[mythtv-users] Hardcode Closed Caption (teletext) into video frame before writing to mpeg.

Bill techbill at stlaware.com
Fri Sep 21 04:19:05 UTC 2007

Yes Caption data are saved in the mpeg using happauge because I can 
extract them into srt file using ccextrator with no problem but it seem 
that Happauge or the IVTV driver are not using standard Line21 to save 
the CC date in mpeg file because none of the mpeg player with build in 
caption decoder are seeing the caption data in the mpeg file. And the 
same mpeg player are able to decode and play the Caption from DVD disc.

Windows dub hrmm I will have to google on this one and see if that 
meaning is what I am looking for but basically I want the caption to be 
decode and written into the video frame permanently and saved as video 
mpeg which is normally called "Open Caption" since you will not need any 
decoder to view the captions but it cannot be turn off since it part of 
the video and always will be displayed.

I will check this Mplayer's mencoder out.

Thank for replying!

For others, Closed Caption / Teletext is not the same thing as subtitle 
so to let you know because I have seen posts or discussions on forums 
from folks thinking both are the same thing.
Closed Caption / Teletext are saved into video line 21 (line 22 for PAL) 
while the subtitle are not save anywhere in video or mpeg instead it is 
saved in a completely separate file (most of the time .srt) which is 
loaded by the mpeg player when you enable the subtitle

Jay R. Ashworth wrote:
> On Thu, Sep 20, 2007 at 09:34:18PM -0500, Bill wrote:
>> I am aware that Closed Caption (teletext) uses VBI to overlay the 
>> caption (text) on top of the video before sending video out to TV or 
>> Monitor but the overlay is not saved into the mpeg video frame.
>> Is there a way to set or a setting to force MythTV to hardcode the VBI 
>> overlay into the video frame before it saved into mpeg file? Or is it 
>> something that can be written as a plugin for MythTV?  If no setting 
>> exists or plugin then I will donate for such feature or plugin
>> I wanted to be able to take mpeg with me and watch it on any mpeg player 
>> and still have caption without having to find or look for a "special" 
>> mpeg player that could decode the caption from mpeg file.
> It's in there somewhere, clearly, though I don't know whether Hauppauge
> cards MPEg encode line 21, or decode the captions and put them
> somewhere else.
> What you're looking for, though, is something akin to a "window dub",
> which is the traditional name for a tape made off the output of a
> timecode decoder/display unit, except with the captions.
> Mplayer's mencoder *might* be able to do what you're looking for; it
> can handle lots of subtitle formats; EIA captions might be one of them.
> I haven't looked into that aspect of it deeply, lately.
> Cheers,
> -- jra

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