Only show preview tally if source is shown and not active#1405
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Pull request overview
This PR adjusts NDI source tally behavior so preview tally is only set when a source is showing and not active, preventing simultaneous preview+program tallies that cause rapid blinking when a source is in Program (and thus both active and showing in OBS).
Changes:
- Update tally state transitions so
on_previewis suppressed when the source is active (program takes priority). - Add a guard in the receiver thread to skip frame reception when the source is not showing, aiming to reduce OBS FPS impact for “Keep Active” sources.
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Trouffman
approved these changes
Feb 19, 2026
paulpv
requested changes
Feb 19, 2026
paulpv
approved these changes
Feb 20, 2026
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This fixes a long standing issue with tally, first reported in issue: #687
This problem is occurring because when a source is in Program, it is both active and showing. This causes the preview and program tally lights to be set.
To fix this using the existing OBS API, we will only show the preview tally if the source is showing and not active. This means DistroAV will never set on_preview and on_program to true. It is only one or the other, with on_program taking priority. These are the two scenarios which change...
Here is when the source is on program, no green line (on_preview) for the cyan scene, only the red line (on_program) is shown.
Here is when the source is on program AND on preview, but we only show the red line (on_program) as it takes priority.
To handle the more robust case of number 2, a change is needed in the OBS API to identify when a source is actually on preview.