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SQI_CHUNK_BOUNDS

  • Origin: vendor
  • Status: supported
  • Summary: Exposes a CHUNK[INT] chunk's first/last integer as Task.Param..Start/.End.

Motivation

Some renderers take the start and end of a frame range as separate integer arguments (e.g. -s START -e END). OpenJD's CHUNK[INT] parameter exposes a chunk only as a single combined range string ({{Task.Param.Frame}} → 1-10), so those renderers otherwise need one task per frame or a wrapper script to split the range. This extension derives the bounds directly, mirroring Smedge's $(SubRange.Start) / $(SubRange.End).

Schema

Declare both extensions:

extensions: [TASK_CHUNKING, SQI_CHUNK_BOUNDS]

When declared, every CHUNK[INT] task parameter named X gains two derived task parameters per task, referenced as {{Task.Param.X.Start}} and {{Task.Param.X.End}}. Start is the smallest integer in the chunk, End the largest. For a single-frame chunk, Start == End.

Example:

parameterSpace:
  taskParameterDefinitions:
    - name: Frame
      type: CHUNK[INT]
      range: "{{Param.Frames}}"
      chunks: { defaultTaskCount: 10, rangeConstraint: CONTIGUOUS }
script:
  actions:
    onRun:
      command: render
      args: ["-s", "{{Task.Param.Frame.Start}}", "-e", "{{Task.Param.Frame.End}}"]

Validation

  • SQI_CHUNK_BOUNDS requires TASK_CHUNKING to also be declared (/extensions).
  • Every CHUNK[INT] parameter must be CONTIGUOUS (the default). A NONCONTIGUOUS chunk is rejected, because .Start/.End are undefined across the gaps of a non-contiguous set. See internal/openjd/validate.go (validateChunkBounds).

Note: .Start/.End describe the enclosing span of the chunk, so a stepped range (e.g. 1-10:2 → frames 1,3,5,7,9) yields Start=1, End=9. A renderer invoked with -s 1 -e 9 will render the full contiguous span, including the frames the step skipped — start/end renderers cannot express a step.

Worker behavior

The derived keys are added to each task's parameters during submission (internal/openjd/expand.go DeriveChunkBounds, wired in submit.go). They are ordinary task parameters, resolved on the worker through the standard Task.Param.* scope; no worker-side change is required.