Re: [Jack-Devel] Using Jack

Greetings Jack masters, think you for your inputs.

[quote] setting your app up as a Jack server is NOT a good idea - because if
other apps use Jack (like Mixbus, for example) they would use the version
provided by your app.  So, when your app eventually shuts down, anything
else that was using Jack would break!  The correct way to use Jack is to
launch it as an external server and let Jack decide whether & when to shut
itself down. [/quote]

I am not worry about this. The whole point is precisely not to install jack
at all but to embed Jack's client/server libraries into our API. That said,
I'm trying to start a Jack server programmatically but little info is
available on this and I do understand why now.

Before going any further. Regardless of if it is a good practice or not. Is
running a Jack server via our API even possible without the need for the end
user to installing Jack in the first place?

If yes, I'm guessing that the next question is for Stéphane. What I did is
this, I installed Jack for Windows x64, copied the include and the libraries
files to my VS project and uninstalled jack completely. Finally, I linked
Jack's libraries to my VS project.

I'm also guessing that the only way to pass parameters to a new Jack server
is with jackctl_server_create, right? To compile our project with
jackctl_server_create, some includes are missing like JackConstants.h and
getopt.h. To solve the compilation errors, I copied the missing .h files
from jack2-master source files and add them to my project's include folder.
With those files, it compiles fine but the problem is that
jackctl_server_create always returns NULL.

What am I missing? I understand it's a little out of scope of the intended
Jack mechanism but I'm hoping it could be feasible without to much trouble. 

-----Original Message-----
From: Stéphane Letz [mailto:[hidden]] 
Sent: Tuesday, March 18, 2014 7:18 AM
To: John Emmas; Yves Perron
Cc: JACK
Subject: Re: [Jack-Devel] Using Jack





Le 18 mars 2014 à 09:32, John Emmas <[hidden]> a écrit :

> On 18/03/2014 07:41, Stéphane Letz wrote:
>> Lack of time to test and answer, possible more time in april.
>> 
> 
> Hi Yves,
> 
> Since Stephane is unavailable at present I can give you a very rough idea
of how we start Jack from within Mixbus.  However, we don't support midi
(within Windows) so it might not be relevant to your situation.  Please bear
in mind what Stephane said previously... setting your app up as a Jack
server is NOT a good idea - because if other apps use Jack (like Mixbus, for
example) they would use the version provided by your app.  So, when your app
eventually shuts down, anything else that was using Jack would break!  The
correct way to use Jack is to launch it as an external server and let Jack
decide whether & when to shut itself down.
> 
> In Mixbus, we seem to create a file called ".jackdrc" (notice that it
begins with a ".", rather than a "j").  Basically, that file contains a list
of commands for starting Jack.  Typical file contents might look like this:-
> 
> "C:\Program Files\Jack\jackd.exe" -S -p 512 -T -d portaudio -r 48000 -p
512 -P  "ASIO::ASIO4ALL v2"  -C  "ASIO::ASIO4ALL v2"
> 
> The first parameter is a path to the Jack server.  "-S" means to start
Jack in synchronous mode (I believe this is mandatory on Windows).  Not sure
what the (two) "-p" parameters are but at least one of them must be the
buffer size (512 in this example). "-T" means "temporary" (Jack will shut
itself down automatically when it detects that nothing is connected to it
any more).  "-d portaudio" is the audio driver (portaudio is almost always
the driver for Windows - so you'll need to install that too.  For testing
purposes you can use "-d dummy").  "-r 48000" is the audio sample rate.
"-P" then gives us the Playback device and "-C" gives us the Capture device
(input device).
> 
> If you typed that complete line into a command prompt (assuming you'd
already installed ASIO4ALL) Jack would launch and would use it.
> 
> Having described all that....  I've no idea what Jack actually does with
that .jackdrc file.  Stephane or Paul will undoubtedly know. It looks like
the file needs to be in the user's personal folder (e.g. C:\Documents and
Settings\<user_name>) but I'm not sure how we tell Jack to look for it
there.  Simply starting Jack with no parameters doesn't seem to make it
search for .jackdrc - so I'm not sure how that happens.  If I manage to get
some spare time this week, I'll try to find out.
> 
> John
> ______________________________________________

OK I forgot this .jackdrc file mechanism was also working on Windows ….

So Yves probably using this system and adding the -X winmme should work, so
something like:

"C:\Program Files\Jack\jackd.exe" -S  -X winmme -p 512 -T -d portaudio -r
48000 -p 512 -P  "ASIO::ASIO4ALL v2"  -C  "ASIO::ASIO4ALL v2"

(note that the first -p 512 is for the wanted number of port in JACK)

Stéphane 

1395238541.9142_0.ltw:2, <002301cf437d$b088c4c0$119a4e40$ at gmail dot com>