GS2972 Datasheet, PDF (79/125 Pages) Semtech Corporation – 3G/HD/SD-SDI Serializer with Complete SMPTE Audio & Video Support

4.9.11 GS2972 3G/HD HANC Space Considerations when Embedding Audio
Standards having more than 1024 HANC words in the blanking can potentially
re-transmit pre-embedded packets twice in CASCADE or AGR modes.
Here is the list of standards at risk:
(1920x1080/24/1:1, 444) = 1648 words in HANC (2048x1080/25/1:1, 444) = 1172 words
in HANC
(2048x1080/24/1:1, 444) = 1392 words in HANC
(1280x720/24/1:1, 444) = 5678 words in HANC
(1280x720/23.98/1:1, 444) = 5678 words in HANC
(1280x720/25/1:1, 444) = 5348 words in HANC
(1280x720/50/1:1, 444) = 1388 words in HANC
(1920x1080/23.98/1:1, 444) = 1648 words in HANC
(1920x1080/50/2:1, 444) = 1428 words in HANC
(1920x1080/25/1:1, 444) = 1428 words in HANC
(1920x1080/25/PsF, 444) = 1428 words in HANC
(1280x720/30/1:1, 422) = 2008 words in HANC
(1280x720/29.97/1:1, 422) = 2008 words in HANC
(1280x720/25/1:1, 422) = 2668 words in HANC
(1280x720/24/1:1, 422) = 2833 words in HANC
(1280x720/23.98/1:1, 422) = 2833 words in HANC
Note: For all of the standards listed above, Semtech recommends using the GS2972 as
the source of any ancillary data packets. If packets already exist in the video coming in
to the GS2972, Semtech recommends deleting all ANC packets if this problem is to be
avoided.
4.9.12 SMPTE ST 372 Conversion
When the IOPROC_EN/DIS pin is HIGH and the CONV_372 bit in the IOPROC register is
LOW, the GS2972 converts SMPTE ST 425 Level A mapping 1 (1080P 4:2:2) to Level B
SMPTE ST 372 dual link prior to serialization.
GS2972 3G/HD/SD-SDI Serializer with Complete
SMPTE Audio & Video Support
Final Data Sheet Rev. 9
GENDOC-047479 September 2013
www.semtech.com
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