AMWA-TV / AS-11_Overview

Used to capture Issues for all AMWA AS-11 rules based Specifications
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AS-11 X9: Change ancillary data mapping for Closed Captions from frame to field #107

Closed Matthew-Marks closed 6 years ago

Matthew-Marks commented 6 years ago

ST 436-1 ANC Wrapping Type should correspond to the field and frame structure of the picture content (i.e., VANC Field 1 and 2 for interlace scanned content, VANC Frame for non-interlace including Progressive and Segmented Frame). But CTA 608 requires that caption distribution packets are marked as field 1 or field 2 for proper assignment for services CC 1-4, XDS and Text, even if the picture content is progressive scanned, and in the case of 59.94 Progressive marked VANC Frame, decoders might have to infer this information by examination of the caption data itself. Therefore, the wrapping needs to be Field 1 or Field 2 in all cases for consistency of the ST 436 embedded line numbers.

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