Some useful High Definition terminology

Below are some definitions of terms you will come across when dealing with HD. If you wonder what they mean here is an answer.

1080/24P
Refers to an internationally standardized High Definition production format (ITU BT 709) having a digital sampling structure of 1920 (H) x 1080 (V) and operating at 24-frames per second progressively scanned. Often used to loosely describe a system that operates at 23.976P as well.

1080/60i
Refers to a standardized High Definition production format (SMPTE 274M and ITU 709) having a digital sampling structure of 1920 (H) x 1080 (V) and operating in interlaced scan mode at 60 fields per second. Often used to loosely describe a system that operates at 59.94i as well.

1280×720
Refers to a high definition digital sampling structure of 1280 horizontally and 720 vertically. All 1280×720 images are progressively scanned (720P).

1920×1080
Refers to a digital sampling structure of 1920 horizontally and 1080 vertically. 1920×1080 images can be scanned either interlaced (1080i) or progressively (1080P).

22:11:11
Defines high definition video signals, where the luminance (Y) is sampled at 74.25 MHz and the color difference samples (R-Y,B-Y) channels are each sampled at 37.125 MHz. Note that it has become commonplace to denote HDTV Y,R-Y,B-Y also as 4:2:2. While technically incorrect, it is popularly used in a great deal of published literature.

22:22:22
Denotes a high definition system where all signals (R,G,B) are sampled at 74.25 MHz. Note that it has become commonplace to denote HDTV RGB also as 4:4:4. While technically incorrect, it is popularly used in a great deal of published literature.

Aspect Ratio (Picture)
The ratio of screen width to screen height. Can be expressed as Width by Height (Example: 16×9, 4×3) or as calculated ratio (1.33:1, 1.78:1)
Some common aspect ratios:
1.33 (4×3) Standard Television or Academy Standard
1.78 (16×9) HDTV
1.85 Academy Flat
2.35 Cinemascope

Aspect Ratio (Pixel)
The ratio of pixel width to pixel height. Standard NTSC (ITU-R 601) digital video has rectangular pixels. Computers and HDTV have square pixels.

CineAlta
Name for a line of products by Sony that are developed for the film market.

Capture Rate
Used to describe the number of times per second that a picture is taken or captured in an imaging system. In a progressive system the capture rate is equal to the frame rate. In an interlaced system, the capture rate is double the frame rate because at each capture interval, only one field (a half resolution image) is acquired. It takes two fields to make a complete frame. It is standard practice to refer to the capture rate of an image as well as how it is captured when describing it instead of the frame rate (i.e. 60i (60 captures, 30 frames per second), 30P (30 captures, 30 frames per second) and 60P (60 captures, 60 frames per second)) Also see Frame Rate, Interlace Imaging, Progressive Imaging.

Downconversion
The process of converting high resolution video to lower resolution video. Often done to high definition camera reels so that programs can be offlined on inexpensive standard definition editing systems before being conformed in High Definition. Also done to finished HD programs for delivery to non-HD clients

Progressive Imaging
All lines (whole frame) are captured at the same instant. Each frame represents a single moment in time. See Interlace Imaging, PsF Imaging, Frame Rate, Capture Rate

PsF Imaging
Progressive-Segmented Frame Imaging. All lines (whole frame) are captured at the same instant. Each frame represents a single moment in time. After the frame is captured, it is then separated (Segmented) into two halves. One half is the odd lines and the other is the even lines. (Now this may sound like interlace, but each frame represents only one moment in time, not two). Though transmitted similarly as an interlaced signal, if treated as a progressive signal, does not cause the same harmful artifacts that interlace scanning causes. Often image can be processed with much of the same transmission hardware that was designed for interlace. Processing hardware can also be designed to handle both Interlace and PsF (ie Switchable). See Interlace Imaging, Progressive Imaging

Y, R-Y, B-Y
Describes the luminance (Y) and color difference signals (R-Y) and (B-Y) of component video. Y is luminance information and the R-Y and B-Y signals together provide the color information. These signals, derived from the original RGB source, are used in most video systems as a bandwidth reduction technique.