[mythtv-users] No Display
Andy
mizeraka at yahoo.com
Mon Feb 7 18:54:55 UTC 2011
Guys,
Thanks for all the helpful advice. I have become convinced, however, that my problem is a problem with the television as suggested by Greg and Jay. If anyone knows how to get the audio signal "always on" either through Xorg.conf or ALSA, I would appreciate a nudge in the right direction.
This is why I am sure that it is not a problem with the resolution:
- Video comes on with any audio signal from any source (including when I play a YouTube through Firefox), which I surmise means that there is no change in the resolution of the video signal.
- I changed my audio settings (through the very cool new "scan for audio" feature) to put audio out to a boombox. The audio came through fine, but the video signal did NOT switch on. Which again leads me to believe, as Greg and Jay suggested, that the TV will not display without both audio and video streams over HDMI.
Hopefully I can get some help with TV settings from LG, other wise the easy solution will be to return it for a model that DOES display HDMI without an audio signal. I will be carrying my mythtv box with me and demanding to hook it up before I purchase another TV. Or again, if anyone knows how to get the audio signal "always on" either through Xorg.conf or ALSA, I would appreciate the help.
Thanks,
Andy
On 02/06/2011 10:39 AM, Jay Ashworth wrote:
> ----- Original Message
-----
>> From: "Andre"<mythtv-list at dinkum.org.uk>
>
>>
Sounds like the TV is the issue then, it's a long shot but if you
are
>> running nvidia v260 drivers it might be worth trying the two
different
>> output modes now available. RGB is the default but YCrCb
is now
>> selectable in nvidia-settings. I've seen various TVs behave
quite
>> differently when given YCrCb instead of RGB (sometimes called
TV mode
>> rather than PC mode, although there's a little more to it
than just
>> this).
>
> To me, off hand, this sounds
like:
>
> The TV expects that the bitstream on the HDMI cable will
always include a
> video *and* an audio stream, *even if there's no audio
in that stream*, and
> the video card on the PC *isn't generating an audio
stream*, unless there's
> actual, y'know, audio to put there. Therefore,
the TV intemperately refuses
> to display the perfectly good
video.
>
> Finding a way, probably in the Xorg screen config, to
force that card to
> send an audio stream all the time, will I think be
the solution...
>
> if it's possible. The people who work on the
drivers for the card you have
> are probably the best people to be asking:
this is probably going to be a
> general problem.
I think your card
and hardware are fine.
Your earlier recounting of the problem was not quite
clear to me, but it
sounded like you can get a desktop, but that it 'goes
away' when
mythfrontend starts. If that is correct then the first step is to
stop
any autostarting of myth.
And CONFIRM that this is a myth
problem and not an existing OS problem.
I have a 3 year old 37" LG
flatscreen. The HDMI inputs are *not* all
the same. One of them is slightly
different than the others and is the
one the TV expects will be used for PC
input. ( I pipe the audio output
of myth directly to an amplifier and then
to audio speakers and never
have any sound from the TV when using myth...so
I think this may be a
misleading item.)
You might have to try each
input in turn. THankfully the remote has that
dedicated button in the top
right corner! (Or the buttons on the side of
the TV).
It seriously
sounds like myth is forcing a resolution which the TV does
not like or the
video chipset will not accept and output.( But the
desktop resolution is
fine, if I read correctly)
If you can get a desktop screen and log in
(without autostarting myth)
then the hardware is all right as is the
resolution settings *for the
desktop*.
In which case, you need to
get into Setup -> Appearance and set *myth's*
resolution to something
like 1024x768. If you cannot get into there
without losing the signal, then
you will have to poke the Settings table
directly.
At a mysql
console, try
mysql> select * from settings where value like
"%Vid%";
and
select * from settings where value like
"%Resolution%";
This should give you a largish number of rows. You are
interested in the
GuiResolution, GuiHeight/Width, VidModeHeight/Width and
TVVidModeResolution entries which have screen size values. You need/want
them to be 1920x1200 although you might want to test using
1024x768.
In your particular case, the GuiVidMode, GuiHeight,GuiWidth
entries are
likely the culprit if this diagnosis is anywhere near correct.
You will
need to:
mysql> update settings set data = "1360x768"
where value = "GuiResolution";
My LG TV would NOT accept 1368 or 780 as
proper sizes. I need 1368 for
width, and 768 for height. So you might need
to use 1912 and 1192. (The
30" Dell monitor at work is quite happy with
1920x1200 though!).
HTH
Geoff
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