Having a separate section for audio encoders simplifies navigation
and is slightly more consistent with the rest of the manual.
Signed-off-by: Diego Biurrun <diego@biurrun.de>
Channel coupling is an optional AC-3 feature that increases quality by
combining high frequency information from multiple channels into a
single channel. The per-channel high frequency information is sent with
less accuracy in both the frequency and time domains. This allows more
bits to be used for lower frequencies while preserving enough
information to reconstruct the high frequencies.
