Method

Video blockiness

Macroblock / compression blockiness score

What we measure and how

Macroblock blockiness quantifies the visibility of regular block-aligned edges introduced by lossy compression — the cause of the classic 'mosaic at low bitrate' artefact on natural content. Computed as a per-frame block-edge score (a clean lossless gradient scores around 1; heavily compressed natural content scores 30+), then aggregated as the 95th percentile across the file. The metric is content-dependent and NOT normalised: synthetic test patterns such as SMPTE colour bars score 25–1600 non-monotonically because their sharp deterministic edges also happen to fall on block boundaries — interpret test-pattern scores with caution. Compared against `blockiness_max_score` from the spec.

Spec fields consulted

These Universal Media Delivery Profile paths resolve this check's thresholds against your spec snapshot at the moment the job was submitted.

• · assets.video.quality.blockiness_max_score

The full UMDP schema: /umdp.

Related methods

• Black frames
• Frozen frames
• Video aliasing
• Video blurriness
• Video colour banding

Method identifier: video_blockiness