Texas Instruments DM38x DaVinci, User Manual

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Horizontal
Blanking
Vertical Blanking/
Ancillary Data
Active Field
Luma
Field/Frame
Buffer
Chroma
Field/Frame
Buffer
Vertical
Ancillary
Data Buffer
X Bytes/line
X bytes/line
VIP and
VPDMA
B0
B7
B6
B5
B4 B3 B2 B1
B1 B7 B5 B3
B0 B6 B4
B2
Luma Frame Buffer in DDR
Chroma Frame Buffer in DDR
Horizontal Blanking Ancillary Data
time
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Internal Modules
155 SPRUHI7A – December 2012 – Revised June 2016
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High-Definition Video Processing Subsystem (HDVPSS)
1.2.8.2.5.10 Ancillary Data Storage in Descrete Sync Mode
Ancillary data appearing in horizontal blanking is called Horizontal Blanking Ancillary Data. Ancillary Data
in vertical blanking is called Vertical Blanking Ancillary Data.
Horizontal Blanking Ancillary Data is not commonly used. For the ACTVID data valid mode described in
Figure 1-95 , there is no way to capture Horizontal Blanking Ancillary Data. Using the HSYNC mode in
Figure 1-97 , all blanking pixels are captured. However, the horizontal ancillary data is byte-by-byte
distributed between the Luma and Chroma frame buffers. Chroma sited bytes are saved in the Chroma
frame buffer and Luma sited bytes are saved in the Luma frame buffer. Some CPU effort would be
needed in order to extract ancillary data from the desired Luma or Chroma channel frame buffers. Also,
the video on each line starts after the horizontal blanking period. This situation is shown in
Figure 1-104 .
Figure 1-104. Horizontal Ancillary Data Packing When HSYNC Used as Sync Signal
With Interlaced source material, Vertical Blanking Ancillary data will be stored in a separate Vertical
Ancillary Data Buffer as shown in
Figure 1-105 . The Channel from which vertical ancillary data is extracted
is a configuration option. For an input image of x active pixels per line, each line of Vertical Blanking
Ancillary Data will have x bytes. Unlike the horizontal case, the CPU parsing this Ancillary Data will see a
contiguous section of Vertical Ancillary Data that is not intermixed with Video data.
Figure 1-105. Interlaced Field Vertical Blanking Ancillary Data Storage