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0.25 seektables recording lengths..

 

 

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mythicalbeast at slingshot

May 18, 2012, 4:38 PM

Post #1 of 13 (1716 views)
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0.25 seektables recording lengths..

Anyone else notice that with 0.25+fixes all the old TVNZ recordings
needed their seek-tables rebuilt ?

Thanks,
Brett


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dmoo1790 at ihug

May 19, 2012, 12:41 AM

Post #2 of 13 (1660 views)
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Re: 0.25 seektables recording lengths.. [In reply to]

On 19/05/2012, at 11:38 AM, Brett <mythicalbeast [at] slingshot> wrote:

> Anyone else notice that with 0.25+fixes all the old TVNZ recordings
> needed their seek-tables rebuilt ?
>
> Thanks,
> Brett
>
>
No. In fact I have checked several old TV1 recordings and they are good except that the duration is wrong. The seek tables are fine because seeking works ok. The incorrect duration is not due to seek table errors.
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mythicalbeast at slingshot

May 19, 2012, 3:26 AM

Post #3 of 13 (1653 views)
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Re: 0.25 seektables recording lengths.. [In reply to]

On Sat, 2012-05-19 at 19:41 +1200, David Moore wrote:
> On 19/05/2012, at 11:38 AM, Brett <mythicalbeast [at] slingshot> wrote:
>
> > Anyone else notice that with 0.25+fixes all the old TVNZ recordings
> > needed their seek-tables rebuilt ?
> >
> > Thanks,
> > Brett
> >
> >
> No. In fact I have checked several old TV1 recordings and they are good except that the duration is wrong. The seek tables are fine because seeking works ok. The incorrect duration is not due to seek table errors.
> _______________________________________________
I never said the seek tables were bad...just needed to be rebuilt (to
fix recording lengths implied by subject)
And I don't think that just because you can seek in the recording means
they are okay/correct.

IMO It is safer to use mythcommflag --rebuild --file & easy for a novice
to make a script from ls -m1 etc.

Most of my TVNZ recordings are off tvnz7 so they process at 6000fps.

So why does this only affect TVNZ multiplex ?

Brett



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dmoo1790 at ihug

May 19, 2012, 4:11 AM

Post #4 of 13 (1660 views)
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Re: 0.25 seektables recording lengths.. [In reply to]

On Sat, 19 May 2012 22:26:44 +1200, Brett <mythicalbeast [at] slingshot>
wrote:
> On Sat, 2012-05-19 at 19:41 +1200, David Moore wrote:
>> On 19/05/2012, at 11:38 AM, Brett <mythicalbeast [at] slingshot> wrote:
>>
>> > Anyone else notice that with 0.25+fixes all the old TVNZ recordings
>> > needed their seek-tables rebuilt ?
>> >
>> > Thanks,
>> > Brett
>> >
>> >
>> No. In fact I have checked several old TV1 recordings and they are good
>> except that the duration is wrong. The seek tables are fine because
>> seeking works ok. The incorrect duration is not due to seek table
errors.
>> _______________________________________________
> I never said the seek tables were bad...just needed to be rebuilt (to
> fix recording lengths implied by subject)
> And I don't think that just because you can seek in the recording means
> they are okay/correct.
>
> IMO It is safer to use mythcommflag --rebuild --file & easy for a novice
> to make a script from ls -m1 etc.
>
> Most of my TVNZ recordings are off tvnz7 so they process at 6000fps.
>
> So why does this only affect TVNZ multiplex ?
>
> Brett
>
>
My bad. I'll pay more attention to the subject next time.

I do believe the seek tables are ok or at least as ok as they were before
upgrading. Why would the upgrade trash the tables? They're just an index of
key frames vs file offsets which would only change if the files changed.

I suspect TVNZ is/was doing something not quite standard with timing which
may upset myth. As an example I found that mythcommflag did not correctly
rebuild seek tables in the past. I had to fix some rebuilds by dividing, if
memory serves me correctly, the frame number by two. Something like that
anyway. It was a while ago. :)

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paulgir at gmail

May 19, 2012, 12:50 PM

Post #5 of 13 (1657 views)
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Re: 0.25 seektables recording lengths.. [In reply to]

On Sat, 19 May 2012 11:38:37 +1200, Brett <mythicalbeast [at] slingshot>
wrote:

> Anyone else notice that with 0.25+fixes all the old TVNZ recordings
> needed their seek-tables rebuilt ?
>
> Thanks,
> Brett
>
>
> _______________________________________________
> mythtvnz mailing list
> mythtvnz [at] lists
> http://lists.ourshack.com/mailman/listinfo/mythtvnz
> Archives http://www.gossamer-threads.com/lists/mythtv/mythtvnz/
Yes,I have noticed that on recordings made before the upgrade and on some
recordings made after
the upgrade.It is still occurring on new recordings.

-Paul

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paulgir at gmail

May 19, 2012, 12:52 PM

Post #6 of 13 (1655 views)
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Re: 0.25 seektables recording lengths.. [In reply to]

On Sat, 19 May 2012 19:41:01 +1200, David Moore <dmoo1790 [at] ihug>
wrote:

> On 19/05/2012, at 11:38 AM, Brett <mythicalbeast [at] slingshot> wrote:
>
>> Anyone else notice that with 0.25+fixes all the old TVNZ recordings
>> needed their seek-tables rebuilt ?
>>
>> Thanks,
>> Brett
>>
>>
> No. In fact I have checked several old TV1 recordings and they are good
> except that the duration is wrong. The seek tables are fine because
> seeking works ok. The incorrect duration is not due to seek table errors.
> _______________________________________________
> mythtvnz mailing list
> mythtvnz [at] lists
> http://lists.ourshack.com/mailman/listinfo/mythtvnz
> Archives http://www.gossamer-threads.com/lists/mythtv/mythtvnz/
Sorry I misread the question,the problem I am seeing is with the
duration,too.

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mythicalbeast at slingshot

May 20, 2012, 3:14 AM

Post #7 of 13 (1647 views)
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Re: 0.25 seektables recording lengths.. [In reply to]

> Sorry I misread the question,the problem I am seeing is with the
> duration,too.
>
My bad I should said rebuilt seektables to fix duration.

Are you still getting recordings with incorrect duration?
Any pattern to the source multiplex ?



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paulgir at gmail

May 20, 2012, 4:01 AM

Post #8 of 13 (1650 views)
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Re: 0.25 seektables recording lengths.. [In reply to]

On Sun, 20 May 2012 22:14:15 +1200, Brett <mythicalbeast [at] slingshot>
wrote:

>
>> Sorry I misread the question,the problem I am seeing is with the
>> duration,too.
>>
> My bad I should said rebuilt seektables to fix duration.
>
> Are you still getting recordings with incorrect duration?
> Any pattern to the source multiplex ?
>
>
>
I am still getting duration errors and it does appear to be source related,
but I will have to have a closer look to confirm this.
To be honest,it hasn't bothered me much.

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dmoo1790 at ihug

May 20, 2012, 7:47 PM

Post #9 of 13 (1644 views)
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Re: 0.25 seektables recording lengths.. [In reply to]

On 20/05/12 22:14, Brett wrote:
>
>> Sorry I misread the question,the problem I am seeing is with the
>> duration,too.
>>
> My bad I should said rebuilt seektables to fix duration.
>
> Are you still getting recordings with incorrect duration?
> Any pattern to the source multiplex ?
>

Damn. It seems there are multiple issues related, I think, to timing.
Here's what I'm seeing:

- Duration error. Seems to be on TVNZ only. Interestingly duration is
correct if viewed during recording.
- Seeking back to the start of the recording causes a glitch which takes
a second or two to clear. This is on all recordings, old and new after
0.25 upgrade.
- Audio/video sync drifts after a while. All recordings. Can be fixed by
pausing playback.
- Occasional very brief stutter in playback. All recordings.

My system is almost up to date with upgrades (myth and OS). Might be
time to raise the problems with myth devs.

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mythicalbeast at slingshot

May 20, 2012, 11:59 PM

Post #10 of 13 (1638 views)
Permalink
Re: 0.25 seektables recording lengths.. [In reply to]

> Damn. It seems there are multiple issues related, I think, to timing.
> Here's what I'm seeing:
>
> - Duration error. Seems to be on TVNZ only. Interestingly duration is
> correct if viewed during recording.
> - Seeking back to the start of the recording causes a glitch which takes
> a second or two to clear. This is on all recordings, old and new after
> 0.25 upgrade.
> - Audio/video sync drifts after a while. All recordings. Can be fixed by
> pausing playback.
> - Occasional very brief stutter in playback. All recordings.
>
> My system is almost up to date with upgrades (myth and OS). Might be
> time to raise the problems with myth devs.
>
I never used 0.25.
I'm running 0.25+fixes from git on lucid ..dvb-t freeview
I don't see any recording duration errors on TVNZ, my duration errors
were only on old recordings & fixed by mythcommflag --rebuild.
A/V sync is good.

Seeking back to beginning does cause 2-3 second hiccup..

Video playback is bad compared to 0.24+fixes, stuttering like cheap
digital handi-cam recording. 24p & i60 recordings seem to play okay (to
me).
This comparison was made by running 0.24+fixes & 0.25+fixes on the same
install/database etc.

I toyed with the idea of trying to reverse the, new to 0.25,p predictive
frame dropping/repeating/timing "feature" but can't understand how it
works.





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dmoo1790 at ihug

May 21, 2012, 1:09 AM

Post #11 of 13 (1638 views)
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Re: 0.25 seektables recording lengths.. [In reply to]

On 21/05/12 18:59, Brett wrote:
>
>> Damn. It seems there are multiple issues related, I think, to timing.
>> Here's what I'm seeing:
>>
>> - Duration error. Seems to be on TVNZ only. Interestingly duration is
>> correct if viewed during recording.
>> - Seeking back to the start of the recording causes a glitch which takes
>> a second or two to clear. This is on all recordings, old and new after
>> 0.25 upgrade.
>> - Audio/video sync drifts after a while. All recordings. Can be fixed by
>> pausing playback.
>> - Occasional very brief stutter in playback. All recordings.
>>
>> My system is almost up to date with upgrades (myth and OS). Might be
>> time to raise the problems with myth devs.
>>
> I never used 0.25.
> I'm running 0.25+fixes from git on lucid ..dvb-t freeview
> I don't see any recording duration errors on TVNZ, my duration errors
> were only on old recordings& fixed by mythcommflag --rebuild.
> A/V sync is good.
>
> Seeking back to beginning does cause 2-3 second hiccup..
>
> Video playback is bad compared to 0.24+fixes, stuttering like cheap
> digital handi-cam recording. 24p& i60 recordings seem to play okay (to
> me).
> This comparison was made by running 0.24+fixes& 0.25+fixes on the same
> install/database etc.
>
> I toyed with the idea of trying to reverse the, new to 0.25,p predictive
> frame dropping/repeating/timing "feature" but can't understand how it
> works.
>
To be more clear: I am also running 0.25+fixes from mythbuntu repo on
lucid. Also wrong duration is not consistent. Sometimes it is ok on
recent TVNZ recordings, sometimes not. Bizarre.

Where do you set up the predictive frame dropping/repeating/timing feature?

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dmoo1790 at ihug

May 21, 2012, 4:05 AM

Post #12 of 13 (1634 views)
Permalink
Re: 0.25 seektables recording lengths.. [In reply to]

On 21/05/12 20:09, David Moore wrote:
> On 21/05/12 18:59, Brett wrote:
>>
>>> Damn. It seems there are multiple issues related, I think, to timing.
>>> Here's what I'm seeing:
>>>
>>> - Duration error. Seems to be on TVNZ only. Interestingly duration is
>>> correct if viewed during recording.
>>> - Seeking back to the start of the recording causes a glitch which
>>> takes
>>> a second or two to clear. This is on all recordings, old and new after
>>> 0.25 upgrade.
>>> - Audio/video sync drifts after a while. All recordings. Can be
>>> fixed by
>>> pausing playback.
>>> - Occasional very brief stutter in playback. All recordings.
>>>
>>> My system is almost up to date with upgrades (myth and OS). Might be
>>> time to raise the problems with myth devs.
>>>
>> I never used 0.25.
>> I'm running 0.25+fixes from git on lucid ..dvb-t freeview
>> I don't see any recording duration errors on TVNZ, my duration errors
>> were only on old recordings& fixed by mythcommflag --rebuild.
>> A/V sync is good.
>>
>> Seeking back to beginning does cause 2-3 second hiccup..
>>
>> Video playback is bad compared to 0.24+fixes, stuttering like cheap
>> digital handi-cam recording. 24p& i60 recordings seem to play okay (to
>> me).
>> This comparison was made by running 0.24+fixes& 0.25+fixes on the same
>> install/database etc.
>>
>> I toyed with the idea of trying to reverse the, new to 0.25,p predictive
>> frame dropping/repeating/timing "feature" but can't understand how it
>> works.
>>
> To be more clear: I am also running 0.25+fixes from mythbuntu repo on
> lucid. Also wrong duration is not consistent. Sometimes it is ok on
> recent TVNZ recordings, sometimes not. Bizarre.
>
> Where do you set up the predictive frame dropping/repeating/timing
> feature?
I believe TVNZ is at least part of the problem. I have extracted PCR
values from several TV1 recordings and have found two with PCR
discontinuities. The values suddenly reset to near zero and start
incrementing again. These files have playback glitches at the point of
the discontinuities. Also seems the discontinuity indicator bit is not
set in the MPEG TS packet Adaptation Field. If I understand the purpose
of this bit I believe it should be set to tell the decoder that a PCR
discontinuity has occurred so playback sync timing can be handled
properly. I'm rapidly losing respect for TVNZ technical people. I wonder
what else they're not doing right.

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paulgir at gmail

May 21, 2012, 12:04 PM

Post #13 of 13 (1625 views)
Permalink
Re: 0.25 seektables recording lengths.. [In reply to]

On Mon, 21 May 2012 14:47:44 +1200, David Moore <dmoo1790 [at] ihug>
wrote:

> On 20/05/12 22:14, Brett wrote:
>>
>>> Sorry I misread the question,the problem I am seeing is with the
>>> duration,too.
>>>
>> My bad I should said rebuilt seektables to fix duration.
>>
>> Are you still getting recordings with incorrect duration?
>> Any pattern to the source multiplex ?
>>
>
> Damn. It seems there are multiple issues related, I think, to timing.
> Here's what I'm seeing:
>
> - Duration error. Seems to be on TVNZ only. Interestingly duration is
> correct if viewed during recording.
> - Seeking back to the start of the recording causes a glitch which takes
> a second or two to clear. This is on all recordings, old and new after
> 0.25 upgrade.
> - Audio/video sync drifts after a while. All recordings. Can be fixed by
> pausing playback.
> - Occasional very brief stutter in playback. All recordings.
>
> My system is almost up to date with upgrades (myth and OS). Might be
> time to raise the problems with myth devs.
>

I'm only seeing problems on TVNZ channels,too

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