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GS1582 Data Sheet
40117 - 1 November 2007
65 of 114
4.8.3 VANC Insertion
Ancillary data insertion into the VANC space can be selected via the host interface.
Data is inserted contiguously starting at the TRS SAV or the first available location
following any pre-existing ancillary data packets. Data insertion terminates when
all provided data words have been inserted or at the start of the TRS EAV code,
whichever occurs first. If termination occurs before all words have been inserted,
the PACKET_MISSED bit will be set in the host interface.
NOTE: When ancillary data is inserted into the active region of the video raster
using the VANC feature, if the ILLEGAL_REMAP in the IOPROC_DISABLE
register bit is set to 0, then the ADFs are remapped to '004 | 3FB | 3FB' and the
downstream devices will not detect the ancillary data packets.
4.9 Additional Processing Functions
The GS1582 incorporates additional data processing which is available in SMPTE
mode only, see
SMPTE Mode on page 28
.
4.9.1 ANC Data Blanking
The horizontal and vertical ancillary spaces of the input video may be 'blanked' by
the GS1582. In this mode, the TRS words and active video will be preserved. Any
additional processing functions including audio embedding, including ancillary data
insertion, occur after blanking and will be present in the output video stream.
This function is enabled by setting the ANC_BLANK pin LOW.
4.9.2 Automatic Video Standard Detection
The GS1582 can detect the input video standard by using the timing parameters
extracted from the received TRS ID words, the supplied H_Blanking, V_Blanking,
and F_Digital timing signals, or the CEA 861 timing signals, see
HVF Timing on
page 28
and
CEA 861 Timing on page 29
. This information is presented in the
VIDEO_STANDARD register (
Table 4-32
).
Total samples per line, active samples per line, total lines per field/frame and active
lines per field/frame are also calculated and available via the
RASTER_STRUCTURE registers (
Table 4-33
). These line and sample count
registers are updated once per frame at the end of line 12.
After device reset, the four RASTER_STRUCTURE registers default to zero.