Compression artifact

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File:Glitch video.ogg Compression artifact refers to a noticeable distortion of media (including images, audio, and video) caused by the application of lossy data compression. Lossy compression algorithms reduce file size by removing some of the data, which can result in a loss of quality and the introduction of artifacts.

Types of Compression Artifacts

Compression artifacts can manifest in various forms depending on the type of media and the compression algorithm used. Common types include:

Image Compression Artifacts

• Blocking artifacts: These occur when an image is divided into blocks for compression, and the boundaries between these blocks become visible.
• Ringing artifacts: These appear as halos or ghosting around sharp edges in an image.
• Color banding: This occurs when smooth gradients are replaced by abrupt changes in color.

Audio Compression Artifacts

• Pre-echo: This is a faint sound that precedes the main sound, often noticeable in percussive audio.
• Quantization noise: This is a type of noise introduced by the quantization process in digital audio compression.
• Aliasing: This occurs when high-frequency components are misrepresented as lower frequencies.

Video Compression Artifacts

• Mosquito noise: This appears as random noise around edges in a video.
• Macroblocking: This is similar to blocking artifacts in images but occurs in video frames.
• Color bleeding: This happens when colors spread beyond their intended boundaries.

Causes of Compression Artifacts

Compression artifacts are primarily caused by the loss of data during the compression process. The severity of artifacts depends on the compression ratio and the algorithm used. Higher compression ratios typically result in more noticeable artifacts.

Mitigation Techniques

Several techniques can be employed to reduce the visibility of compression artifacts:

• Post-processing filters: These can be applied to smooth out artifacts after decompression.
• Adaptive compression algorithms: These adjust the compression parameters based on the content to minimize artifacts.
• Higher bitrates: Using higher bitrates can reduce the amount of data loss and thus the severity of artifacts.

Related Pages

• Lossy compression
• Image compression
• Audio compression
• Video compression
• Quantization (signal processing)
• Aliasing

See Also

• Data compression
• Digital signal processing
• Noise reduction