Removing the aperture creates an ‘open gate’ format which may have no black bar between frames – then all 1556 lines carry picture information.
4K is a x4-area version of 2K, with 12.76 M pixels. Once again the format includes ‘black’ lines – 40 this time, so the actual full frame image is 4096 x 3092. Historically many aspects of handling 4K have been problematical – not least due to the large data rate (over 1.1 GB/s) and the amount of data produced – about 4 TB/h. However modern technologies applied all the way from scene to screen have now made 4K far more readily accessible. For some time, 4K has been the format of choice for some complex effects shots where it was felt these needed extra quality (over 2K) to still look good after all the necessary processes are completed, specially where the finished shots are inter-cut with the original negative. Now it is increasingly being used for whole movies.
DCI 4K and 2K sizes for exhibition in digital cinemas are not the same as the DPX values above. They are 2K (2048 x 1080), 4K (4096 x 2160), quite close to the 1.85:1 aspect ratio of Cinemascope. In addition, different camera apertures can be used to shoot at different aspect ratios. All these (below) are ‘four perf’ (a measure of the length of film used) and so all consume the same amount of stock per frame. Note that scanners (and telecines) typically change scan size to maintain full 2K or 4K images regardless of aspect ratio. It is no longer normal for work to be scanned at a fixed full frame size. F There are many more 35 mm formats in use. See also: MTF
Film recorder Equipment which inputs digital images and outputs exposed negative film.
Film scanner A general term for a device that creates a digital representation of film for direct use in digital television or for digital intermediate work. For television, film scanners are now replacing traditional telecines. For digital film, they should have sufficient resolution to capture the full detail of the film so that, when transferred back to film, the film-digital-film chain can appear as an essentially lossless process.
FireWire See IEEE 1394
Flash Memory
Non-volatile solid-state memory that offers fast read times, but not as fast as DRAM, and can withstand considerable shock (G-force). Hence its popularity for storage on battery-powered devices. Also when packaged in a memory card or a USB stick, it is enormously durable, withstanding intense pressure, extremes of temperature and even water immersion. There is an emerging potential for flash memory to replace computer hard drives – with solid-state drives (SSD).
Flash – double and triple
Double flash is commonly used in film projectors so that each of the 24 f/s is shown twice – a total of 48 f/s. This means the movie presentation has less flicker. Triple flash is better still with a frames rate of 72 f/s. When presenting 3D cinema, the left and right eyes want motion and the parallax to appear at the same time but the sequential frame presentation of 3D, often using a single projector, naturally offsets motion timing. Double, or better triple, flash improves the motion portrayal.
Floating edges or Floating window (Stereoscopic) See: Breaking the frame (Stereoscopic)
Flop
A floating point calculation per second. Flops are a measure of processing power and today this runs into Gigaflops. For example, the powerful Cell processor used in PlayStation 3 is rated at somewhere between 218 and 250 Gigaflops.
Format conversion Changing the format of television or other moving media images without changing the vertical (frame or field) refresh rate. So, starting with 1920 x 1080/50I and converting to 720 x 576/50I is a format conversion. This only alters the format spatially, changing the vertical and horizontal size which technically is a relatively straightforward task. Note that this may include aspect ratio conversion (ARC) typically to account for 16:9 and 4:3 displays. See also: ARC, Down-res, Standards conversion, Up-res
Format (television) General term to define television pictures by the number of active pixels per line and number of active lines. For example, SD digital television in Europe has a format of 720 x 576 and 1920 x 1080 is an HD format. See also: Standards (television)
Fragmentation
The scattering of data over a (disk) store caused by many recording and deletion operations. Generally this will eventually result in store access becoming slow – a situation that is not acceptable for video recording or replay. De-fragmentation routines rearrange the data (by copying from one part of the disk to another) so that it is quickly accessible in the required order for replay. See also: Consolidation
Frame-rate conversion The process of changing the vertical rate of moving pictures. This has become far more important with the use of HD and its inclusion of many frame rates in the standards. For example 1080-line standards are defined for 23.98P, 24P, 25P, 29.97P, 30P, 50I, 50P, 59.96I, 59.96P and 60I and 60P Hz. Changing from one rate to another, even just I/P changes, requires considerable technology to produce high quality results. Further frequencies are used in other media markets, such as mobile and some web-based areas with more restricted bandwidth, where lower rates such as 15 f/s and others are found.
Framestore
A name given to solid-state video storage, usually built with DRAMs. Technically it implies storage of one complete frame or picture, but the term is also used more generically to encompass the storage of a few lines to many frames. With large DRAM capacities available, framestores are increasingly used to enhance equipment performance for instant access to material. See also: DRAM
Frequency The number of oscillations of a signal over a given period of time (usually one second). For example, it defines the color subcarrier frequencies in analog television color coding systems, or clock rate frequencies in digital systems. Here are some commonly found frequencies in TV: PAL subcarrier: 4.43 MHz NTSC subcarrier: 3.58 MHz ITU-R BT.601 luminance sampling
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GLOSSARY OF TERMS
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