Did you take a look at "BeHappy"?
Its very useful for Audioencoding.
When importing an audio file, it generates a temp. avisynthscript where NicAudio.dll's audio import functions are used to properly decode the source, even 5.1ch. Finally BeHappy pipes the avs resulting audiostream to the selected audio encoder binary internally via commandline where finally your desired target result will be on disk.
So, as it does generate a temp avs file maybe its possible to use avs commands for altering the amplitude of a specific channel. In your case the 'center' one.
Im not shure if BeHappy permits direct imports of avs scripts with the specific volume mods already done, but even if not, you can use BePipe.
Generate avs script -> use Bepipe to pipe to the desired target encoder binary (ffmpegAC3, NeroAAC, ffmpegMp2) -> target audio encoding will be on your HD.
As avs is capable to frameserve the 6 channels of a 5.1 ac3 source by using NicAudio.dll then such a workout would be no problem.
Hmmmmmm .... anyway ... I wanted to test the new binary stream piping capabilities of PureBasic v4, maybe its time to crack that nut on an audio transcoder, similair to BeHappy. It would use an embedded binary of ffmpeg for everything: AC3 (ac3enc, which is fixed since month), mp2 (mp2enc), aac (libFaac) etc., "aften" could be used as an optinal ac3 encoder and NeroAAC.exe as AAC alternative. (just thinking)
So do test BeHappy/BePipe and tell me what could be done better. But ... actually time is not my friend, so paaaaatience
Edit: Not Needed as it seems that aften is supported by BeHappy and also a GUI is available:
http://forum.doom9.org/showthread.ph...ighlight=aften
http://forum.doom9.org/showthread.ph...ighlight=aften