packMP3 v1.0d release: Open source under the GPL v3

[packDEV]

I've finally released the packMP3 source code for everyone to optimize and toy around with it. It is attached here and you can also download it from:
www.matthiasstirner.com.

packMP3 is a compression program specially designed for further compression of MPEG-1 Audio Layer III audio files without causing any further loss. Typically it reduces the file size of a MP3 file by 16% based on tests with 6000 randomly selected files.

[Mangix]

Initial impressions after ~10 minutes of playing around:

It achieves pretty good compression of around 86% to 88% on my files. Embedded album art does not seem to be compressed in the way that packJPG compresses it(jpegrescanned mp3 procuded a smaller file). It also seems that using mp3packer prior to compression is not quite a good idea. I'll do more tests on this later.

I just created a CBR mp3 using LAME from a lossless source and repacked it afterwards using mp3packer. The mp3packer file ended up being slightly bigger than the original CBR. However I also took a ~264kbps VBR file and repacked it to 320kbps CBR where compression was hurt. This seems to be a pattern with pack* compressors where preprocessing hurts compression.

Overall, nicely done

[binarysoup]

Very nice work! I tried it out on a ~1gb directory of mp3's of c64 game music remixes (from http://remix.kwed.org/) and got a overall compression ratio of 82.96%.

I had to add -fpermissive to get it to compile using GCC 4.8.1 (Linux 64-bit) due to a invalid conversion from const char* to char* .

[Mangix]

I have several problem samples which were retagged from the original source. Here's one.

https://mega.co.nz/#!TJBlSTjC!COv3OR...Q_NUSOrHaMUgkE

The error I get is (no mpeg audio data recognized)

I redownloaded the album and have no issues with the stock. Will be investigating further...