Resolutions and frame rates, in practical terms
Resolution and frame rate are the two numbers that describe how much raw visual information a video contains: resolution is how much detail is captured in each frame, and frame rate is how many of those frames appear per second. Both feed directly into how much bitrate a video needs to look right.
Common resolution names
| Common name | Dimensions | Total pixels |
|---|---|---|
| SD (480p) | 854×480 | ~0.41 MP |
| HD (720p) | 1280×720 | ~0.92 MP |
| Full HD (1080p) | 1920×1080 | ~2.07 MP |
| QHD / 1440p | 2560×1440 | ~3.69 MP |
| 4K UHD (2160p) | 3840×2160 | ~8.29 MP |
| 8K UHD (4320p) | 7680×4320 | ~33.2 MP |
Each step up roughly doubles or quadruples the pixel count of the one before it — 4K has exactly four times the pixels of 1080p, which is why the jump in file size and required bitrate between them is so much bigger than the resolution names alone suggest.
Aspect ratio
Aspect ratio is the ratio of width to height. 16:9 is the standard for most modern video — TVs, monitors, and the resolutions in the table above are all built around it. 4:3 was the standard for older television and is now mostly seen in archival footage. 21:9 (and similar ultrawide ratios) shows up in cinematic content and ultrawide monitors. Mixing aspect ratios without accounting for it results in either stretched image or letterboxing (black bars).
Frame rate
Frame rate is measured in frames per second (fps). A few values account for most content:
- 24 fps
- The traditional film standard, still widely used for a cinematic look because of the specific motion blur it produces.
- 25 / 30 fps
- Common for television and general video, historically tied to regional broadcast standards (25 fps in PAL regions, closer to 30 fps in NTSC regions).
- 50 / 60 fps
- Used where smooth motion matters more than a cinematic feel — sports, gaming footage, and screen recordings all benefit from the reduced motion blur and judder.
Progressive vs. interlaced
You'll sometimes see resolutions written with a "p" or an "i" — for example 1080p versus 1080i. Progressive ("p") scanning draws every line of a frame in order, which is what virtually all modern displays and encoding expect. Interlaced ("i") scanning, a holdover from older broadcast television, draws alternating lines in two passes to save bandwidth on analog signals. Interlaced content generally needs to be deinterlaced before it looks correct on modern progressive displays; new content today is produced progressive from the start.
How resolution and frame rate affect bitrate
Both increase the amount of raw information the encoder has to represent, and roughly speaking their effect on bitrate need multiplies rather than adds: doubling the frame rate at a fixed resolution requires meaningfully more bitrate to maintain the same quality, and so does doubling the resolution at a fixed frame rate. When bitrate is constrained — a strict file size limit, a bandwidth-limited stream — dropping either resolution or frame rate is usually a more effective way to fit the budget than simply lowering quality settings and accepting more compression artifacts.