Premiere Pro ExtendScript addSequence preset resolution inconsistency

Answer

The addSequence API resolves a preset name by first searching the internal factory‑preset registry, then the user‑defined registry. When a name exists in both places, the factory preset’s settings are applied. If the name is not found in either registry, the call falls back to Premiere’s default sequence template (640 × 480, 0.333 pixel aspect, 30 fps) rather than throwing an error. A custom preset that shares a name with a factory preset does not override the factory preset; it remains available under its own entry and can be selected manually from the Presets panel.

Confirmed Facts (based on current testing)

• Factory preset takes precedence over a custom preset with the same name.
• Missing preset name → default 640 × 480 sequence.
• Custom preset is still accessible but not used automatically.

Likely Explanation

Premiere registers factory presets first during startup, so the lookup routine finds the factory entry before it checks the custom list. The fallback to defaults is a safety net to avoid script failures when an unknown name is supplied.

Steps to Verify for Your Project

1. Create a factory preset named TestPreset (use the built‑in Presets panel and rename an existing factory preset).
2. Create a user‑defined preset also named TestPreset (via File > New > Sequence Preset).
3. Run the following ExtendScript snippet:

   var seq = app.project.items.addSequence(
       "DemoSeq",
       1920,
       1080,
       1,
       10,
       "TestPreset"
   );
   alert("Sequence width: " + seq.width + ", height: " + seq.height);
   

4. Inspect the resulting sequence’s settings. If it matches the factory preset’s values, factory precedence is confirmed; if it matches the custom preset, the custom takes precedence.
5. Repeat the test on at least two Premiere Pro releases (e.g., CC 2023 and CC 2024) to detect any version‑specific differences.

What to Do in Production

• Use unique preset names to avoid accidental precedence.
• Prefer referencing presets by ID if the API exposes it, or manually load the preset object through the UI.
• Document the Premiere Pro version you target, as older releases may exhibit slightly different fallback behavior.

Missing Diagnostic Detail

Could you confirm which Premiere Pro version (e.g., CC 2023, CC 2024) you are targeting? The fallback to default settings and the exact precedence can vary between releases.