In 1974, discrete cosine transform (DCT) compression was introduced by Nasir Ahmed, T. Natarajan and K. R. Rao. During the late 1980s, a number of companies began experimenting with DCT lossy compression for video coding, leading to the development of the H.261 standard. H.261 was the first practical video coding standard, and was developed by a number of companies, including Hitachi, PictureTel, NTT, BT, and Toshiba, among others. Since H.261, DCT compression has been adopted by all the major video coding standards that followed.