 H.120 used motion-compensated DPCM coding, a lossless compression algorithm that was inefficient for video coding.During the late 1980s, a number of companies began experimenting with discrete cosine transform (DCT) coding, a much more efficient form of compression for video coding.The CCITT received 14 proposals for DCT-based video compression formats, in contrast to a single proposal based on vector quantization (VQ) compression.