[Chris Borjis] "I've been capturing and outputting closed captioning on SD video for the last month with no problem at all. cc data is maintained.
HD closed captioning is another story though and only the mxo2 and the future kona
driver fixes that.
"
OK,
let just confirm that we all understand that CC is standard def is different from CC content in HD.
In HD the data is written in a different manner, at a vastly different place in the metadata structure as part of the transport stream. Originally, CC information was included in the picture ("line 21"), but there is no equivalent capability in the HDTV 720p/1080i interconnect.
The HD-SDI closed caption and related data can be as much as 10x the amount of info used in a standard def CC schema and is carried in three separate portions of the HD-SDI bitstream. They are the Picture User Data, the Program Mapping Table (PMT) and the Event Information Table (EIT). The caption text and window commands are carried in the HD-SDI Transport Channel (which in turn is carried in the Picture User Bits).
Understand why it is harder to do CC in an HD stream?
gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows
Check out
http://www.aja.com/kiprotour/
Inside look at the IoHD
http://library.creativecow.net/articles/adcock_gary/AJAIOHD.php
