Rec. 601

ITU-R Recommendation BT.601, more commonly known by the abbreviations Rec. 601 or BT.601 (or its former name, CCIR 601) is a standard originally issued in 1982 by the CCIR (an organization which has since been renamed as the International Telecommunication Union – Radiocommunication sector) for encoding interlaced analog video signals in digital video form. It includes methods of encoding 525-line 60 Hz and 625-line 50 Hz signals, both with an active region covering 720 luminance samples and 360 chrominance samples per line. The color encoding system is known as YCbCr 4:2:2.

The Rec. 601 video raster format has been re-used in a number of later standards, including the ISO/IEC MPEG and ITU-T H.26x compressed formats – although compressed formats for consumer applications usually use vertical as well as horizontal chroma subsampling, thus using 4:2:0 sampling rather than directly using the 4:2:2 sampling used in Rec. 601.

The standard has been revised several times in its history. Its edition 7, referred to as BT.601-7, was approved in March 2011 and was formally published in October 2011.