Internal Modules
166
SPRUHI7A – December 2012 – Revised June 2016
Copyright © 2012–2016, Texas Instruments Incorporated
High-Definition Video Processing Subsystem (HDVPSS)
1.2.8.2.8 Channel ID Extraction for 2x/4x Multiplexed Source
1.2.8.2.8.1 Channel ID Extraction Overview
For 2-way and 4-way multiplexed source, the Channel ID is either embedded in the four protection bits
inside the EAV/SAV code words or in the horizontal blanking pixel data. A configuration setting determines
where the VIP Parser would search for the Channel ID.
1.2.8.2.8.2 Channel ID Embedded in Protection Bits for 2- and 4-Way Multiplexing
The four-bit channel ID is an identifier corresponding with the source number (camera) of the incoming
video. As shown in
, the Channel ID is placed in the code fourth byte of the EAV/SAV code
words normally used for protection bits. With 4 bits, the maximum number of sources that can be defined
in this range is 16. However, only Channel IDs in the range {0:7} are supported. Obviously, error
correction cannot be performed on the FVH flags since the protection bits are no longer there.
Table 1-61. Channel ID Embedded in EAV/SAV
7
(fixed)
6
(F)
5
(V)
4
(H)
3
(ch_id[3])
2
(ch_id[2])
1
(ch_id[1])
0
(ch_id[0])
Description
1
0
0
0
Ch_id = {0:15}
SAV, Field 0, Active Video
1
0
0
1
Ch_id = {0:15}
EAV, Field 0, Horizontal
Blanking
1
0
1
0
Ch_id = {0:15}
SAV, Field 0, Vertical Blanking
1
0
1
1
Ch_id = {0:15}
EAV, Field 0, Horizontal
Blanking in Vertical Blanking
Region
1
1
0
0
Ch_id = {0:15}
SAV, Field 1, Active Video
1
1
0
1
Ch_id = {0:15}
EAV, Field 1, Horizontal
Blanking
1
1
1
0
Ch_id = {0:15}
SAV, Field 1, Vertical Blanking
1
1
1
1
Ch_id = {0:15}
EAV, Field 1, Horizontal
Blanking in Vertical Blanking
Region
1.2.8.2.8.3 Channel ID Embedded in Horizontal Blanking Pixel Data for 2- and 4-Way Multiplexing
In Horizontal Blanking and Vertical Blanking, non-ancillary data pixels should be Y=0x10 and
Cb=Cr=0x80. When the Channel ID is embedded in the Horizontal Blanking for 2 and 4-way multiplexing,
the lower nibbles of all Luma and Chroma pixels are replaced by the 4 bit Channel ID. This scenario is
shown in
. The maximum number of values defined by this 4-bit range is 2
4
= 16. However,
only Channel IDs in the range {0:7} are supported.