192 or 224 kbps is decent enough but 320kbps or VBR-encoded MP3s are better. Yes, it uses more space but that's a trade-off well worth it if you're into CD quality MP3s.
if the song in mp3 format is of lesser bit rate, is there a converter or something to increase the song's bit rate to 224?
Ok thanks for the info. I tried 192 and 224, I can't discern any diff, so I think 192 will be ok for me because of its smaller file size. Sinubukan ko yung VBR, ok din pero parang may ibang sound or noise na nadagdag sa musuc?
Yes, I think its possible pero siguro hindi mag iimprove yung quality ng sound, lalaki lang yung file size. Please correct me if I'm wrong.
gamit ko mp4. try comparing a 64kbps mp4 with 64kbps mp3 using winamp, you'll see what i mean ...