Compression artifacts
Also known as: artifacts, codec artifacts, video noise from compression
Visible flaws created when a codec throws away too much detail: blocks, smearing, banding, mosquito noise around edges and shimmering in fine textures.
Updated
What it means
Lossy codecs save space by discarding information they predict you will not notice. When there is not enough data for the scene, the guesses become visible. These visible mistakes are compression artifacts, and they come in several forms: blocky squares, smeared textures, ringing or mosquito noise around sharp edges, and banding in smooth gradients.
Artifacts depend on three things: the codec, the Bitrate and the content. Calm scenes compress easily, while water spray, falling snow, gravel, leaves in wind and fast camera movement change almost every pixel and demand much more data.
Each new lossy encode, such as a platform upload, can add a fresh layer of artifacts on top of the old ones.
How it works in practice
To avoid them, record at the highest bitrate your camera and card support, and export at a generous bitrate. Action cameras often have a high bitrate option that is worth enabling for busy scenes like surf and powder.
In editing, strong sharpening, heavy contrast and big saturation boosts make artifacts more visible. A light touch keeps them hidden. Adding subtle film grain can also help mask banding in skies, because the fine texture breaks up the steps between shades.
When uploading, give platforms a clean, high-bitrate master, because their own recompression will add some artifacts regardless.
What to watch out for
Artifacts cannot be fully removed afterwards. Denoising and deblocking filters can soften them, but they also soften real detail. Prevention during recording and export is far more effective.
Low light makes everything worse. Sensor noise looks like detail to the encoder, which spends data on it and runs short for the real picture. Better light or a lower frame rate helps more than any setting.
Do not judge artifacts on a small phone screen. Review footage on a large display, where blocks and smearing in fast moments become obvious, and fix the source before publishing.
How RawClip handles it
RawClip uses the files you upload as the source for the 4K and 1080p highlight, so cleaner originals give a cleaner result. Upload camera files straight from the card rather than compressed copies for your highlight.