[mythtv-users] MythTV Raspberry Pi2 frontend testers

Lawrence Rust lvr at softsystem.co.uk
Tue Dec 1 19:50:07 UTC 2015


On Tue, 2015-12-01 at 11:18 -0500, Peter Bennett (cats22) wrote:
> On 11/30/2015 02:09 PM, Lawrence Rust wrote:
> > On Sat, 2015-11-28 at 12:50 -0500, Peter Bennett (cats22) wrote:
> >>
> >> Subtitles
> >> I am not seeing subtitles with either xcb or eglfs.
> >> With normal front end on a particular show I get a choice of ATSC CC1
> >> Subtitles or VBI CC1 subtitles. Either of these shows the same
> >> subtitles, I don't know why two are shown.
> >> With Raspberry Pi frontend I only see ATSC CC1 as a choice. Selecting it
> >> says "Subtitles enabled" but they never appear on the screen.
> >> I believe that the problem is a missing libass-dev package.  It's an
> >> optional lib that's used for certain types of subtitle - I've never seen
> >> a difference in the UK so it must be an ATSC issue.  The new
> >> mythbuild.sh adds this lib and is included in the updated build.  You
> >> will need to install libass4 on the Rpi to use this.
> >> I already had libass4 installed. With the new build I am still not
> >> seeing subtitles.
> > OK, I think a need another favour - could you post a small recording
> > which demonstrates the subtitle problem.  Thanks.
> >
> > -- Lawrence Rust
> >
> >
> I have put a 30 second recording, with subtitles that work in regular
> mythtv but do not show in raspberry pi mythtv
> 
> https://dl.dropboxusercontent.com/u/45325311/Today_30sec.mpg

Many thanks for the clip.  I've tracked down the problem to the openmax
decoder - it just doesn't support line21 cc608 captions.  Normally, the
ffmpeg decoder handles captions but if decoding is passed on to an
external decoder (i.e. openmax) then that also has to decode the
captions.  If the channel supports VBI captions or DVBdata (as in the
UK) then use those otherwise the only solution is to revert to ffmpeg.

> Regarding xcb and eglfs: I see no jerkiness or audio problems with xcb,
> only with eglfs. I have not tried the overclock settings, since with xcb
> I am perfectly happy with my setup. The only issue is jerkiness with the
> OSD, which is not a problem since the ODS does not show up very often.

I don't understand how or why xcb mode is better (it shouldn't be) but
if it works, great.

> With regular mythtv it has been stated that running it without an X
> window manager is not supported. Maybe for consistency the raspberry pi
> should aim for the same environment.

The only drawback is that in xcb mode Qt doesn't support EGL for the OSD
overlay which forces the OSD to be CPU rendered softblend.  Maybe I'll
research some more to see if there's a way of supporting or fudging a
video overlay window in xcb mode.

-- Lawrence Rust



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