www.FOURCC.org - Video Codecs and Pixel Formats

Video-related Acronyms


At the request of some readers, here is a list of some common acronyms thrown around when discussing PC video and video in general. I'll add to these over time as I find missing information or people suggest new terms.

Acronym Definition
ATSC Advanced Television Standards Committee. The technical group that defined the high definition TV standard for US terrestrial transmission.
AVC Advanced Video Codec. Otherwise known as MPEG4, part 10 this is the codec that most of the world's broadcasters are moving to for HD transmissions.
AVI Audio Video Interleave - a Windows file format used to store movies.
Codec Compressor/Decompressor - a software or hardware component that can compress and/or decompress video using a particular compression algorithm.
FOURCC Four Character Code - an 8 digit (or 4 ASCII character) value used to identify the pixel format or compression standard (codec) used to store images or video files. FOURCCs are also used for a similar purpose in some audio applications.
HD High Definition. This refers to a video picture size higher than SD (see below) and typically one of the set of resolutions defined by ATSC such as 1080i (1920x1080), 720p (1280x720) or 480p (720x480).
JPEG Joint Photographics Expert Group. The standards group that defined the hugely successful JPEG still image codec.
MPEG Motion Pictures Expert Group. The clever people who brought you all the ISO standard codecs that are used in TV broadcast today.
NTSC National Television Standards Committee. The group which defined the 480 (visible) line video standard used for analog and pre-HD digital TV transmissions in the USA.
RGB Red Green Blue - a method of describing colours commonly used in PC graphics.
SD Standard Definition. The size of a typical video image for a "legacy" TV system. In the US, this will typically describe an image with 480 lines (and one of a number of widths, 720 being the maximum, 480, 640 and 704 being other common choices). In Europe (and other areas which use PAL TV standards), SD refers to an image with 576 lines of resolution.
YCrCb I have no idea where the specific letters are derived from but this is a colour format typically used in video processing. A colour is defined in terms of a luminance (Y, brightness) value and two "colour differences" or chrominance values (Cr and Cb). One correspondant indicates that Y,R and B likely refer to primary colors yellow, red and blue and "C" indicates a color difference.
YIQ Ditto. YIQ is another way of defining a colour and is commonly used in NTSC video systems as far as I can remember.
YUV Ditto. This term also describes a luminance/chrominance colour model. This is frequently used interchangably with YCrCb though, technically, they are different.
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