Audio suddenly drifting out of sync

[dubmunkey]

Hi All,

On sunday my laptop was working fine, on Monday the audio started to drift on an AVI i was playing on MP Classic. I opened the same file up in VLC and had the same problem. I then watched another AVI and found that that was slipping as well, again on both players. I then tried an MKV file and had the same issue.

In fact anything I play has the same issue.

I started by reinstalling my codec pack (K-Lite Mega Pack) but that has made no difference so I am at a loss as to what has suddenly caused my laptop to start losing sync between audio and video.

Does anyone have any ideas? I'm pulling my hair out and unable to watch anything on my latop.

Cheers

[filmboss80]

Check the AVI file with GSpot to see if the audio stream is VBR (variable bitrate). If so, it might help to change it to CBR (constant bitrate) with VirtualDub.

I started by reinstalling my codec pack (K-Lite Mega Pack)...

Not sure if that contributes to the problem, but it sure doesn't help. You've been a member here for 3 years. Never read about all the codec pack nightmares in this forum?

[Calidore]

Hi, dubmunkey. You said the "laptop was working fine," but an audio sync problem is unlikely to be the laptop's fault. Have you watched these same AVIs on the same laptop with the same software without problems, or were those different AVIs? Did you create these yourself?

Codec packs are evil. They're believed to caused the deaths of millions of people throughout history. Download (from the official site) and install yourself any codecs you actually need, or just get ffdshow, which is not a codec pack and thus works.

Best,

Calidore

[redwudz]

From the description:

Doesn't sound like a codec problem, or a player problem, or a video file problem, unless all your files are corrupted. If the files are on a hard drive, not likely it either.

I would check to see what programs may be running in the background. Maybe a anti-malware program scanning the files as they play?

When the sound goes out of sync, does it help to pause the playback for a couple of seconds? Does the sync error stay the same during the playback, or does it gradually get worse? The first is an offset error, sometimes caused by corrupted files. The later is usually a problem with the length of the video and audio being different. Worse is a combination of both

I would drop one of the files, probably a AVI, not a MKV, into Gspot and use the render tool at the bottom to see how the file is being converted to audio and video. You may find something is messing with your playback. Pay especial attention to the audio path.

Also check your Task Manager for unusually high CPU or RAM activity. I'm assuming all your programs run at normal speed or I would also suggest a antimalware scan, Malware Bytes or Trend Micro. Both are freeware.

[dubmunkey]

Hi Guys,

Thanks for the replies, it is an issue affecting all files and is happening on files that have played absolutely fine before.

I am running an anti-malware (malware bytes) scan now so hopefully when I get back from work it will have finished and will be showing anything dodgy to be removed.

The audio can start of out of sync but gets progressively worse, I've tried the pausing trick to try and the coax them back into sync but it doesn't work, also the problem seems to start happening when I change from normal screen to full screen view, rather than maximising smoothly it seems to pause and then play and it's rarely in sync.

I've tried offsetting the audio but it doesn't stay locked in for long and gradually drifts out more and more. I am happy to remove the codec pack, I've only found it useful to play files like MKV's on Media Player and just use FFDShow but FFDShow is what I tend to use anyway.

Hopefully the scan will come back with something that needs removing, Ill also keep an eye on process explorer/task manager whilst playing. The problem did seem to go away after I did a full rebooot but had returned within say 20 minutes.

I will also try the GSpot thing.

I am now beginning to wonder if my audio is fine and that it's the video going out of sync as I do get a bit of flicker and judder (which I only really noticed last night), I'm wondering if something is happening to the framerate causing it to speed up and slow down and lose the lock on the audio- I am really hoping I can crack this as I have GB's of video that used to all work spot on.

I even moved the files to a different hard drive (because my external one would make a clicking sound every now and then) but it didn't seem to have any affect.

Thanks for all your suggestions so far, going to try them all tonight and get back to you.

Cheers

Dubs

[dubmunkey]

Hi All,

Reinstalling FFDShow and running a virus scan has seemed to have solved it, thanks vcery much for your answers I now know what I have to do if anything like this happens again.

Cheers

[dubmunkey]

Codec packs are evil. They're believed to caused the deaths of millions of people throughout history. Download (from the official site) and install yourself any codecs you actually need, or just get ffdshow, which is not a codec pack and thus works.

Best,

Calidore

Hi,

It looks like my problem has returned, it only seems to happen on MKV files now, so what I want to do is remove my codec pack and just stick to FFDShow but I have two problems.

First I can't get MPC to use FFDShow Audio, it never appears on my list of filters. I used to have two icons showing both FFDShow Audio and Video in my task bar but do not anymore and I don't know how to have them running as default for either MPC or VLC.

Secondly I would like to play MKV files through MPC. I don't like the VLC interface as much as MPC but I can't play MKV files through MPC if I uninstall my codec pack.

Could you point me to what I need to run, I think using a codec pack could be causing me problems but don't know how else to play MKV's through MPC.

Cheers

[dubmunkey]

anybody?

[AlanHK]

It looks like my problem has returned, it only seems to happen on MKV files now, so what I want to do is remove my codec pack and just stick to FFDShow but I have two problems.

There is nothing wrong with K-Lite. The ffdshow it includes is exactly the same as the one you get as a separate download. It just simplifies the install.

You can use K-Lite to activate/deactivate and reorganise your codecs. If you like you can set it to just use ffdshow and Haali splitter, which it includes, and that should do just about everything, including MKVs.

See K-Lite's "Codec tweak tool" and the configuration utilities it installs.

Codec problems are more likely to give complete failure to render rather than slowing. That indicates either some background process is sucking up your CPU cycles, or some setting in your video or audio drivers are off.

You can use Process Explorer to see what is running and how much processing it is using.


On my elderly machine if I try to do anything else at the same time as I'm playing an MKV, it starts stuttering -- though not getting out of sync that I notice.

[dubmunkey]

Thanks AlanHK

I think i've worked it out and now understand what codecs I can get away with.

Many Thanks