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Crop Black Bars (Clustered)

FFmpeg Builder: Crop Black Bars (Clustered)

This flow element scans the video file to detect black bars using a clustered approach, analyzing multiple points in the video to provide a more reliable crop suggestion. It is designed to handle videos where black bars may appear inconsistently or only in certain segments.

The flow element checks for black bars at several intervals throughout the video, then clusters the results to determine the most consistent cropping area. This helps avoid incorrect cropping due to temporary black screens, title cards, or transitions.

Processing is performed when this flow element is first called, scanning the video and storing the crop information. Actual cropping is only applied when the FFmpeg Builder: Executor flow element is executed.

Detection Mode​

Choose a preset for black bar detection:

  • Default
  • Deep
  • Extreme
  • Custom (enables all custom options below)

Custom Options​

The following options are only available when Detection Mode is set to Custom.

Analysis Frames​

Number of frames to analyze per segment.
Default: 15

Minimum Crop Difference​

Minimum number of pixels (width + height) that must be removed before applying crop.
Default: 10
Prevents cropping for very small black bars. This is always used, but only user-configurable in Custom mode.

Consistency​

Percent of frames that must agree on a crop.
Default: 65

Crop Detect Limit​

FFmpeg cropdetect limit (0.0–1.0, default 0.1). Lower values are more sensitive.
Default: 0.1

Crop Detect Round​

FFmpeg cropdetect rounding value.
Default: 5

Cluster Tolerance​

Tolerance (%) for merging crops of similar size.
Default: 5

Min Crop Res​

Minimum crop dimension relative to input resolution (1–100).
Default: 50

Alt Crop Threshold​

Maximum percent for a significant alternative crop before rejecting the majority crop.
Default: 30

Outputs​

  • Output 1: Black bars were detected and meet the threshold.
  • Output 2: No significant black bars detected, or not above the threshold.

Notes​

  • Cropping is only applied when the FFmpeg Builder: Executor flow element is executed.
  • Use the custom mode to fine-tune detection for difficult or unusual video sources.
  • Adjust thresholds and tolerances to avoid false positives from temporary black screens or overlays.