Is ZIP compression really lossless?

>>105752067 (OP)
No it's lossy. But only the unimportant bytes are discarded.

>zip a file
>unzip the zip
>you get the same file
>>Is ZIP compression really lossless?

>>105752067 (OP)
Is OP truly a faggot?

Wikipedia
https://en.wikipedia.org › wiki › ZIP_(file_format)
ZIP is an archive file format that supports lossless data compression.

>>105752067 (OP)
It's not lossy, but sometimes the zip gets stuck.

>>105752067 (OP)
>12gbfile
that's pretty big. Better zip it before transfer over wifi
>takes like 2 full minutes to zip
>11.8gbfile.zip
yeah thanks for nothing

>>105753296
try .7z with max compression

>>105753296
try .7z with max compression
and also try not being poor

>>105753296
retard.

>>105753305
>>105753308
>implying

>>105753317
>>implying
implying what? 7z is the best archive format and its not close

>>105752135
this 2pbp /thread

>>105752067 (OP)
Look up the LZW algorithm to understand how .zip and .gif work. It is genius.

>>105752067 (OP)
You know you can recover files just from the checksum (or even a few checksum of diff algortihms) filetype, file length, etc using powerful enough processing. It'll be a possibility on powerful quantum processors using a more jacked up grovers algorithm. It's completely lossy.. as in retains 0 of the original file, but completely lossless in restoration

>>105752067 (OP)
no, you get bitrot exactly like mp3s
don't keep your files in zips for too long

>>105752067 (OP)
Yes. verify it by compressing some files, decompressing them, and comparing them byte-by-byte against the originals.

>>105753296
If you want to fully understand this, research "entropy" (the information sense of the word, not the physics sense).
tldr: lossless compression works by finding redundant information and removing the redundancy. If your 12gb file has a lot of redundancy (maybe it's 12gb of logs or a massive CSV) then it'll compress very well.
But if it's a video compressed with a decent video compression codec, then it already has very little redundancy and you won't make it any smaller by zipping it.

>>105753296
huffman coding only works for text, only idiots try to compress media files (already compressed)

>>105753804
>huffman coding only works for text
False. Huffman coding works for any data, and in fact isn't that great for text on its own because it doesn't take advantage of repeating runs of data.

>Is ZIP compression really lossless?

I've seen literal 6 year olds ask more intelligent questions. How the fuck did these people manage to get on the internet and ask this question on a forum BEFORE just googling shit?

>>105753308
>>105753305
WinRAR is still the king I'm afraid. 7zip has issues with giant files. There's a reason all the pirates still use rar.

>>105753321
won't make a meaningful difference if the file just doesn't compress well, maybe he'll get to 11.7 GB but that'll be about it

>>105754584
It does make a huge difference in transfer speed when you zip thousands of files tho, because you can avoid all the overhead of individual file transfers

>>105754609
both zip and 7z do this though

>>105754418
???
1. 99% of shit i pirate is in .7z format
2. it just works, rajeesh upgrade your core 2 duo

>>105755570
you replied to a shill

>>105753296
zstd -21
that will cut a gig or three after a few years of compression

>deranged bait thread
>people reply unironically

>>105752196
Oh no bro

>>105753296
Why would (you) need more in the era of cheap storage and high internet bandwidth

>>105752067 (OP)
if your files get caught in the zipper yes