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 

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