This standard defines three mapping formats: Level A, Level B Dual-Link mapping and Level B Dual-Stream mapping as described below; - Level A specifies: - The direct mapping of various uncompressed video image formats as defined in Table 1; - The direct mapping of packetized data; - The carriage of ancillary data such as the audio data, the audio control packets, the payload ID, the time code, etc.; - into a serial digital interface operating at a nominal rate of 3 Gb/s. - Level B Dual-Link mapping specifies: - The mapping of the SMPTE ST 372 Dual Link interface (Dual-Link mapping) as defined in Table 13 into a serial digital interface operating at a nominal rate of 3 Gb/s. - Level B Dual-Stream mapping specifies: - The mapping of 2 × SMPTE ST 292-1 (HD-SDI) interfaces (Dual-Stream mapping) as defined in Table 14 into a serial digital interface operating at a nominal rate of 3 Gb/s. - Uncompressed video image formats or packetized data, and all applicable ancillary data such as the audio data, the audio control packets, the payload ID, the time code, etc. shall be mapped into SMPTE ST 372 Dual Link and 2 × SMPTE ST 292-1 interfaces prior to mapping into the virtual interfaces. - It is not necessary for implementations to include support for all formats defined in Table 1, Table 13 and Table 14 to conform to this standard. Implementers should indicate supported formats in commercial publications.