Kia ora David
I'm also interested in getting better performance out of GNU/Linux for
audio/video editing purposes. My technical experience here is limited but
here are some things worth considering:
* firstly, is software really the bottleneck? Is your hardware really up to
the task? Do you have enough processor power, RAM etc?
* is your hardware well supported by libre firmware/ drivers? Annoyingly this
is not an either/or (ie it works or it doesn't). Fully libre GNU/Linux often
supports some of the functions of your hardware and not others. The secrecy
of hardware vendors is at fault here, not GNU/Linux developers, but for now
its something we have to be aware of.
* is your machine sufficiently cooled? Because I use laptops, and repurpose
older PCs, I have seen what a difference it makes when a PC has sufficient
fans, heatsinks, ventilation etc to keep it cool when it's working hard.
* is your OS as minimal as possible while still allowing you to do your work?
Some graphical applications on GNU/Linux including desktop managers like
GNOME have become as bloated and resource hungry as Windows. Have you tried
using Trisquel Mini, or another more lightweight desktop like XFCE or LXDE?
Have you tried Musix?
http://distrowatch.com/table.php?distribution=musix
* Do you have a decent graphics card? I've heard there are ways to use the
graphics card to do some of the heavy-lifting in audio processing too (no
idea how though).
* do you have a second computer that you could run as a headless system (no
graphical desktop) for your audio processing, while operating it remotely
from your main computer?
Again, these are all just things to think about. Sorry I can't give any
specific advice for successful experience, but from everything I've read,
doing audio/video work on GNU/Linux is a pretty bleeding edge area all round.
