
Philips Semiconductors
Enhanced Video Out
PRODUCT SPECIFICATION
7-5
7.8.3
SAV and EAV Codes
The End Active Video (EAV) and Start Active Video
(SAV) codes are issued at the start of each video line.
EAV and SAV codes have a fixed format: a 3-byte pre-
amble of 0xFF, 0x00, 0x00 followed by the SAV or EAV
code byte. The EAV and SAV code byte format is shown
in Figure 7-12 for reference. The EAV and SAV codes
define the start and end of the horizontal blanking inter-
val, and they also indicate the current field number and
the vertical blanking interval.
The SAV and EAV codes have a 4-bit protection field to
ensure valid codes. The EVO generates these protection
bits as part of the SAV and EAV codes as defined by
CCIR 656. There are 8 possible valid SAV and EAV
codes shown with their correct protection bits in
Table 7-2. The EVO generates SAV and EAV sync
codes and inserts them into the video out data stream
according to the CCIR 656 specification under all condi-
tions, whether it is generating or receiving horizontal and
frame timing information.
7.8.4
Video Clipping
SAV and EAV codes are identified by a 3-byte preamble
of 0xFF, 0x00 and 0x00. This combination must be
1
19 20
262 263
282
525 1
One Frame
One Line
Field 2
Field 1
Blanking
Active Video
1/2 Line Interlace Offset
Vertical
Sync
Video
Lines
Figure 7-9. Interlaced timing—NTSC analog sync. signals.
U0
Y0
V0
Y1
U2
Y2
V2
Y3
U4
Byte 0
Line Scan @ 27 MHz = 13.5 Mpix/sec
VO_DATA[0:7]
VO_CLK
Y4
Figure 7-10. CCIR 656 pixel timing.
ES
S
E
Blanking
Active Video
Blanking
Active Video
Line i
Line i+1
SAV, EAV Codes
YUV 4:2:2 pixels
Figure 7-11. CCIR 656 line timing.
Figure 7-12. Format of SAV and EAV timing codes.
Preamble
11111111
00000000
1 F V H PPPP
Timing reference code
Protection bits
(error correction)
H = 0 for SAV
H = 1 for EAV
V = 1 during field blanking
V = 0 elsewhere
F = 0 during Field 1
F = 1 during Field 2