Category Archives: U

UHDTV (A.K.A. UHD)

Ultra High Definition Television has two picture sizes, correctly referred to as UHD-1 (4K) and UHD-2 (8K), though more commonly known as 4K UHD and 8K UHD respectively. Both are standardized in ITU-R.BT. 2020.

The 4K UHD image is four times the area of 1920 HD at 3840 x 2160. There is now a choice of equipment for 4K UHD production and a number of programs have been produced in the format. 4K UHD TV screens are widely available; transmission trials have proved the delivery system using HEVC video compression via DVB.

What is now known as 8K UHD started life as Super-Hi vision in the laboratory at NHK in about 2001. The picture size is 7680 x 4320 – 16 times the area of 1920 HD. There are plans for transmission in Japan.

ITU-R BT.2020 describes framerates from 23.98 to 120 Hz with only progressive scans and a wider color gamut which can reproduce richer colors than HD. The 4K format has already been used for a number of broadcasts. For sport the 50 or 60 Hz framerate is popular. Even at lower rates the format produces very large quantities of data that require faster video links and more storage than HD. This requirement is four times larger with 8K.

See also: ITU-R BT.2020, Storage capacity, Viewing Distance

Uncommitted editing

Editing where the decisions are made and the edits completed but any can still easily be changed. This is possible in an edit suite with FrameMagic that includes true random access editing – where the edits need only comprise the original footage and the edit instructions. Nothing is re-recorded so nothing is committed. This way, decisions about any aspect of the edit can be changed at any point during the session, regardless of where the changes are required. Where new frames are generated, such as in mixes, dissolves and compositing, all the tools and their settings are available – preferably on the edit timeline.

See also: True random access

Unicode

Unicode allows computers to consistently represent and manipulate text in most of the world’s writing systems – 30 are currently implemented – describing about 100,000 characters. Before Unicode, there were hundreds of different encoding systems to assign numbers to characters, and no single one could contain enough characters to cover all languages – in Europe alone. Unicode provides a unique number for every character, regardless of platform, program or language. The Unicode Standard is widely adopted and supported by the computer industry.

Website: www.unicode.org

Up-res

The process which increases the size, or number of pixels used to represent an image by interpolating between existing pixels to create the same image on a larger format. There is no implied change of vertical scan rate. Despite its name, the process does not increase the resolution of the image; it just spreads the same over a larger canvas. The quality of the result depends on that of the original image as well as the accuracy of the interpolation process that creates the new larger image. Speed is an issue for realtime work, as good quality requires a large amount of processing, which also increases with the picture area.

See also: Down-res, Format conversion

USB

Universal Serial Bus – has been evolving. It is common to have four or six USB connectors on a PC or laptop computer. These are usually USB 2.0 (introduced in 2000), identifiable by the ports which are generally black. The maximum transfer rate is 480 Mb/s which offers potentially useful connectivity for media applications on PCs and Macs. It is very cheap and widely used for connecting PC peripherals. It is a PAN, and so the service provided to any one device depends on their specification and what other connected devices are doing. Actual speeds achieved for bulk data transfers are about 300 Mb/s – but this is likely to rise.

The newer (2008) USB 3 ports are generally blue. They add a new transfer mode called SuperSpeed working at up to 5 Gb/s, more than ten times faster than USB 2. It is also full duplex (USB 2 is half duplex) meaning it can both simultaneously transmit and receive at full speed – making a total of 10 Gb/s I/O. USB 3.1 was released in 2013 which doubled the top speed to 10 Gb/s, with full duplex.

See also: IEEE 1394