I was downloading some music and the band was offering links to download in many compression formats.
Recommended one was "Mp3 320k". The one I was told to download due to it better quality was "AAC".
However, something's weird: how comes the AAC format was something like 2 times less big of a file than the Mp3 one?
Should I consider AAC is indeed of a better quality, or the bigger file size is a good clue as of the quality of the sound?
None.
I order you to forgive yourself!
I'm not a professional on the matter, but if you want quality, AFAIK, you should go for an uncompressed audio format (But I probably don't know what I'm talking about).
Audio File Format
We can't explain the universe, just describe it; and we don't know whether our theories are true, we just know they're not wrong. >Harald Lesch
http://en.wikipedia.org/wiki/Advanced_Audio_CodingNext time google yourself...
Advanced Audio Coding (AAC) is a standardized, lossy compression and encoding scheme for digital audio. Designed to be the successor of the MP3 format, AAC generally achieves better sound quality than MP3 at similar bit rates.[2]
This pretty much answers your question. AAC is better when using similar bitrates (=filesize). It's not that much better that it can compensate for much inferior bitrates.
more technical info:
http://en.wikipedia.org/wiki/Comparison_of_audio_codecs
Then, which is the best format I can download my music at in order to:
1) Lose 0 quality
2) Be able to play it in my iPod
None.
I order you to forgive yourself!
Even though you "lose" quality, I would go for MP3, the file size should be small enough so you can have quite a lot of music and you should still be happy with to listen to your music. (Good enough for you?)
Not sure if it has anything to do with anything, but I found my old MP3 player. For some reasons, all the music that is added to it is converted to ".DAT". I tried converting them back to ".MP3" (Using WinFF) but the files size goes up by a couple KBs so I kept it in that format.
A 92 kbps AAC file is equivalent to a 128 kbps mp3 file.
320 kbps is virtually lossless. I can't hear the difference between anything higher than 160 kbps average using any lossy codec.
bigger filesize=better quality, almost always.
"Parliamentary inquiry, Mr. Chairman - do we have to call the Gentleman a gentleman if he's not one?"
I can hear the difference between 320kbps and FLAC fairly well on most tracks with my setup. However, there's a few factors beforehand that make a big difference. First, the source must be lossless to begin with - converting from a lossy format to a lossless format is basically aids. Some conversion methods can also result in loss of information but I am not technical enough to get into that aspect.
I have no clue what an iPod supports but for the most part you can probably stick with mp3 (Make sure you are always downloading 320 coming from a lossless source like a CD rip though). If it supports AAC, go for that if it's available, but don't bother cross converting. It's like taking a shitty jpeg and converting it into a TGA.
Show them your butt, and when you do, slap it so it creates a sound akin to a chorus of screaming spider monkeys flogging a chime with cacti. Only then can you find your destiny at the tip of the shaft.
Make sure you get some transparent acrylic cable risers to keep the light pollution out of your audio cables.
I just use rockbox, which basically supports everything.
"Parliamentary inquiry, Mr. Chairman - do we have to call the Gentleman a gentleman if he's not one?"
NudeRaider -- blessed innocent soul knows nothing of the strife we had before EUDs were discovered 
DarkenedFantasies -- Probably just didn't care. For example, at some point before release, they've updated the graphics of some of the Protoss buildings (Forge, CyberCore, Citadel, Observatory, Arbiter Tribunal), but instead of properly re-rendering them with edited 3D models, they did crappy copy-paste jobs on the rendered graphics.
