Kodi Community Forum
24p and audio sync issues - Printable Version

+- Kodi Community Forum (https://forum.kodi.tv)
+-- Forum: Support (https://forum.kodi.tv/forumdisplay.php?fid=33)
+--- Forum: General Support (https://forum.kodi.tv/forumdisplay.php?fid=111)
+---- Forum: Windows (https://forum.kodi.tv/forumdisplay.php?fid=59)
+---- Thread: 24p and audio sync issues (/showthread.php?tid=80247)



RE: 24p and audio sync issues - chris.j.schultz - 2012-09-16

fwiw

I had major issues with sync of audio when "Adjust display refresh rate to match video" was set. It was only happening on one TV (Samsung LCD) and not on my other telly (Samsung Plasma). It would drop frames like crazy! I discovered that I had set "Deinterlace Video" to "On". Changing it back to "Auto" has fixed the issue completely. I have "Sync playback to display" set to "Video clock (Drop/Dupe audio).

I run at a default of 1080 50Hz (NZ broadcast DVB-T at 50Hz) and I now auto-adjust to 1080 24Hz (or whatever the source video is) and it is perfect. I am running my own build from "Master" on September 8, 2012 post the merge of PVR code. I have live tv working perfectly using TVHeadend and now ALL content is running buttery smooth with perfect audio sync.

Both cards are Nvidia. One is native HDMI while the other is DVI-HDMI cable. Audio in both cases is via SP-DIF via the onboard audio of the motherboard (both optical and via a shared 3.5m port).

I am running Debian Testing and compiled using gcc 4.6.


RE: 24p and audio sync issues - Stefanhvt - 2012-09-16

(2012-09-12, 10:09)steelman1991 Wrote:
(2012-09-12, 01:01)liquidskin76 Wrote: Hmmm... it would appear i have been a bit harsh on AE. Blush

Out of interest, i downloaded Eden and tested sync again at 24p. Well, compared to AE, it was a mile out. So i dug out a BD disc (Lord of the Rings: Fellowship of the Ring) and sync checked with my DB player. Guess what... that sync matched XBMC AE's sync perfectly. LOTRFOTR was one of the vids that always looked out of sync to me on my HTPC, so was always my main test clip. Guess it must be something with the sync on that DB that looks funny to my eyes.

So i stopped being a dushbag, and started checking alot more vids. I'm very happy to report sync is actually good. Not sure what the hell i was seeing or thinking previously... time for an eye test i think. Rolleyes

Really sorry guys for the red herring. DDDamian... sorry buddy. Looks like you have been right on the money with Windows AE and sync. One less person to worry about anyway!! Big Grin

Cheers
(liquidskin slowly backs out of forum thread, trying to look cool and not too embarrassed... Blush Wink)
Laugh the eyesight problem only gets worse - believe me. Mate, glad its working for you.

Your right on that one .. Millisecond sensitivity has returned to my eyes.

(2012-09-08, 15:37)DDDamian Wrote: You will *never* achieve 0.0003s with any player or HTPC in the foreseeable future, and even the gadget you linked doesn't adjust in those units. You have far more to gain by either buying that, tracking down the code errors or becoming a hardware developer.

Can you tell me why this is so? What is the amount of ms accuracy I can achieve according to you ?




RE: 24p and audio sync issues - Hoox - 2012-09-19

(2012-09-16, 09:38)chris.j.schultz Wrote: I had major issues with sync of audio when "Adjust display refresh rate to match video" was set. It was only happening on one TV (Samsung LCD) and not on my other telly (Samsung Plasma). It would drop frames like crazy! I discovered that I had set "Deinterlace Video" to "On". Changing it back to "Auto" has fixed the issue completely. I have "Sync playback to display" set to "Video clock (Drop/Dupe audio).

Chris, I have the same exact problem with my Samsung LCD. I have tried several machines on this TV and all is out of sync at 24hz.
Where did you change the deinterlace setting? On the tv or in xbmc or in gfx driver? Also, do you have any other settings on the tv you would think were significant?


RE: 24p and audio sync issues - DDDamian - 2012-09-19

(2012-09-16, 12:53)Stefanhvt Wrote: Can you tell me why this is so? What is the amount of ms accuracy I can achieve according to you ?

0.0004s.....

Really, have you considered any of the variables?? See above for how much just the TV affects it, then consider receivers, computers, OS's, software processes and threads, system events, frequency and air currents....


RE: 24p and audio sync issues - chris.j.schultz - 2012-09-19

(2012-09-19, 10:42)Hoox Wrote: Chris, I have the same exact problem with my Samsung LCD. I have tried several machines on this TV and all is out of sync at 24hz.
Where did you change the deinterlace setting? On the tv or in xbmc or in gfx driver? Also, do you have any other settings on the tv you would think were significant?

I ended up changing nothing on the TV (I did flick over to game mode at one point but it had no impact). Start up a video, while it is playing hit the "Enter" key on your keyboard. You will get a menu overlay appear. Scroll across to the video reel icon and again hit "Enter". You will get a new menu, the first option being "Deinterlace Video". I set this to auto, equally you could set it to off. At the bottom of the dialog there is an option "Set as default for all movies". This applies to all non-pvr videos. I am not sure if you have come across it, but the "o" (not zero) key gives you an overlay that tells you about the streams that are currently playing, including frames being dropped.

I have the latest nvidia drivers (provided by Wheezy at least).

Code:
root@bed:~# dpkg -l nvidia*
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                        Version                     Description
+++-===========================-===========================-======================================================================
ii  nvidia-alternative          302.17-3                    allows the selection of NVIDIA as GLX provider
un  nvidia-common               <none>                      (no description available)
ii  nvidia-glx                  302.17-3                    NVIDIA metapackage
un  nvidia-glx-any              <none>                      (no description available)
un  nvidia-glx-dev              <none>                      (no description available)
un  nvidia-glx-legacy           <none>                      (no description available)
...

Let me know how you get on.


RE: 24p and audio sync issues - chris.j.schultz - 2012-09-20

(2012-09-19, 23:29)chris.j.schultz Wrote:
(2012-09-19, 10:42)Hoox Wrote: Chris, I have the same exact problem with my Samsung LCD. I have tried several machines on this TV and all is out of sync at 24hz.
Where did you change the deinterlace setting? On the tv or in xbmc or in gfx driver? Also, do you have any other settings on the tv you would think were significant?

I ended up changing nothing on the TV (I did flick over to game mode at one point but it had no impact). Start up a video, while it is playing hit the "Enter" key on your keyboard. You will get a menu overlay appear. Scroll across to the video reel icon and again hit "Enter". You will get a new menu, the first option being "Deinterlace Video". I set this to auto, equally you could set it to off. At the bottom of the dialog there is an option "Set as default for all movies". This applies to all non-pvr videos. I am not sure if you have come across it, but the "o" (not zero) key gives you an overlay that tells you about the streams that are currently playing, including frames being dropped.

I have the latest nvidia drivers (provided by Wheezy at least).

Code:
root@bed:~# dpkg -l nvidia*
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                        Version                     Description
+++-===========================-===========================-======================================================================
ii  nvidia-alternative          302.17-3                    allows the selection of NVIDIA as GLX provider
un  nvidia-common               <none>                      (no description available)
ii  nvidia-glx                  302.17-3                    NVIDIA metapackage
un  nvidia-glx-any              <none>                      (no description available)
un  nvidia-glx-dev              <none>                      (no description available)
un  nvidia-glx-legacy           <none>                      (no description available)
...

Let me know how you get on.

I should also say that mutil-channel audio transcoding from AAC to AC3 also has caused issues with stuttering video (not framedropping tho). When playing MP4 files containing H264 and AAC I have to disable Dolby Digital capable receiver and DTS capable received from System Settings | Audio Output. mkv files containing H264 and AC3 are fine however.


Re: 24p and audio sync issues - Stefanhvt - 2012-09-20

(2012-09-19, 16:34)DDDamian Wrote:
(2012-09-16, 12:53)Stefanhvt Wrote: Can you tell me why this is so? What is the amount of ms accuracy I can achieve according to you ?

0.0004s.....

Really, have you considered any of the variables?? See above for how much just the TV affects it, then consider receivers, computers, OS's, software processes and threads, system events, frequency and air currents....

I understand that. Thats why I ask you when all this factors are taken in consideration, what would be the most realistic goal ?

And what amount of accuracy is achieved in cinemas for example ?



RE: 24p and audio sync issues - DDDamian - 2012-09-20

The standard is lead 15ms, lag 45ms: http://www.webcitation.org/60UbU5Ziv

For nicer charts see: http://www.atsc.org/cms/pdf/audio_seminar/12%20-%20JONES%20-%20Audio%20and%20Video%20synchronization-Status.pdf

I've said before to start a thread or use avsforums for this - let's keep this thread practical.


RE: 24p and audio sync issues - robl45 - 2012-09-22

I posted on here last night, did it get deleted?


RE: 24p and audio sync issues - chris.j.schultz - 2012-09-23

(2012-09-22, 23:08)robl45 Wrote: I posted on here last night, did it get deleted?

I didn't see it, post again.


RE: 24p and audio sync issues - davilla - 2012-09-23

HAHAHA, 0.0004s -> 400 microseconds. The human physiology is unable to detect changes on that time scale be it hearing or vision.




RE: 24p and audio sync issues - robl45 - 2012-09-23

(2012-09-23, 00:48)chris.j.schultz Wrote:
(2012-09-22, 23:08)robl45 Wrote: I posted on here last night, did it get deleted?

I didn't see it, post again.

well it was kind of long, don't know what happened, to make a long story short, after fooling around for too long again last night and still having the same issues as well as hearing from at least 3 people that have "fixed" the sync issues by turning off sync to display, it seems pretty obvious to me that it is the problem. That coupled with the fact that other resolutions besides 24P seem fine. Further since the other resolutions don't suffer from rounding like 23.976 apparently does in xbmc and since reclock wouldn't work correctly for me when it was getting the refresh as 24 instead of 23.97542 which my display is set at, it would seem that possibly this might last post might fix the problem.

http://forum.xbmc.org/showthread.php?tid=118258&page=5&highlight=sync+to+dis



RE: 24p and audio sync issues - braz - 2012-09-23

(2012-09-20, 04:38)chris.j.schultz Wrote: I should also say that mutil-channel audio transcoding from AAC to AC3 also has caused issues with stuttering video (not framedropping tho). When playing MP4 files containing H264 and AAC I have to disable Dolby Digital capable receiver and DTS capable received from System Settings | Audio Output. mkv files containing H264 and AC3 are fine however.

Thank you so much for this, I had tried just about everything else trying to figure how why my mp4 files were stuttering. I didn't have a problem with stuttering mp4s until I upgraded to Frodo alpha 5 from Eden. Hopefully it will be sorted out by the time Frodo is released.




RE: 24p and audio sync issues - chris.j.schultz - 2012-09-24

(2012-09-23, 07:26)robl45 Wrote: well it was kind of long, don't know what happened, to make a long story short, after fooling around for too long again last night and still having the same issues as well as hearing from at least 3 people that have "fixed" the sync issues by turning off sync to display, it seems pretty obvious to me that it is the problem. That coupled with the fact that other resolutions besides 24P seem fine. Further since the other resolutions don't suffer from rounding like 23.976 apparently does in xbmc and since reclock wouldn't work correctly for me when it was getting the refresh as 24 instead of 23.97542 which my display is set at, it would seem that possibly this might last post might fix the problem.

http://forum.xbmc.org/showthread.php?tid=118258&page=5&highlight=sync+to+dis

OK, I had a look at that thread a few days ago, some of those issues sound awesome Big Grin I have syncing enabled on both on my TV's with HDMI and DVI/HDMI and am not seeing these crazy issues, infact, other than the AAC transcoding issues I am working better than I ever have previously.
(2012-09-23, 07:43)bryanbrazil Wrote: Thank you so much for this, I had tried just about everything else trying to figure how why my mp4 files were stuttering. I didn't have a problem with stuttering mp4s until I upgraded to Frodo alpha 5 from Eden. Hopefully it will be sorted out by the time Frodo is released.

Wink I am sure they will. If it doesn't get fixed soonish, I will file a bug report (if there isn't one already).


RE: 24p and audio sync issues - Kokonutcreme - 2012-09-25

I had the same issue with stuttering video playback after upgrading from Alpha4 to Alpha5 and posted what worked for me in another related thread.

http://forum.xbmc.org/showthread.php?tid=135990&pid=1198863#pid1198863