[mythtv] Ticket #10172: Bad cc708 output from mythccextractor

Daniel Kristjansson danielk at cuymedia.net
Wed Nov 23 22:45:10 UTC 2011

On Wed, 2011-11-23 at 13:48 -0800, Jim Stichnoth wrote:
> Thanks.  The durations now look like what shows up during playback.
> Interestingly, at least in this recording, the end times of the cc708
> captions are usually within a couple frames of the cc608 end times,
> but the cc708 start times are usually substantially later than the
> cc608 start times, making cc708 a lot harder to use.  Mythccextractor
> is a great tool for looking into this.

Have you tried with a program that was captioned in 708? I believe
there may be some 608->708 converter on the market which uses sets
the start time of a 708 caption set to be when the last character
of a 608 set was output. The 608 is a very low bitrate stream so
you actually get a bit of time to read the first part of the caption
before each set finishes. If the end time of the generated 708 is
set to about the same time as the 608 so you end up having 
significantly less time to read the text.

If this is the case we can adjust for that when we display 708 captions,
but I need a bit more confidence there isn't just a bug in our 708

-- Daniel

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