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IDProjectCategoryView StatusLast Update
0007775ardourbugspublic2020-03-28 13:03
Reporterandrew246 Assigned To 
Status newResolutionopen 
PlatformUbuntu 14.04 (Trusty)OSUbuntuOS Version14.04 (Trusty)
Product Version5.12 
Summary0007775: The waveform display shows erroneous bits of signal depending on what track is selected.
DescriptionI have recorded a few tracks of hand drumming and am trying to improve the timing. So I am selecting several bars and then doing detailed edits to move individual notes to their correct position. Doing this by cutting and dragging. Once I have a decent set of several bars, I am combining regions and then building up a longer track (say 20mins) by repeatedly copy-pasting the section to the end and then combining the two regions, thus doubling the length each time.
I find I get a corruption and the waveforms start showing glitches. For example the only difference between pics 1 and 2 is that I am selecting either track bell-sm57 or high-sm57. Similarly the only difference between pics 3 and 4 is that no.4 is one more level zoomed in.
This was happening on my Dell laptop so I've also tried on my desktop with lots of memory but the same is happening.
I also found that trying to clean up the projects caused Ardour to hang.
I tried to find out when the problem was creeping in. I did a number of "save as" ops as I progressed with the editing, typically quitting Ardour fully in case of say some internal error. It seems the problem starts after combining regions but take this with a pinch of salt. Pic 5 shows where I've re-timed the bell pattern and this project doesn't seem to have the problem. But the next save-as with the regions combined does show the problem. I could try to upload the projects if anyone is able to look at them.
I've selected "always" reproducible above though I haven't tried lots of different projects. Also I'm a relative novice and only occasional user with Ardour.
TagsNo tags attached.



2019-07-17 11:20


2-glitches-gone.png (123,935 bytes)   
2-glitches-gone.png (123,935 bytes)   
1-showing-glitches.png (123,861 bytes)   
1-showing-glitches.png (123,861 bytes)   


2019-07-26 07:04

reporter   ~0020705

Same issue here with 5.12.0 on Ubuntu Studio 16.x (with KXStudio packages on top, but I don't think this is relevant): splitting and recombining regions lead to randomly erroneous waveform display, depending on zoom level etc (randomly: for the same region, the display is sometimes ok - or seemingly ok at least - and sometimes just plain wrong). This is usually fixed by resizing the track display (horizontally or vertically) a couple times. This doesn't seem to affect the audio out at all, but it quickly becomes annoying when doing some heavy edit jobs...


2019-07-26 12:20

administrator   ~0020706

There seem to be some sleeping bugs in the waveform cache. A related issues is that after recording a stereo-track, sometimes the right channel displays as silent.
The waveform display image is cached is per x-axis zoom-level and per y-axis scale. So indeed zoom or resize can work-around.

However, so far the root cause of the issue isn't understood.


2019-07-27 09:40

reporter   ~0020707

Well if it's a waveform cache issue (which I indeed suspected given the symptom) I noticed a possibly related one yesterday: unhiding a track that was previously hidden, the wafeform lane for the track appears empty, and gets "repopulated" when resizing the track vertically. The sound plays correctly of course...


2019-07-27 09:51

reporter   ~0020708

hi bigb, I found the clean-up function was misbehaving. Is it possible you could try it on the project you mention above please?


2020-03-28 13:03

reporter   ~0021071

I noticed this issue is still happening in testing release 6.0.

Issue History

Date Modified Username Field Change
2019-07-17 11:20 andrew246 New Issue
2019-07-17 11:20 andrew246 File Added: 5-bell-regions-before-combining.png
2019-07-17 11:20 andrew246 File Added: 4-press-equal-key-and-glitches-reappear.png
2019-07-17 11:20 andrew246 File Added: 3-press-minus-and-glitches-gone.png
2019-07-17 11:20 andrew246 File Added: 2-glitches-gone.png
2019-07-17 11:20 andrew246 File Added: 1-showing-glitches.png
2019-07-26 07:04 bigb Note Added: 0020705
2019-07-26 12:20 x42 Note Added: 0020706
2019-07-27 09:40 bigb Note Added: 0020707
2019-07-27 09:51 andrew246 Note Added: 0020708
2020-03-28 13:03 andrew246 Note Added: 0021071