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Closed Caption Sync Problem

Dec 13, 2013 at 7:21 PM
I can't seem to get CC to be in sync no matter what I do with the OFFSET parameter. No matter what I do it gets out of sync more and more after each commercial cut. Also your online documentation leads me to believe that I need to use a negative number, such as -3, if I have and SS value of -3, but I have found that I need to use a positive number instead.

I also have a case where I recorded two shows on the same channel on the same night and one of them starts off being in sync and the other one starts out being out of sync. I assume this has something to do with commercials being cut at the beginning of one show and not the other?

If can submit logs if you think it would be helpful.
Dec 13, 2013 at 8:40 PM
This is a known problem due to the way GOP boundaries are calculated and whole encoding and how CC data is extracted. It can lead to progressively out of sync captions as each GOP boundary for each commercial cut puts the video ahead by a few seconds cumulatively.

For this propose I introduced two types of CC offsets. One which is a static offset which adjusts the initial offset (positive or negative)
Second is a Subtile segment offset which can be found under Settings -> Expert settings. This is a cumulative number which offsets the subtitle after each commercial cut. Try setting this to 0 or some other number till you find your sweet spot. This helps to compensate for progressive shifting to subtitle after each commercial cut.

Marked as answer by rboy1 on 1/29/2014 at 1:00 AM