mp3s @ varying bitrates

I have a half dozen mp3s at varying bitrates that are to be used on an upcoming release. Unfortunately these mp3s are all I have left of these 6 or so tracks. Most of them are 128...with a couple that are 256. Would it be completely destructive to re-encode all of them at 320? I just think a release with mp3s at varying bitrates looks sloppy, but at the same time I don't want to degrade the quality of the tracks just for the sake of keeping things consistent. If there is a 'safe'/'non destructive" way to re-encode these tracks, then please let me know.

Thanks folks.

loafeye

IIRC correctly if you reencode them at 320, you won't get a decrease in quality... however.... you won't get an increase either. You'll just be bloating the filesize. Also, if you reencode, you can save to a separate file to see how the output sounds while keeping the original. Why don't you just keep them the way they are?

Agree'd, whats lost is lost. However, you may degrade slightly in that it's possible that whatever encoding program you use could introduce some alias/noise/crap when encoding anything, and re-enoding an already really lossy and crappy mp3 will add more to it. Either way, it's definately not going to get better at 320.

yeah, don't bother. unless appearances are that important. the quality has already been sacrificed.

thanks guys..........I am not sure what I'm going to do

Nope. If you "reencode" to 320 kb theres maybe additional frequencies that are lost. reencoding from one lossy to another lossy format (what includedes mp3 to mp3) can cause audible artifacts (i can hear them). now these noises are mostly like glitch noises, but unwanted ones. now if you "upgrade" you will get less than when u downgrade to lower bitrates, but its not impossible that you get a lower quality then you had before the additional encoding. not to mention that you use more space then necessary (you encoded to lower quality but take space like for higher)

so i agree to the point that's lost thats lost.