[mythtv-users] Dvico FusionHDTV5 Gold Plus - A/V sync

[Joe Votour]

--- Steve Skarda <steveskarda at gmail.com> wrote:

> If you have this card, can you tell me if you have
> any issues with A/V sync
> on OTA, ATSC HDTV programs?
> 
> I have had an ongoing issue with audio 200-300mS
> behind video on most HDTV
> shows.   I have considered several sources of the
> problem (kernel, playback,
> Alsa) but have come to the conclusion that it must
> be in the recording.   I
> could very well be wrong but I think it is the tuner
> card because the
> problem is consistently worse on some channels
> (PBS).   If it were a kernel
> latency, Alsa, or Myth sync issue, I would expect
> the problem to show up
> more consistently across channels, programs, and
> formats.  Not to metion,
> this doesn't
> seem to be a widespread problem and the Dvico Fusion
> card does not seem to
> be that common.
> 
> Any guidance on how to troubleshoot this issue or
> comparative experience
> with this card would be greatly appreciated.
> 
> List of troubleshooting steps I've tried with no
> impact on the problem:
> -Reload Alsa from cvs
> -mythfrontend -v audio (nothing unusual)
> -spdif, analog, alsa, no alsa, passthrough, no
> passthrough.
> -standard kernel, prememptive kernel
> -realtime priority, rtlimits, run as root
> -Myth 0.18, 0.19, svn
> -Ubuntu Breezy, Ubuntu Dapper
> 
> Info on my system:
> Two Dvico FusionHDTV5 cards (considering getting
> third HD3000 just to
> compare)
> Intel Motherboard with on-board sound
> Latest Ubuntu Dapper kernel
> 
> Other potential:
> -I read somewhere that a weak signal can create a/v
> sync issues.  95% of
> shows record OK with no obivous problems or bad
> fragments listed in the log
> but I will occasional miss a show due to weak
> signal/weather or see bad
> fragments show up in log.   Any experience or
> knowledge to confirm that as a
> possiblity?
> 
> One last item:
> As long as I have the attention of Dvico owners, can
> you tell me if you
> typically see this show up in your syslog?  I don't
> think it is a problem
> but am surprised that I have it logging in the
> system log.
> 
> May  3 08:00:02 localhost kernel: [4513310.340000]
> cx88[0]/2: queue is empty
> - first active
> May  3 08:00:02 localhost kernel: [4513310.340000]
> cx88[0]/2:
> cx8802_start_dma w: 0, h: 0, f: 2
> May  3 08:00:02 localhost kernel: [4513310.340000]
> cx88[0]/2: setting the
> interrupt mask
> May  3 08:00:02 localhost kernel: [4513310.340000]
> cx88[0]/2: [d8fd2a80/0]
> cx8802_buf_queue - first active
> May  3 08:00:03 localhost kernel: [4513311.061000]
> cx88[0]/2:
> cx8802_restart_queue
> May  3 08:00:03 localhost kernel: [4513311.061000]
> cx88[0]/2:
> cx8802_restart_queue: queue is empty
> May  3 08:00:03 localhost kernel: [4513311.063000]
> cx88[0]/2: queue is empty
> - first active
> May  3 08:00:03 localhost kernel: [4513311.063000]
> cx88[0]/2:
> cx8802_start_dma w: 0, h: 0, f: 2
> May  3 08:00:03 localhost kernel: [4513311.063000]
> cx88[0]/2: setting the
> interrupt mask
> > _______________________________________________
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>
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> 

I have the FusionHDTV5 Lite, which uses a BT878 chip
as opposed to the newer Conexant replacement model,
and I do see some A/V sync issues.  But, if they show
up, it's usually well into watching a stream (like at
least a half-hour), and not all that often. 
Restarting the recording/LiveTV fixes it.

I figure that it's an antenna alignment issue (causing
some weak signals), as I never really took the time to
properly align it (I just pointed it in the "general"
direction).

I see nothing in my system logs regarding the
FusionHDTV5 Lite at all.

-- Joe

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