24p and audio sync issues - Printable Version
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RE: 24p and audio sync issues - robl45 - 2012-06-10 07:46
i can assure you the gt430 card won't do it. i'm convinced the problem is because xbmc is reading the refresh rate wrong but no one seems to be able to fix it. when reclock reads the refresh rate wrong, it doesn't work either and you have crappy video. xbmc is reading 24hz whether the card is set for 23.976 23.970 or whatever. this is causing speed to be adjusted on the OSD when it shouldn't be. a 25p movie plays perfect with no issues because the refresh is 50hz, xbmc nails that, there is no speed up, no missed frames except when pausing and everything is perfect. but because xbmc is using directdraw instead of direct3d to get the refresh rate, its getting 24hz, same thing reclock does on my system if you don't set it to direct3d for refresh rate. then you have the issue where sometimes it locks on and doesn't have the miss counter flying up and other times when the missed counter is just counting up and up.
EDIT: I just checked and a movie encoded as 24fps doesn't show +.100 on the speed in the OSD. thats kind of weird for two reasons. for one when the refresh rate isn't actually 24hz which it definately isn't on my system and most peoples systems, 24FPS should be the one with speed adjustment, not 23.976. And second, i'm on my monitor now which supports 60hz and 75hz only. I'd drag my computer downstairs to definitively test this but I don't know that its worth it as over a year plus already this is going on and I don't see it getting fixed anytime soon.
RE: 24p and audio sync issues - griffin - 2012-06-10 08:01
(2012-06-08 21:17)PsychoCheF Wrote:(2012-06-07 22:59)griffin Wrote: This is my workaround for 24p audio sync issues, it may or may not work for you, it works great for me.
Those options do not work against each other. Your video card may or may not hit the precise refresh rate needed with 'adjust display refresh rate to match video", "sync playback to display" will correct this and also apparently do a good job at providing an artificial v-sync.
As far as I can tell my card is hitting the precise refresh rates (23.976), but if I enable vertical blank sync audio is delayed 250-300ms on this material. With vertical blank sync disabled I must enable sync playback to display to avoid tearing.
XBMC Decodes it to multichannel PCM and surround is fine.
The bottom line is these setting completely fixed my 250-300ms audio delay on 24p material, I know this is a more complex issue and it might not help everyone, but worth a try if you are having the issue.
RE: 24p and audio sync issues - robl45 - 2012-06-10 17:32
well i tried it with sync to display on and vertical blank sync off. now it seems to be working correctly, hard to tell without watching a full movie but it didn't seem to be tearing. also hard to tell if its actually keeping the sync and will keep the sync through the whole movie, I tried to fast forward a bit through the movie to different parts and sync was held so I guess next week we will find out. would be nice to not have to run a variety of software to watch a simple movie.
RE: 24p and audio sync issues - robl45 - 2012-06-11 00:09
Well sync was on but it was tearing. But at least it proves it can work correctly if the tearing can be fixed
actually it only seems to be tearing on the AVI file I have, the other files seem to be working without tearing so thats at least a start to having decent audio sync working.
RE: 24p and audio sync issues - igor - 2012-06-11 06:28
This is something I've learned to live with over the years with xbmc. Currently the best I've come up with are these settings(which are the same I've used with ati 4550,5570,nvidia 7600,8600,gt220,gt440 on both intel and amd rigs)
adjust refresh to display
sync method - resample audio
and set default delay of 125ms for 23-24fps material in advancedsettings.xml
It's not perfect, but 90% of the time never notice anything outside of +-25ms
Here is the advancedsettings used(from wiki) for anyone not familiar:
RE: 24p and audio sync issues - Stefanhvt - 2012-08-02 18:18
All of you,
I think it's time to give op on this issue. We will properly never have perfect playback with the hardware of nowadays. The main core of the problem seems to be this:
1. Video cards of nowadays are not capable of playing material at steady 23.976 HZ.
2. The Old audio engine was definitely a cause. The new one is much better, I would say almost perfect.
3. The Sync options are not making things better, they are making it worse. All the custom setting people are applying to the new builds, especially the openelec builds, are not gonna help for so far I know. My personal opinion: The less sync options used, the closer you are to perfect playback.
I have recently tested a new frodo build form this website: http://www.xbmcfreak.nl/xbmcbuntu-12-04-with-pre-frodo-end-july-release/
This is the first build I have ever seen that finally play's the movie in sync with the audio. I would say it's almost perfect, or maybe fully perfect. I can't tell exactly because there is another factor that has influence on this, and that's the hardware issue, the incapability of video cards to play at 23.976 hz.
So for all of you considering to give it a last try, try this new build. Keep all settings to standard. The only thing you need to do is adding a 23.976 modeline to the xorg.conf. No sync options. They only mess things up. The only option you need to turn on in xbmc is the "Adjust display refresh rate to match video" option. This is not a sync option, it's just a mechanism that chooses the proper modeline from the xorg.conf or the correct mode from the video card's EDID.
Give it a try,
RE: 24p and audio sync issues - robl45 - 2012-08-05 17:17
(2012-08-02 18:18)Stefanhvt Wrote: All of you,
so your option to fix the sync issue is to turn the sync off? So if the ABS brakes don't work in a car, and there is a little light warning you they don't work, we just cover it up with a piece of tape and move on right? True story by the way. So that is what you are suggesting, just ignore the warning light that it doesn't work and everything will be great?
Adjusting refresh rate to display only changes to the closest refresh rate or multiple that it can use. Depending on the video card and how close it is, this may work okay, but then you will get frame drops, thats the whole point of the sync is to not have frame drops because you can resample or drop/dupe the audio to keep it in sync with the video.
Reclock does this fine so why would people not do it correctly? It works fine with 50hz refresh when watching 25FPS material, it works fine with 60hz when watching 29.9 fps material so its obviously a programming issue in XBMC.
RE: 24p and audio sync issues - Karimpje - 2012-08-05 20:45
(2012-08-05 17:17)robl45 Wrote:(2012-08-02 18:18)Stefanhvt Wrote: All of you,
I need the refresh rate to be synced, because else I get ghosting on my 3D movies. So please fix this.
By the way, I'm using XBMC now for a couple of weeks, before I was using Mediaportal on a Windows 7 installation. But with my new hardware (Zotac Zbox Nano XS AD11) I had an issue that Windows 7 was killing my resources and didn't leave anything for Mediaportal to play the movies with. So HD content was not playing fluent. Now I'm running Openelec which leaves almost all my resources for XBMC. Everything is running smooth, except the Audio Offset issue is ruining my joy.
I've been surfing on the internet and I read about people having these issues since 2010. How in Gods name didn't anyone fix this issue since then?? Mediaportal, Media Player Classic and VLC are running every movie with the audio and video perfectly synced. This issue is not due to hardware related matters or content related matters, it is a XBMC issue. I read that people from every platform (WinXP, Win7, Openelec, Ubuntu, Lubuntu, XBMCbuntu) have these issues, there isn't even a hardware relationship, all videocards (Intel, AMD, Nvidia), all interfaces (HDMI, Component, Optical) all have this issue.
So please solve this issue and make XBMC the best there is!!
RE: 24p and audio sync issues - Skram0 - 2012-08-05 23:49
RE: 24p and audio sync issues - Stefanhvt - 2012-08-12 13:47
(2012-08-05 17:17)robl45 Wrote:(2012-08-02 18:18)Stefanhvt Wrote: All of you,
My suggestion is that perfect playback should be achieved with as less workarounds possible. The core of the problem is not going to be solved by turning on sync options. When doing that, we do exactly as you say, we are hiding the problem and covering it up with custom settings. It may look a little better, but it's not fully solved. If it was, this discussion would not still be here since 2008 and people would not still be claiming that the 24p / audio out of sync issue is still unfixed.
That the problem is still considered as unfixed is not just my opinion, this is a fact you can see on forums all over the web ..
I on the other hand solved it .. I bought a Samsung ES8000