[mythtv-users] HD-PVR dropped frames / MythTV AV glitches
Will Dormann
wdormann at gmail.com
Tue Nov 11 18:31:49 UTC 2014
Hi John,
On 11/11/14 10:53 AM, John P Poet wrote:
> Are you using the S/PDIF input on the HD-PVR, or the analog input? If
> it is the S/PDIF input, try the analog and see if the problem goes away.
Ahh, you might be on to something here! Since I obtained a digital
amp, I switched to S/PDIF (optical) to retain 5.1 audio from start to
1d2finish. And now that I think about it, I suspect that around this
time was that I started noticing audio glitching. But given the number
of changes that happened around that time, I never really drew a 1-to-1
mapping about cause / effect. My suspicion was that the audio was
perhaps always glitching, but I was only just noticing it because of the
new amp and hookups.
> When using the S/PDIF, the HD-PVR muxes the digital audio into the video
> without modification. If you use the analog inputs, then the HD-PVR
> converts it to digital before muxing it in -- encoding the audio.
Good to know. So basically, with analog audio you're more guaranteed
to have a valid video stream with proper A/V sync?
> Myth uses the audio for timing and synchronization. If the audio has
> any glitches in it, it can cause the kind of problem you are
> describing. If you are using S/PDIF and switching to analog fixes it,
> then your cable company is sending you bad digital audio.
I'll try switching back to analog audio input to the HD-PVR to see how
it works. If it works, then I guess I'll have to decide between
glitchy digital 5.1 and smooth analog pro logic audio, right?
If it is Comcast's fault that the audio isn't perfect, I am skeptical
that I could ever talk to anybody who would be able to know and/or do
anything about.
Thanks
-WD
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