What is the best software to compress a mp3 file to the same format?
You can decrease the bitrate.
Best option : if it is in 160, 192,256 or 360 kbps, set it to 128 kbps, which is not great as much as 360 but enough for quality purpose.
It does not make much difference with 360 kbps on 2.1 channel speakers.
If your files are already in 128 kbps, then you will have to decrease the bit rate and compromise with quality.
Decrease the quality to 96 kbps or 64 kbps, set the bit rate according to your requirement of size.
Or you can use 100 kbps, so it will compress a little, and lose less quality, and appying on all the files can make a difference of total size.
If you don't want low quality, then you can trim the high quality file.
If you compress it with RAR, you will get 2% compression.
So if you many large and long mp3 files, you can try it.
Apply on files with constant bit rate only.
I tried a 45 mb mp3 file and it compressed to 44 MB .rar.
Else convert it to AAC.
you can't decease the size without losing the quality.
Hello, mp3 is already a compressed format. Have you heard about wave format? Wave format is audio in an uncompressed state. A song that would use 80 MB in wave format, would be around 3.5 MB when converted to mp3. If you want an open source mp3 encoder, you could try Lame MP3 encoder:
Mp3 implements a lossy compression scheme automagically. No additional compression is necessary.