At both algorithms' highest levels, xz seems to be on average a few percent better at compression ratio, but zstd is a bit faster at compression and much much faster at decompression. So if your goal is to compress as much as possible without regard to speed at all, xz -9 is better, but if you want compression that is almost as good but faster, zstd --long -19 is the way to go
At the lower compression presets, zstd is both faster and compresses better
It means it can capture any frequency up to half the sample rate, perfectly. The "extra detail" in the waveform is higher frequencies beyond the range of human hearing
Why? What reason could there possibly be to store frequencies as high as 96 kHz? The limit of human hearing is 20 kHz, hence why 44.1 and 48 kHz sample rates are used
People are able to on some songs because mp3 is poorly optimized for certain sounds, especially cymbals. However, opus can achieve better quality than that at 128k with fewer outliers than mp3 at 320k, which saves a lot of space.
It's a 30 year old format, and large amounts of research and innovation in lossy audio compression have occurred since then. Opus can achieve better quality in like 40% the bitrate. Also, the format is, much like zip, a mess of partially broken implementations in the early days (although now everyone uses LAME so not as big of a deal). Its container/stream format is very messy too. Also no native tag format so it needs ID3 tags which don't enforce any standardized text encoding.
Zip has terrible compression ratio compared to modern formats, it's also a mess of different partially incompatible implementations by different software, and also doesn't enforce utf8 or any standard for that matter for filenames, leading to garbled names when extracting old files. Its encryption is vulnerable to a known-plaintext attack and its key-derivation function is very easy to brute force.
Rar is proprietary. That alone is reason enough not to use it. It's also very slow.
Yes, all compression levels of gzip have some zstd compression level that is both faster and better in compression ratio.
Additionally, the highest compression levels of zstd are comparable in compression level to LZMA while also being slightly faster in compression and many many times faster in decompression
Theoretically, you don't even have to post it anywhere. Just leave it seeding long enough and it will get picked up by a DHT indexer like btdig.com. However, posting it to some indexer does improve discoverability because not everyone will search btdig.
You can also name the file cover.jpg or folder.jpg and put it in the album's folder, and most players will pick it up. I prefer this method as it saves space
Just use the nicotine-plus client for soulseek instead. It's much more stable, and it's foss