[mythtv-users] Left Channel Audio Only - LiveTV and Recordings

[Tom Gutwin]

An update so this issue gets into the MythTV list archive...

I initially suspected ALSA and thus did a bit of read up on it.
I decided today to start watching the bug tracker for ALSA and I found something.

https://bugtrack.alsa-project.org/alsa-bug/view.php?id=1658
you will have to login as a guest and then bring up bug 1658

It mimics what we have experienced.
Capture problems with only one channel.
One note also stated the same nForce motherboard with intel8x0.
Regular use of MythDVD and MythMusic work fine because they do not do a capture.
Its LiveTV and recording that bring this issue up.

I am going to follow up with the ALSA bug tracker.
I am going to start logging our info there and post updates back to the MythTV list.

I'll update when there is more info.

tom

Brian Stults wrote:
 > Tom,
 >
 > I'm also using a recent svn build (8336).  This is a frontend/slave
 > backend that I've had mostly stable for over a year.  I'm using a
 > PVR-150 and a PVR-350.
 >
 > It's not a problem with the capture card drivers because I can play
 > recorded files just fine with mplayer or xine.  I reverted back to older
 > drivers that I know work, and that didn't change anything.
 >
 > I also tried every possible mixer setting.  Then I removed and
 > reinstalled all the alsa drivers and utilities.  I even reverted back to
 > older alsa drivers.  I checked all my cabling, too.  None of that helped.
 >
 > All of this leads me to the same conclusion as you - it must be a
 > problem with myth.  My next step is going to be backing up and removing
 > the database and installing the stable version of myth.  That way I'll
 > know for sure whether something happened in one of the svn updates.  At
 > that point I'll probably post a message to the developers' mailing list.
 >  Let's keep each other posted.
 >
 > 	-Brian
 >
 >
 > Tom Gutwin wrote:
 >> I saw your post too. No luck here.
 >>
 >> I have gone through ALSA, and all my cabling on my system.
 >> I have search through every search able mail list and faq.
 >> It has got to be an issue within MythTV.
 >>
 >> Did you do a SVN update and rebuild yourself?
 >>
 >> My system is a freshly built system specifically to be a home for
 >> Myth And a Video Security system:
 >>  AMD X2
 >>  Asus A8N-e with onboard nvidia CK804/intel8x0
 >>  Fedora core 4 built for x86_64
 >>  with smp kernel 2.6.14-1.1653_FC4
 >>  Alsa Version 1.0.10rc3  for kernel 2.6.14-1.1653_FC4smp (SMP)
 >>  I am using a bt878 based video capture card
 >>  NTSC based satellite tuner to supply the composite video and simple 2
 >> channel audio
 >>
 >> I can monitor the 2ch audio fine but when it gets recorded through Myth
 >> (or Live)
 >> it loses its right channel of audio with plain old analog 2 channel output.
 >> NO digital AC3 used here (yet)
 >>
 >> I have gone through the alsa setup with a fine tooth comb. it looks
 >> correct.
 >> plus all audio and video apps outside of MythTV work correctly.
 >>
 >> The sound setup looks good.
 >> I am going to try a different sound card.
 >>
 >> tom
 >>
 >>
 >>
 >> Brian Stults wrote:
 >>> Hello,
 >>>
 >>> You and I appear to have the exact same audio issue.  In fact, we posted
 >>> it to the mythtv-user list only 10 minutes apart.  I haven't seen any
 >>> responses.  Have you received any suggestions, or have you been able to
 >>> figure it out?
 >>>
 >
 >

Tom Gutwin wrote:
> Hi all,
> 
> Just set up a new MythTV box. Very Happy except one thing.
> I am getting audio out of the left channel ONLY for Live and recorded TV.
> NO Right Channel sound.
> Sound out with MythDVD, and MythMusic is fine, as is other non-Myth Apps.
> I know the right audio is getting into the box because I can monitor the 
> line in.
> 
> Does this ring a bell with anyone?
> 
> I have surfed the list archives and tried just about every sound setting
> I could think of but could not find a reason for it.
> 
> I am running:
>  - MythTV - the latest svn build (8463)
>  - FC4 on x86_64
>  - asus A8N MB with nforce2 intel8x0 ac97 sound
>  - The sound is set up with basic 2 channel settings with the capture only
>    on the line input.
>  - Back and frontend on the same box.
>  - I am also running a remote frontend on another box and the same
>    left channel only audio is present
> 
> TV signal
>  is composite from an external satellite decoder with the l&R audio
>  running into my line in on the motherboard line-in.
>  alsa mixer is set to capture from the line-in
> 
> 
> I have trouble shot all cables and methods of input and no matter what
> Left Channel only :(
> 
> Its like the conversion to nuv file is leaving the right channel off.
> What should I look to change.
> I can even look into the code
> 
> 
> tom

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