Audio Sync Issues

nekokate · Joined: 13 Dec 2006 Location: West Yorkshire, UK

I posted this in a different forum, but I'm re-posting it here incase anyone can help.

Re: John Pilger documentary:

The streaming video works ok from the Google site, but the download audio is about a second behind.

I downloaded it from Google Video as an mp4, noticed the problem and then converted it to an avi, but with the same problem.

I think it might be my computer, since I've been having audio-sync problems with things I upload to YouTube, too.

faceless · admin Joined: 25 Apr 2006

ok, first of all you need to get Virtual Dub. www.virtualdub.org

As long as you've got the right codecs installed you should be able to just drag the mp4 file into it. There are video and audio settings, but for this you would just set the video to 'direct stream copy'. To sort the delay in audio you will need to work with the 'audio interleaving' and save test files find the correct amount of skew required to make the whole video work.

I realise that's not exactly an in-depth answer, but it's pretty simple to get started. the real skill lies in getting things perfect and that can only be done by trial and error.

major.tom · Posted: Sat Aug 25, 2007 1:26 am Post subject:

I find audio sync/skipping issues can often be solved by saving the audio to a .wav file and re-encoding to Constant Bitrate (CBR). I also use VirtualDub to do this...

- open the video file
- select "Full Processing Mode" from the Audio menu
- select "Save WAV" from the File menu and give it a name
- select "WAV Audio" from the Audio menu and find the .wav file you just saved
- select Compression from the Audio menu and pick an CBR MP3 codec at roughly the same bitrate as the original. (You can tell this by selecting "File Information" from the file menu.)
- select "Direct Stream Copy" from the Video menu (this prevents re-encoding the video which can be very time-consuming and unnecessary)
- File menu, Save as AVI...

nekokate · Joined: 13 Dec 2006 Location: West Yorkshire, UK

Sounds good! Thanks! Smile

Bob · Joined: 01 May 2006 Location: US

ntsc/pal conversion issue in the video encode? that usually courses the sound to go out of sync ain't it? just wondering if re-encoding the video would fix this issue?