Pixelation commonly describes visible block-like image damage or coarse detail. It can result from compression, lost or damaged media information, low source resolution or other processing conditions. The appearance alone does not identify one cause, and increasing a television's output resolution cannot necessarily restore picture information lost earlier in the delivery or encoding process.
A practical example
A fast-moving scene may break into visible blocks while a static scene looks acceptable. Comparing another source and noting whether the damage appears alongside interruptions can help separate limited encoding quality from a delivery-related error affecting that particular presentation.
A common misunderstanding
Do not assume that every blocky image is a weak Wi-Fi signal. The original encoded source can already contain artefacts, and enlarging it on a sharper screen can make them easier to notice.
Related terms
Stable technical definition. Editorial approach