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Working-1 NL 06/06/2022 Examples of Common Video Compression Artifacts Nigel Lee Video Quality Analysis Work 05 Aug 2013

Euclid artifacts

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In addressing today's complex video environment, tackling artifacts or issues that appear with video remains a challenge for many in the industry. In his presentation Examples of Common Video Compression Artifacts, our lead technologist Dr. Nigel Lee identifies some of the various types of artifacts found in today's compressed digital video outputs.

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Page 1: Euclid artifacts

Working-1NL 04/10/2023

Examples of CommonVideo Compression Artifacts

Nigel Lee

Video Quality Analysis Work

05 Aug 2013

Page 2: Euclid artifacts

Working-2NL 04/10/2023

• Visibility of underlying block encoding structure– Caused by coarse quantization, with different quantization

applied to neighboring blocks• More visible in smoother areas of picture

Block Distortion(Blocking, Blockiness, Pixelation)

Page 3: Euclid artifacts

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• Special case of blocking noise along diagonal or curved edges; here, blocking distortion looks like staircase

Staircase Noise

Page 4: Euclid artifacts

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• Reduction in sharpness of edges, spatial details– Caused by quantization/truncation of high-frequency

transform (DCT/DWT) coefficients during compression• More noticeable around edges, textured regions

Blurring (Fuzziness, “Unsharpness”)

Page 5: Euclid artifacts

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• Colors of contrasting hue/saturation bleed across sharp brightness boundaries, looks like “sloppy painting”

– Caused by chroma subsampling• Worse in images with high color detail

Color Bleeding (Smearing)

Original

Compressed

Page 6: Euclid artifacts

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• Haziness, shimmering, blotchy noise around objects/edges– Varies from frame to frame, like mosquitos flying around

person’s head

Mosquito Noise (Gibbs Effect)

Page 7: Euclid artifacts

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• Halo surrounding objects and edges– Caused by quantization/truncation of high-frequency transform

(DCT/DWT) coefficients during compression• Doesn’t move around frame-to-frame (unlike mosquito noise)

Ringing (Echoing, Ghosting)

Page 8: Euclid artifacts

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• Looks like random noise process (snow); can be grey or colored, but not uniform over image

– Caused by quantization of DCT coefficients

Quantization Noise