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720p HD content from WPVI in Philly periodic a/v sync issues

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wpoland at gmail

Dec 10, 2009, 7:20 PM

Post #1 of 42 (5461 views)
Permalink

720p HD content from WPVI in Philly periodic a/v sync issues

for the past couple of months anything I record from WPVI in Philadelphia
(delivered via clear qam from Verizon FIOS in Wilmington, DE), has had
playback problems where the video and audio fall out of sync, and myth then
speeds up the video and/or drops frames for a second or 2 to catch up. I've
read the list and seen other threads describing a similar phenomenon,
including being isolated to one channel. All other 720p and 1080 recordings
are playing back fine. I've yet to find a solution though, and don't have
much hair left to pull out.

I have 2 front-ends (with a remote backend) and I'm experiencing the same
thing on both. I've tried forcing the recording with both my pci-tuner, and
my HD Homerun, but no difference.

I put a small piece of log from -v playback up on pastebin:
http://pastebin.com/f1b8af467

Any pointers or suggestions... thanks!

gallatin at cs

Dec 11, 2009, 7:54 AM

Post #2 of 42 (5342 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

Byron Poland [wpoland [at] gmail] wrote:
> for the past couple of months anything I record from WPVI in Philadelphia
> (delivered via clear qam from Verizon FIOS in Wilmington, DE), has had
> playback problems where the video and audio fall out of sync, and myth then
> speeds up the video and/or drops frames for a second or 2 to catch up. I've
> read the list and seen other threads describing a similar phenomenon,
> including being isolated to one channel. All other 720p and 1080 recordings

<..>

I think this is the same problem as reported here, nearly
2 years ago:
http://www.gossamer-threads.com/lists/mythtv/dev/317736

As DanielK said "they are just using an encoding extension we don't
support very well.....I believe they are broadcasting about 40 fps on
a 60fps stream and marking some of the frames as repeatable"
If this is true, you may have luck complaining to the broadcaster like
the people in that thread did. Unfortunately, that's not much of an
option for me, as multiple broadcasters in my market have their
encoders setup this way. The only way I was able to play back these
sorts of streams was by using a non-MythTV front end (sigma based
SageTV HD100).

I'd love to come back to MythTV, and I'm eagerly looking forward to a
fix to this. I have a mythbox setup running trunk, and I'm happy to
test patches, make snippets of these streams available to the devs,
etc.

Drew
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

tralph11 at yahoo

Dec 11, 2009, 10:03 AM

Post #3 of 42 (5332 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

--- On Fri, 12/11/09, Andrew Gallatin <gallatin [at] cs> wrote:

> From: Andrew Gallatin <gallatin [at] cs>
> Subject: Re: [mythtv-users] 720p HD content from WPVI in Philly periodic a/v sync issues
> To: "Discussion about mythtv" <mythtv-users [at] mythtv>
> Date: Friday, December 11, 2009, 10:54 AM
> Byron Poland [wpoland [at] gmail]
> wrote:
> > for the past couple of months anything I record from
> WPVI in Philadelphia
> > (delivered via clear qam from Verizon FIOS in
> Wilmington, DE), has had
> > playback problems where the video and audio fall out
> of sync, and myth then
> > speeds up the video and/or drops frames for a second
> or 2 to catch up. I've
> > read the list and seen other threads describing a
> similar phenomenon,
> > including being isolated to one channel. All
> other 720p and 1080 recordings
>
> <..>
>
> I think this is the same problem as reported here, nearly
> 2 years ago:
> http://www.gossamer-threads.com/lists/mythtv/dev/317736
>
> As DanielK said "they are just using an encoding extension
> we don't
> support very well.....I believe they are broadcasting about
> 40 fps on
> a 60fps stream and marking some of the frames as
> repeatable"
> If this is true, you may have luck complaining to the
> broadcaster like
> the people in that thread did. Unfortunately, that's
> not much of an
> option for me, as multiple broadcasters in my market have
> their
> encoders setup this way. The only way I was able to
> play back these
> sorts of streams was by using a non-MythTV front end (sigma
> based
> SageTV HD100).
>
> I'd love to come back to MythTV, and I'm eagerly looking
> forward to a
> fix to this. I have a mythbox setup running trunk,
> and I'm happy to
> test patches, make snippets of these streams available to
> the devs,
> etc.
>
> Drew

I've got a couple patches attached that might help. They are both based on 0.22-fixes but the latest av-sync changes to trunk will probably break the repeat_pict patch. Let us know if these help at all.

Also, if you provide samples then I'll have a look.

--
Taylor

Attachments:

mythtv_repeat_pict_v2.diff (1.78 KB)

mythtv_vsync_rm_delay_restriction.diff (0.50 KB)

gallatin at cs

Dec 11, 2009, 12:29 PM

Post #4 of 42 (5325 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

Taylor Ralph [tralph11 [at] yahoo] wrote:
> --- On Fri, 12/11/09, Andrew Gallatin <gallatin [at] cs> wrote:
>
> > From: Andrew Gallatin <gallatin [at] cs>
> > Subject: Re: [mythtv-users] 720p HD content from WPVI in Philly periodic a/v sync issues
> > To: "Discussion about mythtv" <mythtv-users [at] mythtv>
> > Date: Friday, December 11, 2009, 10:54 AM
> > Byron Poland [wpoland [at] gmail]
> > wrote:
> > > for the past couple of months anything I record from
> > WPVI in Philadelphia
> > > (delivered via clear qam from Verizon FIOS in
> > Wilmington, DE), has had
> > > playback problems where the video and audio fall out
> > of sync, and myth then
> > > speeds up the video and/or drops frames for a second
> > or 2 to catch up.? I've
> > > read the list and seen other threads describing a
> > similar phenomenon,
> > > including being isolated to one channel.? All
> > other 720p and 1080 recordings
> >
> > <..>
> >
> > I think this is the same problem as reported here, nearly
> > 2 years ago:
> > ? http://www.gossamer-threads.com/lists/mythtv/dev/317736
> >
> > As DanielK said "they are just using an encoding extension
> > we don't
> > support very well.....I believe they are broadcasting about
> > 40 fps on
> > a 60fps stream and marking some of the frames as
> > repeatable"
> > If this is true, you may have luck complaining to the
> > broadcaster like
> > the people in that thread did.? Unfortunately, that's
> > not much of an
> > option for me, as multiple broadcasters in my market have
> > their
> > encoders setup this way.? The only way I was able to
> > play back these
> > sorts of streams was by using a non-MythTV front end (sigma
> > based
> > SageTV HD100).
> >
> > I'd love to come back to MythTV, and I'm eagerly looking
> > forward to a
> > fix to this.? I have a mythbox setup running trunk,
> > and I'm happy to
> > test patches, make snippets of these streams available to
> > the devs,
> > etc.
> >
> > Drew
>
> I've got a couple patches attached that might help. They are both based on 0.22-fixes but the latest av-sync changes to trunk will probably break the repeat_pict patch. Let us know if these help at all.

I checked out a fresh 22-fixes and applied the patch.
Unfortunately, it actually seemed to make things worse.
I've attached -v playback from a problematic file.
This is using an Ion 330 using VDPAU, displaying to
a 1080p panel.

> Also, if you provide samples then I'll have a look.

I'll email you a link to a snippet off-list.

Thanks,

Drew

Attachments:

myth-log.gz (12.2 KB)

wpoland at gmail

Dec 11, 2009, 12:49 PM

Post #5 of 42 (5332 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

On Fri, Dec 11, 2009 at 1:03 PM, Taylor Ralph <tralph11 [at] yahoo> wrote:

> --- On Fri, 12/11/09, Andrew Gallatin <gallatin [at] cs> wrote:
>
> > From: Andrew Gallatin <gallatin [at] cs>
> > Subject: Re: [mythtv-users] 720p HD content from WPVI in Philly periodic
> a/v sync issues
> > To: "Discussion about mythtv" <mythtv-users [at] mythtv>
> > Date: Friday, December 11, 2009, 10:54 AM
> > Byron Poland [wpoland [at] gmail]
> > wrote:
> > > for the past couple of months anything I record from
> > WPVI in Philadelphia
> > > (delivered via clear qam from Verizon FIOS in
> > Wilmington, DE), has had
> > > playback problems where the video and audio fall out
> > of sync, and myth then
> > > speeds up the video and/or drops frames for a second
> > or 2 to catch up. I've
> > > read the list and seen other threads describing a
> > similar phenomenon,
> > > including being isolated to one channel. All
> > other 720p and 1080 recordings
> >
> > <..>
> >
> > I think this is the same problem as reported here, nearly
> > 2 years ago:
> > http://www.gossamer-threads.com/lists/mythtv/dev/317736
> >
> > As DanielK said "they are just using an encoding extension
> > we don't
> > support very well.....I believe they are broadcasting about
> > 40 fps on
> > a 60fps stream and marking some of the frames as
> > repeatable"
> > If this is true, you may have luck complaining to the
> > broadcaster like
> > the people in that thread did. Unfortunately, that's
> > not much of an
> > option for me, as multiple broadcasters in my market have
> > their
> > encoders setup this way. The only way I was able to
> > play back these
> > sorts of streams was by using a non-MythTV front end (sigma
> > based
> > SageTV HD100).
> >
> > I'd love to come back to MythTV, and I'm eagerly looking
> > forward to a
> > fix to this. I have a mythbox setup running trunk,
> > and I'm happy to
> > test patches, make snippets of these streams available to
> > the devs,
> > etc.
> >
> > Drew
>
> I've got a couple patches attached that might help. They are both based on
> 0.22-fixes but the latest av-sync changes to trunk will probably break the
> repeat_pict patch. Let us know if these help at all.
>
> Also, if you provide samples then I'll have a look.
>
> --
> Taylor
>
>
I don't know if I will get a chance to build with the patches for a few
days. I'll try and get a snippet of a sample file out at in the next day or
so though Thanks!

gallatin at cs

Dec 11, 2009, 1:04 PM

Post #6 of 42 (5329 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

Andrew Gallatin [gallatin [at] cs] wrote:
> Taylor Ralph [tralph11 [at] yahoo] wrote:
> > --- On Fri, 12/11/09, Andrew Gallatin <gallatin [at] cs> wrote:
> >
> > > From: Andrew Gallatin <gallatin [at] cs>
> > > Subject: Re: [mythtv-users] 720p HD content from WPVI in Philly periodic a/v sync issues
> > > To: "Discussion about mythtv" <mythtv-users [at] mythtv>
> > > Date: Friday, December 11, 2009, 10:54 AM
> > > Byron Poland [wpoland [at] gmail]
> > > wrote:
> > > > for the past couple of months anything I record from
> > > WPVI in Philadelphia
> > > > (delivered via clear qam from Verizon FIOS in
> > > Wilmington, DE), has had
> > > > playback problems where the video and audio fall out
> > > of sync, and myth then
> > > > speeds up the video and/or drops frames for a second
> > > or 2 to catch up.? I've
> > > > read the list and seen other threads describing a
> > > similar phenomenon,
> > > > including being isolated to one channel.? All
> > > other 720p and 1080 recordings
> > >
> > > <..>
> > >
> > > I think this is the same problem as reported here, nearly
> > > 2 years ago:
> > > ? http://www.gossamer-threads.com/lists/mythtv/dev/317736
> > >
> > > As DanielK said "they are just using an encoding extension
> > > we don't
> > > support very well.....I believe they are broadcasting about
> > > 40 fps on
> > > a 60fps stream and marking some of the frames as
> > > repeatable"
> > > If this is true, you may have luck complaining to the
> > > broadcaster like
> > > the people in that thread did.? Unfortunately, that's
> > > not much of an
> > > option for me, as multiple broadcasters in my market have
> > > their
> > > encoders setup this way.? The only way I was able to
> > > play back these
> > > sorts of streams was by using a non-MythTV front end (sigma
> > > based
> > > SageTV HD100).
> > >
> > > I'd love to come back to MythTV, and I'm eagerly looking
> > > forward to a
> > > fix to this.? I have a mythbox setup running trunk,
> > > and I'm happy to
> > > test patches, make snippets of these streams available to
> > > the devs,
> > > etc.
> > >
> > > Drew
> >
> > I've got a couple patches attached that might help. They are both based on 0.22-fixes but the latest av-sync changes to trunk will probably break the repeat_pict patch. Let us know if these help at all.
>
> I checked out a fresh 22-fixes and applied the patch.
> Unfortunately, it actually seemed to make things worse.
> I've attached -v playback from a problematic file.
> This is using an Ion 330 using VDPAU, displaying to
> a 1080p panel.
>

I have a very high-level understanding of what's going on here, so I
apologize if my assumptions are incorrect, but here is my theory: The
broadcaster is using the mpeg2 video repeat flags to save bandwidth.
So he's broadcasting, on average, about 54fps and marking about 10% of
them repeatable, which brings the frame rate up to 60fps. But
mythtv's mpeg2 decoder is not counting these repeats, and the a/v sync
code thinks the frame rate is all messed up. From what I can tell,
your patch adds a delay based on the repeat flags. Rather than adding
delays, wouldn't it be simpler to use the actual decoded frame count
(or rate, or whatever the code uses)? Also, is the video portion of
MythTV honoring the repeat flag? Does it matter than I'm using VDPAU?

Again, sorry if I'm being dumb, and thanks for the interest!!

Drew
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

tralph11 at yahoo

Dec 11, 2009, 1:44 PM

Post #7 of 42 (5332 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

--- On Fri, 12/11/09, Andrew Gallatin <gallatin [at] cs> wrote:

> > I checked out a fresh 22-fixes and applied the patch.
> > Unfortunately, it actually seemed to make things
> worse.
> > I've attached -v playback from a problematic file.
> > This is using an Ion 330 using VDPAU, displaying to
> > a 1080p panel.
> >
>
> I have a very high-level understanding of what's going on
> here, so I
> apologize if my assumptions are incorrect, but here is my
> theory: The
> broadcaster is using the mpeg2 video repeat flags to save
> bandwidth.
> So he's broadcasting, on average, about 54fps and marking
> about 10% of
> them repeatable, which brings the frame rate up to
> 60fps. But
> mythtv's mpeg2 decoder is not counting these repeats, and
> the a/v sync
> code thinks the frame rate is all messed up.
> From what I can tell,
> your patch adds a delay based on the repeat flags.
> Rather than adding delays, wouldn't it be simpler
> to use the actual decoded
> frame count (or rate, or whatever the code uses)?

The total video frame count is irrelevant to syncing the audio with video. The av-sync code has to compare the current audio timecode with the current video timecode of the frame being displayed. It then needs to make adjustments as necessary. If they are close enough then the added video frame delay is simply one frame interval (1/fps). If they are far enough apart then other measures are taken depending on if the audio is ahead or behind the video. This involves reducing or adding delay or for extreme cases skipping (dropping) frames or extending the frame interval.

The patch I provided simply adds video delay when a frame is to be repeated. It's odd that it made your video worse. Something else is then obviously wrong.

> Also, is the video portion of MythTV honoring the repeat flag?

That's what my patch was intended to do. The NVP player code controls the delays between displayed frames and my patch simply added additional delay when a video frame was flagged for repeating.

> I'm using VDPAU?

I use VDPAU also and it should not matter.

>
> Again, sorry if I'm being dumb, and thanks for the
> interest!!
>

A couple of questions for you:

1. What vsync method are you using: BusyWait, OpenGL, DRM?
2. Are you by any chance using "video as timebase"?

I look forward to your samples.

--
Taylor

_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

wpoland at gmail

Dec 11, 2009, 1:51 PM

Post #8 of 42 (5329 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

On Fri, Dec 11, 2009 at 4:44 PM, Taylor Ralph <tralph11 [at] yahoo> wrote:

> --- On Fri, 12/11/09, Andrew Gallatin <gallatin [at] cs> wrote:
>
> > > I checked out a fresh 22-fixes and applied the patch.
> > > Unfortunately, it actually seemed to make things
> > worse.
> > > I've attached -v playback from a problematic file.
> > > This is using an Ion 330 using VDPAU, displaying to
> > > a 1080p panel.
> > >
> >
> > I have a very high-level understanding of what's going on
> > here, so I
> > apologize if my assumptions are incorrect, but here is my
> > theory: The
> > broadcaster is using the mpeg2 video repeat flags to save
> > bandwidth.
> > So he's broadcasting, on average, about 54fps and marking
> > about 10% of
> > them repeatable, which brings the frame rate up to
> > 60fps. But
> > mythtv's mpeg2 decoder is not counting these repeats, and
> > the a/v sync
> > code thinks the frame rate is all messed up.
> > From what I can tell,
> > your patch adds a delay based on the repeat flags.
> > Rather than adding delays, wouldn't it be simpler
> > to use the actual decoded
> > frame count (or rate, or whatever the code uses)?
>
> The total video frame count is irrelevant to syncing the audio with video.
> The av-sync code has to compare the current audio timecode with the current
> video timecode of the frame being displayed. It then needs to make
> adjustments as necessary. If they are close enough then the added video
> frame delay is simply one frame interval (1/fps). If they are far enough
> apart then other measures are taken depending on if the audio is ahead or
> behind the video. This involves reducing or adding delay or for extreme
> cases skipping (dropping) frames or extending the frame interval.
>
> The patch I provided simply adds video delay when a frame is to be
> repeated. It's odd that it made your video worse. Something else is then
> obviously wrong.
>
> > Also, is the video portion of MythTV honoring the repeat flag?
>
> That's what my patch was intended to do. The NVP player code controls the
> delays between displayed frames and my patch simply added additional delay
> when a video frame was flagged for repeating.
>
> > I'm using VDPAU?
>
> I use VDPAU also and it should not matter.
>
> >
> > Again, sorry if I'm being dumb, and thanks for the
> > interest!!
> >
>
> A couple of questions for you:
>
> 1. What vsync method are you using: BusyWait, OpenGL, DRM?
> 2. Are you by any chance using "video as timebase"?
>
> I look forward to your samples.
>
> --
> Taylor
>
>

Here's a ~2:15 second sample from WPVI. the last minute or so has the most
visible issues on my end (both my frontends - one a mac-mini intel graphics,
the other a dual core athlon with a 6000 series nvidia, so neither uses
VDAPU).

when there is dialog the problem is most visible, however I can see some
accelerated frames during some of the lip shots (when you can't see lips
moving, to really notice if things are out of sync).

http://dl.dropbox.com/u/2386241/sample.mpg

-Byron

tralph11 at yahoo

Dec 12, 2009, 12:02 AM

Post #9 of 42 (5298 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

--- On Fri, 12/11/09, Byron Poland <wpoland [at] gmail> wrote:

> Here's a ~2:15 second sample from WPVI. the last
> minute or so has the most visible issues on my end (both my
> frontends - one a mac-mini intel graphics, the other a dual
> core athlon with a 6000 series nvidia, so neither uses
> VDAPU).
>
>
>
> when there is dialog the problem is most visible, however I
> can see some accelerated frames during some of the lip shots
> (when you can't see lips moving, to really notice if
> things are out of sync).
>
> http://dl.dropbox.com/u/2386241/sample.mpg
>

Byron,

I've attached a new patch that fixes playback for your recording. Please apply to a clean 0.22-fixes. The new patch includes support for repeat_pict and removes some very suspect code.

Please let us know the results.

--
Taylor

Attachments:

mythtv_repeat_pict_v3.diff (3.32 KB)

rbonafied at gmail

Dec 12, 2009, 6:26 PM

Post #10 of 42 (5259 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

Byron Poland wrote:
> for the past couple of months anything I record from WPVI in
> Philadelphia (delivered via clear qam from Verizon FIOS in Wilmington,
> DE), has had playback problems where the video and audio fall out of
> sync, and myth then speeds up the video and/or drops frames for a second
> or 2 to catch up. I've read the list and seen other threads describing
> a similar phenomenon, including being isolated to one channel. All
> other 720p and 1080 recordings are playing back fine. I've yet to find
> a solution though, and don't have much hair left to pull out.
>
> I have 2 front-ends (with a remote backend) and I'm experiencing the
> same thing on both. I've tried forcing the recording with both my
> pci-tuner, and my HD Homerun, but no difference.
>
> I put a small piece of log from -v playback up on pastebin:
> http://pastebin.com/f1b8af467
>
> Any pointers or suggestions... thanks!
>
>
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Hi Byron,

I have comcast in Wilm. I'll set up a few recordings with my HDHR and
see if I see the same problem. I'm curious if it's isolated to fios.
I'm using 0.21-fixes. Any shows in particular I should pay attention to?

Regards,
R
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

wpoland at gmail

Dec 12, 2009, 8:48 PM

Post #11 of 42 (5254 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

On Sat, Dec 12, 2009 at 9:26 PM, Rick <rbonafied [at] gmail> wrote:
>
> Byron Poland wrote:
>>
>> for the past couple of months anything I record from WPVI in Philadelphia (delivered via clear qam from Verizon FIOS in Wilmington, DE), has had playback problems where the video and audio fall out of sync, and myth then speeds up the video and/or drops frames for a second or 2 to catch up. I've read the list and seen other threads describing a similar phenomenon, including being isolated to one channel. All other 720p and 1080 recordings are playing back fine. I've yet to find a solution though, and don't have much hair left to pull out.
>>
>> I have 2 front-ends (with a remote backend) and I'm experiencing the same thing on both. I've tried forcing the recording with both my pci-tuner, and my HD Homerun, but no difference.
>>
>> I put a small piece of log from -v playback up on pastebin: http://pastebin.com/f1b8af467
>>
>> Any pointers or suggestions... thanks!
>>
>>
>>
>>
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> mythtv-users mailing list
>> mythtv-users [at] mythtv
>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
> Hi Byron,
>
> I have comcast in Wilm. I'll set up a few recordings with my HDHR and see if I see the same problem. I'm curious if it's isolated to fios. I'm using 0.21-fixes. Any shows in particular I should pay attention to?
>
> Regards,
> R

Hi, I notice it on any new primetime programming I record off abc
(WPVI). I have an OTA antenna at my parent's house who live a few
miles away that I will try as well.

Thanks for looking into it from the comcast end.
_______________________________________________
mythtv-users mailing list
mythtv-users [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

wpoland at gmail

Dec 12, 2009, 8:58 PM

Post #12 of 42 (5252 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

On Sat, Dec 12, 2009 at 3:02 AM, Taylor Ralph <tralph11 [at] yahoo> wrote:
> --- On Fri, 12/11/09, Byron Poland <wpoland [at] gmail> wrote:
>
>> Here's a ~2:15 second sample from WPVI. the last
>> minute or so has the most visible issues on my end (both my
>> frontends - one a mac-mini intel graphics, the other a dual
>> core athlon with a 6000 series nvidia, so neither uses
>> VDAPU).
>>
>>
>>
>> when there is dialog the problem is most visible, however I
>> can see some accelerated frames during some of the lip shots
>> (when you can't see lips moving, to really notice if
>> things are out of sync).
>>
>> http://dl.dropbox.com/u/2386241/sample.mpg
>>
>
> Byron,
>
> I've attached a new patch that fixes playback for your recording. Please apply to a clean 0.22-fixes. The new patch includes support for repeat_pict and removes some very suspect code.
>
> Please let us know the results.
>
> --
> Taylor

Taylor, Thanks for the patch. I gave it a try, and still see messed
up a/v sync with the sample I provide.

Here's a log, I started by trying the original recording I used to
create the sample, and then tried the sample.

http://pastebin.com/f4489d5c7

Thanks.
-Byron
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tralph11 at yahoo

Dec 13, 2009, 9:38 AM

Post #13 of 42 (5228 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

--- On Sat, 12/12/09, Byron Poland <wpoland [at] gmail> wrote:

> From: Byron Poland <wpoland [at] gmail>
> Subject: Re: [mythtv-users] 720p HD content from WPVI in Philly periodic a/v sync issues
> To: "Discussion about mythtv" <mythtv-users [at] mythtv>
> Date: Saturday, December 12, 2009, 11:58 PM
> On Sat, Dec 12, 2009 at 3:02 AM,
> Taylor Ralph <tralph11 [at] yahoo>
> wrote:
> > --- On Fri, 12/11/09, Byron Poland <wpoland [at] gmail>
> wrote:
> >
> >> Here's a ~2:15 second sample from WPVI. the
> last
> >> minute or so has the most visible issues on my end
> (both my
> >> frontends - one a mac-mini intel graphics, the
> other a dual
> >> core athlon with a 6000 series nvidia, so neither
> uses
> >> VDAPU).
> >>
> >>
> >>
> >> when there is dialog the problem is most visible,
> however I
> >> can see some accelerated frames during some of the
> lip shots
> >> (when you can't see lips moving, to really notice
> if
> >> things are out of sync).
> >>
> >> http://dl.dropbox.com/u/2386241/sample.mpg
> >>
> >
> > Byron,
> >
> > I've attached a new patch that fixes playback for your
> recording. Please apply to a clean 0.22-fixes. The new patch
> includes support for repeat_pict and removes some very
> suspect code.
> >
> > Please let us know the results.
> >
> > --
> > Taylor
>
>
> Taylor, Thanks for the patch. I gave it a try, and
> still see messed
> up a/v sync with the sample I provide.
>
> Here's a log, I started by trying the original recording I
> used to
> create the sample, and then tried the sample.
>
> http://pastebin.com/f4489d5c7
>

Before the patch your sample played horribly on my system and with the patch it's near perfect. So even though you still see some a/v sync problem did the patch improve playback any? I did see one very brief instance where the timecodes went a little wacky but it was extremely brief and recovered properly.

Could you please provide another log with -v playback,timestamp?

Thanks.

--
Taylor

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tralph11 at yahoo

Dec 13, 2009, 10:22 AM

Post #14 of 42 (5217 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

>
> Before the patch your sample played horribly on my system
> and with the patch it's near perfect. So even though you
> still see some a/v sync problem did the patch improve
> playback any? I did see one very brief instance where the
> timecodes went a little wacky but it was extremely brief and
> recovered properly.
>
> Could you please provide another log with -v
> playback,timestamp?
>
> Thanks.
>

Byron,

One significant difference between your setup and my setup is that you are using the DRM vsync method. Could you try setting the return equal to false at the end of DRMVideoSync::TryInit in libs/libmythtv/vsync.cpp. This should cause you to use one of the other vsync methods. Please report your results and include logs with -v playback,timestamp.

Thanks.

--
Taylor

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tralph11 at yahoo

Dec 13, 2009, 10:57 AM

Post #15 of 42 (5217 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

>
> One significant difference between your setup and my setup
> is that you are using the DRM vsync method. Could you try
> setting the return equal to false at the end of
> DRMVideoSync::TryInit in libs/libmythtv/vsync.cpp. This
> should cause you to use one of the other vsync methods.
> Please report your results and include logs with -v
> playback,timestamp.
>

Byron,

BTW, wanted to make sure you also apply the latest patch when testing with DRM disabled. I've confirmed that the latest patch calculates the correct delays between frames when repeats occur. So I'm guessing that DRM may not be waiting the appropriate amount of time or something. This is why I need the timestamp information in your logs.

Thanks,

--
Taylor

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wpoland at gmail

Dec 13, 2009, 11:17 AM

Post #16 of 42 (5213 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

On Sun, Dec 13, 2009 at 1:57 PM, Taylor Ralph <tralph11 [at] yahoo> wrote:
>>
>> One significant difference between your setup and my setup
>> is that you are using the DRM vsync method. Could you try
>> setting the return equal to false at the end of
>> DRMVideoSync::TryInit in libs/libmythtv/vsync.cpp. This
>> should cause you to use one of the other vsync methods.
>> Please report your results and include logs with -v
>> playback,timestamp.
>>
>
> Byron,
>
> BTW, wanted to make sure you also apply the latest patch when testing with DRM disabled. I've confirmed that the latest patch calculates the correct delays between frames when repeats occur. So I'm guessing that DRM may not be waiting the appropriate amount of time or something. This is why I need the timestamp information in your logs.
>
> Thanks,
>
> --
> Taylor

Taylor,

these are all cases with the patch.

With the DRM timing, the sample playback is crap.
With openGL timing enabled via playback setup, it looks a little
better, but still a lot of issues.
With Usleep and wait timing (the result of changing the code you
suggested), playback looks great!

here are 3 log files for the case above. (on my dropbox as pastebin
was throwing an error)
http://dl.dropbox.com/u/2386241/wpvi-with-patch-DRM.log.gz
http://dl.dropbox.com/u/2386241/wpvi-with-patch-opengl.log.gz
http://dl.dropbox.com/u/2386241/wpvi-with-patch-Usleep.log.gz

Is there any way to disable the DRM timing method (or enable the
Usleep one) without modifying the code?

Are you going to submit this patch for possible inclusion upstream?
it makes unwatchable recordings watchable for me. I appreciate your
effort, and time.

Thanks
-Byron
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gallatin at cs

Dec 13, 2009, 11:36 AM

Post #17 of 42 (5216 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

Taylor Ralph [tralph11 [at] yahoo] wrote:
>
> I've attached a new patch that fixes playback for your recording. Please apply to a clean 0.22-fixes. The new patch includes support for repeat_pict and removes some very suspect code.
>
> Please let us know the results.

Awesome, this seems to fix the playback of my worst offender (ST:TNG
in 720p)! I can't wait to see how it does on our problematic 1080i
channels. I've set up some recordings for tonight.

Do you plan to submit this patch officially?

Thanks,

Drew
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tralph11 at yahoo

Dec 14, 2009, 3:15 PM

Post #18 of 42 (5154 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

>
> Is there any way to disable the DRM timing method (or
> enable the
> Usleep one) without modifying the code?
>

The only way to do this without modifying the code is use a video card that doesn't support DRM. :) Let's first try to get your video to work with DRM. It seems the vsync methods, DRM or OpenGL, which use the hardware retrace to reach the next trigger has issues. I've attached a new patch for you to try out.

>
> Are you going to submit this patch for possible inclusion
> upstream?
> it makes unwatchable recordings watchable for me. I
> appreciate your
> effort, and time.
>

Yes, I'll probably create a ticket in the next day or two.

Please let us know if the new patch helps at all when using DRM or OpenGL vsync.

--
Taylor

Attachments:

mythtv_repeat_pict_v5.diff (5.81 KB)

wpoland at gmail

Dec 14, 2009, 6:02 PM

Post #19 of 42 (5151 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

On Mon, Dec 14, 2009 at 6:15 PM, Taylor Ralph <tralph11 [at] yahoo> wrote:
>>
>> Is there any way to disable the DRM timing method (or
>> enable the
>> Usleep one) without modifying the code?
>>
>
> The only way to do this without modifying the code is use a video card that doesn't support DRM. :) Let's first try to get your video to work with DRM. It seems the vsync methods, DRM or OpenGL, which use the hardware retrace to reach the next trigger has issues. I've attached a new patch for you to try out.
>
>>
>> Are you going to submit this patch for possible inclusion
>> upstream?
>> it makes unwatchable recordings watchable for me. I
>> appreciate your
>> effort, and time.
>>
>
> Yes, I'll probably create a ticket in the next day or two.
>
> Please let us know if the new patch helps at all when using DRM or OpenGL vsync.
>
> --
> Taylor

This patch worked well with the sample recording on my system using
DRM vsync. I didn't notice any offensive a/v sync errors. Thought I
notices a couple ghost-like frames but I'm not sure.

Here's the log: http://dl.dropbox.com/u/2386241/patch-v5-DRM.log.gz

opengl vsync didn't seem to work on my mac-mini install, even when
enabled it defaulted to DRM. Previously it would run opengl vsync, as
all my testing as been on this machine. I'll definitely try to
compile on my other frontend, with different hardware and report back
with an update as to whether opengl vsync is working.

Thanks
-Byron
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tralph11 at yahoo

Dec 15, 2009, 1:19 PM

Post #20 of 42 (5078 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

>
> This patch worked well with the sample recording on my
> system using
> DRM vsync. I didn't notice any offensive a/v sync
> errors. Thought I
> notices a couple ghost-like frames but I'm not sure.
>
> Here's the log: http://dl.dropbox.com/u/2386241/patch-v5-DRM.log.gz
>

Thanks for all your testing. I checked youf logs and it does look better. I did see one instance where 2 frames were dropped.

> opengl vsync didn't seem to work on my mac-mini install,
> even when
> enabled it defaulted to DRM. Previously it would run
> opengl vsync, as
> all my testing as been on this machine. I'll
> definitely try to
> compile on my other frontend, with different hardware and
> report back
> with an update as to whether opengl vsync is working.
>

I've attached a new patch with a slight change for DRM and OpenGL vsync and some additional debug. Please try again and let us know your results.

Thanks.

--
Taylor

Attachments:

mythtv_repeat_pict_v6.diff (6.87 KB)

wpoland at gmail

Dec 15, 2009, 3:40 PM

Post #21 of 42 (5080 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

n Tue, Dec 15, 2009 at 4:19 PM, Taylor Ralph <tralph11 [at] yahoo> wrote:
>>
>> This patch worked well with the sample recording on my
>> system using
>> DRM vsync. I didn't notice any offensive a/v sync
>> errors. Thought I
>> notices a couple ghost-like frames but I'm not sure.
>>
>> Here's the log: http://dl.dropbox.com/u/2386241/patch-v5-DRM.log.gz
>>
>
> Thanks for all your testing. I checked youf logs and it does look better. I did see one instance where 2 frames were dropped.
>
>> opengl vsync didn't seem to work on my mac-mini install,
>> even when
>> enabled it defaulted to DRM. Previously it would run
>> opengl vsync, as
>> all my testing as been on this machine. I'll
>> definitely try to
>> compile on my other frontend, with different hardware and
>> report back
>> with an update as to whether opengl vsync is working.
>>
>
> I've attached a new patch with a slight change for DRM and OpenGL vsync and some additional debug. Please try again and let us know your results.
>
> Thanks.
>
> --
> Taylor

Taylor,

Thanks. I compiled this patch on both my frontends. my mac-mini
which seems to only work with DRM vsync played the sample I've been
using for testing well. Again I noticed some ghosting of frames (my
terminology) most obvious place in the sample was at about :50-:55
seconds into the sample when they are walking up the stairs.

Here's the log file for that playback:
http://dl.dropbox.com/u/2386241/patch-v6-DRM.log.gz

On my other frontend which is a little beefier than the mini, and has
an integrated nvidia card, opengl vsync worked fine, and the sample
played back flawlessly.

Here's the log file for that playback:
http://dl.dropbox.com/u/2386241/patch-v6-opengl.log.gz

thanks again.

-Byron
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tralph11 at yahoo

Dec 15, 2009, 4:12 PM

Post #22 of 42 (5073 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

>
> Thanks for all your testing. I checked youf logs and it
> does look better. I did see one instance where 2 frames were
> dropped.
>

I just noticed why a couple frames got dropped. You are running your X display frequency at 59.94 fps and playing a video at 60 fps. When repeated pictures occur it allows the video to catch up but in your video it has some long periods where there are no repeated pictures and when the video gets far enough behind it drops frames to catch up. If your display's refreshrate is higher than the frame rate then it shouldn't need to drop frames but occasionally extended the trigger. Your latest log with DRM indicate that the most recent patch is working correctly.

Please try a higher display frequency to determine if the occasional dropped frames are eliminated. Other than this I think you should be good to go.

--
Taylor

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wpoland at gmail

Dec 15, 2009, 6:07 PM

Post #23 of 42 (5060 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

On Tue, Dec 15, 2009 at 7:12 PM, Taylor Ralph <tralph11 [at] yahoo> wrote:
>>
>> Thanks for all your testing. I checked youf logs and it
>> does look better. I did see one instance where 2 frames were
>> dropped.
>>
>
> I just noticed why a couple frames got dropped. You are running your X display frequency at 59.94 fps and playing a video at 60 fps. When repeated pictures occur it allows the video to catch up but in your video it has some long periods where there are no repeated pictures and when the video gets far enough behind it drops frames to catch up. If your display's refreshrate is higher than the frame rate then it shouldn't need to drop frames but occasionally extended the trigger. Your latest log with DRM indicate that the most recent patch is working correctly.
>
> Please try a higher display frequency to determine if the occasional dropped frames are eliminated. Other than this I think you should be good to go.
>
> --
> Taylor

Thanks. I'll take a look into the X display frequency tomorrow.
Thanks for your patches, I'm glad I could help test things out. I
have watched a few other shows with no problems as well. I'm hopeful
this patch can go into upstream. If you create a ticket, please post
the number here, and I'll keep an eye on it.

-Thanks.
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tralph11 at yahoo

Dec 15, 2009, 7:02 PM

Post #24 of 42 (5055 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

>
> Please try a higher display frequency to determine if the
> occasional dropped frames are eliminated. Other than this I
> think you should be good to go.
>

Byron,

Since your beefier machine plays back perfectly and your slower machine has some ghosting I'm curious if you are maxing out the CPU. I notice in your logs it is taking too long to process some frames. Could you monitor the CPU usage on both your machines while playing the video and report back?

Thanks.

--
Taylor

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wpoland at gmail

Dec 15, 2009, 7:47 PM

Post #25 of 42 (5057 views)
Permalink

Re: 720p HD content from WPVI in Philly periodic a/v sync issues [In reply to]

On Tue, Dec 15, 2009 at 10:02 PM, Taylor Ralph <tralph11 [at] yahoo> wrote:
>>
>> Please try a higher display frequency to determine if the
>> occasional dropped frames are eliminated. Other than this I
>> think you should be good to go.
>>
>
> Byron,
>
> Since your beefier machine plays back perfectly and your slower machine has some ghosting I'm curious if you are maxing out the CPU. I notice in your logs it is taking too long to process some frames. Could you monitor the CPU usage on both your machines while playing the video and report back?
>
> Thanks.
>
> --
> Taylor

Taylor,

The cpu usage on the mac-mini is ranging around 35-50% on each core
during playback of 720p recording so I think it's got enough power.
The big issue with the mac-mini is the i915 graphics, but I've never
really had a problem, until the a/v sync issues popped up on the one
channel. I'm going to try and get the display frame rate figured out.
On a sidebnote I recently picked up a pair broadcom cyrstal hd cards
for an appletv and for the mini just for the hell of it, though they
won't be much use for mythtv for a while from the sounds of it.

I appreciate your help, I'll keep after the ghosting for a bit.

-Byron
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