Downloaded video out of sync - how to fix

[steviewilson]

I downloaded a Weller gig as a DVD file (vobs etc) but its slightly out of sync, how best do I sort it before burning to disk?

Stevie

[AlanHK]

Convert it to MPEG (VOB2MPEG).
Load the MPEG in a media player, take note of a couple of exact time events you can sync sound against.
Eg, something falling and making a bang.

Then demux, then load the audio into a sound editor (eg Audacity) -- probably best to convert it to wave first -- find the "bang" you noted, work out how much it has to be shifted.

One possibility is a constant shift, i.e. 1 second throughout. In that case insert, or cut, the correct amount from the beginning. Otherwise, if it starts in sync and gradually goes out, stretch the sound, (in Audacity, use Effect:Tempo) and save out a new wave, convert to AC3 or MP2. Reauthor with the demuxed video.

Simple!

[Nelson37]

I would recommend doing a search for the THOUSANDS of other posts on this subject, you might find one of the many complete Guides for handling this situation, also some tips on how to properly explain your problem.

There are basically two types of de-synch, audio off by a constant value which does not change throughout the video (This is extremely easy to fix), and the other kind, where audio is off by a gradually changing amount throughout the video. This is much more difficult and sometimes impossible to fix, though it may very well be caused by playback or processing software on your end.

[Alex_ander]

If you are trying to open separate VOBs you can get this result from a perfectly synched DVD (some VOBs may have an audio delay and it's OK). It might be actually in sync if you initiate playback using VIDEO_TS.ifo in a player like MediaPlayerClassic or WinDVD/PowerDVD.

[steviewilson]

If you are trying to open separate VOBs you can get this result from a perfectly synched DVD (some VOBs may have an audio delay and it's OK). It might be actually in sync if you initiate playback using VIDEO_TS.ifo in a player like MediaPlayerClassic or WinDVD/PowerDVD.

Well mate, watching it in PowerDVD actually SHOWS the sync issue, I test these files before making coasters, and saw the problem, just want an easy way to fix it first.

[Alex_ander]

Then I'd convert it to elementary video/audio streams (e.g. in TMPGEnc MPEG Editor) and find the delay/duration values for both (in most cases delay is enough). I usually do it in MPEGVideoWizard - very good for previewing and setting delay value (right-click the stream on timeline and type it) for audio or video. If after adjusting delay in the beginning you also get it synched in the end you can output it to MPEG and re-author.
If there's also a difference in duration, its value can be found by moving a stream on timeline for synching in the beginning, then in the end. Then you'll have to correct this in a sound editor, encode the audio back and re-author.

[Barnabas]

Really no way to fix it unless the audio and video are out of sync by the same amount from the beginning to end.

[Alex_ander]

Really no way to fix it unless the audio and video are out of sync by the same amount from the beginning to end.

You are too pessimistic . If video/audio match in the beginning and gradually (not by jumps) go apart by the end due to accumulating difference in duration, there's a good chance to correct this by applying time stretch function (+/-) in a sound editor (e.g. SoundForge).

[steviewilson]

Thank you, gents. Merry Christmas