tnmpg audio not in sync after 40 minutes or so it is then 3

[soccer09_9]

hi i have tried this with about 5 different movies and i tried to look for this in the forum and on this webpage but can't find it i have used virtual dub and have not used virtual dub and when i use virtual dub for the conversion in tnmpg it will be fine at the start and in sync then later onin the movie it is out about 3 seconds or so so what is up with that, please help it works fine with not using virtual dub but some movies it won't reconige that i have audio so i have to use virtual dub and i am using avi files if that helps any

[dinesh]

What are you converting from ? DivX?
Does the AVI File play perfectly on Windows Media player?
Sometimes sync problems are experienced with DivX video/mp3 audio. Try the following:
Open the AVI file in VirtualDub.
Click Audio->Full Processing
Click Audio->Conversion. Set Sampling Rate,Precision and Channels as required(44100Hz,16bit, Stereo).Click OK.
Click File -> Save WAV..Enter wav file name and save it.

Open the WAV file in WindowsMediaPlayer to check the duration. Your video and Audio should have the same duration.
You can reencode using the WAV file as your Audio Source in TMPGEnc.

[soccer09_9]

what happens if the duration of the wav isn't the same as the duration what do i do then??

[TheNob]

Did you have any droped frames when you captured? This can cause the Video and Audio to be out of sync.

[dinesh]

Audio and Video having different times is NOT a good sign.
How much is the difference?
I would do the following if faced with the same problem:
Play the original video.
Observe carefully where sudden offset in audio occurs.I would cut the clip just before that and with the remaining clip, take the audio separately, and offset it in an attempt to sync it. This approach may work only if there is a abrupt sync difference and this difference is constant for the remaining clip.

If the clip is such that you find a gradual drift in sync like 2 sec after 10min, 3 sec after 20 min, or so, change the frame rate.The following might help.
open the clip in Virtualdub, click Video -> Frame Rate, select "Change so that Audio and Video durations match".
the final clip from Vdub should be OK-although at a new "non standard" frame rate.

Note that trying to sync Audio and Video is a painful job as this requires severe human intervention and can get on your nerves.
You can get some info on http://nickyguides.digital-digest.com/index.htm

TheNob:
Dropped frames may not necessarily cause audio/video desync. Frames are sometimes dropped to maintain synchronization.





<font size=-1>[ This Message was edited by: dinesh on 2002-01-11 13:10:14 ]</font>

[soccer09_9]

it is 2 seconds different from the whole movie even if i use the video and audio durations match so how can i get rid of 2 seconds of the movie or what is wrong!!!

[nakis]

I have had some success with this same problem when using TMPGEnc to convert from divx to mpg, by setting the Audio sample rate from 44100Hz to 48000Hz the audio matches the video.

[dinesh]

Ok. If your original video has a constant desync of 2 seconds do NOT use the Change FrameRate to match Audio and Video.Use this method only if you find the Audio Desync increasing with time.
For Constant desync, open the Clip in virtualdub.
Click on Audio->Interleaving.
In the section Audio skew correction, enter the delay value in milliseconds. In your case +2000(if audio is playing 2 secs early) or -2000(if audio is playing 2 secs late). Note that 2000 need not be an exact figure. You may need to output as AVI for about 5 minutes footage and check your result. Alter the delay time accordingly and redo.
As I mentioned earlier, correcting audio sync is a real painful task.
For some info, check http://nickyguides.digital-digest.com/index.htm