Author Topic: Why is it always producing out of sync audio?  (Read 6205 times)

thany

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Why is it always producing out of sync audio?
« on: March 15, 2013, 10:06:30 AM »
Every single video I convert, EVERY single one of them has audio out of sync with video.

I'm only producing MKV, and it does not matter wether I'm copying the audio stream, or recoding it to Vorbis. It also doesn't matter whether I convert the entire video or part of it, whether that part starts and/or ends on a keyframe or not. The input codec doesn't matter either, neither for video or for audio.

Like I said E-V-E-R-Y video has unsynced audio, which means I will have to jump into mkvtoolnix and guesstimate how much to shift the audio stream by.

Why is this happening?
« Last Edit: March 15, 2013, 10:08:25 AM by thany »

Jan Gruuthuse

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Re: Why is it always producing out of sync audio?
« Reply #1 on: March 15, 2013, 10:13:37 AM »
not happening here

thany

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Re: Why is it always producing out of sync audio?
« Reply #2 on: March 15, 2013, 03:29:36 PM »
So what could be wrong then?
There isn't a config option that says "keep A/V in sync", is there? It must be *something*

mean

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Re: Why is it always producing out of sync audio?
« Reply #3 on: March 15, 2013, 06:28:14 PM »
In most cases it is in sync, that was the point of 2.6
You do not give *any* detail about what you are doing, so dont be surprised if you dont get a good reply

Jan Gruuthuse

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Re: Why is it always producing out of sync audio?
« Reply #4 on: March 16, 2013, 09:50:55 AM »
So what could be wrong then?
There isn't a config option that says "keep A/V in sync", is there? It must be *something*
Ever considered something you're doing could be the cause of all your mishaps. I'm happily creating mkv's from several sources in SD/HD (hardware/internet) that play on most players.
As you're keeping secretive on what you're exactly doing: perhaps you have some issues of the (il)legal kind.

Sartre

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Re: Why is it always producing out of sync audio?
« Reply #5 on: March 18, 2013, 03:49:59 AM »
I transcoded a couple AVC/mkv movies today and, while the resulting mkv ran in sync with the original audio as an external file, when I muxed them together with mkvmerge, the video was advanced 750ms.   ???

thany

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Re: Why is it always producing out of sync audio?
« Reply #6 on: August 12, 2013, 06:35:12 PM »
Well, it's been a while, and this issue hasn't resolved itself.

I'm a bit secretive? I don't think so, it's just that I'm doing nothing out of the ordinary. I'm (still) at avidemux 2.5.6 and it's (still) producing out-of-sync videos almost all the time.

Here's what I do:
I download an MP4, which is somewhat legal (meaning illegal in some countries, but not in mine).
I load it up in avidemux.
Avidemux asks me the the imfamous "YOU WILL LOSE FRAME ACCURACY" question (this should be fixed, btw. it's like I did something wrong)
If I choose Yes -> it's fine and avidemux starts with a (infamous, again) green screen. There's is definately no frame accuracy to speak of. In fact, it jumps all over the place, even when navigating keyframes.
If I choose no -> Rebuilding frames -> CRASH. Marvellous.
(so I always have to choose Yes)
And then I just set the output to H.264, set some output options, I set the audio to Vorbis, the container to MKV, and let 'er rip (meaning Ctrl+S and go)

That is not a very exotic workflow. The files are not exotic in any way, because it [out of sync A/V] happens for every damn video it produces. At least the MP4->MKV workflow described does that.

Someone mentioned 2.6? Avidemux 2.6 is frakking unusable. It's clearly an unfinished product. See my other post about that. I have no reason to believe it's gotten better, so I have to stick with 2.5 to spare myself those kind of frustration (and deal with these).

Now, anyone knows a solution other than "it works for me"? That would be immensly helpful. Thanks!

mean

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Re: Why is it always producing out of sync audio?
« Reply #7 on: August 12, 2013, 06:39:13 PM »
First reply : out of sync issues are for 2.6.


thany

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Re: Why is it always producing out of sync audio?
« Reply #8 on: August 12, 2013, 06:57:45 PM »
Then at the VERY least, the 2.6 version should have filters loading/saving back in. No idea why that was removed, or by whom, but I was using that.

Also, other problems. I will make posts* for each of them for the sake of clarity.

/edit
* done (for now)
« Last Edit: August 12, 2013, 07:25:19 PM by thany »

mean

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Re: Why is it always producing out of sync audio?
« Reply #9 on: August 12, 2013, 07:45:27 PM »
Save as a project, only keep the filter part, done

thany

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Re: Why is it always producing out of sync audio?
« Reply #10 on: August 12, 2013, 08:19:01 PM »
The filter dialog could do exactly that.

No matter how you put it - it's removed functionality, and as you one-lined: it's rediculously easy to add back.

AQUAR

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Re: Why is it always producing out of sync audio?
« Reply #11 on: August 13, 2013, 02:01:14 AM »
I always take 2.6.x as a work in progress and its doing very nicely IMHO.

If it hasn't yet got a feature that is available in 2.5.6, and both are un-able to perform the task at hand then:
try a work around eg avisynth + avidemux 2.5.6.
try a different work flow.
or maybe just this one time another video program.

Feedback is great but does anyone really expect the developers of this program to provide instant fixes to end users?

« Last Edit: August 13, 2013, 02:13:24 AM by AQUAR »

mean

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Re: Why is it always producing out of sync audio?
« Reply #12 on: August 13, 2013, 04:00:17 AM »
indeed it 's easy to add it back. I'll see what i can do