Is it possible to transcode 5.1 HE AAC to 5.1 AC3?

[bugmenot]

I've been trying to do so with no success. I can't seem to find anything that can decode the multichannel AAC to any other format. I know from the FAQ that there is a filter to convert the AAC to AC3 on the fly but I need to convert the file itself. Is it just not meant to be? At this point, I would even take a down-mixed 2 channel wave file... Thank to anyone that can help.

[KpeX]

Try using faad (www.rarewares.org) to decode to six-channel wav, or possibly use foobar2k (is there an AC3 encoding plugin for fb2k? I can't remember)

However if you transcode HE-AAC to AC3 the result will be at best horrendous. HE-AAC is already very highly compressed and close to half the dynamic range is replicated, not encoded.

[Sakuya]

If I transcode HE-AAC to AC3, would the channels be kept in the same place or will it be mixed up? Would the volumes be mixed up? :( How can I preserve the AAC's audio quality on a DVD?