LMMS / LMMS/lmms

Mono VST plugins output only to the left channel

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#6,558 4 comments 0 reactions 0 assignees View on GitHub
bug vst
Dominant language
C++
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Forks
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Avg merge
2d 13h
Merged PRs (30d)
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Description

### Bug Summary
When using a mono VST plugin via VeSTige, sound is produced only in the left channel instead of both channels.

#### Steps to reproduce
Load this Windows VST in VeSTige https://github.com/bsutherland/JuceOPLVSTi/releases/download/1.0.1/JuceOPLVSTi.x64.dll and play any note.

#### Expected behavior
Same audio should play in both channels.

#### Actual behavior
Audio is hard-panned to the left.

#### Affected LMMS versions
Version 1.3.0-alpha.1.102+g89fc6c9 (Linux/x86_64, Qt 5.6.3, GCC 5.4.0 20160609).
AppImage downloaded from here https://github.com/LMMS/lmms/releases/download/v1.3.0-alpha.1/lmms-1.3.0-alpha.1.102%2Bg89fc6c9-linux-x86_64.AppImage

Contributor guide

No contributing guide indexed for this repository

Research direction

Reproduce the issue by loading the linked JuceOPLVSTi.x64.dll in VeSTige and playing a note. Trace VeSTige's VST audio-output handling for mono plugins, then verify that the same signal reaches both channels rather than being hard-panned left.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
audio-video-rtc, desktop
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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