it sems like many losssy encoders are not hand optimizing the huffman bitpack. because it reveals little or no gain.

Is there any program that rehuff's mp3/aac/m4a/vorbis etc. files to just get the extra bit of compression ?

just like the utility pngout which reall squezes every last bit out of an .png file

In AAC and MP3 the Huffman tables are defined by the standard, so you can not create your own ones.

damns so rehuff'ing only works with vorbis ?

does that mean there would be nothing to gain from an encode where the tables weren't chosen wisely? that's a pity. i always wondered what a 128kbps Xing encode would come out as if it were run through something like rehuff.

Wasn't Takehiro planning some sort of rehuff for MP3?

http://sourceforge.net/projects/recomp3/

Or was it another kind of size optimization?

You can do something like rehuff, but it is limited to the standard tables. It could help because some mp3 encoders do not search through all the available tables, but are using the most probable ones.

But such a tool would not be able to create custom tables.

Edit: I guess recomp3 would also feature "peeling".

Yes, I remember Takehiro saying it wouldn't help with files created by recent Lame versions because they are already using the best tables.

And AAC can benefit extra from grouping huffman tables. If an AAC encoder doesn't do a full search it might benefit even more from a "rehuff" tool.

AFAIK Nero encoder wouldn't need this.

Menno