea edi kan no. Wɔ lossy compression ho no, compression cycle foforo biara taa de quality loss foforo ba, a wonim no sɛ “generation loss.” Eyi yɛ ɔhaw titiriw bere a wode algorithms anaa nhyehyɛe ahorow redi dwuma wɔ awo ntoatoaso ahorow mu no. Sɛ nhwɛso no, sɛ wosiesie JPEG mfonini mpɛn pii na wode sie a, ɛbɛma ne su asɛe nkakrankakra. Sɛnea ɛbɛyɛ a awo ntoatoaso a wɔhwere no so tew no, yɛ adwuma fi fibea fael a ɛkorɔn sen biara a ɛwɔ hɔ bere nyinaa, na sie mfinimfini adwuma wɔ nkyerɛwde a enni adehwere mu bere a woreyɛ nsakrae.
Si Compression Ho Gyinaesi a Wode Nim So
Nsonsonoeɛ a ɛda lossless ne lossy compression ntam nteaseɛ boa wo ma wo digyital adwumayɛ nhyehyɛeɛ no yɛ yie, sie baabi a wode nneɛma sie, na wohwɛ sɛ wo nsɛm no kura su a ɛfata ma ne deɛ wɔahyɛ da ayɛ.