[mythtv-users] Jitters during playback

[Brent Bolin]

On Sat, Jan 28, 2012 at 10:15 AM, Michael T. Dean
<mtdean at thirdcontact.com> wrote:
>
> On 01/28/2012 03:06 AM, Mark Kendall wrote:
> > On 28 January 2012 04:30, Mitchell Gore wrote:
> >> When I play back many recording I constantly get jitters/pixelations and
> >> sometimes a complete drop of vido playback.  In the frontend log I see:
> >>
> >> 2012-01-27 22:16:33.328 [ac3 @ 0x9d8ae0]frame CRC mismatch
> >> 2012-01-27 22:18:21.705 AFD Error: Unknown audio decoding error
> >> 2012-01-27 22:18:33.646 [ac3 @ 0x9d8ae0]incomplete frame
> > These errors suggest to me a signal issue.
> >> mitchell at mythfe:/var/log/mythtv$
> >> mitchell at mythfe:/var/log/mythtv$
> >> mitchell at mythfe:/var/log/mythtv$ tail -n 400 mythfrontend.log
> >> 2012-01-27 22:10:30.344 AFD Error: Unknown audio decoding error
> >> 2012-01-27 22:10:30.349 [ac3 @ 0x9d8ae0]frame CRC mismatch
> >> 2012-01-27 22:10:30.378 [ac3 @ 0x9d8ae0]frame sync error
> >> 2012-01-27 22:10:30.378 AFD Error: Unknown audio decoding error
> >> 2012-01-27 22:10:30.433 [ac3 @ 0x9d8ae0]frame CRC mismatch
> >> 2012-01-27 22:10:30.460 [ac3 @ 0x9d8ae0]frame sync error
> >> 2012-01-27 22:10:30.461 AFD Error: Unknown audio decoding error
> >> 2012-01-27 22:10:32.518 Player(0): Waited 100ms for video buffers
> >> AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
> >> 2012-01-27 22:10:42.148 Player(0): Waited 100ms for video buffers
> >> AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
> >> 2012-01-27 22:10:42.157 Player(0): Waited 100ms for video buffers
> >> AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
> >> 2012-01-27 22:10:54.930 [ac3 @ 0x9d8ae0]frame CRC mismatch
> >> 2012-01-27 22:10:54.962 [ac3 @ 0x9d8ae0]frame sync error
> >> 2012-01-27 22:10:54.962 AFD Error: Unknown audio decoding error
> >> 2012-01-27 22:10:55.180 [ac3 @ 0x9d8ae0]frame CRC mismatch
> >> 2012-01-27 22:10:55.210 [ac3 @ 0x9d8ae0]frame sync error
> >> 2012-01-27 22:10:55.211 AFD Error: Unknown audio decoding error
> >> 2012-01-27 22:10:56.046 [ac3 @ 0x9d8ae0]frame CRC mismatch
> >> 2012-01-27 22:10:56.076 [ac3 @ 0x9d8ae0]frame sync error
> >> 2012-01-27 22:10:56.076 AFD Error: Unknown audio decoding error
> >> 2012-01-27 22:10:56.254 [ac3 @ 0x9d8ae0]frame CRC mismatch
> >> 2012-01-27 22:10:56.267 [ac3 @ 0x9d8ae0]frame sync error
> >> 2012-01-27 22:10:56.268 AFD Error: Unknown audio decoding error
> > and perhaps an even worse signal...
> >> My source is a Prime Cable card.  I get nearly a 100% signal
> >> strength/quality acording the the HDHR meters.  Im kinda at a loss on how to
> >> fix this.  Is it caused by VDPAU?
> > Have you tried playing back with vdpau disabled?
>
> FWIW, I had been getting a lot of OTA recordings that showed
> "jitters/pixelation" during playback.  When I switched my profile from
> VDPAU decode + VDPAU render to ffmpeg decode + VDPAU render, all the
> issues went away.  I don't think it's a problem with MythTV code, but a
> problem with VDPAU's ability to cope with small errors in the stream due
> to small signal issues.
>
> Mike
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I would agree with this.  I recently upgraded one of my front ends
from a zotac A-U series mb  to a gigabyte mb using nvidia gt430 video
card.

All I record is OTA HD broadcasts in the Chicagoland area.

All channels are fine except wbbm channel 2 that's still broadcasting
on VHF(who knows why).  All others are UHF and have better quality
then wbbm.

I'm not saying wbbm is really bad cause it isn't.  It just gets short
bursts of pixelation randomly.

I've tried splitter amplifiers and pre amplifiers with not a whole lot
of difference other then being able to pull in even more stations.
I'm only 20 miles from the old Sears tower where most broadcasts come
from.

When I change my profile to "Standard" that uses ffmpeg I see cpu
usage go up from about 7% to 60%.  Good thing this gigabyte mb has a
two core amd 3ghz cpu.

fyi