Lossy/lossless Compression Format W/ Recover File?

2002-09-21 03:43:57

I think I remember reading about this audio compression format a while back.  If I remember right, it could compress losslessly, but it also had a "lossy" format that created a recover file along with it.  The program could take the lossy output and the recover file and combine the two to recreate the original WAV.  If there isn't a format like this right now, it would be REALLY nice.  I don't have the understanding yet of compressor coding or the actual encoding process to understand if this could even be possible, but it would be really handy.  For example, if this idea could be integrated into a compression technology like mp3, we could keep the mp3 file and it's recover file on our huge harddrive.  When we needed to go somewhere with our music, of course all we would need is the mp3, and we would leave the recover file on our computer.  when we needed the original losslessly, just run software to recover the original from the mp3 and the recover file.  No need to re-rip (tho, without huge modifications, i would assume that the recover process would take longer than ripping...but there are other applications to a process like this than the speed issue)  It would seem to me that ideally, the mp3 filesize plus the recover file filesize would equal the original WAV size, but that might not be accurate to what it actually would be, i don't know. 

Has this methodology been implemented?

Lossy/lossless Compression Format W/ Recover File?

Reply #1 – 2002-09-21 04:43:39

Yes! WavPack:
http://www.wavpack.com/

Lossy/lossless Compression Format W/ Recover File?

Reply #2 – 2002-09-21 05:58:45

you beat me to answering my own question!  Yeah, i just read it again in another post on this board.  I still appreciate it tho. 

I await answers to my other questions! 
edit:  More specifically, i would like to know what is keeping this from being implemented into psychoacoustic analyzing type lossy encoders?  If i remember correctly, you cannot compare WavPack lossy 320kbps files to LAME 320 CBR, i think someone mentioned that the WavPack encoded audio was not as good, maybe it could be compared to 192CBR i believe he said. I dont know if THAT is even accurate (I assume a comparison between different theory format types is not very easily done), i guess you would just have to ABX them.  Quality is not yet even my concern though.  I am just interested in more widespread implementation of "split and weighted ratio" audio encoding, or whatever one might call this special lossy method only? WavPack uses.

Lossy/lossless Compression Format W/ Recover File?

Reply #3 – 2002-09-21 08:22:33

Using flac + ogg vorbis was discussed  here.

MP3 would be troublesome to use for something like this because it cannot create the exact length...

Lossy/lossless Compression Format W/ Recover File?

Reply #4 – 2002-09-27 06:44:06

I appreciate it, that thread helped a lot.