Macroblocking
Also known as: blocking, pixelation, blocky video
A compression artifact where parts of the image break into visible square blocks, usually during fast motion or detailed scenes when the bitrate runs short.
Updated
What it means
Codecs divide each frame into blocks of pixels and compress them separately. When the encoder has enough data, the block edges blend invisibly. When the scene is too complex for the available Bitrate, whole blocks get simplified to a few flat colors, and the grid becomes visible as squares. That is macroblocking.
It is one of the most recognizable compression artifacts. You often see it in streams on weak connections, in dark scenes with smooth gradients, and in action footage full of spray, snow, gravel or leaves.
In Long GOP video, blocking can also spread across frames when a reference frame is damaged.
How it works in practice
The main fix is more data. Record in the camera high bitrate mode, export at a higher target bitrate, and use variable bitrate with a generous maximum so the encoder can spend more on difficult moments.
Content choices help too. Very fast pans over detailed ground, water close to the lens, and dark, noisy scenes are the hardest to compress. Good light lowers noise, which leaves more data for real detail.
For live streams, a stable connection and a sensible bitrate for that connection reduce blocking more than any camera setting.
What to watch out for
Upscaling or sharpening a blocky clip makes the squares more obvious. Avoid strong sharpening on low-bitrate footage, and keep it modest on footage that already looks soft.
Repeated compression compounds the problem: a clip that was shared through a chat app, downloaded and edited again often shows heavy blocking. Edit from originals whenever possible.
Blocks in short bursts that look like corruption can also point to a failing card or an interrupted transfer, so copy the file again and check the card before blaming the codec. Replacing a worn card is far cheaper than losing a day of footage to it.
How RawClip handles it
RawClip uses your upload as the source for the highlight, so original camera files give the cleanest result. Avoid uploading clips that were already shared or compressed several times, and the AI builds a sharper highlight.