[mythtv-users] Can't play live TV or videos

[Joseph A. Caputo]

On Monday 24 November 2003 11:02, Douglas Phillipson wrote:
> Joseph A. Caputo wrote:
> > On Monday 24 November 2003 02:46, Douglas Phillipson wrote:
> >>Douglas Phillipson wrote:
> >>>Installed MythTV from apt-get install mythtv-suite.  Using Redhat
> >>>9, NVidia Gforce4, WinTV Go capture card.
> >>>
> >>>My backend is on the same machine as my frontend.  Recording is
> >>>taking place.  I can see the recordings in lower left of screen
> >>>when I'm in "Watch Recordings".  When I choose to play a recording
> >>>or try watching live TV I get a blank screen.  I have "Video
> >>>player" set to "mplayer -fs %s".
> >>>
> >>>Question:  What does MythTV use to play live TV and playback
> >>>recorded video?  Is it Mplayer?  What???  My xawtv works fine.
> >>>
> >>>What am I missing?
> >>>
> >>>Thanks
> >>>
> >>>Doug P
> >>
> >>I discovered I had to install Xine, sorry about that.  Now i can
> >>playback a recorded video (no sound yet)  I hear sound during the
> >>recording in the lineout jack of the WinTV Go board though.  But I
> >>still can't watch Live TV, screen goes black.  Any suggestions are
> >>appreciated...
>
> I saw xine, ogle mentioned in a step by step guide
> (http://pvrhw.goldfish.org/tiki-page.php?pageName=rh9pvr250) and just
> installed it.  When I did my playback (video only) started working so
> I thought...
> That was my problem, I thought...  Should my Hauppage 190 be similar
> to the PVR250 as far as this install is concerned?

No, the WinTV-GO is just a regular V4L (Video4Linux) card with no 
hardware encoding.


> I'm curious, why was an "internal player" used/created instead of one
> of the many available?  I hope that's not a dumb question.

Well, first of all, Myth records in a 'tweaked' NuppelVideo format that 
isn't natively supported by external players, and second, having an 
internal format & player allows better control over playback features 
(bookmarks, commercial skip, etc).


> > Whatever gave you the idea you needed to install Xine or mplayer? 
> > Myth uses its own internal player to play back recorded programs. 
> > You only need an external player if you want to play back non-Myth
> > content using the MythVideo plugin.
> >
> > The reason you can't watch LiveTV is likely because your sound card
> > or driver doesn't support (or isn't configured properly for) full
> > duplex.
>
> Is sound required to see the video?

The frontend basically blocks on trying to open the sound device.  If it 
can't open the sound device, it won't start playback, hence a black 
screen.  There are two likely reasons why this might be happening.  One 
reason (and the most common) is that you're running Gnome or KDE and 
need to disable or kill the sound daemon (esd in Gnome; artsd in KDE); 
other processes like mythfrontend can't access the sound device for 
output while another app (esd/artsd) already has it open for output.  
The other possibility is that your sound card or driver doesn't support 
full duplex (i.e., simultaneous record & playback).  In LiveTV, what's 
happening is the live feed is being recorded & encoded and then 
immediately played back.  So, if your card isn't doing full duplex, 
then the frontend can't open the device because the backend already has 
it open for recording.


> > The reason you have no sound when you play back a recording is
> > likely because your recordings have no sound (i.e., your sound is
> > mis-configured for Myth).
>
> I'm now hearing sound when I attempt live watching, so I thought I
> had sound licked...

But is your sound out of sync, as in a couple of seconds ahead of the 
video?


> > Read the section in the docs about troubleshooting audio (http://
> > www.mythtv.org/docs/mythtv-HOWTO-7.html and
> > http://www.mythtv.org/docs/ mythtv-HOWTO-20.html#ss20.11 & try to
> > get your audio configured properly.
> >
> > -JAC
> >
> > PS- In future, it would be helpful to submit your system specs when
> > asking for help.  Include things like: motherboard, CPU, sound
> > card, video card, Linux distro, sound drivers, video card, tuner
> > card, version of Myth & source of Myth (i.e., RPM, Deb, source
> > tarball or CVS)
>
> OK, Thanks I'll keep plugging away at it and post my resulting
> successful procedure.  And thankyou VERY much for the support!  Are
> you the author of any of this great stuff?

Sorry, I didn't see your specs at the top of your original post... but 
you haven't indicated what kind of sound card you have or whether 
you're using ALSA or OSS.  This is important information when 
troubleshooting audio!

-JAC