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0.25 Major AV sync problems

 

 

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bryan.bennetts at gmail

Jun 20, 2012, 1:24 AM

Post #26 of 33 (1273 views)
Permalink
Re: 0.25 Major AV sync problems [In reply to]

On 19 June 2012 22:03, Jean-Yves Avenard <jyavenard [at] gmail> wrote:

> On 19 June 2012 01:02, Bryan Bennetts <bryan.bennetts [at] gmail> wrote:
>
> > Ehm, I'm seeing similar symptoms (blushes, shuffles feet) haven't
> mentioned
> > it as there seemed to be others having a dig and once I'd shifted my
> audio
> > by 100ms it hasn't really bothered me, also I had done a fresh install
> to a
> > new FE using a different OS and upgraded myth version so there are an
> awful
> > lot of variables.
>
> A fixed delay is an entirely different matter and is something that
> can't be avoided as hardware along the way introduce delays...
>
> This is what the A/V delay settings is for.
>

Indeed, and is one reason I was keeping quiet, unfortunately I changed h/w
at the same time as s/w so its not trivial to pin down without actual time
and effort.

Note however that I *think* its not a hard and fast delay - 100 ms is
'good enough' but it still varies slightly. Until I have time to
investigate properly I'll keep schtum as there's plenty of traffic on this
thread without my additional noise.


Cheers, Bryan.


glen.hawksworth at bigpond

Jul 3, 2012, 4:23 AM

Post #27 of 33 (1219 views)
Permalink
Re: 0.25 Major AV sync problems [In reply to]

I thought I had fixed my AV issues 5 mins ago. I altered my VDPAU HQ
playback profile to use all 4 cpu cores. My AV sync went from 2.5+-0.5
to 0.1+-0.5.
As soon as I clicked reply on this email it shot back up to 2.7.
It seems to be fluctuating now. When it hits an add break it seems to
drop back to 0.1 and then when the program returns it creeps back up.

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jyavenard at gmail

Jul 3, 2012, 6:16 AM

Post #28 of 33 (1218 views)
Permalink
Re: 0.25 Major AV sync problems [In reply to]

Hi

On Tuesday, 3 July 2012, Glen wrote:

> I thought I had fixed my AV issues 5 mins ago. I altered my VDPAU HQ
> playback profile to use all 4 cpu cores. My AV sync went from 2.5+-0.5
> to 0.1+-0.5.
> As soon as I clicked reply on this email it shot back up to 2.7.
> It seems to be fluctuating now. When it hits an add break it seems to
> drop back to 0.1 and then when the program returns it creeps back up.
>
>
??

Why would think that changing the VDPAU profile to use more CPUs would have
a single effect ?? VDPAU is 100% GPU decode. CPU usage has no bearing on
it, it's not used!


glen.hawksworth at bigpond

Jul 3, 2012, 4:45 PM

Post #29 of 33 (1214 views)
Permalink
Re: 0.25 Major AV sync problems [In reply to]

On Tue, 2012-07-03 at 23:16 +1000, Jean-Yves Avenard wrote:
> Hi
>
> On Tuesday, 3 July 2012, Glen wrote:
> I thought I had fixed my AV issues 5 mins ago. I altered my
> VDPAU HQ
> playback profile to use all 4 cpu cores. My AV sync went from
> 2.5+-0.5
> to 0.1+-0.5.
> As soon as I clicked reply on this email it shot back up to
> 2.7.
> It seems to be fluctuating now. When it hits an add break it
> seems to
> drop back to 0.1 and then when the program returns it creeps
> back up.
>
>
>
> ??
>
>
> Why would think that changing the VDPAU profile to use more CPUs would
> have a single effect ?? VDPAU is 100% GPU decode. CPU usage has no
> bearing on it, it's not used!

Well that is what I thought, but for some reason the option is still
available so I thought I'd see what happens. As I said above I thought
it had had an effect because it was all of a sudden greatly reduced but
before I could type "I thought..." it was back to 2.7, it was purely a
coincidence. I changed it back to 1 and there was no change. It would
seem something is different about the video specs of the commercials and
the program to cause the AV delay to fluctuate in this manner.

PS: are there any other settings that are redundant in the VDPAU
profiles?

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jyavenard at gmail

Jul 3, 2012, 5:48 PM

Post #30 of 33 (1217 views)
Permalink
Re: 0.25 Major AV sync problems [In reply to]

On 4 July 2012 09:45, Glen <glen.hawksworth [at] bigpond> wrote:
> PS: are there any other settings that are redundant in the VDPAU
> profiles?

The video profile page is shared across all decoders... there's no
mechanism to hide some field according to the decoder being used
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glen.hawksworth at bigpond

Jul 4, 2012, 4:56 AM

Post #31 of 33 (1201 views)
Permalink
Re: 0.25 Major AV sync problems [In reply to]

On Wed, 2012-07-04 at 10:48 +1000, Jean-Yves Avenard wrote:
> On 4 July 2012 09:45, Glen <glen.hawksworth [at] bigpond> wrote:
> > PS: are there any other settings that are redundant in the VDPAU
> > profiles?
>
> The video profile page is shared across all decoders... there's no
> mechanism to hide some field according to the decoder being used

How do they do it in the Audio page? Certain audio devices grey-out
TrueHD, DTS, etc.

Anyway, regarding my question, ARE there any other redundant settings in
the VDPAU settings? Is it just the CPUs field that is redundant?

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peper03 at yahoo

Jul 5, 2012, 12:41 PM

Post #32 of 33 (1184 views)
Permalink
Re: 0.25 Major AV sync problems [In reply to]

On 19/06/12 06:24, Jean-Yves Avenard wrote:
>> I'll upload a sample when I can figure out where to upload it to. The things
>> I see are common across all DVB-T broadcasts in NZ. No difference if I
>> select AAC or AC3 audio on channels where this is possible. The problem
>> seems to be something to do with audio PTS so I guess it's independent of
>> codec type.
> it's bizarre that it's not something everyone would see
>

I get the feeling it has several causes (whether individually or together).

I just had another play around and found turning off 'Separate video
modes for GUI and TV playback' seemed to cure it. The resolution for
both GUI and Video output were both set to 1920x1080 with the frame rate
set to 'auto'. I'd originally turned this setting on to handle the one
or two US DVDs I have but I noticed that although I'm in PAL land, the
GUI had a tendency to end up refreshing at 60Hz, which causes the TV to
go black for a second or two whilst it re-syncs.

After turning it off and jumping backwards and forwards in a recording
that had been getting out of sync before, everything was fine. Then I
turned it back on again and tried explicitly setting the frame rate to
50Hz or 25Hz but that still gave me sync errors. After I turned it off
again, I was *still* getting sync errors.

Changing the deinterlace method from 'Temporal 2x' to 'Temporal 1x' also
fixed the problem (although it doesn't look quite as good).

Then I tried running nvidia-settings and explicitly set the refresh rate
to 'Auto'. Now I could set the deinterlace method back to 'Temporal 2x'
and not get sync errors.

I see the ticket (10797) has been closed and marked as fixed although I
don't think it *is* fixed. I think it may well be caused by several
conditions having to be present, but in one of several combinations.
You change one setting and think you've cured it and then something else
changes (perhaps due to restarting the system) and the problem is back
again.

Regardless of all the different settings, *something* is stopping the
audio and video getting into sync after a jump. They're in sync when
you first start playing and only get out of sync if you jump (whether
manually or because of a cut-point). If you pause playback for a few
seconds and then unpause it, they're back in sync again and stay that
way until the next jump so it can't just be a case of 'the hardware
isn't up to this deinterlace method' or 'the audio buffers are too low'
or whatever. If that were the case, the two streams should either
always be out of sync or possibly get progressively more out of sync.

I'll keep an eye on my system over the next few days.

Richard.
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peper03 at yahoo

Jul 23, 2012, 11:26 AM

Post #33 of 33 (1095 views)
Permalink
Re: 0.25 Major AV sync problems [In reply to]

On 05/07/12 21:41, Richard wrote:
> On 19/06/12 06:24, Jean-Yves Avenard wrote:
>>> I'll upload a sample when I can figure out where to upload it to.
>>> The things
>>> I see are common across all DVB-T broadcasts in NZ. No difference if I
>>> select AAC or AC3 audio on channels where this is possible. The problem
>>> seems to be something to do with audio PTS so I guess it's
>>> independent of
>>> codec type.
>> it's bizarre that it's not something everyone would see
>>
>
> I get the feeling it has several causes (whether individually or
> together).
>
> I just had another play around and found turning off 'Separate video
> modes for GUI and TV playback' seemed to cure it. The resolution for
> both GUI and Video output were both set to 1920x1080 with the frame
> rate set to 'auto'. I'd originally turned this setting on to handle
> the one or two US DVDs I have but I noticed that although I'm in PAL
> land, the GUI had a tendency to end up refreshing at 60Hz, which
> causes the TV to go black for a second or two whilst it re-syncs.
>
> After turning it off and jumping backwards and forwards in a recording
> that had been getting out of sync before, everything was fine. Then I
> turned it back on again and tried explicitly setting the frame rate to
> 50Hz or 25Hz but that still gave me sync errors. After I turned it
> off again, I was *still* getting sync errors.
>
> Changing the deinterlace method from 'Temporal 2x' to 'Temporal 1x'
> also fixed the problem (although it doesn't look quite as good).
>
> Then I tried running nvidia-settings and explicitly set the refresh
> rate to 'Auto'. Now I could set the deinterlace method back to
> 'Temporal 2x' and not get sync errors.
>
> I see the ticket (10797) has been closed and marked as fixed although
> I don't think it *is* fixed. I think it may well be caused by several
> conditions having to be present, but in one of several combinations.
> You change one setting and think you've cured it and then something
> else changes (perhaps due to restarting the system) and the problem is
> back again.
>
> Regardless of all the different settings, *something* is stopping the
> audio and video getting into sync after a jump. They're in sync when
> you first start playing and only get out of sync if you jump (whether
> manually or because of a cut-point). If you pause playback for a few
> seconds and then unpause it, they're back in sync again and stay that
> way until the next jump so it can't just be a case of 'the hardware
> isn't up to this deinterlace method' or 'the audio buffers are too
> low' or whatever. If that were the case, the two streams should
> either always be out of sync or possibly get progressively more out of
> sync.
>
> I'll keep an eye on my system over the next few days.

Ok, since I turned off 'Separate video modes for GUI and TV playback',
I've not had any sync problems. I don't believe this particular feature
is broken since even with it turned on, it's possible to get picture and
audio in sync (via pause) but it's certainly helping to get the stars in
alignment on my system so that the problem *can* occur.

Richard.
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