Author Topic: Playback getting a little choppy  (Read 4064 times)

fearingsept

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Playback getting a little choppy
« on: May 19, 2008, 05:01:52 pm »
I was watching a dvd last night on my hybrid/core and noticed that the playback was starting to get a little choppy. I thought that this might be just an issue with the dvd but then I noticed it on regular TV and playback of recorded video.

Has anyone else had this issue?
If so, is there a work around?

-Dustin
Core: Broken :(

skerit

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Re: Playback getting a little choppy
« Reply #1 on: May 19, 2008, 05:10:15 pm »
Choppy? Do you mean the tearing-problem?

Probably if you have an nvidia card - I'm still baffled about this one.

fearingsept

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Re: Playback getting a little choppy
« Reply #2 on: May 19, 2008, 05:20:02 pm »
It could be described as that... Its like whenever there is fast action there is this lag, but almost unnoticeable.
Core: Broken :(

royw

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Re: Playback getting a little choppy
« Reply #3 on: May 19, 2008, 10:10:42 pm »
Yes, I see this every few days.  Rebooting the core/hybrid temporarily solves the problem.  I'm noticing the problem more since I upgraded TV from NTSC to 1080p.  BTW, there are a couple of other threads currently going on this issue.  You might want to try: 

http://wiki.linuxmce.org/index.php/Nvidia_Card_Tweaks_For_Better_MythTV_and_UI_Performance

HTH,
Roy

colinjones

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Re: Playback getting a little choppy
« Reply #4 on: May 20, 2008, 12:39:35 am »
For completeness, I think "choppy" and tearing are quite different problems. I get choppiness, mostly - this is visible in big pans/zooms, lots of motion. It is irregular, but it looks like the image is "sticking" and then suddenly jumping to the new position in the pan/zoom without going through the intervening steps. So effectively missing frames which I know exist in the media (happens on media files, live TV, DVDs, etc). Doesn't appear to be CPU related as the CPU is very low. I have been completely unable to determine how much hardware acceleration LMCE is able to achieve out of my nVidia chipset - it should be more than capable, but just doesn't seem able to achieve it.

Tearing is more related to screen drawing, or flipping, not being sync'd with the vertical retrace of the TV, thus momentarily capturing two different images on screen at the same time, with a "tear" line being the join between them. When I turn off my vsync in nvidia-settings, I get vastly higher frame rates in glxgears (1100fps as opposed to 40fps) and the tearing starts (fairly minor), but the jerkiness/choppiness doesn't get any better! Completely stumped!
« Last Edit: May 20, 2008, 12:41:11 am by colinjones »

fearingsept

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Re: Playback getting a little choppy
« Reply #5 on: May 20, 2008, 02:36:12 am »
Quote
Tearing is more related to screen drawing, or flipping, not being sync'd with the vertical retrace of the TV, thus momentarily capturing two different images on screen at the same time, with a "tear" line being the join between them. When I turn off my vsync in nvidia-settings, I get vastly higher frame rates in glxgears (1100fps as opposed to 40fps) and the tearing starts (fairly minor), but the jerkiness/choppiness doesn't get any better! Completely stumped!

I think tearing better discribes my issue.

I really hope someone figures this out soon... I wish I knew more.
Core: Broken :(

colinjones

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Re: Playback getting a little choppy
« Reply #6 on: May 20, 2008, 08:10:12 am »
If its tearing for you, have you tried turning on the vsync options? That's the point of them - to sync screen drawing/flipping with the vertical retrace so that it is never drawing at the same time as refreshing the TV.

Also, are you using alpha blended mode? As you will see from all the commentary, this always displays some tearing and there's not much you can do about it as it relates to the lack of Linux support for various hardware acceleration features, currently. Do a search for totallymaxed's posts with the word tear, as he has plenty of experience of testing this. Drop back to masked mode...

skerit

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Re: Playback getting a little choppy
« Reply #7 on: May 20, 2008, 12:53:01 pm »
I searched for totallymaxed's posts and I saw someone was also pointing to the UI-Alpha mode, but I don't completely get what's so special about this mode...

(I have all the vsyncing options turned on) I run compiz on another computer, with a newer card, but I don't have any tearing there. I also tried mythbuntu for a few days (for my DVB-S card) on the HTPC and I didn't have any tearing there, either! I even copied the monitor & screen related sections from the mythbuntu xorg.conf but still nothing.

Are the drivers in 0710 older then in Ubuntu 8.04?

gazlang

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Re: Playback getting a little choppy
« Reply #8 on: May 20, 2008, 02:48:56 pm »
The drivers for nVidia cards can be updated using ENVY -> http://albertomilone.com/nvidia_scripts1.html
But its not an issue of old drivers (I think the drivers used in ubuntu 0804 are the same as in LMCE)
With UI2 alpha there is a lot of graphics overhead for the transparancy element of the UI. Dropping to UI2 masked does get rid of tearing.
You will notice in mythbuntu 0804 etc that the UI is very simple and so not hardware demanding.
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fearingsept

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Re: Playback getting a little choppy
« Reply #9 on: May 20, 2008, 04:46:47 pm »
I will try to use UI2 without the alpha blending and see what happens.
Hopefully this will take care of it.

Core: Broken :(

jeff_rigby

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Re: Playback getting a little choppy
« Reply #10 on: May 21, 2008, 04:19:24 pm »
Tearing, stuttering and interlace issues all appear to go away when you use the DVI out rather than component or VGA out and input the DVI to a HDMI port on a good TV.  The TV takes the data stream and converts it to video rather than require the video card in the computer to do this.

DVI out using 720P or 1080I resolution with transparancy off.  Perfect picture. 

royw

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Re: Playback getting a little choppy
« Reply #11 on: May 21, 2008, 10:41:28 pm »
You are lucky.  nvidia 7600 GS DVI out to 1080p HDMI input on Hitachi P60X901, masked UI2, still stuttering here...

colinjones

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Re: Playback getting a little choppy
« Reply #12 on: May 22, 2008, 01:16:25 am »
Same, nvidia 7050PV HDMI out to HDMI in, still stuttering...

fearingsept

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Re: Playback getting a little choppy
« Reply #13 on: May 25, 2008, 01:32:45 am »
I finially got around to turning of the Alpha blending and my issue was resolved.
Thanks for helping

-Dustin
Core: Broken :(

fearingsept

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Re: Playback getting a little choppy
« Reply #14 on: May 27, 2008, 04:04:14 am »
*Update*

After changing to UI 2 I had to change back to UI 2 with alpha blending. For some reason when watching live tv my menu was not responding correctly. I would hit the menu button and it would be a good 30 seconds or more before the menu would actually appear.
I figured that a little tearing was ok compaired to delay in menu function. When I changed back to UI 2 with alpha blending the problem with the menu went away... Has anyone else had this issue?
Core: Broken :(