Before revision: 26 40 42 40 58 0 Reserved, zero 74 1 11 C "Color frame" flag 27 P Even parity bit 43 1 Binary group flag 59 2 Binary group flag 75 1 12 User bitsfield 2 28 User bitsfield 4 44 User bitsfield 6 60 User bitsfield 8 76 1 13 29 45 61 77 1 14 30 46 62 78 0 15 31 47 63 79 1 Bit 10 is set to 1 if drop frame numbering is in use; frame numbers 0 and 1 are skipped during the first second of every minute, except multiples of 10 minutes.
After revision: 26 40 42 40 58 BGF1 Clock flag 74 1 11 C "Color frame" flag 27 (flag, see below) 43 (flag, see below) 59 (flag, see below) 75 1 12 User bitsfield 2 28 User bitsfield 4 44 User bitsfield 6 60 User bitsfield 8 76 1 13 29 45 61 77 1 14 30 46 62 78 0 15 31 47 63 79 1 Bit 10 is set to 1 if drop frame numbering is in use; frame numbers 0 and 1 are skipped during the first second of every minute, except multiples of 10 minutes.