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Field Timing

The Field-timing dialogue is a diagnostic tool used to inspect temporal structure and continuity at the field level within a decode-orc pipeline. Like Preview and Line-scope, it is not a pipeline stage, but a read-only analysis view that attaches to preview-capable stages.

The Field-timing dialogue focuses on when fields occur and how they relate to one another, rather than how they look. It is primarily concerned with cadence, continuity, alignment, and metadata hints that describe timing.

Purpose and use cases

The Field-timing dialogue is used to:

  • Verify field order and parity continuity
  • Inspect dropped, duplicated, or skipped fields
  • Validate alignment between multiple sources
  • Diagnose cadence issues (e.g. irregular field progression)
  • Confirm correct behaviour of field re-mapping and alignment stages

It is especially useful when working with:

  • Multiple captures of the same material
  • Pipelines using field_map and source_align
  • Stack-based workflows
  • Sources with known timing instability or capture errors

Attaching the field-timing dialogue

The Field-timing dialogue attaches to the currently previewed stage and analyses the post-stage output stream.

All timing information shown reflects:

  • Upstream transforms
  • Field reordering
  • Alignment offsets
  • Parity inversion or correction

Core concepts

Field index

Each output field is identified by a zero-based field index, corresponding to the index used throughout the pipeline.

If fields are reordered or dropped upstream, the field indices shown here reflect the effective output ordering, not the original capture numbering.

Field parity

Each field carries a parity hint:

  • First field
  • Second field

The dialogue visualises parity progression across time, making it easy to spot:

  • Incorrect parity flips
  • Repeated parity
  • Effects of the field_invert transform

Field continuity

The dialogue tracks continuity of fields over time, highlighting:

  • Missing fields
  • Duplicated fields
  • Unexpected jumps in source field references

This is critical for diagnosing issues introduced by capture errors or incorrect range mapping.

Visualisation and indicators

The Field-timing dialogue presents a timeline-style view of fields.

Typical elements include:

  • Sequential field indices
  • Parity markers per field
  • Source-origin indicators (where applicable)
  • Alignment offsets or discontinuity markers

Visual cues are used to flag anomalies, such as breaks in expected progression.

Interaction with transform stages

The Field-timing dialogue reflects the effects of timing-related transform stages directly.

Field Map

After field_map, the dialogue shows:

  • Reordered field indices
  • Gaps where ranges were omitted
  • Non-monotonic source field references

This allows immediate verification that range specifications behave as intended.

Source Align

After source_align, the dialogue shows:

  • Aligned starting points across sources
  • Dropped leading fields
  • Enforced first-field alignment (when enabled)

This is the primary tool for confirming that multiple inputs are correctly synchronised before stacking.

Stacker

After stacker, the dialogue shows:

  • A single, unified field timeline
  • Stable parity progression (assuming aligned inputs)
  • Absence of per-source discontinuities

It is useful for confirming that stacking did not introduce timing artefacts.

Typical workflows

Common uses of the Field-timing dialogue include:

  • Verifying field order immediately after a source stage
  • Confirming correct behaviour of field_map range specifications
  • Validating multi-source alignment before stacking
  • Diagnosing parity issues observed in preview output
  • Comparing timing behaviour before and after transform changes

Limitations

  • The Field-timing dialogue is read-only and non-destructive.
  • It does not display sample-level or image-level data.
  • Interpretation assumes that upstream metadata (VBI, timecode, parity hints) is present and valid.

Notes on field-timing analysis

  • The dialogue always reflects the current preview stage output.
  • Timing anomalies shown here often explain visual artefacts seen in Preview.
  • For best results, use the Field-timing dialogue together with Preview and Line-scope.

The Field-timing dialogue provides essential visibility into the temporal correctness of decode-orc pipelines, complementing visual and waveform-based inspection tools.