Common Intermediate Format

CIF (Common Intermediate Format), also known as FCIF (Full Common Intermediate Format), is a format used to standardize the horizontal and vertical resolutions in pixels of YCbCr sequences in video signals, commonly used in video teleconferencing systems. It was first proposed in the H.261 standard.

CIF was designed to be easy to convert to PAL or NTSC standards. CIF defines a video sequence with a resolution of 352 × 288 like PAL Source Input Format, a framerate of 30000/1001 (roughly 29.97) frames like NTSC, with colour encoded using YCbCr 4:2:0.

QCIF means "Quarter CIF". To have one fourth of the area as "quarter" implies the height and width of the frame are halved.

Terms also used are SQCIF (Sub Quarter CIF, sometimes subQCIF), 4CIF (4× CIF) and 16CIF (16× CIF). The resolutions for all of these formats are summarized in the table below.

Format	Video Resolution
SQCIF	128 × 96
QCIF	176 × 144
SCIF	256 x 192
SIF(525)	352 x 240
CIF/SIF(625)	352 × 288
4SIF(525)	704 x 480
4CIF/4SIF(625)	704 × 576
16CIF	1408 × 1152
DCIF	528 × 384

xCIF pixels are not square, instead having a native aspect ratio of ~1.222:1. On older television systems, a pixel aspect ratio of 1.2:1 was the standard for 525-line systems (see CCIR 601). On square-pixel displays (computer screens, many modern televisions) xCIF rasters should be rescaled horizontally by ~109% to 4:3 in order to avoid a "stretched" look: CIF content expanded horizontally by ~109% results in a 4:3 raster of 384 × 288 square pixels.

The CIF "image sizes" were specifically chosen to be multiples of macroblocks (i.e. 16 × 16 pixels) due to the way that discrete cosine transform based video compression/decompression is handled. So, by example, a CIF-size image (352 × 288) corresponds to 22 × 18 macroblocks.

SIF (Source Input Format) is practically identical to CIF, but taken from MPEG-1 rather than ITU standards. SIF on 525-Line ("NTSC") based systems is 352 × 240, and on 625-line ("PAL") based systems, it is identical to CIF (352 × 288). SIF and 4SIF are commonly used in certain video conferencing systems.

DCIF means Double CIF, proposed as a compromise resolution between CIF and 4CIF that is more balanced (in terms of horizontal vs vertical resolution) and suited to common CCTV equipment (with 480+ scanlines but a maximum of about 560 TVL) than 2CIF (704x288). The pixel and therefore data rate is exactly double that of CIF[1], but the 1:1.375 image aspect ratio is a lot closer to standard 4:3, with essentially square pixels.

Image and Video Formats – GIF, TIFF, SIF, CIF, QCIF – Image compression: READ, JPEG – Video Compression: Principles-I,B,P frames, Motion estimation, Motion compensation, H.261, MPEG standard

References

• ITU-T H.261 standard

See also

• H.261
• H.263
• H.264
• List of common resolutions
• DVB
• DVD
• HDTV
• VCD
• Source Input Format

This article related to telecommunications is a stub. You can help Wikipedia by expanding it.v · Categories: Telecommunications stubs Telecommunications standards Videotelephony Wikimedia Foundation. 2010. Игры ⚽ Нужно сделать НИР? Karen National Union Bonnemaison Look at other dictionaries: Common Intermediate Format — Common Intermediate Format,   CIF …   Universal-Lexikon Common Intermediate Format — CIF (англ. Common Intermediate Format), также известный как FCIF (англ. Full Common Intermediate Format)  это формат, используемый для стандартизации вертикального и горизонтального разрешения в пикселях в YCbCr последовательностях …   Википедия Common Intermediate Format — Videoauflösungen Format NTSC PAL SQCIF 128 × 96 QCIF 176 × 144 QCIF+ 176 × 220 CIF 352 × 288 2CIF 704 × 288 4CIF 704 × 576 9CIF 1056 × 864 …   Deutsch Wikipedia Common Intermediate Format — CIF, abréviation de Common Intermediate Format, est une définition standardisée d image numérique définie par l Union internationale des télécommunications (ITU) : 352 × 288 pixels. Définitions des formats dérivés Abréviation Définition (en… …   Wikipédia en Français Common Intermediate Format — El Common Intermediate Format, más conocido por su acrónimo CIF es un formato definido en la recomendación H.261 de la ITU, que utiliza para compatibilizar los diversos formatos de vídeo digital. Es un formato normalizado que es utilizado por… …   Wikipedia Español Full Common Intermediate Format — Full Common Intermediate Format,   CIF …   Universal-Lexikon Quarter common intermediate Format — Quarter common intermediate Format,   QCIF …   Universal-Lexikon common intermediate format —    (CIF)    Describes the type of coded video frame transmitted when using ITU TSS Rec …   IT glossary of terms, acronyms and abbreviations Common Intermediate Language — For the counterpart to compiled assembly in the Microsoft .NET framework, see .NET assembly. Common Intermediate Language (CIL, pronounced either sil or kil ) (formerly called Microsoft Intermediate Language or MSIL) is the lowest level human… …   Wikipedia Common Intermediate Language — Dans l environnement de programmation Microsoft, le Common Intermediate Language (CIL) est le langage de programmation de plus bas niveau qui peut être lu par un humain. Le code de plus haut niveau dans l environnement .NET Framework est compilé… …   Wikipédia en Français 18+ © Academic, 2000-2024 Contact us: Technical Support, Advertising Dictionaries export, created on PHP, Joomla, Drupal, WordPress, MODx. Mark and share Search through all dictionaries Translate… Search Internet Share the article and excerpts Direct link … Do a right-click on the link above and select “Copy Link”