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View Full Version : Handbrake audio/video sync problem...or is it itunes.




talkinghead80
Jan 5, 2011, 04:21 PM
I am completely stumped and hoping someone might have a solution, or suggestion for this.

I've been using Handbrake to encode DVD material for playing on ipad. I have tried every single preset; Universal, ipad imports from other sites, Apple TV, etc.

Every single encode has a delay between the audio and video of several milliseconds when played in itunes and synced to idevices. It's not enough for my grandmother to notice - but I notice and it never happened with previous encodes using handbrake.

I've played the videos in VLC player, mplayer, half a dozen others - no audio/video issues. The VLC player on ipad plays the videos with perfect audio/video sync. Only in itunes and idevices does this absolutely infuriating delay occur.

I've read on some other forums that people are having similar problems with their ipod touches and iphones and am wondering if it is a bug in itunes or is the ipad simply not able to handle the encoding. It can't be that, because the videos downloaded from itunes, both standard def and hd, are playing perfectly on it.

I'll add that I'm still on PowerPc iMac g5, but I can't see that it's a processor problem, because this never happened before.

Any help would be appreciated and let me know if anyone else is having similar issues.



talkinghead80
Jan 5, 2011, 04:40 PM
Edit - Forgot to mention that this audio issue is not constant throughout the video. For example, take Batman, which I'm using as my test. The audio is in sync in the beginning, and then there are some segments where it is distorted, then it goes back to normal a third through, then audio gets ahead of the video again, then back to normal, then audio ahead of the video AGAIN at the end. This is all a matter of milliseconds but it is incredibly distracting.

I can't figure what would cause a *not constant audio/video delay. This will sound incredibly stupid to some, but could it be my computer going to sleep mode at times during encodes?

I just do not understand it all.

dh2005
Jun 13, 2012, 05:25 PM
Edit - Forgot to mention that this audio issue is not constant throughout the video. For example, take Batman, which I'm using as my test. The audio is in sync in the beginning, and then there are some segments where it is distorted, then it goes back to normal a third through, then audio gets ahead of the video again, then back to normal, then audio ahead of the video AGAIN at the end. This is all a matter of milliseconds but it is incredibly distracting.


Yep, I have the exact same problem. I happened upon this thread by Googling (in vain) for an answer. I can confirm from my testing that the problem remains in the second- and third-generation iPads.


The deafening silence in this thread is, I expect, symptomatic of what frequently happens on this forum. At the heart of the issue - unless somebody would like to make my day by correcting me - is that the Videos app on the iPad is rubbish, and nobody wants to say so. Given that what Apple really want us to do with that app is watch content bought from iTunes - rather than watching our own transcodes - I don't think we should hold our breath waiting for them to improve it, either.

Before I give up completely; can anybody offer anything in reply?

mic j
Jun 13, 2012, 05:51 PM
Yep, I have the exact same problem. I happened upon this thread by Googling (in vain) for an answer. I can confirm from my testing that the problem remains in the second- and third-generation iPads.


The deafening silence in this thread is, I expect, symptomatic of what frequently happens on this forum. At the heart of the issue - unless somebody would like to make my day by correcting me - is that the Videos app on the iPad is rubbish, and nobody wants to say so. Given that what Apple really want us to do with that app is watch content bought from iTunes - rather than watching our own transcodes - I don't think we should hold our breath waiting for them to improve it, either.

Before I give up completely; can anybody offer anything in reply?
Not sure what you mean by the "deafening silence". Maybe no one has a clue as to how to help you. I have an iPad 2, watched lots of movie on it with no problem. Sorry, but that's my experience. Have you tried posting at the Apple Forum to see if anyone there has had experience with this?

dh2005
Jun 14, 2012, 04:05 AM
Not sure what you mean by the "deafening silence". Maybe no one has a clue as to how to help you. I have an iPad 2, watched lots of movie on it with no problem. Sorry, but that's my experience. Have you tried posting at the Apple Forum to see if anyone there has had experience with this?

I agree that no-one has a clue. The reason being that the app is defective and, thus, there is nothing positive that anyone can suggest.

Several people have posted this question in the Apple forum at different times over the last couple of years, and the only two replies I've come across are "make sure you're not running too many apps at the same time" (I'm not), and deafening silence.

I've watched lots of transcoded TV shows on my iPad - three whole series of Mad Men, for instance - and they worked fine. But as soon as I started watching movies on it, the audio-sync was seen to wander. For instance; when I was watching Airplane the other night, the sync was fine until about an hour into the movie, then it started to wobble. Previously I'd never watched anything longer than a 45-minute TV show; so maybe the length of the file is a factor. Skipping straight to that part of the file - rather than watching from the beginning - caused the error to recur, however, so it's not related to the sequential running of the file.


You say that you have watched movies successfully, and I don't doubt it. However, it is a matter of fact that certain people are more sensitive to audio-sync problems than others, and it may be that you are experiencing similar phenomena without them distracting you. My father, for instance, managed to watch the whole of Blade Runner on his iPad last night and said that he didn't see anything wrong with it: I watched it for thirty seconds, and the sync was all over the place. I do not consider this an 'impressive' attribute: on the contrary, I really wish that I wasn't lumbered with it, as it has cost me hours-upon-hours during which I should have been enjoying my media.


EDIT: In case the above reads at all provocatively, it's not meant to. There's no sense in arguing about/debating this. It works for you, and that's great. It doesn't work for me, however, and that rather sucks.

It looks like there's nothing to be done about this. Other than, perhaps, jailbreaking my iPad and seeing whether VLC can play these files properly. If anybody can comment on this, please let me know.

heliocentric
Jun 14, 2012, 08:05 AM
I have found audio sync problems when encoding DVDs using 'variable fps' (kept going in and out of sync), try switching to a set fps (25 if uk). That helped me...

dh2005
Jun 14, 2012, 09:29 AM
I have found audio sync problems when encoding DVDs using 'variable fps' (kept going in and out of sync), try switching to a set fps (25 if uk). That helped me...

Thanks for the suggestion. I'll look into it. Though I don't understand why the files should run perfectly well in iTunes, VLC, etc. but choke on the iPad.

heliocentric
Jun 14, 2012, 03:36 PM
Thanks for the suggestion. I'll look into it. Though I don't understand why the files should run perfectly well in iTunes, VLC, etc. but choke on the iPad.

some devices don't like videos with variable fps

dh2005
Jun 19, 2012, 09:03 AM
some devices don't like videos with variable fps

Didn't work. I mean, it did fix the audio sync issue - but the video flow was rendered stuttery, which created a new and equally irritating problem.

dynaflash
Jun 19, 2012, 10:15 AM
Didn't work. I mean, it did fix the audio sync issue - but the video flow was rendered stuttery, which created a new and equally irritating problem.
did you pick the appropriate constant frame rate for your source ?

Mackan
Jun 20, 2012, 09:33 AM
did you pick the appropriate constant frame rate for your source ?

Do you still recommend variable frame rate for normal use? It seems choosing constant frame rate is a safer choice in general? While I haven't had any problems myself so far, I would hate to encounter playback problem on some device in the future just because my movies are all variable frame rate.

dynaflash
Jun 20, 2012, 09:53 AM
Do you still recommend variable frame rate for normal use? It seems choosing constant frame rate is a safer choice in general?

Depends. In my case none of my devices have an issue with variable (same as source) so thats what I use. I wasn't aware the ipad had an issue with vfr. So if your going to choose cfr (constant frame rate) then make sure you pick the appropriate framerate for the source or its going to be choppy.

dh2005
Jun 21, 2012, 06:37 AM
did you pick the appropriate constant frame rate for your source ?

I did, yes. That wasn't the problem.

I read an explanation on another site explaining that framerates are ever-so-slightly changeable in movies. If you forcibly, robotically fix the framerate to be always 24/25/30fps then you will get mild stuttering.

Basically, this plan is sunk.

dynaflash
Jun 21, 2012, 08:56 AM
I read an explanation on another site explaining that framerates are ever-so-slightly changeable in movies.

Well of course ... hence handbrakes vfr (variable frame rate) being default. Actually the frame rate can vary by quite a bit. from 24 fps up to 30 fps sometimes depending on cgi etc.

heliocentric
Jun 21, 2012, 09:18 AM
It's definitely solved the problem for me sometimes.

I think blu-rays are a constant framerate at 24p unlike dvds which are variable?

But quite alot I've always noticed audio sync problems when encoding dvd's and changing to constant usually solved it...

All this encoding business is a bit of a minefield ;)

mic j
Jun 21, 2012, 09:29 AM
So if you set HB to variable frame rate/same as source, it shouldn't matter whether it is BR or dvd as the frame rate should match the source...what ever it is. Or am I missing something?

And from the posts above, it really sounds like an iPad player problem not a transcoding problem. So are you really trying to use HB settings to fix a player issue? And that might result in other unwanted artifacts, e.g. stuttering?

dynaflash
Jun 21, 2012, 09:43 AM
So if you set HB to variable frame rate/same as source, it shouldn't matter whether it is BR or dvd as the frame rate should match the source...what ever it is. Or am I missing something?
Nope, your not missing anything. Thats exactly how it works.

Mackan
Jun 22, 2012, 07:36 PM
Nope, your not missing anything. Thats exactly how it works.

I've seen that my source (MKV, Blu-Ray rip) is sometimes constant frame rate (when checking in MediaInfo), but when checking my conversion (using Handbrake, variable frame rate, same as source), MediaInfo shows it's variable, showing minimum and maximum frame rate which is different.

So what actually happened here? Did some frames get dropped at parts in the movie, and others increased?