Audacity...Why must you hate NicoNico Sound? D:

Hmmmm... do you save the files in their original video names. The original Japanese? It might have something to with the program not being able to read the foreign characters.

NicoSound. I use that too. No worries.
If the problem still persists, try using NicoMimi instead. It's just like NicoSound. http://www.nicomimi.net/

Ah, the current "stable" version of Audacity (not the beta one) isn't capable of reading foreign characters. I had that problem before and I usually just rename the file to something readable (alphanumeric).

I'm almost sure that is your problem, but if you tried importing other MP3s with foreign characters not from Nicosound and it works, then... I don't know. Sorry. XD

wow i have the same problem!!and even when i rename it it doesnt work!

i had this problem too
what i did was to rename the mp3 file into it's "romanized" form + ".mp3"
it works for me

Well maybe try a mix of these two, to download a FLV, and then convert it.
http://code.google.com/p/nicofox/
http://www.aoamedia.com/audioextractor.htm

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I say this because I tried putting the FLV into audacity, and all I got was a one second squeek. But renaming it to alphanumeric title, and AoA Extractor worked. And then Audacity opened it up just fine.

This is the setup I used to use on Youtube before I started using this:
http://www.dvdvideosoft.com/products/dvd/Free-YouTube-to-MP3-Converter.htm

rayen wrote:i had this problem too
what i did was to rename the mp3 file into it's "romanized" form + ".mp3"
it works for me

that works for me.

Audacity can read foreign characters. But when your computer can't read foreign characters and it shows up as squares or some random letters, Audacity can't read those file. Because the character coding messes with the extension (.mp3 ,.wav etc)

in this case you have to FULLY rename the file along with the extension file. (just right click and rename) in roman alphabet.

the only other way that Audacity can't read files is IF the mp3 itself is RAW/PCM material taken from raw data when composing. Because in this case, it doesn't matter what extension you have (even if its mp3). You can't import it NOT UNLESS you reconvert them again, so Audacity can read them.

I ripped files from CD once, and I forgot to compressed it so its readable, and Audacity couldn't read it. even if it was in .mp3 format/ was listenable in any music player.