Jittery Video?

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bobo1on1 Offline
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Post: #361
The refreshrate detection doesn't work that well yet, there's an option to override it, but that only helps if you always use the same refreshrate.

Also some movies don't produce nice pts values, so they play strange, and fast-forwarding can produce weird effects.
This is on my todo list, it has to do with syncing the dvdclock properly, right now it's in a state where it works but I don't know why.
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ArtVandelae Offline
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Post: #362
alanwww1 Wrote:So all fine until i the auto refresh rate changer really changes the refresh rate to any direction. This way the refresh rate detection is not working properly.

I noticed this as well. The audio is always adjusted to match the original refresh rate and not the adjusted refresh rate. I also noticed that even when playing videos that match the desktop refresh rate there is still a fair amount of "warbling" in the audio as it constantly bounces between too fast->too slow->too fast->too slow. It seems to be adjusting it far more then it needs to when simply compensating for small clock discrepancies.
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alanwww1 Offline
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Post: #363
ashlar Wrote:Confused
I suppose XBMC already displays 24fps material in a 3:2 pattern when running at 60Hz. Are you saying that that is not the case?

I am not sure, but i see a lot of juddering when i try that.

Always read the XBMC online-manual, FAQ and search the forum before posting.
Do not e-mail XBMC-Team members directly asking for support. Read/follow the forum rules.
For troubleshooting and bug reporting please make sure you read this first.
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bobo1on1 Offline
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Post: #364
Smoothvideo now has it's own thread:
http://forum.xbmc.org/showthread.php?tid=46091
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Hitcher Offline
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Post: #365
bobo1on1 Wrote:The refreshrate detection doesn't work that well yet, there's an option to override it, but that only helps if you always use the same refreshrate.
So would reading the fps from what ever the 'auto refresh rate' decides help this problem?
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Jester Offline
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Post: #366
bobo1on1 Wrote:Smoothvideo now has it's own thread:
http://forum.xbmc.org/showthread.php?tid=46091

Nice one, no clue if anything had a go at building this under windows....but i'll have a go over the weekend (maybe tomorrow If i have time)

Current XBMC Platform: ATV2
Extra XBMC Platform: Raspberry Pi
Read the iOS FAQ
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dpassent Offline
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Post: #367
i tried

few svns ago it built. now it complains about samplerate.h. I downloaded libsamplerate sources but now VS2008 Express spits out bunch of errors, and I am total moron when it comes to debugging build errors Smile

DP
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ashlar Offline
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Post: #368
Jester Wrote:Nice one, no clue if anything had a go at building this under windows....but i'll have a go over the weekend (maybe tomorrow If i have time)
Jester, has the channel mapping been corrected under Windows?

I guess the majority of testing will happen with AC3 or DTS material... and testing the functionality with wrong mapping... it's like asking people to play table tennis with their hands tied. A royal pain... Shocked
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RockDawg Offline
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Post: #369
Most of this technical video stuff is way over my head, but I was just wondering why the Xbox doesn't exhibit these problems? Is there something built into it that sync all the clocks?
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dteirney Offline
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Post: #370
For those having issues with Auto Refresh Rate not appearing to do anything in linuxport, double check that the screen resolutions and refresh rates known to XBMC are what you expect them to be.

For some reason my LCD HDTV's native panel resolution (1368x720) only supports a refresh rate of 60Hz. "Overdriving" it at 1920x1080 gives the full range of resolutions (60Hz, 50Hz, 30Hz and 25Hz). 60Hz is the worst refresh rate for PAL content which is likely why we were getting jittery playback.

With playback automatically changed to 25Hz things appear to be much better.

Also confirm what resolution gets selected by default if using "Auto" for the screen resolution. With XBMC set to Auto it would default to 720p (even if the resolution in XFCE was set to 1920x1080) which also only supported 60Hz. Manually setting the resolution to 1920x1080@60Hz seems to have things working quite well.
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Hitcher Offline
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Post: #371
dteirney, can you check if my findings below are the same for you?
Hitcher Wrote:Ah, we're getting somewhere.

I turned off 'High Quality Upscaling' to lessen the load on my HTPC and both 23.98fps and 25fps videos were showing 60fps. Again I tried the override but no change.

After much testing (and a lot of WTH moments) I've finally figured out what it's doing on my system.


It only uses the start up refresh rate of XBMC as the fps of any video - even changing the GUI refresh rate during testing will have no effect unless XBMC is then shutdown and restarted.
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dteirney Offline
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Post: #372
I'm definitely having the refresh rate change because I ran into the issue in http://forum.xbmc.org/showthread.php?p=2...post290935.

My startup frequency is set to 60Hz, and playback for most content is switching to 50Hz (most of our stuff is PAL).

I only had one resolution that had a series of frequencies "known" to XBMC.

I've got High Quality Upscaling turned off as well.

I'm starting xbmc with the -fs flag (for full screen). Not sure if that makes any difference. The resolution set in XBMC isn't the "xyz (Full Screen)" resolution.
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pseudoheld Offline
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Post: #373
not wanting to go grave digging but i still have this bug.
a video with 30fps (on a 60hz tv) plays buttery smooth in vlc but lags and jitters something dreafull in xbmc Sad
was there ever any solution found?
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marc.aronson Offline
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Post: #374
pseudoheld Wrote:not wanting to go grave digging but i still have this bug.
a video with 30fps (on a 60hz tv) plays buttery smooth in vlc but lags and jitters something dreafull in xbmc Sad
was there ever any solution found?

The only solution I found was to use an external media player. I run on windows and I've found that configuration XBMC to use Media Player Classic Home Cinema ("MPC-HC") will work ifyou configure MPC-HC to use the power-dvd video codec, which takes full advantage of the Nvidia ION's ability to do hardware decoding and de-interlacing.

A key root cause of these problems is that NTSC / ATSC can use multiple interlacing techniques (simple even/odd interlacing; telecined; random "non-standard" variations on the usual Telecine pattern.

I am headed back to mythtv from my frontend. The XBMC frontend is a much more aesthetically pleasing interface, but the folks in mythtv land sorted all these issues out years ago. After a year on XBMC as my frontend, I find that the improved aesthetics are not worth the pain caused by a lack of proper support for deinterlacing & closed caption decoding.

Marc


Marc
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pseudoheld Offline
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Post: #375
thats a shame that this bug still hasn't been fixed completely then.
interestingly i only have this bug on fps. mostly its videos with 30fps almost all others play with no problems at all...
i find this pretty strange, seen as my tv runs on 60hz (like most LCD TVs) and 60 is a plural of 30 so you would think it should be easy to produce smooth playback Confused

any other ideas?
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