Re: Creating a Mixdown, new wiki page

On 02/07/2025 15:02, chuck elliot wrote:
> Please include details of how to obtain 'jack_capture'. I couldn't 
> find it in fedora or rpmfusion repos
>
> so I found it on github but it failed to compile properly (couldn't 
> find '-ljack)? after ok-ing dependencies.
>
I'm on Majaro (arch based) and there's a dedicated jack_capture package 
which works as expected including with pipewire (I can see it's inputs 
with qjackctl)
>
> I think it might be useful to include some explicit account of the 
> role of
>
> virtual synths like fluidsynth etc when using 'jack_capture'.
>
> I infer from what is said about synth plugins and 'export WAV' that 
> jack_capture can capture virtual synth output
>
> but I wasn't able to confirm this owing to previous build fail and 
> e.g. presumably fluidsynth needs to be set up to
>
> use jack as its audio driver too?

jack_capture can capture any (and multiples simultaneously) jack 
output(s), so for example you could use it to record even synths which 
are external to rosegarden (like fluidsynth or yoshimi run as 
standalone) and being 'driven' by rosegarden via midi as long as they 
are using jack (audio). The only point of attention is that you have to 
indeed explicitly connect these to jack_capture _before_ it starts 
rolling (i.e. before you start playback and therefore trigger jack 
transport in the wiki example).

Given that this is still 'real-time' recording (i.e. it takes as long as 
your piece lasts) I usually prefer to use something as simple as 
mhwaveedit so that I can first check levels and see if there's any 
clipping and just do the recording 'manually'. This also allows me to 
add a bit of silence at the beginning if a piece starts at measure 1. 
But I think this is all personal preference also based on the scenario.

What _would_ be nice is jack freewheeling allowing 'faster than 
realtime' expoert / render (like in ardour for instance). But that has 
been long debated on different mailing list, and I think it implies 
ditching alsa-midi in favour of jack-midi. As well as much more thorough 
testing of LV2 plugins which tend to still be rather unstable, at least 
for me.

Lorenzo