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+---- Thread: 24p and audio sync issues (/showthread.php?tid=80247)
RE: 24p and audio sync issues - robl45 - 2012-09-04
(2012-09-04, 13:17)torcar Wrote: The core issue here is unfortunately that XBMC never seems to get a good hang of 24p audio sync.
I'm no expert just to state that first of all, but it also seem strange to me that almost any other videoplayer I try plays back 24p material with excellent sync.
The upside here is that it seems that the devs are working on the problem, so we'll just have to cross fingers and hope that this will be a forgotten chapter some time in the close future
really? its been over a year and a half already so I don't think it will ever be fixed. I've seen a lot of reasons for why it doesn't work even though it works on other platforms, but no fixes yet.
(2012-09-03, 20:18)steelman1991 Wrote:(2012-09-03, 19:44)robl45 Wrote: So what, if you want bitstreaming and likely crappy video, you can turn the option off. People have blown bitstreaming way out of proportion
Touchy! Touchy! Who or what rattled your cage?
and what does bitstreaming have to do with 'crappy video'?
All I was pointing out was that this was not a solution for those who want to bitstream.
what does bitstreaming have to do with this issue? without a sync method, video will be crappy if the audio clock and video clock are not the same which is the case in 99% of situations. Further, 99% of people will not know the difference between bitstreaming and not bitstreaming and from what i've heard, if its decoded properly, no one will tell the difference. Finally, development seems to be full speed for bitstreaming while the thing that 99.9% of people are using xbmc for doesn't work which is video sync with bluray videos.
RE: 24p and audio sync issues - steelman1991 - 2012-09-04
LOL. Made up stats - or can you actually substantiate them. There are a few (somewhat less than 99.9% of users), yourself included who seem (?) to have a problem with sync.I had problems earlier in the dev cycle with audio sync, but the introduction of the new AE cured those in one foul swoop. If this was more widespread there would be numerous threads and comments from users to that end. There has been sporadic activity in this thread which hardly proves the existence of this as a major issue - it may be to you, but I would suggest to 82% of users it isn't - see I can make up stats as well.
I also never made any differentiation between bitstreamed and decoded audio - the reason why 99% (sorry that should read 100%) of people will not know the difference is because there is no difference
I appreciate that the overall experience isn't nice to the end user, but audio bitstreaming has no effect on the visual quality of the video (pixelation, lack of detail due to poor encode all contribute to crappy video - but certainly not bitstreaming) - so no your wrong it doesn't lead to crappy video - just poorly synched audio
Re: 24p and audio sync issues - Stefanhvt - 2012-09-04
Well, in the frodo version it IS FIXED.
RE: 24p and audio sync issues - DDDamian - 2012-09-04
Been a while since I waded into this, but for those who have had success with AE (both for bitstreaming and sync) I'm glad to hear it.
For those who still experience issues with sync (I never have or at least have never seen it) I'm not sure what to tell you. I've not heard of a single dev who sees it on their rigs, at least not in team chats. Are we blessed or blind?
RE: 24p and audio sync issues - Stefanhvt - 2012-09-04
(2012-09-04, 20:03)DDDamian Wrote: Been a while since I waded into this, but for those who have had success with AE (both for bitstreaming and sync) I'm glad to hear it.
For those who still experience issues with sync (I never have or at least have never seen it) I'm not sure what to tell you. I've not heard of a single dev who sees it on their rigs, at least not in team chats. Are we blessed or blind?
I probably all depends on the time of delay a specific lcd panel creates of it's own.
Most cables send synced signals so there is no problem anymore. The only thing people wan't to make sure is the ms delay the tv has itself.
For all those that are still experiencing sync issues it's good to first explore a special input mode on your tv. Like gamemode, or pc mode. They will probably have no sync issues.
After that try to find the proper audio delay for your tv in normal mode and be exact to milliseconds. Studies have proven that people can sense only 1 ms or even 1/3 ms of delay.
RE: 24p and audio sync issues - sim888 - 2012-09-05
Thanks Stefanhvt, i'll give that a go tonight (PC / Game setting), as i have been experiencing all manners of frustrations with sync issues
DDDamian, i'd love to know what the setups are for those that have zero issues, across all video/audio types, containers & frame rates...i've just gone through all types of setups over the past week - xbmcbuntu releases - final & xbmcfreak releases / various windows releases - finals, nightlies & snapshots / openelec finals & beta's, and all have had some manner of issues on my samsung series 6 tv / atom+ion setup - who knows though, maybe Stefanhvt's suggestion of PC/Game mode will work, i'll report back (its about the only thing i haven't thought to try
At the moment, i'm OK with Openelc + standard gui setting of change refresh rate to match, video vsync + an advancedsetting.xml entry to delay 24p stuff by about 300ms - that and i now have about 6,654,745 8GB usb drives that i can boot various releases from haha
RE: 24p and audio sync issues - djon - 2012-09-05
(2012-09-04, 20:03)DDDamian Wrote: or blind?
This
Or maybe you just spend all your time on developing instead of watching stuff on XBMC. I've broken several friends' hearts when they thought they didn't have any sync issues and I then showed it to them. Guess I should have let them decide between red og blue pill first
I've seen it on 3 different TVs (both LCD and plasma), Windows, Linux in several versions and on at least 3 different PC's, so I'm sure that those who don't see it either don't watch "scene releases" or are blind. For me it's not a 100% science. Some movies/TV episodes don't suffer from it, others do. There's no pattern that I can see. Currently I have set a default delay of 125ms for 23-24fps material in advancedsettings.xml, and now I don't see it too much anymore. Well I do, but it's not quite as annoying and sometimes I actually watch something fully without reminding myself that it's there.
RE: 24p and audio sync issues - DDDamian - 2012-09-05
(2012-09-05, 08:14)djon Wrote:(2012-09-04, 20:03)DDDamian Wrote: or blind?
This
Lol - that's pretty much the case
- That and I'm much more audio-(ec)centric. Sometimes ignorance is bliss, but I just can't see it on three different PC's
Re: RE: 24p and audio sync issues - Stefanhvt - 2012-09-06
(2012-09-05, 08:14)djon Wrote:(2012-09-04, 20:03)DDDamian Wrote: or blind?
This
I've broken several friends' hearts when they thought they didn't have any sync issues and I then showed it to them. Guess I should have let them decide between red og blue pill first
I've seen it on 3 different TVs (both LCD and plasma), Windows, Linux in several versions and on at least 3 different PC's, so I'm sure that those who don't see it either don't watch "scene releases" or are blind. For me it's not a 100% science. Some movies/TV episodes don't suffer from it, others do. There's no pattern that I can see. Currently I have set a default delay of 125ms for 23-24fps material in advancedsettings.xml, and now I don't see it too much anymore. Well I do, but it's not quite as annoying and sometimes I actually watch something fully without reminding myself that it's there.
Your right. That's the only cure.
RE: 24p and audio sync issues - steelman1991 - 2012-09-06
(2012-09-05, 08:14)djon Wrote:Ciould it have something to do with the source of the material being watched? (Crappy encode). I don't watch scene releases, or downloaded material of any kind and I certainly don't have the problem. Perhaps time to watch some legitimate sources or change your scene downloads to another group and see whether it resolves any issues. Worth a try?(2012-09-04, 20:03)DDDamian Wrote: or blind?
This
I've broken several friends' hearts when they thought they didn't have any sync issues and I then showed it to them. Guess I should have let them decide between red og blue pill first
I've seen it on 3 different TVs (both LCD and plasma), Windows, Linux in several versions and on at least 3 different PC's, so I'm sure that those who don't see it either don't watch "scene releases" or are blind. For me it's not a 100% science. Some movies/TV episodes don't suffer from it, others do. There's no pattern that I can see. Currently I have set a default delay of 125ms for 23-24fps material in advancedsettings.xml, and now I don't see it too much anymore. Well I do, but it's not quite as annoying and sometimes I actually watch something fully without reminding myself that it's there.
RE: 24p and audio sync issues - torcar - 2012-09-06
Already tried that... no doubt there are bad encodes out there and they play back bad on any player... but the average blockbuster/series etc tend to have good sync.
So... i've tried this many many times and when XBMC fails to sync I can start the same file in another player and it plays back with perfect sync. No other changes than just closing xbmc and opening MPC or some other player...
I've also basicaly replicated the hardware setup of one of the devs and no doubt the hardware is good and with the AE branch there is much less trouble than it was with EDEN, but... it's still there in a much bigger degree than on any other player i've tested.
I've tuned my system to compensate for TV-lag etc, but XBMC still goes in and out of sync.
And yes... as someone else said... it has been like this for a couple of years now, but hey... that doesn't mean we should stop crossing fingers and hoping;p
RE: 24p and audio sync issues - steelman1991 - 2012-09-06
Here's something to try - just for the hell of it and it may just give DDDamian and the others something to ponder. Try a file without vsynch enabled. I seem to remember that turning it off brought things back to sync when I was having issues (pre AE). Makes the video unwatchable but perhaps something that if confirmed by someone else could be looked at by the devs.
RE: 24p and audio sync issues - torcar - 2012-09-06
Another thing... i have been looking for this several times but never found anything usable and i'm not into encoding video myself.
It would be extremely helpful both for users and devs to have a 24p .mkv file to test audio sync with. Something like this: http://www.youtube.com/watch?v=bCPEidaVzQU only in 24p and in a .mkv container.
Even if XBMC plays back in perfect sync most people will still have a slight "audio before video" issue due to the processing of both audio and video signal in recievers, TV's and so on... so to have a good quality (good encode) 24p .mkv file to test with would make people able to use the built in lip-sync function in most recievers to adjust for best possible sync.
Does anyone know of a clip like this or is anyone up to the task of making one?
RE: 24p and audio sync issues - liquidskin76 - 2012-09-06
I'm into video encoding, and creating video backups from my BD/DVD collection so i'm well placed to carry out tests as i also still see the 250ms delay on AE builds. I did lots of testing a while back, however would like to recheck some stuff. Leave it with me, i'll do that tonight and update on it then.
If memory serves me right, basically, i saw differences in sync based on av container. For example, an M2TS file from a BD folder backup was fine on sync, however when the audio/video from that same BD folder was muxed to MKV using either MakeMKV or MKVMerge, sync was out.
If i give the MKV a 250ms audio delay (during mux using MKVMerge), then sync was good at 24p. Can't remember the sync issue when audio was decoded by XBMC to lpcm.
Now, as an interesting (and totally unrelated!) side note... not sure how audio is handled when played at 60Hz using 2:3 pull down, however even with that 250ms audio delay muxed into the MKV file, XBMC played it in perfect sync at 60Hz! I was expecting it to be out by 250ms!! Anyway...
Another interesting (and very very relevant) side note... again if memory serves me right, i saw the exact same sync problem using mpc-hc and refresh rate switching.
As well as testing sync on decoded audio, i'll also test sync with display set manually to 24Hz, and with refresh rate switching disabled.
Anyway, i'll get testing again tonight to confirm, and post an update. What i'd like to know is what container people are using when they see the sync issue? Is it only MKV?
Cheers
I believe providing files for devs to test with won't be of any help. I've already covered that with dddamian, and on a file i had sync issues with, he didn't.
Cheers
RE: 24p and audio sync issues - liquidskin76 - 2012-09-06
Not sure if any of the above will help with narrowing the cause down?
[EDIT] If it turns out that the same issue is present with mpc-hc and directshow codecs, then my bet is on it being hardware related (most likely av receiver). Strange that it appears to be 250ms for everyone. Maybe it's just that it's delayed and by everyone going with a 250ms delay to fix, that 250ms usually pulls it close enough to sync so that people think sync is then spot on, however it's actually just close to being spot on (but by a varying amount for different people)?
Everyone confused now... good!