::  Posts  ::  RSS  ::  ◂◂RSS  ::  Contact

Goodbye ChucK; hello straight C with JACK

May 1st, 2010
looper, music, tech  [html]
The chuck-using looper software was being too annoying. I couldn't figure out why latency was being slightly off and variable between runs, I couldn't figure out how to get it to run realtime, and chuck kept crashing when I went to record long loops, giving:
subgraph starting at RtApiJack timed out (subgraph_wait_fd=9, status = 0, state = Running, pollret = 0 revents = 0x0)
I decided to have a look at writing this in straight C against the JACK api. Which seems to have worked quite well. It wasn't that much work, and now I know exactly what's going on. Chuck was good for prototyping, and really easy to get started with, but I have a lot more trust in this new version. One downside is that unless OSX has /dev/input/mouse then this is linux only. Which is sad. If there's an easy fast way to get mouse events on OSX I could add it.

So. This requires at leas the following:

$ sudo apt-get install jackd libjack-dev
$ gcc -std=c99 -o looper_sync -ljack -lpthread -lrt looper_sync.c
$ sudo chmod ugo+r /dev/input/mouse*
$ jackd -d alsa -p 256 &
$ ./looper_sync
Unfortunately, while I was testing this one last time before writing it up, I managed to get the exact same "subgraph timed out" error in the C version that I'd gotten in the chuck version. I don't get it as easily in the new version; sometimes I can record three full length loops and not get it. Perhaps, though, this error means I'm trying to do too much work on one processing cycle? I need to look at it more. On my desktop it runs great, so I'm thinking it has to do with the eeepc being substantially less powerful.

Comment via: facebook

Recent posts on blogs I like:

Incoming Gantz-Led Government to Invest in Israel’s Infrastructure

Israel’s incoming prime minister Benny Gantz unveiled an emergency government, to take power following an upcoming confidence vote in the Knesset. The last two MKs required to give Gantz a 61-59 majority, two members of Gantz’s own Blue and White Party wh…

via Pedestrian Observations April 1, 2020

Finding home in the time of coronavirus

Disclaimer: I’m going to say this once. Obviously, I am not happy about the coronavirus’s threat to public health or the economic toll it’s taking. I do not think the existence of this pandemic is good. Just so happens that social distancing and remote wo…

via Holly Elmore March 31, 2020

Massachusetts should shut down immediately

We’ve been running 30x fewer tests than other states, and have been extremely tardy in responding to the Biogen outbreak.

via benkuhn.net March 15, 2020

more     (via openring)

More Posts:


  ::  Posts  ::  RSS  ::  ◂◂RSS  ::  Contact