Hi

I'm using Kdenlive 0.8 on Ubuntu 10.04 Lucid Lynx and I'm having problems with the audio being bad and out of sync.
If I just add a clip to the project tree and play it, the audio is fine. If I cut the clip to shorten it, it gets out of sync.
For example; a person runs into a room and you hear the foosteps once, then once more after a second and after that the audio is out of sync the rest of the clip.

I've tried all the tips I found here. But it didn't help.

Then I found this and it solved the problem for me.
The solution is to separate the video from the audio (with Avidemux) and edit them on different tracks.

So, that solves the problem but is kind of a couple of extra steps. Does anyone have a simplier solution?

//Yosh

I just started having this problem. I tried Openshot too and had the same problem so I think it has something to do with MLT or FFMPEG. I like your solution. I'm going to give that a try unless I see some software updates today.

dana

If you play the source clip with ffplay and do some seeking on it while playing, does it exhibit the a/v sync problem?

No, it does not. The audio and video stays in sync.

Hi,

Also having the same frustrating issue here with both Kdenlive 0.8.1SVN and Openshot 1.4alpha1 notably with MPEG-2 (.mpg) files captured with a Hauppauge WinTV PVR 150. The files are captured from Satellite TV as DVD MPEG-2 and I cut them into clips with AviDemux, The resulting clips play with perfect AV Sync in AviDemux, Totem and VLC and can also be edited and rendered to H.264 via ffmpeg pipe without sync problems in Cinelerra/Cinecutie.

These clips playback without AV sync in both Openshot and Kdenlive as soon as they are imported before any heavy duty seeking, they playback seemingly better with ffplay but also suffer from loss of sync after some repeated random seeking. I'll gladly post up a clip if anyone would like to test and verify this behaviour.

I should mention that other types of Video (flv, dv, and even m4v) from an iPod touch do not seem to exhibit this loss of sync.

Any suggestions?

If you want to provide a sample clip, you can ftp it to mltframework.org. The ftp site is anonymous-only and upload-only meaning you can not list the files or download anything on it - only upload. If you upload something please let me know by private message.

@ddennedy

I sent an PM/Email to you via the forum mechanism here and I sent a copy to myself which I haven't received so I'm guessing you didn't receive it either. I appreciate you allowing me to upload to mltframework.org but I have my own webspace so I don't need to trouble you for that. I'll just post the link to the clip here. Clip: http://www.bandshed.net/files/Everyday%20People.mpg

Thanks very much for taking the time to have a look :)

I got the PM. I checked it out. It is proving tough to debug. I did find that running
melt "Everyday People.mpg" video_delay=0.5
(half second) fixes the sync problem.
A way to do that in Kdenlive is to use the delay0r effect set to 500. I will still try to look into the root of the problem.

@ddennedy

Your efforts on this are much appreciated, in some further testing I tried delayOr and found 480 was the ticket for perfect sync on my own machine and then the clips on the timeline have AV Sync...however unfortunately rendering is not producing an in-sync file. Have you tested a render from the timeline from the test clip? For comparison's sake I rendered to the iPod Touch 700k preset and the resulting file appears to be the same as the original file, in other words delay0r is either not taken into account in the rendered file OR it is throwing the rendered file 480ms ahead, I'll have to look closer and perhaps I'll try a render directly from the original file without delay compensation and see what the end result is and post back.

*EDIT*

Hmmm, as I guessed the delay compensation corrects the sync on the timeline but is definitely pushing the audio 480ms ahead upon rendering and if I leave the clips alone without it they are out of sync on the timeline but render correctly...weird!

No, I did not test with render. That is a very interesting and odd finding. Maybe it will give me another hint about the problem.

Hmmm,

Another wrinkle...

I grabbed a captured file that had not been edited at all or cut into clips and if I import into Kdenlive (0.8.1SVN) it plays on the timeline in-sync, however if I cut it into clips with AviDemux the resulting clips lose sync in Kdenlive as decribed previously. So it would appear that however Avidemux truncates the streams is the factor not necessarily MLT or Kdenlive. Thought I'd pass that along...

I guess what still is a bit of a mystery is why the AviDemux clips play back in VLC and Totem without the loss of sync..?

Thanks very much for looking into this.