Bitrate

What it means

Bitrate is how much data the camera writes for every second of video, usually given in megabits per second (Mbps). It sets the budget the codec has to describe each frame. Resolution decides how many pixels there are; bitrate decides how much information is available to describe them accurately.

When the budget is generous, fine textures like grass, snow and water survive. When it runs short, the encoder simplifies: detail smears, flat areas show banding, and fast motion breaks into blocky artifacts. Most action cameras use variable bitrate, spending more on complex, fast scenes and less on a static shot of the sky.

How it works in practice

Typical numbers: recent GoPros record 4K and 5.3K at roughly 100 to 120 Mbps with the High bitrate setting on, and DJI Osmo Action and drone cameras sit in a similar range. Phones usually record 4K at a noticeably lower rate.

The storage math is simple once you divide by eight. 100 Mbps equals 12.5 megabytes per second, which is about 45 GB per hour of footage, so a 128 GB card holds under three hours at that setting. The card must also keep up: look for V30 or faster for 100 Mbps recording. HEVC uses its bitrate more efficiently than H.264, so the same number looks better.

What to watch out for

A high bitrate is not a substitute for good settings. A clip shot at too slow a shutter speed or in poor light stays soft at any bitrate, and more data simply records the noise in greater detail.

The opposite trap is starving the encoder. Mountain-bike runs through trees, spray off a wave or a snowstorm are the hardest scenes to compress; at a low bitrate they turn to mush exactly when the action peaks. Use the high bitrate mode for those, and keep a fast card so the camera does not stop recording.

Finally, remember that platforms re-encode everything you upload. A 200 Mbps export will not survive YouTube or Instagram intact; export at a sensible rate for the destination, and keep the highest quality for your raw footage archive.