Mac OS X - Audio sync off with refresh rate switching (nightly builds)

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juramusger Offline
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Post: #31
interesting! I think that for me the problem only showed up in beta 3, which makes it the inverse of what you describe, but I am not 100% sure about the earlier betas. I only switched to gotham in the beta stage.

Edit: OK, I was wrong, I have the problem in beta 2 as well.

Edit 2: checked with my MBP sporting an Nvidia 320m - same problem. Damn!

Still looking for a good collection of test files and any further tests I could run.


Edit 3: a couple more test results:
"Sync playback to display" makes no difference for me, enabled or disabled, either of the three methods when enabled.
I tried the build xbmc-20140325-c49edc4-osxffmpegvda-x86_64 from http://trac.xbmc.org/ticket/14978 with vdaffmpeg enabled:
The MBP with the 320m crashed so hard I didn't even get a crash log, had to force shutdown.
The MBA with the Intel HD4000 works slightly better with this build, pausing only throws the sync off approximately 100ms and seeking in either direction consistently gets it back to perfect sync.

So, what to do now?
(This post was last modified: 2014-04-05 17:47 by juramusger.)
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JensGH Offline
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Post: #32
(2014-04-05 09:00)Rassi Wrote:  Yes, it is well known that switching to software decoding "fixes" this. But I think the majority of us would prefer hardware acceleration to save cpu/fan noise.

Which graphics card do you have, since you also have sync problems with hardware acceleration?

I use a Mini 2012 with Intel HD Graphics 4000.

For myself it is no audible difference, but this is something everybody must try for himself...
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juramusger Offline
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Post: #33
So, some more testing and interesting results:

1. I installed SwitchresX, created a 23,976 hz profile and tested with this, no change. I also noticed that if sync playback to display is enabled with either method XBMC would still play at 24hz, not 23,976. Anyway, this didn't help. Or did it?

2. It seems to have something to do with refresh rate switching after all. SwitchresX needed me to restart a couple of times, and I noticed something: The problem only occurs if the refresh rate of the TV has been changed at least once. After a fresh restart with 24hz everything is alright. Switching it once, whether done by XBMC for the playback of a file of another refresh rate or via System Preferences the problem occurs. Restarting and staying at 24hz fixes it again. Even unplugging and replugging the MDP-HDMI cable now seems to fix it until the next refresh rate change.
I am pretty sure none of this helped before, maybe some residue from SwitchresX helps here? The TV is now labeled "SwitchresX 4 LG TV" instead of just "LG TV". I have no idea what's going on, but this is an almost acceptable state of affairs for me atm. I just have to replug the cable after watching some non-24p content before watching some 24p content.

3. Even if I am now hesitant to change something again because I am almost content with the result I would do it of course to help fix the underlying issue. So if any of the devs need me to follow certain steps and provide a log I will do it.

Edit: I am back on beta3 btw, still on OSX.9.2 on the 2012 MBA
(This post was last modified: 2014-04-07 17:15 by juramusger.)
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juramusger Offline
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Post: #34
I really don't want to come off as feeling entitled to anything, I am very grateful for the awesome piece of software that is XBMC.

With that said, a question to the developers: Don't you want me to investigate further? Have you really given up on this issue for Gotham?
As I said, I can live with the current state of affairs. It's still strange that this issue seems to be resolved for SpaceMonkey in the latest builds but not for JensGH or me.
Did I miss something in my reporting of my investigations that makes you seem to disregard them?

Again, I thank everyone for their efforts and if you say: "live with it!" or "there is more important work to be done at the moment" I'll understand. It would just be nice to hear what you are thinking or if I did something wrong in my posting behaviour.

Thank you!
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Memphiz Offline
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Post: #35
You ever considered that we are busy in real life? *sigh* ...

AppleTV2/iPhone/iPod: HowTo find debug logs and everything else which the devs like so much: click here
HowTo setup NFS for XBMC: Wiki NFS
HowTo configure avahi (zeroconf): Wiki Avahi
READ THE IOS FAQ!: iOS FAQ
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juramusger Offline
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Post: #36
Hey Memphiz,

sorry if I came off as impatient, of course I considered that and I tried to convey in my last post that I don't feel entitled to anything. I just got the feeling that this thread became abandoned and I was mostly talking to myself over the last 10 days. This is why I also asked if I made any mistakes in the reporting of my tests that made them useless.

As I tried to express in my last post my question was mainly if this issue is still considered "interesting". Maybe I am a little obsessive about those things, but maybe you too know how you need to tick things off to get them off your mind, even if just by knowing that you hit a dead end (as an Apple user I'm pretty accustomed to those).

I did not want to accuse you or anyone else of being negligent or anything. Sorry to have made you sigh.
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Memphiz Offline
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Post: #37
Interesting yes - someone around with the needed time and knowledge to fix or reproduce it - no. Same like with the dozens of other osx and ios related issues. You can count the osx/ios devs in our team on one hand. You can count the active ones without a hand.

AppleTV2/iPhone/iPod: HowTo find debug logs and everything else which the devs like so much: click here
HowTo setup NFS for XBMC: Wiki NFS
HowTo configure avahi (zeroconf): Wiki Avahi
READ THE IOS FAQ!: iOS FAQ
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BDPNA Offline
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Post: #38
Memphiz has been the only reason (or one of the few) I have been able to enjoy the latest XBMC builds on my mini. I'll ride the ship until it sinks to the bottom of the ocean then sell my mini and build an ion or something, I guess.

This bug is a bit of a pain, but once I remember to do a step forward, step back, after a pause or an info window display, it gets more tolerable. Still, pretty weird bug for sure. Wish it was as easy to troubleshoot as it is to produce, but it sounds like the limited hardware specs to make it happen plus the limited amount of devs to deal with it, we may be stuck with this one for a while.

Gotta say sir big thanks for all you have done so far though, I think everyone who posts here with issues (hope so anyway) understands all the work on XBMC is not done for payment but for the love of the product and what it represents. Long live XBMC (even if it means I can't run it on my Macs anymore!)
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juramusger Offline
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Post: #39
(2014-04-16 01:38)BDPNA Wrote:  Memphiz has been the only reason (or one of the few) I have been able to enjoy the latest XBMC builds on my mini. I'll ride the ship until it sinks to the bottom of the ocean then sell my mini and build an ion or something, I guess.

This bug is a bit of a pain, but once I remember to do a step forward, step back, after a pause or an info window display, it gets more tolerable. Still, pretty weird bug for sure. Wish it was as easy to troubleshoot as it is to produce, but it sounds like the limited hardware specs to make it happen plus the limited amount of devs to deal with it, we may be stuck with this one for a while.

Gotta say sir big thanks for all you have done so far though, I think everyone who posts here with issues (hope so anyway) understands all the work on XBMC is not done for payment but for the love of the product and what it represents. Long live XBMC (even if it means I can't run it on my Macs anymore!)

Total agreement! Again, many thanks to Memphiz and all the other devs, XBMC IS awesome!
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SpaceMonkey Offline
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Post: #40
Beta 3 was fine for me in every regard. I mostly watch only tv shows but i did watch few movies as well and those were fine.

After upgrading to beta 4 all seemed fine while i had been watching episodes, but after watching the first movie, i immediately noticed that all the issues were back. AV sync goes off just be letting the movie play.

I thought maybe this has something to do with how the video is encoded, and the bitrate since episodes seemed fine so i thought maybe it has something to do with vdadecoder, but no. Only fix i could find was to turn off refresh rate switching.

I know debugs logs are missing, i had planned to grab them today and maybe even shoot videos, but something else came up. I'll try to post them tomorrow just in case there's hope for solving this.

Edit: now that i've read my earlier posts, i did infact have this same issue in beta 3 with movies.
(This post was last modified: 2014-04-27 22:14 by SpaceMonkey.)
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xorcist83 Offline
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Post: #41
I'm also having this issue on the final 13.0 version. Audio is ahead of video by about half a second. Seeking fixes it. Seems to happen with all content, I just didn't notice it at first because a lot of content (i.e. movies and tv shows with intros) I usually skip and this fixes the delay. If there's anything I can contribute to with logs or testing, I'm happy to do it.

OS X 10.9.2
Mac Mini Late 2012 (i7 and Intel HD 4000)
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BDPNA Offline
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Post: #42
I believe we narrowed this down to 24fps content but I'm not even sure as I seem to recall some TV shows doing it as well.

I'll do some testing on the final build today and see, but this may be one of those items that never gets fixed, since it seems isolated to certain mac minis and running the latest version of OSX. I seem to recall earlier versions of OSX didn't have this issue.

Shame though as I'd love to keep using this mini as it's been a solid HTPC performer with a great form factor though maybe it's time to build a cheaper ion box or something!
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juramusger Offline
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Post: #43
(2014-05-08 17:21)BDPNA Wrote:  I believe we narrowed this down to 24fps content but I'm not even sure as I seem to recall some TV shows doing it as well.

I'll do some testing on the final build today and see, but this may be one of those items that never gets fixed, since it seems isolated to certain mac minis and running the latest version of OSX. I seem to recall earlier versions of OSX didn't have this issue.

Shame though as I'd love to keep using this mini as it's been a solid HTPC performer with a great form factor though maybe it's time to build a cheaper ion box or something!

As from my testing the issue seems to be correlated only with 24p material and only with hardware acceleration and vertical blank enabled. Or there are different issues, as SpaceMonkey reports having it with other material as well.
It is however not isolated to a specific chip or OS. Both my Macbook Pro with an Nvidia 320m and my Macbook Air with Intel HD exhibit it. I didn't test Mountain Lion on the MBA but the MBP has the issue under 10.8.5 and 10.9.2.
I also recall a similar issue reported in the Windows section of this board so I am not even sure if the root of the problem is Mac specific, but here I speculate. Edit: This is the thread I was referring to, seems to be fixed in Gotham final for at least one member though.

I also stand by for further testing.
(This post was last modified: 2014-05-09 00:38 by juramusger.)
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ercaronte Offline
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Post: #44
I guess this is the right thread to post what I observed today, while migrating from 12.3 to 13.0 on a MacMini.

When the video starts, no out-of-sync (Sync error close to 0%)
I observe out of sync issues on any video after pause or a "goto" action, like going next chapter or to a specific time. Typica sync errors are around 800-1200% (from the overlay status).
Interestingly, when I press the pause the sync error continues to increase. When I press play again, XBMC does not manage to bring it back to 0.

Problem occurs on all 24p content (mostly 1080p on MKV, but also BD), ONLY when "Display refresh rate to match video" and "Sync Playback to Display" are both set.

Problem is independent from:
- software or hardware acceleration setting.
- Vido Sync method
- any Audio settings (fixed, optimized, best...).

Needless to say, on Froyo 12.3 everything is perfect.

HW/SW/XBMC
MacMini 2010
Maverick 10.9.2
Direct connection to Monitor via HDMI, Audio Output device: HDMI, #channels 2.0

Let me know if I can help
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juramusger Offline
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Post: #45
Sounds like the same problem. But...

Are you sure that "sync playback to display" is necessary for it to happen? For me it is independent. "Vertical blank sync" is necessary for me to produce the issue though. (And definitely needs to be on to make stuff watchable, otherwise: screen tearing)

Are you sure that you *really* tried with software decoding? I ask because for me hardware acceleration is only disabled on Gotham final when I disable "use vda decoder", a toggle only active when hardware decoding is selected. Just switching to software decoding does nothing for me, XBMC keeps using vda. You can check this in the codec info overlay, hw says something like "vda-x264", sw says "ffmpeg-x264". There is definitely no problem for me when I really use sw.
(I did report that strange settings behaviour in the Gotham bug-testing thread but didn't get an answer)

And just in case the developers find time to further look into this problem you should provide a debug log.
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