HD

From Mographwiki.net

HDTV, or "high definition television" is a digital broadcast standard that comes in a variety of flavors. For the sake of brevity, we'll stick to the resolutions defined in ITU-R BT.709 (aka Rec. 709) part 2 as this covers most modern HDTVs. Part 1 dealt largely with earlier, now obsolete versions of the system.

Sizes and Resolutions The part 2 systems use a 16:9 aspect ratio based on square pixels. The common resolutions are: 720p - 1280 X 720 1080i - 1080 X 1920 1080p - 1080 X 1920

Frame Rates In Rec. 709, frame rates are specified separately from resolutions. An "i" after the number denotes that the frames are drawn using the "interlaced" technique, drawing every other line in two passes. A letter "p" for "progressive" indicates the frames are drawn from top to bottom in a linear sequence. 23.976 24p 25p 30p 50i 50p 60i (59.94) 60p

Gamma Rec. 709 specifies a gamma value of 2.25.

Previewing Techniques At the desktop level, you can use Adobe Photoshop or Adobe After Effects 7 or newer to approximate what your work will look like when displayed on a Rec. 709 display by using the Rec. 709 Working color space in an After Effects project, or by specifying Rec. 709 as the color profile or color proofing mode in Adobe Photoshop. For absolute accuracy, use a video card with HD/SDI or DVI-D output to view your work on a broadcast grade Rec 709 monitor such as the eCinema Systems DCM23. Also be advised that while many HDTV manufacturers are now advertising that their displays are manufactured to accurately reproduce Rec. 709, the majority of LCD / Plasma / DLP HD TV's in the market today don't live up to the standard. Lower end HDTV's tend to accentuate contouring or banding artifacts as well as compression artifacts.