The VideoLAN Forums

Fairly new to this, but here it goes:

I have a track from a CD encoded as an MP3 with a bitrate of 128kbps. My main is question is this; if this MP3 was originally ripped from a CD as a WAV, is there any way of decoding (interchangeable with decompressing?) this MP3 back to its original state with WAV quality, or is the quality lost indefinitely after being encoded/(compressed?)?

For some reason it's proven quite difficult to get a rundown of all this information online, otherwise I wouldn't be posting here. It's also possible I'm just impatient

this MP3 was originally ripped from a CD as a WAV, is there any way of decoding (interchangeable with decompressing?) this MP3 back to its original state with WAV quality

No, no way to get back the original WAV quality.

or is the quality lost indefinitely after being encoded/(compressed?)?

Yes it is.

MP3 is a lossy codec. Only lossless codecs allow you to store the original quality and to go back to the original WAV.
Some well known and well used lossless audio codecs: FLAC, WavPack, Monkey's Audio, ALAC, WMAL, True Audio, but there are other ones.
AAC, Vorbis, Musepack are examples of well known lossy codecs like MP3 is.

Thank you for your well-written and educated response, Lotesdelere!

Over the past couple weeks I've become familiar with a lot of those codecs, my primary dilemma being that I wasn't sure if "lossy" meant "permanently lost".

Now I know though, thanks a bunch!


EDIT: Would you also happen to know a good analogy for bitrates? I read one time the sample rate is like taking snapshots of the track. Also when referring to 16-bit, it's described as being 2^16 different possible combinations, ways of being interpreted, or something of the sort.

Only lossless codecs allow you to store the original quality and to go back to the original WAV.

That's almost true. If you want a bit-for-bit encoding, conventional methods of restoring a compressed file, even a lossless file, back to the original WAV format are not exactly accurate. For example: When compressing to FLAC format, FLAC will discard the none-audio bits from the file by default. It's possible to preserve this information, though (insert into the commandline: --keep-foreign-metadata), but really it's not important information pertaining to the audio data.

Second, you won't be able to archive true 'bit-accurateness' with most CD ripping programs (ex: iTunes, Nero, Window Media Player) as they don't accommodate for a drive's read offset, among other things. Anyway, you all know where CloudStalker is heading with this one: Exact Audio Copy. This might be one of the few programs that can give you a bit-identical copy of the original audio data from the CD, with a bit of tweaking (*cough* see here for tweaking *cough*).

Wha, CloudStalker had something in his throat.

Anywho, that's enough of CloudStalker's technobabble! or is it? naw, it is. Now if only CloudStalker can do something about this terrible...*cough*. Oops. You guys do NOT want to see what CloudStalker just coughed up!