[Polysemous]

First off, THANK YOU for all of the great work on this project--and not to forget this incredible forum! This being my first post in 5 years of using XBMC is a testament to how user-friendly the software is and how useful these forums are... I've scoured the boards for the answer to this question and finally decided it's time to break my silence.

I've made the jump to XBMC for Linux because I want HD playback capability. Using suggestions from other members I purchased hardware that I thought would get the job done for 1080p.
Here's what I bought:
- E8400 3.0ghz C2D
- ABIT I-N73HD LGA 775 NVIDIA GeForce 7100 HDMI Micro ATX Intel MB
- 2GB DDR2 800Mhz RAM

Now for the problem:
HD content stutters frequently in 1080p. Some sources play *okay*, but I was hoping for flawless playback of anything I throw at it. For my highest quality Blu-ray encodes the video is unwatchable. Dropped frames number in the thousands, but CPU usage never pegs at 100%. Even playback at 720p stutters at times.

I've done my best to troubleshoot on my own, but I'm out of ideas. A couple of areas I think could be the culprit:
-Hardware --is the onbard video good enough?
-Software --I'm a Linux noob and running XBMC on top of the Ubuntu GUI with EnvyNG installed drivers
-My encodes --I basically have been remuxing my blu-rays into an MKV container (no compression)

[icekiller]

more info plz
which build (revision) which hardware etc.

also try to disable vsync?

[Polysemous]

Sorry...
I initially tried XBMC using l.capriotti' s LIVEUSB. Now I'm running Ubuntu Hardy ISO downloaded one week ago... and running the XMBC Hardy PPA current as of two days ago. My current installation is on a 200gb IDE drive I pulled from an old Maxtor external USB HD.

Both installations (LIVEUSB or HD install) have the same results whether played via a windows network share or from the local HD.

I have not tried to disable VSYNC. I'll give that a go tonight.

[Razor_109]

i have the _exact_ same setup running,

i noticed dropped frames but in my case they almost only where sound frames i guess since the video didn't show any stutters.

KillaSample (1080p uncapped x264 mkv) though never played well, but now just like 2 hours ago i rebooted and changed EIST in the BIOS to 'Enabled'.

(I guess i have Vsync Enabled as well, will have to check tonight)

Now it's running perfectly without dropping frames, CPU only 70% instead of the 95% it showed before.

Well i build XBMC my self from SVN pulldown, have a quite new svn from like 2 days ago.
Will check more tonight and let you know.

[Polysemous]

Made a few changes when I got home today.... no luck.

I disabled vertical blank sync via the XBMC GUI
I verified that EIST is enabled in the BIOS

I'm using the killa sampla now so I have a performance baseline.

Dropped 531 frames on the last try with CPU usage peaking at ~65%

[Razor_109]

noticed one more thing,

make sure you have no Video Post Processing enabled.. i had the Brightness and contrast setup, (so not the default) and it caused terrible playback.. leave the video settings default i suggest.

[Polysemous]

Is that option included in XBMC for Linux?
I've been through all of the settings menus and can't find it!

[Polysemous]

Not sure if this is typical or not, but I've noticed during troubleshooting that when running XBMC in a window (resolution still set at 1080 fullscreen) playback is flawless.
I start to drop frames when I resize the window to fill the entire desktop.

[ShortySco]

I also have this exact same setup.

Ran near perfect with a straight install of ubuntu 8.04 no messing about with drivers...etc (Other than a couple of irrelevant teething problems)

Only things i remember doing were... enabling the restricted nvidia driver and i also toggled the vsync settings in the nvidia-settings window (didn't seem to make a difference)

One thing that caused bad playback was when i somehow got my screen at 1080p/24 and was playing a 25fps movie, it dropped hundreds and hundreds of frames and was ok when i changed to 1080p/60

Also disabling desktop visual effects is a must if you didn't already.

I also tried LiveUSB with great success.

Shorty

[BLKMGK]

Installing the latest NVIDIA binary drivers using ENVY might be a good idea. NVIDIA will hardly even speak to you on their support boards if you aren't current and last I checked the stuff Ubuntu was using was pretty dated.

[Polysemous]

The latest:
I'm running NVIDIA drivers as configured by Envy.
Resolution is: 1920x1080/60hz

Not really sure where to go from here... have tried all suggestions above with no change.

[Razor_109]

Is that option included in XBMC for Linux?
I've been through all of the settings menus and can't find it!

I meant this: http://wiki.xbmc.org/?title=OSD_Video_Settings
you can enter this setupscreen while playing a movie --> START/MENU --> Then the video-button. (That means Number 3 in the following picture http://wiki.xbmc.org/images/7/77/Osd.myvideso.png)

those settings should be default, well that goes for Brightness, Contrast and Gamma. Viewmode shouldn't make a diffrence i guess.

I dropped many frames untill i reset these values to default. Now it runs perfectly.

[Polysemous]

D'oh!
Those settings should all be default, but I'll check them tonight.

If nothing else, I'm learning TONS about Linux!

[CapnBry]

Are you reading the CPU% from the info screen in XBMC or somewhere else? You may want to ssh into it and check the output from 'top' maybe your X server is eating cpu cycles and this may be fixed with setting UseEvents to true in the Screen section of your xorg.conf and restarting the X server.

I'm following this thread hoping you can find your problem because your hardware is pretty close to what I want to replace my box with (currently an AMD X2 3800 isn't cutting it for me and need HD playback).

[Polysemous]

Thanks for the suggestion... I pull the cpu numbers from XBMC while video is playing (hitting play on my remote).

:confused2: Could you explain how to "check the output from 'top' "? :confused2:

thanks!