[mythtv-users] non-printable character in CC track from Handbrake

Joey Morris rjmorris.list at zoho.com
Sat Sep 14 01:40:16 UTC 2013


Jim Stichnoth <stichnot at gmail.com> wrote on Fri, Sep 13, 2013 at 05:18:43PM -0700:
> On Fri, Sep 13, 2013 at 3:56 PM, Joey Morris <rjmorris.list at zoho.com> wrote:
> 
> > Jim Stichnoth <stichnot at gmail.com> wrote on Fri, Sep 13, 2013 at
> > 06:59:52AM -0700:
> > > On Thu, Sep 12, 2013 at 6:28 PM, Joey Morris <rjmorris.list at zoho.com>
> > wrote:
> > >
> > > > I'm playing MKV files that I ripped from my DVDs using Handbrake on
> > > > Linux. When I enable closed captions, MythTV displays a little empty
> > > > box at the end of every caption, representing what I assume is a
> > > > non-printable character. Like maybe the captions end in \n\r and
> > > > MythTV can't handle the \r. I used mkvextract to export a CC track to
> > > > an SRT file. When I examined the captions, I didn't see any unusual
> > > > characters at the end of them, just a 0x0a.
> > > >
> > > > Closed captions from OTA recordings do not exhibit this behavior.
> > > >
> > > > I'm running 0.26-fixes. Does anyone else have this problem? Any
> > > > thoughts on what's causing it or additional steps to debug?
> > > >
> > > > If you run mythfrontend with "-v vbi", it should produce logs
> > describing
> > > the text strings it's trying to render, which would hopefully also show
> > any
> > > unusual characters that may be rendered as an empty rectangle.  This is
> > > unlikely to be whitespace like \r, since all caption text has leading and
> > > trailing whitespace removed by the QString::trimmed() operation.  From
> > the
> > > QString documentation, "This includes the ASCII characters '\t', '\n',
> > > '\v', '\f', '\r', and ' '."
> >
> > I ran mythfrontend with -v vbi, and I've attached the log file. I
> > don't see any unusual characters, even when viewing in hex mode, but
> > one thing does look odd: The rendered text strings are missing a
> > closing quotation mark everywhere the empty rectangle appears. For
> > example, the first rendered subtitle written to the log is:
> >
> >   text='FROM ALMOST CERTAIN'
> >   text='TEMPTATION,
> >
> > This appears on my screen as two lines of text with an empty
> > rectangle at the end of the second line.
> >
> > Yes, that seems like there might be a ^H backspace character embedded at
> the end of the line.  In my setup, it results in a rectangle outline with a
> question mark inside, but the difference between my funny character and
> yours may be from the font.  A backspace character also does weird things
> to the log message.
> 
> You probably want to figure out how to get the external tool to stop adding
> those extra characters, whatever they are exactly.

Thanks Jim. What did you use to see the rectangle outline with a
question mark in it? MythTV is the only place I've seen my rectangle.
I've looked at the log file in emacs, vi, and in the console, but each
of those seem to have performed the backspace operation instead of
displaying a symbol representing the backspace. I also tried creating
a hex dump using xxd, but that doesn't show the backspace either.



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