Direct Stream Transfer compression was also standardized as an amendment to MPEG-4 Audio standard (ISO/IEC 14496-3:2001/Amd 6:2005 – Lossless coding of oversampled audio) in 2005.[25][26] It contains the DSD and DST definitions as described in the Super Audio CD Specification.[27] The MPEG-4 DST provides lossless coding of oversampled audio signals.