Parameters

The parameter source of truth is protocol/params.schema.json. A stable ID must not be renamed without a project migration.

ID	Label	Range	Mapper	Resources
video.opacity	Opacity	0…1	linear	video, image
audio.mainLevel	Volume	0…2	perceptual	video, audio
audio.pan	Pan	-1…1	equalPower	video, audio

Opacity

0 is transparent and 1 fully visible. It multiplies the file's own alpha.

Volume

0 is silence, 1 nominal gain, and 2 up to double linear gain. Transitions use perceptual/dB-domain mapping. The master limiter protects the sum but does not replace correct gain staging.

Pan

-1 is left, 0 centre, and 1 right. Interpolation uses an equal-power curve.

Resource and cue levels

Showmesh keeps a resource fader and cue playback trim separately:

final opacity = resource opacity × cue opacity
final volume  = resource volume  × cue volume
final pan     = clamp(resource pan + cue pan, -1, 1)

Addresses:

/resource/{resource-id}/opacity
/resource/{resource-id}/volume
/resource/{resource-id}/pan

/cue/{cue-id}/opacity
/cue/{cue-id}/volume
/cue/{cue-id}/pan

OSC directly controls numeric /resource/... addresses in this branch. Cue actions normally write the /cue/... trim.

Troubleshooting

If a cue is unexpectedly silent or transparent, inspect both levels. A zero at either multiplied level produces zero output.