skip forward causes DTS audio to lose sync

[mikep1]

Hi, I'm having trouble playing mkv files with DTS audio. I'm using the Win32 wave output (the DirectX output popped really loudly if I used FF or skip).

When I skip around the movie, there seems to be a problem with the DTS as seen by my AVR - the audio stops, or comes and goes, and when it finally starts up again, it's often out of sync with the video (by as much as a second). The DTS indicator on my AVR flashes on and off while this is happening.

I suspect it's VLC (v2.0.2) because if I go into the audio menu and change from DTS to 5.1 and then back to DTS, the audio will sync up with the AVR in DTS immediately and be properly coordinated with the video. I don't recall this (nor the popping) happening with V1.x, where I was using directx audio.

Am I missing a setting or something?

Mike

[Lotesdelere]

Please open Tools -> Messages (set Verbosity to 2) before you start the playback and then paste the full resulting log here or on Pastebin.com if it's too long.

Also upload a short sample of a problematic file to either http://streams.videolan.org/upload/ or to MirrorCreator.com or to EmbedUpload.com, so it will upload the file for you to several other hosts, and then post the link to the file here.

[mikep1]

Sure - I captured a log and uploaded it at http://pastebin.com/nQfaR0V4. I had to trim it a bit to fit, but I think I preserved everthing important and I marked the places where I snipped.

It took a few jumps around till the DTS stopped. You'll see in the log near the end where I switched to 5.1 then back to DTS over SPDIF, at which point the sound came back.

It'll take me a little while to find a small mkv/dts sample that has the problem, I'll post back when I find one.

Mike

[mikep1]

I've found it happens on most of my mkv/DTS files, while a few others with DTS work just fine. I was able to find a sample mkv that has the problem, which I can get to occur by using the mouse to jump back and forth in time during the movie.

I hope I've got it uploaded properly:
http://www.mirrorcreator.com/files/PGCN ... .mkv_links

Let me know if I can do anything else to help.
Mike

[Lotesdelere]

I can't download the file, please use Rapidshare and Depositfiles through EmbedUpload or use http://streams.videolan.org/upload/ .

[mikep1]

Not sure why, but I can't seem to upload the sample to the videolan site, so I've sent you a private message with a direct link to the file.

Mike

[mikep1]

Any update on this? Do I have a config problem?

Let me know when I can take the file off of my web page.

Thanks!

Mike

[Jean-Baptiste Kempf]

FIle uploading to http://streams.videolan.org/issues/3477 ... Sample.mkv

[Lotesdelere]

I can't reproduce the issue in software mode, as I'm not using an AVR. However I've noticed seeking in this file is quite slow, so you should try to extract all of the streams with MKVToolnix and then remux the raw streams. And finally check if the new file is playing fine.

[mikep1]

Ouch, that's not really practical, they're not my files and it seems like more than half of the MKV/DTS files I get show this problem.

I did find that if I disabled then enabled the audio track, the audio would sink up immediately - works fine for me, but not practical for my gf.

I guess I'll have to switch things on my home theater so that she's using WMP for MKV files. None of the DTS loss, unsync'd audio, nor loud popping over directx (which maybe is linked to the DTS sync issue too?) happen with WMP - all the MKVs work fine. Too bad .

Thanks anyway.

Mike

[gallua]

I'm actually having this same problem with all of my MKV's that have DTS. When I skip it loses sync but if I disable and enable to audio track it works just fine. I didn't used to have this problem when I had my old HTPC (just built a new one) and the only thing that changed was I'm now on a 64 OS. I also have the most updated drivers, etc.

[mikep1]

I was wondering if there's a defect record that I could follow to see when this issue is repaired? I really would prefer VLC to WMP so I'd like to switch back when I'm able.

BTW, I wonder if the slow seek mentioned is related (another symptom) of the DTS sync issue? Perhaps it is indeed a problem with the mkv files (there are many then that have this problem). It seemed that VLC 1.x was able to work fine with them, and as gallua points out, it may not be specific to my machine, config, or files.

[Lotesdelere]

You should create a ticket on the VLC Trac with the links to this thread and to the non working file.

[mikep1]

Ok, done: http://trac.videolan.org/vlc/ticket/7337

[mikep1]

Quick update on this - my gf went back and checked some of her older MKV/DTS movies that worked fine in VLC v1, and they all have this same problem in VLC V2. It sure looks like an audio sync problem - I can see my AVR struggling to sync up after a seek, occasionally succeeding, often needing an audio disable/enable before it recovers. All of the old movies MKV/DTS movies work fine w/ WMP.

[Ebbyb]

I know this is a windows thread, but I'd like to point out that I have this problem too with VLC version 2.0.3 (Intel 64bit) and OS X 10.6.8. I passthru DTS-HD MA audio from bluray sources when I encode my disks using Handbrake to MKV files.

I have found that only the "Built-in Digital Output (Encoded Output)" device on my system will cause the sync issues. I can not recreate the sync issues using "Built-in Output", "Built-in Line Output", and "Built-in Digital Output" Audio devices.

Sync is restored by rewinding a bit, jogging, or changing the audio output to another device and back again.

I hope this helps narrow things down so we can nail this bug.

[sushinut]

Wow. I've had this problem for ages... and only now decided to see what the problem was. I'm using A/52 over S/PDIF. Every single mkv with DTS can be made to desync. Sometimes it happens 50-60% of the times I try... other times, I'll skip around 8 or 9 times until it finally desyncs. But every mkv I have ever watched will desync within 10 or attempts (timeline changes).

Sync is restored by rewinding a bit, jogging, or changing the audio output to another device and back again.

I always have fixed it by clicking on the timeline a few seconds earlier. Often, it doesn't work, and I have to go back and forth two or three times to resync. Occasionally, it will alllllllmost sync-- but it'll be off by an annoying fraction of a second. I spend 10-15 seconds watching lips, rather than watching the movie, just to see if it is correctly sync'd.

I just now tried the audio device "fix." That appears to work very well, but unfortunately, I miss about 5 seconds of dialogue while jumping between the devices.

In my testing, it's not just jumping forward that causes the desync'ing. It can happen in either direction. It can also happen when holding down the forwards or backwards buttons.... basically any skipping/movement of the timeline can throw the audio out of sync.

[yamahaman]

Hi gents,

I have the same issue, it does not happen with AAC/Dolby Digital, only with DTS.

I am playing mkv files form VLC 2.0.5 in Windows 7 to a AV receiver which should decode the DTS signal. Most of the files initially work but loose synch or become completely silent after a while or when skipping.

Any progress regarding this? Seems to be a common problem since six months ago at least (looking at the date of the comments).

Can you please take a look at this?

Regards,
Yamaha.

[Alwinn]

I'm having this issue. Not related to any specific file type. MP4 AVI M4V FLV those are just some of the types I remember. Any type of skipping in the video 'causes it to lose audio. Majorly annoying when you want to go back/forward in a movie and you can't because of the audio. Was running a slightly older version and thought maybe an update went out that had fixed it, but after just updating it and having it still be a problem I went for a solution. Mosts things I found were unrelated or people just never figured it out. Or it was years old (5 years or so) and so I thought I'd post and see if an actual working response can come from the people that program it. It's most irratating when watching a full-length movie. Being an hour in and you need to stop or wanna go back to rewatch a joke or action scene and then having the audio cut-out. You then either need to rewatch the first hour or spend an hour (least I used to till I seen that I can turn the audio on/off) hoping that I jump forward and it doesn't lose audio. While it is minor to turn audio on/off, it's still an annoyance and shouldn't actually be happening.

So, is there any fix in the works (that looks to have been happening for about 5 years or so) so that this can just be fixed? Or will it stay ignored (like it was 5 years ago)? I love VLC over any other media player, but having to turn audio on/off each time I skip will be almost as annoying as closing VLC and reopening media and hoping the audio stays after a jump.

[SpewHole]

I've noticed this worse in DTS .mkv files which have been bookmarked with chapters. (Observed using 2.0.8 x64 Windows.) For those types of files, skipping forward or backward will always cause the audio to desynchronize.

If the DTS file has no bookmarks/chapters, seeking/jumping to an earlier progress points will not desynchronize (and even resynchronizes) the audio for me.

Either way, the .mkv files will also drop the audio or stutter from time-to-time when seeking/jumping, but this is true of Dolby-encoded .mkv's as well.

Fun fact: Dolby's used to be unseekable with VLC. I still catch myself fast-forwarding or rewinding, then quickly pausing and unpausing, hard-wired in my memory from when Dolby had sync issues and that was the workaround.

Thanks for the tip about disabling/enabling the audio. Too bad there is no way to assign that function to a hot-key.