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IDProjectCategoryView StatusLast Update
0009481ardourbugspublic2023-10-17 04:13
Reporterdoojonio Assigned Tox42  
Status resolvedResolutionfixed 
PlatformRedhatOSLinuxOS Version(any)
Product Version8.0 
Summary0009481: MIDI event duplicates on midi buses during session exports when using ALSA
DescriptionIf you use ALSA as a backend for Ardour:
1) MIDI events from midi track to midi bus duplicate during session exports.
2) They don't duplicate in realtime, but duplicate during export.
3) This bug causes increasing volume on the bus during the export, because midi bus instrument will play twice. So volume balance in exported session will be ruined
Steps To Reproduce1) Create new session with ALSA backend
2) Add a midi track without instrument and a midi bus with somo instrument (lsp sampler for example). Set MIDI track output to the MIDI bus
4) Add ACE MIDI Monitors before MIDI bus instrument
3) Draw some notes on the midi track and play them in realtime. Ensure that midi events do not duplicate
4) Export (in realtime) session. During the playback, ensure that midi events duplicate on the midi bus before the instrument. And it plays with more volume.

Additional InformationI uploaded the video. In first part I play session in realtime. In second part I export session. You can see that MIDI bus plays louder during the export and there are duplicates of the midi events (double "On C2" notes)
Tagsalsa, bus, export, Midi



2023-10-14 13:38

administrator   ~0028199

Could you attach your test session as a session archive please? (Use the top level menu .. Session > Archive)


2023-10-14 15:04

reporter   ~0028200


2023-10-14 15:07

reporter   ~0028201

You can easily test it by using realtime export. Export > Time Span (at top) > RT checkbox. When you will export my attached session, piano will clipping, but when you play it in ardour without exporting, it wont


2023-10-16 20:57

administrator   ~0028215

Also happens during normal export (realtime export is not required)


2023-10-17 04:04

administrator   ~0028216

Fixed in 8.0-44-g44a2ef9098

I am however curious which synth produces louder output after receiving a duplicate Note-On (same timestamp).


2023-10-17 04:13

reporter   ~0028217

I use LSP Sampler to add drum samples. It is produces louder sample output after receiving a duplicate Note-On

Issue History

Date Modified Username Field Change
2023-10-14 10:28 doojonio New Issue
2023-10-14 10:31 doojonio Tag Attached: alsa
2023-10-14 10:31 doojonio Tag Attached: Midi
2023-10-14 10:31 doojonio Tag Attached: bus
2023-10-14 10:31 doojonio Tag Attached: export
2023-10-14 13:38 paul Note Added: 0028199
2023-10-14 15:04 doojonio Note Added: 0028200
2023-10-14 15:04 doojonio File Added: midi event duplicates_2023-10-14_200258.ardour-session-archive
2023-10-14 15:07 doojonio Note Added: 0028201
2023-10-16 20:57 x42 Assigned To => x42
2023-10-16 20:57 x42 Status new => confirmed
2023-10-16 20:57 x42 Note Added: 0028215
2023-10-17 04:04 x42 Status confirmed => resolved
2023-10-17 04:04 x42 Resolution open => fixed
2023-10-17 04:04 x42 Note Added: 0028216
2023-10-17 04:13 doojonio Note Added: 0028217