High Definition usually refers to 720 vertical lines of video format resolution or more.
| Pixel Resolution (W×H) | Video Format Supported | Pixels (Advertised Megapixels) | Aspect Ratio (X:Y) | Description | |
|---|---|---|---|---|---|
| Image | Pixel | ||||
| 1024×768 | HD Ready | 786,432 (0.8) | 16:9 | 4:3 | Typically a computer resolution XGA; also exists as a standardized "HD-Ready" TV size on the Plasma display with non-square pixels. |
| 1248×702 | 720p Clean Aperture | 876,096 (0.9) | 16:9 | 1:1 | Used for 750-line video with raster artifact/overscan compensation, as defined in SMPTE 296M. |
| 1280×720 | 720p | 921,600 (0.9) | 16:9 | 1:1 | Typically a computer resolution WXGA, also used for 750-line video, as defined in SMPTE 296M, ATSC A/53, ITU-R BT.1543, Digital television, DLP, LCD and LCOS projection HDTV displays. |
| 1366×768 | 720p/1080i, HD Ready | 1,049,088 (1.0) | 683:384 (Approx 16:9) | 1:1 Approx | Typically a TV resolution WXGA; also exists as a standardized "HD-Ready" TV size. HDTV common pixel resolution, that used on LCD HDTV displays. |
| 1280×1080 | HD Ready 1080p | 1,382,400 (1.4) | 32:27 (Approx 16:9) | 3:2 | Non-standardized "HD-Ready" TV size. Used on HDTV Plasma display. |
| 1440×1080 | HDCAM/HDV 1080i | 1,555,200 (1.6) | 4:3 | 4:3:1 | Used for anamorphic 1152-line video in the HDCAM and HDV formats introduced by Sony and defined (also as a luminance subsampling matrix) in SMPTE D11. |
| 1888×1062 | 1080p Clean Aperture | 2,001,280 (2.0) | 16:9 | 1:1 | Used for 1152-line video with raster artifact/overscan compensation, as defined in SMPTE 274M. |
| 1920×1080 | 1080i/1080p, HD Ready 1080p, Full HD | 2,073,600 (2.1) | 16:9 | 1:1 | Used for 1152-line video, as defined in SMPTE 274M, ATSC A/53, ITU-R BT.709. HDTV common pixel resolution, that used on LCD HDTV displays. |
| 3840×2160 | 2160p | 8,294,400 (8.3) | 16:9 | 1:1 | Quad HDTV, (there is no HD Ready 2160p Quad HDTV format). |
It should be noted that the numbers used for "HD-Ready" image resolutions do not constitute acceptable 750- or 1152-line video signals in most standards-compliant hardware; in this respect terms such as "720p" and "1080p" are mostly used for advertising, though that does not necessarily mean that HD-Ready TVs labeled in this manner are incapable of accepting those formats as input.
Additionally, the "Clean Aperture" numbers are almost always contained within the frames of their respective "Production Aperture" numbers (e.g., a 1888×1062 rectangle would be contained within a 1920×1080 frame). This is to maintain compatibility with analogue signals, which can often become distorted close to the edge of the frame. It also increases the chance that a digital signal being played on overscan-enabled equipment will display the entire picture visibly.
A common pixel resolution used in HD Ready LCD TV panels is 1366 x 768[11] pixels instead of the ATSC Standard 1280 x 720 pixels. This is due to maximization of manufacturing yield and resolution of VGA, VRAM that comes with a 768 pixel format. Hence, LCD manufacturers adopt the 16:9 ratio compatible for the HD Ready 1080p video standard. Nevertheless, every HDTV has an overscan processing chipset to fix resolution scaling and color rendering, eg LG XD Engine, SONY BRAVIA Engine. Only when viewing 1080i/1080p HD contents under HD Ready 1080p where there is true pixel-for-pixel reproduction, and for HD ready LCD TV, do some signals undergo a scaling process which results in a 3-5% loss of picture.
http://en.wikipedia.org/wiki/High-definition_television
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