Plot thickens re. TV Jitter / Stutter

KevinM · 2007-06-09, 12:47

I really like MP but it's still a case of "so near but not quite there" with quite a few outstanding issues to solve. I run TV Server with latest SVN in a single-seat setup (with occasional multiseat use).

Anyway, thought people might be interested to know of a very minor (and embarrassingly simple) change that I have recently made to my setup that has improved TV and video/DVD playback considerably.

I have played around with various decoders, audio renderers (including reclock), and all sorts of settings to get rid of those minor stutters that occur periodically - particularly noticeable on News channel scrolling text messages. I've also turned off various Windows services to minimize the number of processes running. Mostly, this has failed to make any real difference.

Finally, I dug up a copy of Process Explorer and left it monitoring CPU usage while MediaPortal was playing TV, and this showed up something quite interesting :-

Now there's nothing running on my system that normally spikes like this when MP isn't playing TV or video.

Out of interest, I changed the MP Priority setting in the MediaPortal setup from 'Normal' to 'High' and repeated the exercise. Would you believe it ? - the CPU usage profile now looks like this :-

Better still - the video stutter that I was getting a few times a minute has disappeared and those scrolling text messages in live TV news are completely smooth

Shift-! now shows 0 jitter and no lost frames.

Not sure if there is any downside to this yet, but it has certainly made a positive difference on my system.

CHli · 2007-06-11, 08:13

stick this !

nfox · 2007-06-11, 12:48

I think I might have found a downside (for me, anyway). I use Girder for my remote, and if I set MP to run at "Above Normal" or "High" priority, MP doesn't respond to every remote button press. Sometimes it responds, and sometimes it doesn't, which I assume is because Girder is no longer getting all the cpu time it needs.

I will be trying to adjust the priority of Girder too, to see if that helps at all, but at the moment changing the priority of MP is not a viable option when using Girder.

KevinM · 2007-06-11, 17:15

Quote:

Originally Posted by nfox

I think I might have found a downside (for me, anyway). I use Girder for my remote, and if I set MP to run at "Above Normal" or "High" priority, MP doesn't respond to every remote button press. Sometimes it responds, and sometimes it doesn't, which I assume is because Girder is no longer getting all the cpu time it needs.

You'll notice from my CPU graph that I am running at 31% CPU total for all processes on average - so I guess there's still plenty of time to carry out the other tasks. Did you measure your own CPU usage, out of interest?

This isn't the full picture of course; presumably with MP grabbing high priority, other timing-critical processes will need to complete within a fairly short time.

Leaving the remote aside for a moment, did it actually improve TV/Video playback for you?

nfox · 2007-06-11, 17:30

CPU usage isn't an issue - it's running at 20-30%. I haven't really tested the effect on the TV quality, because I was having difficulty actually getting into the TV, let alone changing channel. I am going to give this another go when I have some time, and I'll post the results here.

Topher5000 · 2007-06-13, 01:13

Where in MP setup do find this? I can't seem to locate it.

johns11 · 2007-06-13, 06:37

From memory it's at the very bottom of the "general" options screen in setup.

nfox · 2007-06-13, 07:02

Quote:

Originally Posted by johns11

From memory it's at the very bottom of the "general" options screen in setup.

It's new in the latest SVNs, so if you're running an older version you won't see it.

Topher5000 · 2007-06-13, 14:48

Thanks. I'm running stable 2.2.1.0.
Oh well, I was looking for a reason to update.

diehard2 · 2007-06-14, 00:13

Hi, I'm glad someone found this useful besides me. There was some discussion about whether I should have added this to svn. FWIW, I see the same improvement in video smoothness on my underpowered machine. I would also recommend installing the vmr9 patch linked to in my stuttering sticky if you are on an English version of XP.

2007-06-09, 12:47	#1 (permalink)
KevinM Portal Member Join Date: Apr 2007 Posts: 58 Thanks: 2 Thanked 3 Times in 1 Post Country: My System	Plot thickens re. TV Jitter / Stutter I really like MP but it's still a case of "so near but not quite there" with quite a few outstanding issues to solve. I run TV Server with latest SVN in a single-seat setup (with occasional multiseat use). Anyway, thought people might be interested to know of a very minor (and embarrassingly simple) change that I have recently made to my setup that has improved TV and video/DVD playback considerably. I have played around with various decoders, audio renderers (including reclock), and all sorts of settings to get rid of those minor stutters that occur periodically - particularly noticeable on News channel scrolling text messages. I've also turned off various Windows services to minimize the number of processes running. Mostly, this has failed to make any real difference. Finally, I dug up a copy of Process Explorer and left it monitoring CPU usage while MediaPortal was playing TV, and this showed up something quite interesting :- Now there's nothing running on my system that normally spikes like this when MP isn't playing TV or video. Out of interest, I changed the MP Priority setting in the MediaPortal setup from 'Normal' to 'High' and repeated the exercise. Would you believe it ? - the CPU usage profile now looks like this :- Better still - the video stutter that I was getting a few times a minute has disappeared and those scrolling text messages in live TV news are completely smooth Shift-! now shows 0 jitter and no lost frames. Not sure if there is any downside to this yet, but it has certainly made a positive difference on my system.

2007-06-11, 08:13	#2 (permalink)
CHli Portal Member Join Date: Jul 2005 Location: Switzerland Age: 27 Posts: 1,011 Thanks: 8 Thanked 3 Times in 3 Posts My System	stick this ! __________________ European TV + Radio Channels Logos, add yours !

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2007-06-11, 12:48	#3 (permalink)
nfox Portal Member Join Date: Aug 2006 Location: London Posts: 57 Thanks: 0 Thanked 6 Times in 2 Posts Country: My System	I think I might have found a downside (for me, anyway). I use Girder for my remote, and if I set MP to run at "Above Normal" or "High" priority, MP doesn't respond to every remote button press. Sometimes it responds, and sometimes it doesn't, which I assume is because Girder is no longer getting all the cpu time it needs. I will be trying to adjust the priority of Girder too, to see if that helps at all, but at the moment changing the priority of MP is not a viable option when using Girder.

2007-06-11, 17:30	#5 (permalink)
nfox Portal Member Join Date: Aug 2006 Location: London Posts: 57 Thanks: 0 Thanked 6 Times in 2 Posts Country: My System	CPU usage isn't an issue - it's running at 20-30%. I haven't really tested the effect on the TV quality, because I was having difficulty actually getting into the TV, let alone changing channel. I am going to give this another go when I have some time, and I'll post the results here.

2007-06-13, 01:13	#6 (permalink)
Topher5000 Portal Member Join Date: Apr 2006 Posts: 151 Thanks: 0 Thanked 0 Times in 0 Posts	Where in MP setup do find this? I can't seem to locate it.

2007-06-13, 06:37	#7 (permalink)
johns11 Portal Member Join Date: Feb 2007 Posts: 12 Thanks: 8 Thanked 0 Times in 0 Posts Country:	From memory it's at the very bottom of the "general" options screen in setup.

2007-06-13, 14:48	#9 (permalink)
Topher5000 Portal Member Join Date: Apr 2006 Posts: 151 Thanks: 0 Thanked 0 Times in 0 Posts	Thanks. I'm running stable 2.2.1.0. Oh well, I was looking for a reason to update.

2007-06-14, 00:13	#10 (permalink)
diehard2 Portal Developer Join Date: Apr 2006 Location: Chicago Posts: 510 Thanks: 2 Thanked 13 Times in 9 Posts Country:	Hi, I'm glad someone found this useful besides me. There was some discussion about whether I should have added this to svn. FWIW, I see the same improvement in video smoothness on my underpowered machine. I would also recommend installing the vmr9 patch linked to in my stuttering sticky if you are on an English version of XP.