Fedora 26 x86_64; Pulseaudio REMOVED; ALSA recording and playing from multiple sources - JACK?

[Philip Rhoades]

People,

For playing from multiple sources, ALSA plus the version of .asoundrc 
below has been rock-solid for a couple of years now:

I now want to use things like "recordmydesktop" which work fine with the 
mic but they do not record sound from audio or video clips that are 
playing eg from YouTube or local mpv etc.  So, yet again, I started to 
try and make sense of JACK because I was pretty sure that it could solve 
this problem - but I have found sound on linux has always been a major 
pain and messing around with configs and rebooting etc on my big 
workstation is tedious so I think I will try to get something working on 
my laptop to begin with.

Hopefully some jack gurus will have some suggestions about how to do 
what I want to do?  I presume it is possible?

Thanks,

Phil.

pcm.!default {
         type plug
         slave.pcm "asymed"
}

# This is the audio output:
pcm.dmixer {
         type dmix
         ipc_key 1024
         slave {
                 pcm "hw:1,0"
                 period_time 0
                 period_size 1024
                 buffer_size 4096
                 rate 44100
         }
         bindings {
                 0 0
                 1 1
         }
}

ctl.dmixer {
         type hw
         card 0
}

# This is the microphone
pcm.dsnooped {
         ipc_key 1027
         type dsnoop
         slave.pcm "hw:1,0"
}

# This makes both channels work together.
pcm.asymed {
         type asym
         playback.pcm "dmixer"
         capture.pcm "dsnooped"
}