tune, fastfirstpass and profile are not available through x264opts.
Since some FFmpeg options don't match the names used in libx264, add
libx264 option names as a reference when needed. And last thing, x264
don't have a manpage ATM, so prefer the x264 --fullhelp over the
unexistant manpage reference.
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.
Make Audio Encoders a separate chapter, and decrese the contained
sections level by one.
Improve rendering, and improve consistency with the other parts of the
manual.