Datasheet
Functional Description
13
May 2006 SLES043A
3.12 VBI FIFO and Ancillary Data in Video Stream
Sliced VBI data can be output as ancillary data in the video stream in the ITU−R BT.656 mode. VBI data is
output during the horizontal blanking period following the line from which the data was retrieved. Table 3−2
shows the header format and sequence of the ancillary data inserted into the video stream. This format is also
used to store any VBI data into the FIFO. The size of FIFO is 512 bytes. Therefore, the FIFO can store up to
11 lines of teletext data with the NTSC NABTS standard.
Table 3−2. Ancillary Data Format and Sequence
BYTE
NO.
D7
(MSB)
D6 D5 D4 D3 D2 D1 D0
(LSB)
DESCRIPTION
0 0 0 0 0 0 0 0 0
Ancillary data preamble
1 1 1 1 1 1 1 1 1
Ancillary data preamble
2 1 1 1 1 1 1 1 1
3 NEP EP 0 1 0 DID2 DID1 DID0 Data ID (DID)
4 NEP EP F5 F4 F3 F2 F1 F0 Secondary data ID (SDID)
5 NEP EP N5 N4 N3 N2 N1 N0 Number of 32 bit data (NN)
6 Video line # [7:0] Internal Data ID0 (IDID0)
7 0 0 0 Data
error
Match
#1
Match
#2
Video line # [9:8] Internal Data ID1 (IDID1)
8 1. Data Data byte
1
st
word
9 2. Data Data byte
1 word
10 3. Data Data byte
11 4. Data Data byte
: : :
m−1. Data Data byte
N
th
word
m. Data Data byte
N word
NEP EP CS[5:0] Check sum
4(N+2) 1 0 0 0 0 0 0 0 Fill byte
EP: Even parity for D0−D5 NEP: Negated even parity
DID: 91h: Sliced data of VBI lines of first field
53h: Sliced data of line 24 to end of first field
55h: Sliced data of VBI lines of second field
97h: Sliced data of line 24 to end of second field
SDID: This field holds the data format taken from the line mode register of the corresponding line.
NN: Number of Dwords beginning with byte 8 through 4(N+2). This value is the number of Dwords
where each Dword is 4 bytes.
IDID0: Transaction video line number [7:0]
IDID1: Bit 0/1 = Transaction video line number [9:8]
Bit 2 = Match 2 flag
Bit 3 = Match 1 flag
Bit 4 = 1 if an error was detected in the EDC block. 0 if not.
CS: Sum of D0−D7 of DID through last data byte.
Fill byte: Fill bytes make a multiple of 4 bytes from byte 0 to last fill byte. For teletext modes, byte 8 is the
sync pattern byte. Byte 9 is 1. Data (the first data byte).