Compression artifacts are visible changes introduced when the encoder cannot preserve all source detail. They show up differently across content types, so review the exported clip rather than assuming a setting will work for everything.
Blockiness and smearing
Large blocks or trails around moving objects can indicate insufficient data for the motion or the encoder’s limits. Fast camera pans and busy scenes reveal these problems quickly.
Banding and ringing
Smooth gradients such as skies may show visible bands. Sharpened edges or high-contrast text may develop halos or ringing. Check both large surfaces and fine outlines.
Audio and timing matter too
Listen for distortion, missing audio and sync drift. A video that looks acceptable but has clipped speech or an offset soundtrack is not ready to share.
A practical checklist
- Compare the output and source at the same playback size.
- Check a fast-motion segment and a smooth gradient.
- Read fine text and inspect edges.
- Listen from beginning to end for sync and clipping.
Common mistakes to avoid
- Inspecting only a still frame.
- Comparing a high-resolution source to a small preview window.
- Making a second lossy export from the first compressed result.
Questions people ask
Can compression artifacts be removed later?
Not reliably. A better re-export from the original is usually preferable to trying to reconstruct discarded detail.
Why does text look bad first?
Thin lines and small letters need precise edges, which are vulnerable to scaling and compression.