Add sync subnode for FrameCropper inputs

[tadeas0]

Purpose

Add Sync subnode in front of FrameCropper inputs. This enables non-blocking queue usage earlier in the pipeline and makes the FrameCropper node more robust.

Specification

None / not applicable

Dependencies & Potential Impact

None / not applicable

Deployment Plan

None / not applicable

Testing & Validation

All oak-examples using FrameCropper work same as before after this change.

AI Usage

Assisted-by: Pi Coding Agent:GPT-5.5

Submitted code was reviewed by a human: YES

The author is taking the responsibility for the contribution: YES

Summary by CodeRabbit

• New Features

  • Added optional timestamp synchronization thresholds for frame cropping when pairing frames with detections or manipulation configs.
  • Improved support for waiting on config data so frame processing can stay tightly synchronized with incoming inputs.

• Bug Fixes

  • Made input handling more reliable by using synchronized input groups, reducing mismatches between frames and related metadata.

[coderabbitai]

📝 Walkthrough

Walkthrough

FrameCropper's Script-based cropping pipeline is refactored to synchronize frame and detection/config inputs using dai.node.Sync with a configurable syncThreshold. Script content consumes synchronized groups instead of separate ports, WAIT_FOR_CFG gating is removed, and node construction now uses createSubnode.

Changes

FrameCropper synchronized cropping pipeline

Layer / File(s)	Summary
Init and subnode construction depthai_nodes/node/frame_cropper.py	Adds cast import, initializes _sync and _sync_threshold fields, and constructs ImageManip via createSubnode.
Script content for synced inputs depthai_nodes/node/frame_cropper.py	IMG_DETECTIONS_SCRIPT_CONTENT and MANIP_CONFIGS_SCRIPT_CONTENT read from a synchronized group input instead of separate ports; removes WAIT_FOR_CFG gating in favor of tryGet()-based config updates.
Public syncThreshold API depthai_nodes/node/frame_cropper.py	fromImgDetections(...) and fromManipConfigs(...) accept syncThreshold: timedelta = timedelta(milliseconds=10), document synchronization behavior, and store it into _sync_threshold.
Pipeline wiring with Sync node depthai_nodes/node/frame_cropper.py	_build_detections_cropper uses createSubnode with assertions; _build_manip_configs_cropper wires a dai.node.Sync (using _sync_threshold) linking image and detections/configs into a synced group feeding the Script, switching between synced and non-synced script content based on _wait_for_cfg.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Sequence Diagram(s)

sequenceDiagram
  participant ImageManip
  participant Sync
  participant Script

  ImageManip->>Sync: inputImage
  ImageManip->>Sync: detections/configs
  Sync->>Script: synced group (frame + detections/configs) within syncThreshold
  Script->>Script: crop/process using synced data

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🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: adding a Sync subnode for FrameCropper inputs.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/frame-cropper-input-sync

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@depthai_nodes/node/frame_cropper.py`:
- Around line 201-209: The docstring for the FrameCropper configuration method
should explicitly note the timestamp requirement when waitForConfig=True. Update
the text near inputManipConfigs/syncThreshold to say that the MessageGroup must
carry a timestamp aligned with inputImage because dai.node.Sync uses it to pair
config groups with frames; mention that untimestamped groups will not
synchronize. Keep the existing explanation of reuse behavior when
waitForConfig=False, and reference the FrameCropper method and waitForConfig
branch so the change is easy to locate.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 24191cb7-9ea0-4afe-af23-53f85db3faec

📥 Commits

Reviewing files that changed from the base of the PR and between d98ce6d and f179a35.

📒 Files selected for processing (1)

• depthai_nodes/node/frame_cropper.py