Lossless MP3 compression question

[JamesWasil]

Hi there everyone,

I've noticed something recently with regard to MP3 files. The compression routines I've written and been utilizing seem to compress common executables and text files well but I've been scratching my head when it comes to the mp3s. With LZ4, 7Zip, Rar, and a few other archivers, it seems that mp3 files can be losslessly compressed by about 10 to 20kb on average.

My compression program is not giving me that however, and seems to expand these files by anywhere from 200 bytes to 8k. I've noticed even a standard arithmetic encoder can compress it a little too. What am I doing wrong? Am I missing a step for optimization or precomp of mp3s, not using a range encoder or arithmetic encoding to squeeze out that last 5 to 10%, or is there another way to go about this that I'm not seeing?

Thanks in advance for any insightful tips or helpful commentary, I appreciate it.

James

[xinix]

https://encode.su/threads/271-mp3dump?highlight=mp3
https://encode.su/threads/2826-Compr...?highlight=mp3
https://encode.su/threads/22-StuffIt...?highlight=mp3
https://encode.su/threads/1095-Super...?highlight=mp3
https://encode.su/threads/1237-Compr...?highlight=mp3