Improve vertical footage workflow

[philmodin]

Summary

• Auto-detects when the NLE has pre-rotated vertical footage by comparing host output dimensions against raw video dimensions
• Sets frame_rotation on gyroflow-core so set_output_size() uses portrait reference dimensions (no cropping/scaling)
• Eliminates the need to manually clear clip rotation attributes before applying Gyroflow stabilization

Problem

Vertical footage in DaVinci Resolve requires a cumbersome workaround: users must clear the clip's rotation attribute (undoing the NLE's pre-rotation), then configure video_rotation in Gyroflow to compensate. This is cumbersome, unintuitive, and is not ideal having sideways preview thumbnails in the timeline.

The root cause: the plugin had no way to tell gyroflow-core "the host already rotated this frame" — it could only set video_rotation which conflated gyro alignment with dimension swapping.

Solution

New nle_handles_rotation() detection helper checks:

• Host provides portrait dimensions (height > width)
• Raw video file is landscape (width > height)
• Video metadata rotation is 90° or 270°

When all three are true, the plugin sets frame_rotation = video_rotation on the core. This causes set_output_size() to use portrait reference dimensions, so the output matches the host's portrait buffer (scale=1.0).

The transform pipeline stays in landscape sensor coordinates. The shader's input_rotation (always set to 270°) handles the UV rotation from landscape source coords to portrait buffer layout — this is a trivial per-pixel coordinate transform with negligible GPU cost.

Key design decisions

• InputRotation is always set (shader needs it for landscape→portrait UV mapping)
• org_ratio uses frame_rotation to decide landscape vs portrait aspect ratio
• frame_rotation is set unconditionally before init_size()/set_output_size(), reading from the OFX Rotation param (which the host always restores on project load)

Media

Before	After

Files changed

File	Change
common/src/lib.rs	Added nle_handles_rotation(), frame_rotation catch-all before init, InputRotation always set
openfx/src/gyroflow.rs	org_ratio uses portrait ratio when frame_rotation is 90°/270°, always pass input_rotation to shader

Companion PR

Requires gyroflow-core changes: philmodin/gyroflow#1

Test plan

• Horizontal footage unchanged (frame_rotation stays 0, existing behavior)
• Vertical footage in Resolve Edit page: correct stabilization without clearing clip attributes
• Saved projects load correctly without manual reload
• Fresh plugin application to vertical footage works immediately
• Rolling shutter correction on vertical footage
• Fusion page workflow (manual output size control) still works

Created with assistance from Claude Code.

[CLAassistant]

All committers have signed the CLA.