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Workaround for "bad" Jack output bug (SVN)

2 replies [Last post]
Joined: 04/17/2010

I've had a long-standing problem with hydrogen's Jack output, where the notes sound clipped or badly aliased (sounds similar to a period mismatch). I will detail the problems and then a quick and dirty workaround that solves them.

Starting hydrogen with "--driver jack", or "jack"/"auto" output selected in preferences and just running hydrogen with no options results in:
1) Two jack outputs being created "hydrogen-1" (which has no sound output) and "hydrogen-2" (which has sound output).
2) The resulting sound is terrible (I tried to attached a .ogg but the forum software won't allow it). Note lengths are also shorter. If you record the "GM_kit_demo_1" it will be about 1 second shorter than normal.

3) The following is output to the terminal during startup:
(E) void H2Core::audioEngine_init() Error the audio engine is not in UNINITIALIZED state
(E) void H2Core::audioEngine_startAudioDrivers() The audio driver is still alive
(E) void H2Core::audioEngine_startAudioDrivers() The MIDI driver is still active
(W) static QString H2Core::LocalFileMng::readXmlString(TiXmlNode*, const QString&, const QString&, bool, bool) 'license' node not found
(E) void* H2Core::alsaMidiDriver_thread(void*) seq_handle != NULL

My quick solution:
1) Open hydrogen and in preferences select the "Auto" sound driver. (Do not select "Jack"). Close hydrogen so that the preferences are saved.
2) Start hydrogen with the '--driver alsa' option.
3) Open preferences and click "restart driver"

Now hydrogen+jack work as expected.

Joined: 03/30/2010


Its strange that there are 2 Hydrogen jack clients visible. Which version are you using? I can't reproduce here on ubuntu 8.10RC and debian unstable.

Joined: 04/17/2010

I'm on Intrepid x86_64, all current updates applied

I get the same results with 2.6.27 (non-realtime) and 2.6.24-19-rt kernels

No other Jack software has this problem on my system

If you can't reproduce it there, is there any other info I can give you that might help?