This should be more useful for users since numerical values for channel
layout can be confusing and unintuitive.
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: James Almer <jamrial@gmail.com>

Also, make every addition except for sidedata part of version 1 instead of the
new version 2.
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>

also limit dcinema-encode to 20 frames to avoid huge reference checksum lists
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

This avoids resampling and channel mixing by using a source with
the correct channel layout and sample rate.