[Ardour-Dev] "Click of deaf" bug

Natanael Olaiz nolaiz at gmail.com
Fri Jul 16 01:55:16 PDT 2010


We found a strange and harmful bug in Ardour, and unfortunately, it 
looks difficult to reproduce.

Description: two regions are one just after the other (so, no crossfade) 
makes a several hundred dBs click when the playhead pass over the 
intersection: http://imagebin.ca/view/LSvEnz.html

Some observations:
     - It happens even without any plugin or automation on the track
     - If the gain of the track is 0, it doesn't happens. If it's 
greater, the bug happens and it looks proportional to the track gain.
     - Related to the previous?: when there is a plugin applied, the 
gain bug is happening after the plugin process (1 mono track with 22 
outputs without plugin: all peaks fall -after several seconds- all 
together, meanwhile 1 mono track with 22 outputs with a spacialization 
plugin applied: the peaks fall differently because the process)
     - It looks to happen only when the starting region have the fade-in 
deactivated (no matter the state of the previous ending fade-out).
     - When reloading the session, it doesn't happen. But if you move 
the second region some times, and put it again snapped to the first one, 
it usually happens again each time you pass over the region intersection 
until you close the session again.

We tried to simplify the session removing all the tracks but the 
problematic one, and still happens. Then we tried to remove clean the 
unused sources and move the regions to the begining, and we could not 
reproduce it again...

Any hint to debug it? Maybe a NaN in the fade-in algorithm?

Thanks in advance.

Best regards,

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