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Audio glitches on EPG and local commercals

 

 

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jmorris at beau

May 5, 2012, 7:55 PM

Post #1 of 12 (1061 views)
Permalink
Audio glitches on EPG and local commercals

Finishing up my upgrade to a HDHomeRun Prime from a PVR-350 and
generally enjoying the joys of HD. One of the annoying glitches is that
now if I pull up the Guide while watching LiveTV the sound often
glitches. Hit PageUP or PageDown and it is almost 100% certain to do
it.

Have tried just about everything in the archives and Wiki. Twiddled
settings in Myth. Tried keeping the CPUs running at 100% instead of
letting them loaf at 1GHz. And so on. Then I noticed this in a verbose
log:

Lots of

AO: Pause 1

quickly followed by

AO: Pause 0

Eh? It is pausing the audio intentionally? Or am I reading that right?

Details on my system:

Mythtv 0.24.2fixes installed from Debian-multimedia on Debian 6.0
updated as of this week. Hardware is an Athlon64x2 @ 2.5GHz with a
GeForce 210. Using VDPAU for HD. Connected to a TV through HDMI and
sending the sound through the TV on out an optical cable to a 5.1 amp.

Second glitch is that the local cable company is really hosing the
stream when they insert local commercials. They do appear to be holding
the resolution constant but the audio drops from 5.1 to stereo when they
go to/from local and the amp has to reacquire. Annoying but bearable.
What is more of a problem is that the frontend occasionally bails on
those transitions. And a couple of times it has hung requiring a kill
be sent to it. The changelog for 0.25 seems to imply work in this area
so as soon as it appears in the repo I plan to update and hope this one
goes away.
Attachments: signature.asc (0.19 KB)


jyavenard at gmail

May 5, 2012, 10:17 PM

Post #2 of 12 (1019 views)
Permalink
Re: Audio glitches on EPG and local commercals [In reply to]

On 6 May 2012 12:55, John Morris <jmorris [at] beau> wrote:
> Lots of
>
> AO: Pause 1
>
> quickly followed by
>
> AO: Pause 0
>
> Eh?  It is pausing the audio intentionally?  Or am I reading that right?

Audio is paused during playback if it didn't manage to decode enough
video frames and is in need to catch up.

You would have seen errors before that.

try running myth with -v audio,playback and provide a full log
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jmorris at beau

May 5, 2012, 11:29 PM

Post #3 of 12 (1036 views)
Permalink
Re: Audio glitches on EPG and local commercals [In reply to]

On Sun, 2012-05-06 at 15:17 +1000, Jean-Yves Avenard wrote:
> On 6 May 2012 12:55, John Morris <jmorris [at] beau> wrote:
> > Lots of
> >
> > AO: Pause 1
> >
> > quickly followed by
> >
> > AO: Pause 0
> >
> > Eh? It is pausing the audio intentionally? Or am I reading that right?
>
> Audio is paused during playback if it didn't manage to decode enough
> video frames and is in need to catch up.
>
> You would have seen errors before that.
>
> try running myth with -v audio,playback and provide a full log

I was already capturing important, audio, playback so here is the area
right before pressing Guide to a few seconds after:

2012-05-06 01:07:38.251 Player(6): 2400 progressive frames seen.
'video_output' mean = '16679.77', std. dev. = '84.99', fps = '59.95'
'video_output' mean = '16680.11', std. dev. = '239.33', fps = '59.95'
'video_output' mean = '16679.75', std. dev. = '81.71', fps = '59.95'
'video_output' mean = '16680.02', std. dev. = '196.19', fps = '59.95'
2012-05-06 01:07:44.925 Player(6): 2800 progressive frames seen.
'video_output' mean = '16678.37', std. dev. = '741.90', fps = '59.96'
2012-05-06 01:07:45.291 ScreenSaverX11Private: Calling
gnome-screensaver-command --poke
'video_output' mean = '16659.67', std. dev. = '1083.97', fps = '60.03'
2012-05-06 01:07:47.243 pause_active: 0
2012-05-06 01:07:47.358 Display Rect left: 1410, top: 75, width: 450,
height: 255, aspect: 1.77778
2012-05-06 01:07:47.359 Video Rect left: 0, top: 0, width: 1280,
height: 720, aspect: 1.77778
2012-05-06 01:07:47.359 Display Rect left: 1410, top: 75, width: 450,
height: 255, aspect: 1.77778
2012-05-06 01:07:47.359 Video Rect left: 0, top: 0, width: 1280,
height: 720, aspect: 1.77778
2012-05-06 01:07:47.359 TV: DrawUnusedRects() -- begin
2012-05-06 01:07:47.359 TV: DrawUnusedRects() -- end
2012-05-06 01:07:47.360 TV: DrawUnusedRects() -- begin
2012-05-06 01:07:47.360 TV: DrawUnusedRects() -- end
2012-05-06 01:07:47.361 TV: DrawUnusedRects() -- begin
2012-05-06 01:07:47.361 TV: DrawUnusedRects() -- end
2012-05-06 01:07:47.396 TV: DrawUnusedRects() -- begin
2012-05-06 01:07:47.396 TV: DrawUnusedRects() -- end
2012-05-06 01:07:47.683 Player(6): Video is 6.23899 frames behind audio
(too slow), dropping frame t
o catch up.
2012-05-06 01:07:47.683 AO: Pause 1
2012-05-06 01:07:47.692 AO: OutputAudioLoop: audio paused
2012-05-06 01:07:47.692 ALSA, Error: WriteAudio: buffer underrun
2012-05-06 01:07:47.697 Player(6): Video is 8.95001 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.698 Player(6): Video is 10.7285 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.698 Player(6): Video is 11.8077 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.698 Player(6): Video is 12.3773 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.698 Player(6): Video is 12.5498 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.698 Player(6): Video is 12.4244 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.698 Player(6): Video is 12.0906 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.698 Player(6): Video is 11.5854 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.698 Player(6): Video is 10.9519 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.698 Player(6): Video is 10.2369 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.698 Player(6): Video is 9.4459 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.698 Player(6): Video is 8.59791 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.698 Player(6): Video is 7.70719 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.699 Player(6): Video is 6.79938 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.699 Player(6): Video is 5.86375 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.699 Player(6): Video is 4.90727 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.699 Player(6): Video is 3.95019 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:07:47.699 Player(6): Waiting for video buffers...
2012-05-06 01:07:47.699 AO: Pause 1
2012-05-06 01:07:47.730 AO: Pause 0
2012-05-06 01:07:47.730 AO: Pause 0
2012-05-06 01:07:47.781 IsTunable(2810)
2012-05-06 01:07:47.786 AO: OutputAudioLoop: Play Event
2012-05-06 01:07:47.787 IsTunable(2810) -> true

Snipping a bunch of normal idle messages with the EPG just sitting there
while I cut/pasted the above, now I hit PageUp:

2012-05-06 01:12:18.752 IsTunable(2809)
2012-05-06 01:12:18.758 IsTunable(2809) -> true

2012-05-06 01:12:18.849 Player(6): 19200 progressive frames seen.
2012-05-06 01:12:18.871 Player(6): Video is 3.11437 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:12:18.871 AO: Pause 1
'video_output' mean = '17573.85', std. dev. = '8200.20', fps = '56.90'
2012-05-06 01:12:18.872 Player(6): Video is 3.71438 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:12:18.872 AO: Pause 1
2012-05-06 01:12:18.872 Player(6): Video is 3.92465 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:12:18.872 AO: Pause 1
2012-05-06 01:12:18.872 Player(6): Video is 3.82761 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:12:18.872 AO: Pause 1
2012-05-06 01:12:18.873 Player(6): Video is 3.51508 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:12:18.873 AO: Pause 1
2012-05-06 01:12:18.873 Player(6): Video is 3.04088 frames behind audio
(too slow), dropping frame to catch up.
2012-05-06 01:12:18.873 AO: Pause 1
2012-05-06 01:12:18.874 AO: Pause 0
2012-05-06 01:12:18.881 AO: OutputAudioLoop: Play Event
2012-05-06 01:12:19.046 Player(6): Waiting for video buffers...
2012-05-06 01:12:19.046 AO: Pause 1
2012-05-06 01:12:19.052 AO: OutputAudioLoop: audio paused
2012-05-06 01:12:19.146 Player(6): Waited 100ms for video buffers
AAAAAAAALAALAAAAA
2012-05-06 01:12:19.148 Player(6): Waited 100ms for video buffers
AAAAAAAALAALAAAAA
2012-05-06 01:12:19.152 AO: Pause 0
2012-05-06 01:12:19.152 AO: OutputAudioLoop: Play Event
2012-05-06 01:12:19.202 Player(6): Video is 5.77864 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.236 Player(6): Video is 8.91944 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.269 Player(6): Video is 11.0203 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.303 Player(6): Video is 12.3562 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.336 Player(6): Video is 13.0884 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.369 Player(6): Video is 13.3978 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.403 Player(6): Video is 13.3601 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.436 Player(6): Video is 13.077 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.469 Player(6): Video is 12.625 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.503 Player(6): Video is 12.0462 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.536 Player(6): Video is 11.3274 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.570 Player(6): Video is 10.5635 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.603 Player(6): Video is 9.75082 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.636 Player(6): Video is 8.88653 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.670 Player(6): Video is 7.99856 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.703 Player(6): Video is 7.06288 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.736 Player(6): Video is 6.12132 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.770 Player(6): Video is 5.1604 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.803 Player(6): Video is 4.18498 frames ahead of
audio,
doubling video frame interval to slow down.
2012-05-06 01:12:19.836 Player(6): Video is 3.21363 frames ahead of
audio,
doubling video frame interval to slow down.
'video_output' mean = '19991.35', std. dev. = '13610.29', fps = '50.02'
'video_output' mean = '16680.04', std. dev. = '83.46', fps = '59.95'
'video_output' mean = '16679.06', std. dev. = '82.62', fps = '59.96'
2012-05-06 01:12:25.843 Player(6): 19600 progressive frames seen.
'video_output' mean = '16680.35', std. dev. = '91.23', fps = '59.95'
'video_output' mean = '16679.26', std. dev. = '74.28', fps = '59.95'
'video_output' mean = '16680.06', std. dev. = '74.49', fps = '59.95'
'video_output' mean = '16679.75', std. dev. = '97.32', fps = '59.95'
2012-05-06 01:12:32.516 Player(6): 20000 progressive frames seen.
'video_output' mean = '16679.92', std. dev. = '86.07', fps = '59.95'

It is complaining of underruns but I already did the bit to increase the
buffer with:

# cat /proc/asound/card1/pcm3p/sub0/prealloc
320

The obvious problem is figuring out just what the heck sort of resource
starvation could be happening on this machine, it is more than enough
for the job. Painting the guide isn't exactly hard. But the larger
problem is that it looks like a case where it isn't making an optimal
decision in dealing with the first problem. A media player should keep
the audio streaming at all cost and with realtime priority it is hard to
imagine that not being possible. Cutting audio frames is almost as bad
but preferred to switching off the transmitter, especially on
multi-channel audio. Dropping video frames is almost always the right
decision over breaking the audio.
Attachments: signature.asc (0.19 KB)


jyavenard at gmail

May 6, 2012, 1:43 AM

Post #4 of 12 (1026 views)
Permalink
Re: Audio glitches on EPG and local commercals [In reply to]

On 6 May 2012 16:29, John Morris <jmorris [at] beau> wrote:

> 2012-05-06 01:07:47.683 Player(6): Video is 6.23899 frames behind audio
> (too slow), dropping frame t
> o catch up.
> 2012-05-06 01:07:47.683 AO: Pause 1
> 2012-05-06 01:07:47.692 AO: OutputAudioLoop: audio paused
> 2012-05-06 01:07:47.692 ALSA, Error: WriteAudio: buffer underrun

...

> 2012-05-06 01:07:47.699 Player(6): Video is 4.90727 frames behind audio
> (too slow), dropping frame to catch up.
> 2012-05-06 01:07:47.699 Player(6): Video is 3.95019 frames behind audio
> (too slow), dropping frame to catch up.
> 2012-05-06 01:07:47.699 Player(6): Waiting for video buffers...
> 2012-05-06 01:07:47.699 AO: Pause 1
> 2012-05-06 01:07:47.730 AO: Pause 0
> 2012-05-06 01:07:47.730 AO: Pause 0
> 2012-05-06 01:07:47.781 IsTunable(2810)
> 2012-05-06 01:07:47.786 AO: OutputAudioLoop: Play Event
> 2012-05-06 01:07:47.787 IsTunable(2810) -> true

Well there you go.

video is decoding to slowly and the gap between audio and video
becomes too great and audio needs to be paused for video decoding to
catch up.


>
> It is complaining of underruns but I already did the bit to increase the
> buffer with:

the underruns are not due to buffering here, but because the audio
card is starved

basically, your system is too slow

>
> # cat /proc/asound/card1/pcm3p/sub0/prealloc
> 320
>
> The obvious problem is figuring out just what the heck sort of resource
> starvation could be happening on this machine, it is more than enough
> for the job.  Painting the guide isn't exactly hard.  But the larger
> problem is that it looks like a case where it isn't making an optimal
> decision in dealing with the first problem.  A media player should keep
> the audio streaming at all cost and with realtime priority it is hard to
> imagine that not being possible.  Cutting audio frames is almost as bad
> but preferred to switching off the transmitter, especially on
> multi-channel audio.  Dropping video frames is almost always the right
> decision over breaking the audio.

I would agree with you, except that there's currently only one player,
and audio and video are in sync and comes together.

You can't always continue decoding the audio, without also decoding the video.

If you read the logs, you will see that it does drop video frames
first, but it comes to a point where it's not recoverable.

But thank you for your insightful analysis, and we'll welcome your
future contributions to make things better
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mtdean at thirdcontact

May 7, 2012, 4:11 AM

Post #5 of 12 (1004 views)
Permalink
Re: Audio glitches on EPG and local commercals [In reply to]

On 05/06/2012 04:43 AM, Jean-Yves Avenard wrote:
> On 6 May 2012 16:29, John Morris wrote:
>> 2012-05-06 01:07:47.683 Player(6): Video is 6.23899 frames behind audio
>> (too slow), dropping frame t
>> o catch up.
>> 2012-05-06 01:07:47.683 AO: Pause 1
>> 2012-05-06 01:07:47.692 AO: OutputAudioLoop: audio paused
>> 2012-05-06 01:07:47.692 ALSA, Error: WriteAudio: buffer underrun
> ...
>
>> 2012-05-06 01:07:47.699 Player(6): Video is 4.90727 frames behind audio
>> (too slow), dropping frame to catch up.
>> 2012-05-06 01:07:47.699 Player(6): Video is 3.95019 frames behind audio
>> (too slow), dropping frame to catch up.
>> 2012-05-06 01:07:47.699 Player(6): Waiting for video buffers...
>> 2012-05-06 01:07:47.699 AO: Pause 1
>> 2012-05-06 01:07:47.730 AO: Pause 0
>> 2012-05-06 01:07:47.730 AO: Pause 0
>> 2012-05-06 01:07:47.781 IsTunable(2810)
>> 2012-05-06 01:07:47.786 AO: OutputAudioLoop: Play Event
>> 2012-05-06 01:07:47.787 IsTunable(2810) -> true
> Well there you go.
>
> video is decoding to slowly and the gap between audio and video
> becomes too great and audio needs to be paused for video decoding to
> catch up.
>> It is complaining of underruns but I already did the bit to increase the
>> buffer with:
> the underruns are not due to buffering here, but because the audio
> card is starved
>
> basically, your system is too slow

And if you'd like the post the whole log requested--instead of some
excerpt that you think is important--we can probably tell you why--i.e.
why you're not using VDPAU or whatever.

Mike
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bfrost at brainboy

May 7, 2012, 9:55 AM

Post #6 of 12 (1006 views)
Permalink
Re: Audio glitches on EPG and local commercals [In reply to]

On May 7, 2012, at 6:11 AM, Michael T. Dean wrote:

> On 05/06/2012 04:43 AM, Jean-Yves Avenard wrote:
>> On 6 May 2012 16:29, John Morris wrote:
>>> 2012-05-06 01:07:47.683 Player(6): Video is 6.23899 frames behind audio
>>> (too slow), dropping frame t
>>> o catch up.
>>> 2012-05-06 01:07:47.683 AO: Pause 1
>>> 2012-05-06 01:07:47.692 AO: OutputAudioLoop: audio paused
>>> 2012-05-06 01:07:47.692 ALSA, Error: WriteAudio: buffer underrun
>> ...
>>
>>> 2012-05-06 01:07:47.699 Player(6): Video is 4.90727 frames behind audio
>>> (too slow), dropping frame to catch up.
>>> 2012-05-06 01:07:47.699 Player(6): Video is 3.95019 frames behind audio
>>> (too slow), dropping frame to catch up.
>>> 2012-05-06 01:07:47.699 Player(6): Waiting for video buffers...
>>> 2012-05-06 01:07:47.699 AO: Pause 1
>>> 2012-05-06 01:07:47.730 AO: Pause 0
>>> 2012-05-06 01:07:47.730 AO: Pause 0
>>> 2012-05-06 01:07:47.781 IsTunable(2810)
>>> 2012-05-06 01:07:47.786 AO: OutputAudioLoop: Play Event
>>> 2012-05-06 01:07:47.787 IsTunable(2810) -> true
>> Well there you go.
>>
>> video is decoding to slowly and the gap between audio and video
>> becomes too great and audio needs to be paused for video decoding to
>> catch up.
>>> It is complaining of underruns but I already did the bit to increase the
>>> buffer with:
>> the underruns are not due to buffering here, but because the audio
>> card is starved
>>
>> basically, your system is too slow
>
> And if you'd like the post the whole log requested--instead of some excerpt that you think is important--we can probably tell you why--i.e. why you're not using VDPAU or whatever.
>
> Mike
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://www.mythtv.org/mailman/listinfo/mythtv-users

It is a complete mystery why some people think that the devs are rude... a complete mystery
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jmorris at beau

May 7, 2012, 10:17 AM

Post #7 of 12 (1010 views)
Permalink
Re: Audio glitches on EPG and local commercals [In reply to]

On Mon, 2012-05-07 at 07:11 -0400, Michael T. Dean wrote:

> And if you'd like the post the whole log requested--instead of some
> excerpt that you think is important--we can probably tell you why--i.e.
> why you're not using VDPAU or whatever.

Eh? I did in the parent post. Starting with routine idle messages
through punching guide and the error. Then I snipped a series of
repetitive normal idle traffic between the next problem when I hit page
up. Always a balance between flooding too much log data and not enough
but I figured a window of over ten seconds was enough for a subsecond
glitch in the audio.

I am using VDPAU on HD playback. Not using it on SD because the
processor can decode that itself without breaking a sweat. Literally,
only a 2C rise in temp over idle. And if the content is SD odds are the
auto aspect switching feature will be very helpful and it isn't
available with the hardware based decode. Especially like the half zoom
mode, that feature alone doubles the WAF because she hates the huge
black bars.
Attachments: signature.asc (0.19 KB)


mtdean at thirdcontact

May 7, 2012, 11:35 AM

Post #8 of 12 (993 views)
Permalink
Re: Audio glitches on EPG and local commercals [In reply to]

On 05/07/2012 01:17 PM, John Morris wrote:
> On Mon, 2012-05-07 at 07:11 -0400, Michael T. Dean wrote:
>> And if you'd like the post the whole log requested--instead of some
>> excerpt that you think is important--we can probably tell you why--i.e.
>> why you're not using VDPAU or whatever.
> Eh? I did in the parent post.

Apologies. All my logs start with "mythfrontend started" or
"mythbackend started", so I assumed everyone's did.

> Starting with routine idle messages
> through punching guide and the error. Then I snipped a series of
> repetitive normal idle traffic between the next problem when I hit page
> up. Always a balance between flooding too much log data and not enough
> but I figured a window of over ten seconds was enough for a subsecond
> glitch in the audio.

Well, since you know there are no errors in the rest, I suppose that
means that everything is working fine and your system is just really too
slow to decode the video.

Anyway, it seems I'm too rude to help people (based on another reply to
my message in this thread, but from a different user), so I hope someone
else, who's not so rude, will be able to help.

Mike
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jmorris at beau

May 7, 2012, 7:11 PM

Post #9 of 12 (1006 views)
Permalink
Re: Audio glitches on EPG and local commercals [In reply to]

On Sun, 2012-05-06 at 18:43 +1000, Jean-Yves Avenard wrote:

> Well there you go.
>
> video is decoding to slowly and the gap between audio and video
> becomes too great and audio needs to be paused for video decoding to
> catch up.

That theory doesn't hold. Atom based systems with an NVIDIA GPU play HD
without problems and this system has a lot more grunt. I took off the
governors and it didn't help a bit. But that was still just theory so I
thought about it a bit and decided to get some numbers. the sensors
only read to 1C and the Kill-a-Watt only to a watt and the numbers
bounced around a bit. But by letting it run a hour or more in each mode
and taking a average after letting the temps settle down these numbers
should at least be enough to make some generalizations from:

CPU MB GPU Power
Idle 32 32 40 54
LiveTV SD 35 32 42 65
Play SD 35 32 42 66
LiveTV HD 34 33 56 70
Play HD 34 33 55 69

As expected there wasn't a real difference between LiveTV and playback
from the library. But note the difference between software decode of SD
and hardware decode of HD. It is pretty obvious that the CPU is not
working hard to playback either one while the GPU is earning it's keep
when the HD stream hits it. And for these tests I had the governors
(except C1E, that is disabled in BIOS) enabled and at no time observed
either core running faster than the base 1GHz.

> > It is complaining of underruns but I already did the bit to increase the
> > buffer with:
>
> the underruns are not due to buffering here, but because the audio
> card is starved

That isn't what I read. It is saying the video is behind the audio. It
tried dropping frames to catch up a few times and then gave up and
paused the audio and started it all back from scratch to get everything
in sync. In other words the audio didn't stop because the buffer ran
dry but because it was intentionally put into pause and that caused ALSA
to complain about the buffer running dru.

The question is why? I either have a minor problem that is tickling a
code path that doesn't see enough use to get optimized or I have a
really big problem somewhere so bad it somehow is getting totally
overwhelmed. But it looks like it is actually easier for this system to
play HD vs SD.

Just tried a test. If I tune a SD channel and go to the guide I can
make it skip if I beat on the pageup key a LOT.

Did notice I have a version of the Nvidia driver that is pretty old and
a newer one is in backports. Next maint window I'll try updating that
just to see what happens.
Attachments: signature.asc (0.19 KB)


jmorris at beau

May 7, 2012, 8:29 PM

Post #10 of 12 (987 views)
Permalink
Re: Audio glitches on EPG and local commercals [In reply to]

On Mon, 2012-05-07 at 14:35 -0400, Michael T. Dean wrote:

> Well, since you know there are no errors in the rest, I suppose that
> means that everything is working fine and your system is just really too
> slow to decode the video.

Well I just tried to reply with an entire log, and as expected for most
mailing lists, you can't post a 98KB attachment. Which was why I tried
to cut the original post down to a more reasonable size that would be
postable.

Not to be thwarted, if you want the whole unedited thing I can do that.
Look at http://beau.org/~jmorris/logs/myth-errorlog-120507 I tuned to a
HD channel and stopped the front end. Relaunched and hit Watch TV. It
restarted on Disney SD which the grandkids had on earlier. Ok, quickly
change channels, let i settle and hit Guide. Page up a couple of times
and pick another HD stream. Then exit and stop the front end and copied
out the log.

> Anyway, it seems I'm too rude to help people (based on another reply to
> my message in this thread, but from a different user), so I hope someone
> else, who's not so rude, will be able to help.

Well I'm a crabby old fart from the BBS days, I don't go running away
crying that easy. All this political correctness is a bad sign.
Attachments: signature.asc (0.19 KB)


dekarl at spaetfruehstuecken

May 7, 2012, 9:24 PM

Post #11 of 12 (988 views)
Permalink
Re: Audio glitches on EPG and local commercals [In reply to]

> overwhelmed. But it looks like it is actually easier for this system to
> play HD vs SD.

That is no surprise if you are decoding HD via VDPAU and SD via CPU as
you said in another post in this thread...
The Atom CPU isn't that beafy (depending on what postprocessing and
which kind of compositing etc pp is running in addition it might be
simply to slow for decoding SD video in software)

Does SD video + guide browsing work if you let the chip decode the
video via VDPAU?

Are the glitches only with HD(VDPAU) or with HD(VDPAU) and SD(software)
playback?

As this is happening on 0.24, what playback profile is that?
Quote from 0.25 changelog:
| Removes CPU++, CPU+, and CPU-- playback profile groups [4cd8186]
| Systems set to use any of these profiles groups are changed to use
| the default group, "Normal"
| Changes users' custom profiles to replace XvMC and libmpeg2 decoders
| with standard (ffmpeg) and XvMC video renderer with Xv (xv-blit) and
| ia44blend OSD renderer with softblend.
| Set default on new setups to "Normal"

The libmpeg2 decoding has known issues, might make sense to check your
settings to avoid them. Maybe the raw bitstream from your provider is
triggering some of these issues.

Regards,
Karl
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dekarl at spaetfruehstuecken

May 7, 2012, 10:11 PM

Post #12 of 12 (990 views)
Permalink
Re: Audio glitches on EPG and local commercals [In reply to]

On 08.05.2012 06:24, Karl Dietz wrote:
>> overwhelmed. But it looks like it is actually easier for this system to
>> play HD vs SD.
>
> That is no surprise if you are decoding HD via VDPAU and SD via CPU as
> you said in another post in this thread...
> The Atom CPU isn't that beafy (depending on what postprocessing and

Doh, I just saw that you said you got *more bang then* an Atom... Anyway
letting the GPU do it will certainly take load of the CPU :)

Regards,
Karl
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