[mythtv-users] No closed captioning for any tuner in Mythtv SVN

Sam Logen starz909 at yahoo.com
Sat Nov 17 21:55:35 UTC 2007

Ok, here are my findings.  The V4L drivers for my
cards weren't affecting my loss of subtitles for the
DVB card.  Neither is the version of MythTV I was
using.  A while back I wanted to stop using XVMC for
playback, because it made the OSD really ugly.  So I
chose an alternative video decoder, the libmpeg2
decoder - because it was advertised to run better on
some AMD processors.  Well I've just heard from
various sources that libmpeg2 doesn't display
captioning.  So I think there should be a disclaimer
that says so, if someone wanted to use it.

Switching from libmpeg2 to standard decoding allowed
me to view subtitles on my DVB card for digital and HD
  However, my problem is not over yet.  I still can't
get captions to display on any channels served through
the hardware MPEG card (My Avermedia M150).  In fact,
this card doesn't appear to be supported at all in
MythTV - in any version.  I have to add a 'hack' to
one of MythTV's files to get it to work.  I'll add the
hack below if anyone wants to know what it is.  So
with the hack patch, I can view programs and change
channel, but I still get no subtitles.

Is there anyone that can help get this card supported
in MythTV?  To cap, without the patch, I get a blank
screen and mythfrontend freezes.  With the patch, I
can view and change channels, but I can't get closed
captioning to display.

Thank you all,

Hack patch by Andrew Malota for the Avermedia M150
hardware MPEG card (may be word-wrapped):

Index: libs/libmythtv/mpegrecorder.cpp
--- libs/libmythtv/mpegrecorder.cpp     (revision
+++ libs/libmythtv/mpegrecorder.cpp     (working copy)
@@ -324,7 +324,7 @@

 bool MpegRecorder::OpenV4L2DeviceAsInput(void)
-    chanfd = open(videodevice.ascii(), O_RDWR);
+    chanfd = open(videodevice.ascii(), O_RDWR |
     if (chanfd < 0)
         VERBOSE(VB_IMPORTANT, LOC_ERR + "Can't open
video device. " +
@@ -447,7 +447,7 @@


-    readfd = open(videodevice.ascii(), O_RDWR |
+    readfd = chanfd;
     if (readfd < 0)
         VERBOSE(VB_IMPORTANT, LOC_ERR + "Can't open
video device." +


--- Daniel Kristjansson <danielk at cuymedia.net> wrote:

> On Wed, 2007-11-14 at 17:00 -0800, Sam Logen wrote:
> > Thank you Daniel and Craig for getting back to me
> on
> > this.  On my first email today, I included my
> hardware
> > details at the bottom of my email.  As for my
> settings
> > in the mythtv-setup program, the VBI is set to
> > closed captions for my area (California).  Just to
> > clarify, only my ATSC card used to be able to
> display
> > VBI closed captioning for HD channels when I ran
> > Mythtv 20.2.  After upgrading to SVN, neither card
> > could display CC.  It seems that Mythtv took one
> step
> > forward, and two steps back in its development.
> > 
> > The drivers I am using for the cards are the very
> > latest Conexant 2388x drivers, including the
> latest
> > blackbird driver patches for the hardware mpeg
> card.
> Hmm, did you upgrade the drivers when you upgraded
> to SVN?
> If so this is a possible culprit. I've never gotten
> captions
> with the Conexant 2388x drivers, so I can't tell you
> this will
> work, but the fact that you had it working is
> promising.
> What you probably want to do is first make sure that
> the drivers
> are working. Do this by reverting to 0.20-fixes and
> seeing the
> captions. If the drivers aren't working, the dvb-v4l
> mailing list
> is the next stop. But assuming this is a MythTV
> issue, it's
> probably something happening in
> libs/libmythtv/channel.cpp
> This URL will give you a revision log of the file:
> There have only been 5 changes to that file in that
> time.
> My suggestion would be to test them in this order:
>   12618 -- makes sure it was working a year ago, if
> it
>            wasn't you'll need to start earlier like
> 9524
> if 12618 works try 14444 next
>   if 14444 works try 14592
>      if 14592 works try 14762
>         if 14762 doesn't work it's the probable
> culprit
>      if 14592 doesn't work it's the probable culprit
>   if 14444 doesn't work try 12739
>      if 12739 works 14444 is the probable culprit
>      if 12739 doesn't work try 12619
>         if 12619 works 12739 is the probable culprit
>         if 12619 doesn't work it's the probable
> culprit
> This way of bisecting the change sets means you only
> need
> to check 1 + ceil(log2 n) of the changes. In this
> case 4,
> which is almost as bad as the 6 you would need to
> check
> otherwise; but if 12618 doesn't work and you have to
> check
> the 20 changes back to 9204, it means you only need
> to
> check 6 revisions rather than 20.
> Anyway to check out an old version of MythTV you
> just do
> this: svn co -r REV
> http://svn.mythtv.org/svn/trunk/mythtv mythtv-REV
> replacing REV with the revision you want.
> PS Before doing this make sure you have your V4L
> format set to
> "NTSC" and not "ATSC". MythTV used to be more
> forgiving of this
> configuration mistake back in the day. But DTV
> support in the V4L
> drivers has been completely dropped from the V4L
> drivers since
> the V4L-DVB merger and we no longer have that code
> in SVN as of
> about two months ago.
> -- Daniel
> _______________________________________________
> mythtv-users mailing list
> mythtv-users at mythtv.org

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