[mythtv-users] Transcoders and closed captions

[Andreas]

Am Monday 06 October 2008 14:44:50 schrieb Jim Stichnoth:
> It turns out that closed captions are a key part of the WAF.

As an "ESL", I very much rely on the closed captions, too.

> Normally, 
> MythTV's cc support seems great, but there are some problems with
> transcoding.  When I do a lossless mpeg-2 transcode (for permanently
> removing commercials), the captions are lost completely.

I have found that cc's in recordings from ATSC sources (or QAM) actually 
survive MythTV's lossless transcoding. Sadly, the same can not be said for 
recordings I made from analogue sources with my ivtv-cards.

> When I transcode 
> from mpeg-2 to mpeg-4 with a cutlist, the captions are preserved but
> delayed during playback, presumably because the cutlist is not being
> applied to the captions. 

There is a great little program out there, ccextractor, which can save closed 
captions to a srt file.

> The one workflow I've found that does the right 
> thing is to transcode from mpeg-2 to mpeg-4 without a cutlist, then create
> the cutlist, and finally do a lossless mpeg-4 transcode with the cutlist.

Or apply the cutlist to the generated srt file, and put the resulting srt file 
in your recordings directory. If it has the same name as the recording (minus 
the file extension, obviously), MythTV's internal player will automatically 
pick it up.

> I'm running MythDora 5 (0.21).  Is this a well-known issue?  Would there
> happen to be some patches I can pick up to fix this, or do I need to dig
> into the code myself?

I don't know of any patches for closed captions, sorry.

> On a related topic (and please stop me if this is a verboten topic),

Discussions about torrent downloads are not particularly well received on this 
mailing list.

> I've 
> noticed that the handful of bittorrent TV programs I've downloaded always
> seem to lack captions.  Is this because of problems with the mpeg-4/cc
> specification, or with support in the encoding tools, or a deliberate
> decision by the people doing the encoding?

However, I have found http://www.opensubtitles.org to be well stocked, at 
least for movies. Of course I only look for subtitles of movies I have ripped 
myself (that topic is, strangely enough, not only "nicht verboten", there is 
even an official MythTV Plugin to ease the task of DVD-Ripping).

>
> Jim

-- 
Gruß
Andreas