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IDProjectCategoryView StatusLast Update
0007081ardourbugspublic2016-10-30 16:15
Reporterunfa Assigned To 
PrioritynormalSeveritymajorReproducibilityunable to reproduce
Status newResolutionopen 
Product Version5.4 
Summary0007081: 1 Mb session grew to 100 Mb snapshot resulting in unusably low GUI performance.
DescriptionI was working on one session and I made a snapshot becasue I was about to change the arrangement radically, and I wanted to have the old version around.

After a while I was playing with the tempo map and suddenly Ardour's GUI became so unresponsive I was unable to work with the session anymore and had to xkill it.

I loaded a much much bigger session to see if it's a global Ardour thing - and no, that 10+ MB session was working better than my 1 MB* one.

The first version of the session works ok too, only the new snapshot.

*I've noticed later that my new snapshot weights 106 MB, while the first version of the session is 1,1 MB.

What's more interesting - both the files were compressed down to mere 100 kB with tar.xz. So I guess there's a lot of redundant information.

I guess it might have something to do with the tempo map. I used only two tempo markers. The default 120 BPM at start and a 94 BPM constant marker after that.

I added another 94 BPM marker between the existing two, so I had tempos like this:

120, 94, 94

Maybe the two 94 BPM markers caused the problems?

I then removed the second marker and got again 120 and 94 BPM, but things didn't get better.
Additional InformationI attach my session with two snapshots - one good, one bloated.

One thing is I'd like to help prevent this form happening again to people's sessions, and I'd also like to find out how to fix my bloated session so I don't have to redo my work and be able to continue.
TagsNo tags attached.



2016-10-28 11:17


Sessions.tar.xz (102,000 bytes)


2016-10-28 11:26

reporter   ~0018867

Last edited: 2016-10-28 11:36

I inspected the session files and there was an automation value repeated like several hundred thousand times.

The whole block looks like this:

        <AutomationList automation-id="gain" id="53368" default="1" min-yval="0" max-yval="2" interpolation-style="Linear" state="Play" style="Absolute">
          <events>0 0.965905666351318
3605504 1.0714910030365
3993921 0.288200616836548

And the values:

3605504 1.0714910030365
3993921 0.288200616836548

Were repeated filling in about 105 Mb of space.

I tried fixing this manually by replacing the bloated part with it's "sane" counterpart in the previous session to recover my work but Ardour says it can't be loaded. How can I fix this? The bloated session loads fine.


2016-10-30 15:48

reporter   ~0018883


i looked at the bloated session and noticed thousands of gain automation
events at the same time and value.

i don't think this could have been caused by the tempo map.

i'm wondering how these could have been written in the first place.

are you using an external controller in your setup?
is a synchroniser or similar continually sending ardour to the same location?
do you habitually use locations when writing automation data?

thanks in advance.


2016-10-30 16:15

reporter   ~0018884

This happened in a session that I was mostly using while being synced to Blender through JACK transport.

I saw strange behaviour that Blender would alternate between 2 frames back and forth, instead of playing back as usual.

But that happened a few hours before my Ardour session got 100+ MB of gain automation.

I wasn't using any hardware controller with Ardour.

Issue History

Date Modified Username Field Change
2016-10-28 11:17 unfa New Issue
2016-10-28 11:17 unfa File Added: Sessions.tar.xz
2016-10-28 11:26 unfa Note Added: 0018867
2016-10-28 11:28 unfa Note Edited: 0018867
2016-10-28 11:36 unfa Note Edited: 0018867
2016-10-30 15:48 nick_m Note Added: 0018883
2016-10-30 16:15 unfa Note Added: 0018884