Lots of problems with audio applications on Jetson

I’ve been struggling to get some audio software working with any degree of success on the Jetson TK1. Specifically, I am trying to use Hydrogen, Audour3, and Audacity.

Right out of the box, none of these program will even get past their spash screens because of the issue discussed in this thread.

I’ll try to maintain a coherent train of thought here, but I’ve been bouncing around trying a lot of things for the past couple of weeks, so I’ll just stick to my issues with Hydrogen and jack in this post.

Hydrogen allows the user to specify that they want to use directly use ALSA instead of the jack server by launching the program like so:

hydrogen -d alsa

If I did that, Hydrogen worked just fine even with the broken jack libraries.

I still needed to patch the jack2 issue because of the other programs I want to use, so after going through the steps in the above mentioned thread to patch up the jack2 libs, I was able to launch start up the jack server with qjackctl. There is an error message about there being no MIDI sequencer, but that doesn’t matter much to me at this point.

I again launched hyrogen and let it connect to JACK instead of ALSA, and it seemed to be fine on the surface. qjackctl’s gui showed the connections being made between hydrogen’s output and the system audio output as expected. However, when I tried to play a demo in hydrogen, some deafening screeching stactic was all I got.

If I shut everything down (jack server and hydrogen) and re-launch hydrogen telling it to use ALSA directly, everything still works. But trying to route hydrogen through jack does not work.

Tonight I discovered something a little interesting. If I turn down the master volume on hydrogen to it’s lowest possible non-zero setting, that horrible screeching static actually starts to turn into the expected drum beats. It’s as if there is some layer between jack and ALSA that is over-amplifying the signal and distorting it beyond recognition.

I know that was a long post. Sorry.

Anybody have any ideas what may be causing this? I’ve got more issues I can go into, but I figure I’ll just start with that one because figuring that one out might help with the other issues I have with audio INPUT.

I’ve discovered that forcing the audio to be 16bit instead of the default 32bit seems to have gotten past this particular issue.