Digital TV HD System Ilustrated - pág.32

an «HD ready» logo.

All display devices using such a logo had to comply with the
following requirements:
A widescreen 16x9 format
A minimum resolution of 1280 x 720 pixels (720p)
DVI or HDMI connectivity, with HDCP
HD has been around for a while now, in 720p and 1080i
formats.  As described in Book 2, MPEG2 compression reduces the quantity of
data to a manageable amount using a variety of techniques, including a process
called «discrete cosine transform» where the picture is grouped into 8x8 pixel
blocks (called «macroblocks») and converted to the frequency domain and rounded
up or down.  One luminance and two chrominance (R-Y and B-Y) signals are
processed separately as a 4:2:0 grouping.
Some broadcasters chose to use both scanning
standards, leaving the viewers to choose which standard suits them best.
Full HD standards in a 1080p format were published in
2003 to provide pictures in a 1920 x 1080 format, known as 2K in the trade.
There are currently no 2K broadcasts in the UK, but upscaled standard HD can
look quite stunning.  However, a limited supply of 2K Blu-ray discs is now
available.  Improved MPEG4 compression standards (also known as H264) were
introduced which can reduce the required bandwidth with larger 16 x 16 pixel
blocks.
An enhanced «Full HD» logo is also available for devices that
can display 1080p pictures:

Ultra HD  (4K  or UHD)  is the new high definition
format, with 3840 x 2160 pixels.  This utilises a High Efficiency Video Codec
(HEVC or H265) with up to 64 x 64 pixel blocks, providing even more
compression.  The grouping could be 4:2:0 or 4:4:4, the latter providing four
times as much colour information at the expense of a greater bandwidth