[LAU] Toggle Jack Transport CLI

[hollundertee at gmx.net]

On Mon, 19 Dec 2016 10:52:57 +0000
holger at dehnhardt.org wrote:

> 19. Dezember 2016 11:35 Uhr, hollundertee at gmx.net schrieb:
> > On Wed, 16 Nov 2016 07:04:04 +0000
> > holger at dehnhardt.org wrote:
> >   
> >> Hi lista :)
> >> 
> >> Using an i3 (https://i3wm.org/docs/userguide.html#exec)
> >> shortcut, I can control my jack transport from everywhere, even
> >> when no jack application has focus :
> >> 
> >> bindsym $mod+p exec echo play | jack_transport
> >> bindsym $mod+Shift+p exec echo stop | jack_transport
> >> 
> >> Thanks to FalkTX for the pipe trick BTW, I saw that on
> >> linuxmusicians ; This is very cool if you have some sort of
> >> wireless keyboard, but as you can see it's two different
> >> keystrokes, how do I make it so toggles play/pause? Alternatively,
> >> how do I know when jack transport is rolling, so I can hack my way
> >> into making my own toggle script? I did my homework and read the
> >> inline --help of all the available jack commands on my machine :
> >> With this patch, jack_transport should be able to toggle. I will
> >> suggest it to the jack-develop list but would be happy if some
> >> else can test it. Holger
> >> 
> >> -----------------
> >> 
> >> diff --git a/example-clients/transport.c
> >> b/example-clients/transport.c index c543b41..0b1130f 100644
> >> --- a/example-clients/transport.c
> >> +++ b/example-clients/transport.c
> >> @@ -211,6 +211,29 @@ static void com_timeout(char *arg)
> >> jack_set_sync_timeout(client, (jack_time_t) (timeout*1000000));
> >> }
> >> +/* Set sync timeout in seconds. */
> >> +static void com_toggle(char *arg)
> >> +{
> >> + jack_position_t current;
> >> + jack_transport_state_t transport_state;
> >> +
> >> + transport_state = jack_transport_query (client, ¤t);
> >> +
> >> + switch (transport_state) {
> >> + case JackTransportStopped:
> >> + com_play( arg );
> >> + break;
> >> + case JackTransportRolling:
> >> + com_stop( arg );
> >> + break;
> >> + case JackTransportStarting:
> >> + printf ("state: Starting - no transport toggling");
> >> + break;
> >> + default:
> >> + printf ("state: Unknown - no transport toggling");
> >> + }
> >> +}
> >> +
> >> /* Command parsing based on GNU readline info examples. */
> >> @@ -238,6 +261,7 @@ command_t commands[] = {
> >> {"stop", com_stop, "Stop transport"},
> >> {"tempo", com_tempo, "Set beat tempo "},
> >> {"timeout", com_timeout, "Set sync timeout in "},
> >> + {"toggle", com_toggle, "Toggle transport rolling"},
> >> {"?", com_help, "Synonym for `help'" },
> >> {(char *)NULL, (cmd_function_t *)NULL, (char *)NULL }
> >> };  
> > 
> > Thanks guys,
> > 
> > I was just browsing the list for nice Linux Audio music when I found
> > this thread, which is just what I needed as well :)
> > In my case the purpose is for screencasts.
> > I plan to record the screen using SimpleScreenRecorder and audio
> > through jack into Ardour or somesuch. The problem I had was that if
> > I start SSR and Ardour separately I need to manually align A/V
> > later. It is simpler if A/V starts at the same time.
> > 
> > I was thinking of starting jack transport through qjackctl or
> > somesuch, using the CLI did not occur to me.
> > 
> > SSR lacks jack transport control, but I think assigning the same
> > hotkey to SSR and jack transport should work just fine. I guess I
> > still need to take the alsa/jacks latency into account, but at
> > least that should be small and constant.
> > 
> > Does anyone have a better idea?
> > 
> > @Holger: Thanks, but patching a jack example client requires
> > maintenance since this change would be lost with each new jack
> > package coming through the repo.
> > 
> > Regards,
> > Philipp
> > 
> > _______________________________________________
> > Linux-audio-user mailing list
> > Linux-audio-user at lists.linuxaudio.org
> > http://lists.linuxaudio.org/listinfo/linux-audio-user  
> 
> I know, I know...
> that's why I wanted to send it to the Jack list to get it applied...
> I still did not do it sorry. Will try to send it this evening...
> 
> Holger
> _______________________________________________
> Linux-audio-user mailing list
> Linux-audio-user at lists.linuxaudio.org
> http://lists.linuxaudio.org/listinfo/linux-audio-user

Hey,

no need to say sorry. Thanks for writing the patch.
If it gets applied it will make such scripts simpler in the future.

Regards,
Philipp