 |
|
|
|
|
|
|
You need to upgrade your Flash Player in order to view this Flash Content.
|
|
 |
|
|
|
|
|
|
|
While a number of high-definition television standards have been proposed or
implemented on a limited basis, the current HDTV standards are defined in
ITU-R BT.709 as 1080 active interlaced or progressive lines, or 720 progressive
lines, using a 16:9 aspect ratio. The term "high-definition" can refer to the
resolution specifications themselves, or more loosely to media capable of similar
sharpness, such as photographic film. Currently 11% of American households have
HDTV's. There are 8 HD broadcasting channels.
For example, the format 720p60 is 1280 × 720 pixels, progressive encoding with
60 frames per second (60 Hz). The format 1080i50 is 1920 × 1080 pixels, interlaced
encoding with 50 fields (25 frames) per second. Often the frame or field rate is
left out, indicating only the resolution and type of the frames or fields. Sometimes
the rate is then to be inferred from the context, in which case it can usually be
assumed to be either 50 or 60, except for 1080p which is often used to denote either
1080p24, 1080p25 or 1080p30 at present but will also denote 1080p50 and 1080p60 in
the future.
A frame or field rate can also be specified without a resolution. For example 24p
means 24 progressive frames per second and 50i means 25 interlaced frames per second,
consisting of 50 interlaced fields per second.
|
|
|
|
|
|
|
|
