Insert gaps in audio

[Krumiro]

Dear Forum,
I am a complete newby in video/audio editing.
I have merged some mpg video together with a software into a single avi (xvid+mp3) file.
After deleting the original files I have realized that because of the fading transition between them (I think, because I have tried witout and it is fine) the video is delayed after each point where a new video start.

As I dont have anymore the originals, can you suggest please how I could edit the audio and insert some gap or something in the audio so that I can resincronise the piece audio with its iece of video?

I don't mind to either insert some sort of gas in the audio or cut a bit of the video (not sure if one is better/simler)

Many thanks!

[aedipuss]

welcome to the forum. what do you have for editing software? it shouldn't change the audio any more than the video when doing transitions. they should both be overlapped the same amount.

[Krumiro]

I have merged them using Freemake, unfortunatelly I have realised adter deleting the originals that the videos where I have set the transition to be none are ok while those videos where I have set the transition to be fading have the audio and the video not in sync, robably they have a bug.
The audio seems (I am not 100% sure) seems to be a bit earlier after each transition.

For some videos I have the originals so I can re-encode them while for other I dont, the only option I can think of is to cut here and there soome secs of video or insert some gap in the audio... probably the first option is the best... I dont know a lot about video editing.

[Krumiro]

Can you suggest a software to merge videos instead of Freemake? Ideally I want to input some common format (my camcoder does .MOD which are basically just .MPG and the mobile does 3gp) and I want to output a merged AVI (is xvid the best if I want to play them also on dvd players?)...

[aedipuss]

a video editing software like vegas studio is your best bet.

[Krumiro]

Is this to fix my audio? I have just donloaded it and I will give it a go.

Many thanks

[hello_hello]

It's possible to fix your existing AVIs using VirtualDub...... at least to a certain extent.

The idea would be to split the AVI into sections, ideally with each section being the start and end points where the original video was joined while encoding, so each section would then require the audio sync be adjusted by a specific amount to correct it for the whole section.... if that makes sense.

If you open an AVI with VirtualDub and use the key buttons on the navigation bar (the video needs to be "cut" on keyframes) you can select start and end points for editing. With start and end points selected, while using Direct Stream Copy for the video (from the video menu) you can then save the selection as a new AVI without re-encoding anything.

Once that's done, you'd open each newly saved AVI section with VirtualDub, set an appropriate audio delay (from the Audio/Interleaving menu) and resave it as a new AVI using Direct Stream Copy for the audio and video again. Eventually you'll hopefully have a few smaller AVIs with their audio sync corrected, which you can then join together using VirtualDubMod to resave them as a single AVI again (always using Direct Stream Copy for the audio and video).

The above method should work. I've used it to correct the audio sync for a single AVI many, many times, although having to split an AVI and correct the audio delay for each section by a different amount can involve a bit of trial and error.
You can use MPC-HC to work out the audio delay required to fix the audio sync (positive or negative). Open an AVI with MPC-HC and tap the + and - keys on the numeric keypad. MPC-HC should display the audio delay in the status bar, When the audio is in sync, that's the delay to use for the audio when opening an AVI and resaving it with VirtualDub.

PS You can use VirtualDub to extract the MP3 audio from your AVI (File/Export menu), then edit the extracted MP3 with a program such as MP3DirectCut etc. When you're done editing, VirtualDub can replace the original audio with the edited MP3 and save it as a new AVI (don't forget to use Direct Stream Copy for the video).

[Krumiro]

Many thianks,
This should reasonable.

I will give it a go!

Thanks!