This was the first widely deployed high-definition progressive mode. Each stored frame is a 16:9 grid of 1280 by 720 square pixels, 921,600 pixels in all, and every one of those lines is drawn on every frame.
The number 720 is the active vertical line count, the rows that carry the picture. It is not the horizontal pixel count. Multiply 720 by 16 and divide by 9 and the width is 1280, the exact partner that makes each pixel square. A Standard Definition (SD) raster often uses non-square samples, so its horizontal count does not describe the shape the viewer sees. Lines used for blanking are not part of the 720.
The p means progressive scan. Each frame draws every line in order, from top to bottom, commonly at 50 or 60 Frames Per Second (FPS). Under National Television System Committee (NTSC) timing, that 60-frame rate is 59.94 frames per second. Phase Alternating Line (PAL) systems more often use 50 frames per second.
How the Scan Treats Motion
1080 Interlaced (1080i) stores a 1920 by 1080 picture but paints it as two fields, the odd lines and then the even lines. At a nominal 60 fields per second, each field carries 540 lines, and the two fields in a frame are taken about a sixtieth of a second apart. Motion between those instants combs. A 720-line progressive frame keeps all 720 lines from one instant, which is why fast sports action adopted it despite the lower line count than 1080i.
1080 Progressive (1080p) is 1920 by 1080 square pixels, 2,073,600 pixels, or 2.25 times 921,600. Its line count is one and a half times 720, not double. High Definition (HD) is also applied to 1080i, so the marketing phrase high definition is not a synonym for 720p. A set described as High Definition Television (HDTV) may be showing either scan.
Pixels, Density, and Dynamic Range
Screen density is Pixels Per Inch (PPI). It changes when the same 1280 by 720 grid is shown on a small display or a large television. The active line count does not change with the glass size.
Each of the 921,600 addresses is one pixel of Red Green Blue (RGB) samples. Counting color samples instead of pixels would triple the figure and describe a different thing.
Standard Dynamic Range (SDR) and High Dynamic Range (HDR) are not scan modes. Either can be carried in a 720-line progressive frame, and neither one alters 1280 by 720.
The Society of Motion Picture and Television Engineers (SMPTE) production format for this grid uses 750 total lines per frame, with 720 active. Displays commonly accept that signal over High-Definition Multimedia Interface (HDMI).
Where It Sits on the Ladder
Broadcast sports, conferencing, and streaming stacks use 720p as the rung below 1080p. The frame is cheaper to encode than 1080p and steadier in motion than 1080i.
- 480 Interlaced (480i) and 480 Progressive (480p) are the usual NTSC pair, stored as 720 by 480 non-square pixels. The interlaced form usually runs at 60 fields per second, and the progressive form at 60 frames per second.
- 576 Interlaced (576i) and 576 Progressive (576p) are the usual PAL pair, stored as 720 by 576 non-square pixels, at 50 fields or 50 frames per second.
- Full High Definition (FHD) names the 1920 by 1080 progressive picture, the same grid as 1080p.
- 1440 Progressive (1440p), also called Quad High Definition (QHD), is 2560 by 1440. At 3,686,400 pixels it is exactly four times 921,600, so a 720-line progressive frame is one quarter of that grid.
- 2160 Progressive (2160p) is 3840 by 2160, nine times the pixel count. It is sold as Ultra High Definition (UHD) and as Ultra High Definition (4K). A cinema frame of 4096 by 2160 is a different grid, even when it is marketed as 4K.
- 4320 Progressive (4320p) is 7680 by 4320, 33,177,600 pixels, which is 36 times 921,600. It is sold as 8,000 Pixels (8K).
The rates below are the usual ones. The same grids also run at other rates, including 24 frames per second.
| Mode | Typical Pixels | Scan | Usual Rate |
| 480i | 720×480 | Interlaced | 60 fields |
| 480p | 720×480 | Progressive | 60 frames |
| 576i | 720×576 | Interlaced | 50 fields |
| 576p | 720×576 | Progressive | 50 frames |
| 720p | 1280×720 | Progressive | 50 or 60 frames |
| 1080i | 1920×1080 | Interlaced | 50 or 60 fields |
| 1080p | 1920×1080 | Progressive | 50 or 60 frames |
| 1440p | 2560×1440 | Progressive | 60 frames |
| 2160p | 3840×2160 | Progressive | 24, 30, or 60 frames |
| 4320p | 7680×4320 | Progressive | 24, 30, or 60 frames |