SAP still exist in HDTV?

[GeneMontgomery]

Second Audio Program (SAP) was a feature of the old NTSC television format. But some of the protocol that carried the SAP content went away when NTSC transmissions went away. What is the corollary to SAP in HDTV? Is it still called SAP?

 

[Mark_69]

It has to have another name but not SAP. check the technic book.