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 ITUR BT.656 mode. VBI data is
output during the horizontal blanking period following the line from which the data was retrieved. Table 32
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 32. Ancillary Data Format and Sequence
BYTE
NO.
D7
(MSB)
D6
D5
D4
D3
D2
D1
D0
(LSB)
DESCRIPTION
0
Ancillary data preamble
1
Ancillary data preamble
2
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
Data
error
Match
#1
Match
#2
Video line # [9:8]
Internal Data ID1 (IDID1)
8
1. Data
Data byte
1st word
9
2. Data
Data byte
1
word
10
3. Data
Data byte
11
4. Data
Data byte
:
m1. Data
Data byte
Nth word
m. Data
Data byte
N
word
NEP
EP
CS[5:0]
Check sum
4(N+2)
1
0
Fill byte
EP:
Even parity for D0D5
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 D0D7 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).