I have some 6-channel Vorbis files in my hand, but they are not exactly typical multichannel audio. Instead, the front channels seem to contain music and, the others, assorted effects.
Is there any tool to try to losslessly separate the channels, or pairs thereof, that I'm interested in, while removing the rest?
I could do this in a normal audio editor, but that would imply decoding and keeping as flac or transcoding, which I would like to avoid, and keep the lossy encoding as it is, instead.