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IDProjectCategoryView StatusLast Update
0007840ardourbugspublic2020-03-15 17:01
Reporterike Assigned To 
Status assignedResolutionopen 
Platformx86_64OSFedoraOS Version30
Product Version5.12 
Summary0007840: Stretching MIDI regions wrongly handles time offsets
DescriptionI encountered two (maybe unrelated) issues when using the time-stretch tool on MIDI regions.

Firstly, when stretching a MIDI region that is not placed at the start of the timeline it seems the region is expanded by the equivalent of the offset at which the region is placed. I.e. having a MIDI region at position t=1, lasting until t=3, using the stretch tool to stretch its ending from t=3 to t=4 will (more or less correctly, see below) stretch its contents to the duration t=1 to t=4, but will afterwards expand the region up to t=5.

The second issue concerns cut MIDI regions. When cutting a MIDI region in two pieces, the first part will behave correctly when stretching (except for the expanding bit above, if it is not at the start of the timeline). The second part of the MIDI region however, when stretched, will not only stretch the cut content to the target length, but it will stretch the original content, from the original start point of the data, up to the cut region's end and fit it into the target time length.
TagsMidi, MIDI region



2019-11-01 04:51

administrator   ~0020807

Regarding the first part, this is likely fixed in 6.0-pre0-2723 -- can you test this?

As for the latter, that's likely a follow-up issue to to linked regions:
When you split a region the two regions are still linked. Split is identical to copying the region and then trimming start/end. The use the same underlying source (MIDI file).
After a split, you can trim-drag/extend the 2nd region backward, or the first region forward to reveal the content from before the split.
Editing the content of one of these regions modifies the shared source. Usually handy for patterns

You can use (context or global-menu) Region > MIDI > Unlink from other copies. or disable it globally in Session > Properties > MIsc > MIDI Options


2019-11-02 02:22

reporter   ~0020809

Yes, thanks, that seems to have fixed both issues. However, now I'm encountering a third, that doesn't seem to have been in ardour 5.12, however it does already occur before your fix. (Specifically I'm testing 5e4d641488). Now I'm seeing randomly, incorrectly resized MIDI notes when stretching. I've included two screenshots, one before the stretching operation, one after. I don't know how to debug this more closely, but if you have any ideas, let me know.

Apart from that (even though this probably doesn't matter anymore, because the second point seems to be fixed, too), I didn't really understand your point about unlinking the copies, because I could stretch one of the two cut regions without affecting the other. So I guess either one of these steps (stretching, cutting) seems to implicitly unlink copies, or you are storing stretching-data inside the data-slice views representing the MIDI regions.
after.jpg (187,356 bytes)   
after.jpg (187,356 bytes)   
before.jpg (186,512 bytes)   
before.jpg (186,512 bytes)   


2019-11-02 02:35

administrator   ~0020810

> So I guess either one of these steps (stretching, cutting) seems to implicitly unlink copies

Stretch creates a new source and region.

Issue History

Date Modified Username Field Change
2019-11-01 03:22 ike New Issue
2019-11-01 03:22 ike Tag Attached: Midi
2019-11-01 03:22 ike Tag Attached: MIDI region
2019-11-01 04:51 x42 Assigned To => x42
2019-11-01 04:51 x42 Status new => feedback
2019-11-01 04:51 x42 Note Added: 0020807
2019-11-02 02:22 ike File Added: after.jpg
2019-11-02 02:22 ike File Added: before.jpg
2019-11-02 02:22 ike Note Added: 0020809
2019-11-02 02:22 ike Status feedback => assigned
2019-11-02 02:35 x42 Note Added: 0020810
2020-03-15 17:01 x42 Assigned To x42 =>