Overview
HD stands for High Definition and refers to a family of video formats that offer significantly more image resolution than earlier Standard Definition television (SD, PAL/NTSC). HD is not a manufacturer or device, but rather a resolution and transmission standard for cameras, image recording, editing, and broadcasting. Characteristic features are the 16:9 aspect ratio and the two core formats, 720p and 1080i/1080p.
In camera and post-production workflows, HD is closely linked with codecs like ProRes and DNxHD/DNxHR, as well as signal routing via HD-SDI. Even though 4K and higher resolutions dominate the high-end market today, HD remains a common delivery and broadcast standard – especially for TV broadcasting and streaming.
Resolutions and Terms
| Designation | Resolution | Scanning | Common Marketing |
|---|
| 720p | 1280 × 720 | progressive | HD / “HD ready" |
| 1080i | 1920 × 1080 | interlaced (field scan) | Full HD (broadcast) |
| 1080p | 1920 × 1080 | progressive | Full HD / FHD |
The "p" stands for progressive (full frame scanning), and the "i" stands for interlaced (field interlacing with two fields per frame). 1080p offers approximately 2.1 megapixels per frame.
Technical Standard
The parameters for HDTV are defined in recommendation ITU-R BT.709 (often shortened to Rec. 709). It defines, among other things, the image format with 1080 active lines and 1920 square pixels per line (16:9), signal characteristics, and the associated color space. Rec. 709 remains the reference color space for HD material in acquisition, grading, and playback to this day.
On-Set Usage
In practice, HD is primarily used where the delivery or broadcast standard is limited to 1080 – for example, in classic TV production, live broadcasting, or low-bandwidth streaming. HD material is often cabled via HD-SDI and recorded in HD-compatible codecs (e.g., ProRes or DNxHD). In modern cameras, HD often serves as a proxy or monitoring format, while recording internally at higher resolutions (e.g., 4K or RAW).