[mythtv-users] pvr-350 Live Tv Audio to remote frontend Question

Jim Duda jim at duda.tzo.com
Thu Dec 29 17:59:24 EST 2005


Thanks for the response.

Results of my testing.

If I choose "Watch Videos" and play something which was recorded outside 
of MythTV, the video plays properly.  These videos are those previously 
recorded by Freevo.

If I choose "Watch Recordings" and play something which was recorded by 
MythTV, I get the video, but no audio.

If I play the "nuv" file outside of MythTV, using VLC, I get Video and 
Audio.  As such, the conclusion is that the nuv (mpeg) is complete as 
recorded by MythTV.

I get different log file results when playing "Watch Videos" vs "Watch 
Recordings".  There is less information with "Watch Recordings".

There is something different concerning how MythTV plays recordings done 
outside of MythTV as compared to those inside MythTV, but I cannot 
figure it out.
I suspect this might have something to do with the alsa interface.  
Maybe I have a permissions issue with sound?  I'm running myfrontend 
using the same user login which I use to play the videos with VLC.  I 
don't use root ... does mythfrontend run as user "mythtv"?  Is so, it 
doesn't explain why I can get audio for recordings outside of MythTV, 
when playing within MythTV itself.

I cannot find the setting which allows me to control the PVR-350 audio 
output.  I looked in the setup pages of both the backend and frontend, 
but I cannot find the switch.  I have my frontend setup defined to use 
/dev/dsp, which is the default.  In general, I tried to simply select 
the defaults.

If I attempt to play the "nuv" file, recorded by MythTV in the "Watch 
Recordings" options, the video won't play, however, the other videos 
recorded outside of MythTV will play.  I don't know if this is a clue to 
anyone who might help me.

I did find an old .mplayer directory in my $HOME account, which I 
deleted and allowed mplayer to recreate, but no change in behavior.

I'm puzzled; and very new to MythTV, thanks for you patience.


Jeff Simpson wrote:

> On 12/29/05, *Jim Duda* <jim at duda.tzo.com <mailto:jim at duda.tzo.com>> 
> wrote:
>     I'm currently an avid Freevo user.  I just installed MythTV
>     yesterday and
>     started playing with it.  Mythtv is very impressive.
>     I have mythbackend running on one linux box, with a PVR-350 tuner
>     card.  I
>     have mythfrontend installed and running on multiple linux
>     boxes.  I can
>     view and hear mpeg videos on all the frontend boxes.  For live TV,
>     I can
>     see the video, but I cannot hear the audio.
>     I've read the mailing list and found a couple of postings on this
>     topic.
>     It's my understanding that the livetv audio from a Pvr-350 is
>     exported out
>     of the rear audio jack and not through the PCI bus like it would
>     with the
>     mpeg stream.  Connecting the PVR-350 audio output back into a
>     sound card
>     input would allow a mythfrontend to hear audio, however, only on
>     the box
>     which contains the pvr-350 tuner.  This doesn't help any remote
>     frontend
>     boxes.
> Not entirely correct. The PVR-350 takes audio in and saves it with the 
> MPEG automatically. If you want to output to TV, you can use the audio 
> out of the PVR as well. The loopback audio cable is just to allow that 
> machine to play other audio sources to the TV (mythmusic, mythgame, 
> etc, things that require /dev/dsp). So in the case of remotely playing 
> liveTV, you should not need to use that loopback.
>     Is there any means to get the audio from a pvr-350 in a
>     mythbackend to the
>     mythfrontend on another machine?  Are there any plans to address
>     this in
>     future releases?
> I have 0.18.1 running on my backend/frontend machine with a 350 as 
> well as a frontend only on my laptop, and audio works in all cases, 
> live and recorded. You say that it can play mpeg videos on the 
> back/frontends - do you mean other mpeg videos, or the ones that are 
> recorded by myth?
> I'd also take a look at the frontend logs and setup to make sure the 
> audio is set up properly. Additionally, check to see that the mpegs do 
> contain the audio - you should be able to just play the .nuv files 
> with a fairly recent version of mplayer on any linux machine.
>     In my freevo environment, I handle the remote livetv issue using mpeg
>     streaming from videolan ( www.videolan.org
>     <http://www.videolan.org>).  It works okay, however,
>     mythtv appears much nicer and more integrated, albiet, no audio from a
>     pvr-350.  I'd really like to get this working an give mythtv a
>     shot at
>     replacing freevo.
> That's the same way myth handles remote frontends, by streaming the 
> mpeg. Alternatively, you can also remote-mount the fs and play them 
> that way, but streaming is easy enough and works.
> A likely thing to try is in the remote frontend setup, where it says 
> "Use PVR-350 Output" you want to say NO. That option is only for the 
> machine with the PVR in it - using that option on another machine will 
> make the video and audio try to play through the 350, which won't be 
> there, and won't work. You should set it up to use /dev/dsp or 
> whatever the equivalent device is for your system.

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