Bitrate

A video encoder has to compress each frame. The bitrate is the budget it has to do so: more bits per second preserve more detail, fewer bits mean more compression and, past a point, visible artifacts such as blocks, banding and blur. File size is roughly bitrate multiplied by duration.

Encoders can use a constant bitrate (CBR), the same amount of data every second, or a variable bitrate (VBR), which spends more on complex moments and less on simple ones. Modern codecs such as H.264, H.265 and AV1 differ in how efficiently they use bits, so the same bitrate can look better with a more efficient codec.

Short-form platforms re-encode every upload to their own settings, so the exact bitrate you export matters less than starting from a clean source. Uploading an already heavily compressed file means the platform compresses compression artifacts, which shows on text and fine lines.

Motion graphics are relatively friendly to compression: flat colors and clean shapes compress well. Gradients, fine textures and fast full-screen motion are what typically need more bits.

At 8 Mbps, one minute of video is about 8 × 60 = 480 megabits, roughly 60 megabytes. A flat-design explainer may look clean at a lower bitrate, while a video with grainy footage and fast pans at the same bitrate may show blocky artifacts in dark areas.