Re-syncing audio? How? For Spot

p@mast3rs wrote on 2/14/2004, 12:08 PM
Spot. I bought your book but I didnt see this covered in there.

I have an mpeg-2 that I am trying to convert to another format for a client. I can get the time delay using dvd2avi when I demux. However, i dont see an option in VV4 that allows me to enter an audio delay so that the audio will match up.

My current process is opening the mpeg-2 file, and then moving the audio until it appears in sync with the video. Surely there must be another and more efficient way to enter the amount of ms that audio is delayed to sync it to the video.

is there something I am over looking here?

Comments

Spot|DSE wrote on 2/14/2004, 2:00 PM
Vegas isn't an MPEG editor, and it's weak at most anything edit-related for MPEG. Hence, it's not covered in my book.
You are doing it the best way it can be done. The only other option is to use an audio delay set to the exact offset time of the audio vs video, and then hearing a wet-only mix. This too, is not the best way, but if you've got to edit mpeg,.....and don't have Ulead or FAST products, it's a good workaround.
Ulead's MSP is great for MPEG editing even tho it's weak at most everything else. It does identify I frames, which is critical for mpeg editing.
p@mast3rs wrote on 2/14/2004, 2:19 PM
So is there an easy way to extract lets say for example 92ms off an audio file withouth using the mouse to drag and highlight?
Spot|DSE wrote on 2/14/2004, 2:48 PM
You could always insert a 92 ms delay and hear only the delayed signal, if you are sure it's that far off on everything through out.
p@mast3rs wrote on 2/14/2004, 2:51 PM
are there any mpeg utilties that you know that will allow correct a delay when muxing or maybe even remuxing?
Spot|DSE wrote on 2/14/2004, 3:17 PM
I'm certain there is one, but I'm unaware of it. Messing with editing MPEG has never been my thing, sorry.
farss wrote on 2/14/2004, 4:12 PM
I've some across exactly this problem. I was given the assets for a DVD as elemental streams. The ac3 files had names like:
Soundtrack_01_1250ms.ac3
Now when I just dropped that into DVDA surprise surprise my soundtrack was way off sync, even for a karaoke video! I soon worked out that the soundtrack was encoded to start 1.25 seconds into the video. That's when the real drama began because first I had to convert the ac3 to wav, then recompress the stereo wav back into ac3. Not the best thing for quality and a right royal pain in the butt.

I'd imagine these files came from smoething like Scanarist and there was about 200 CDs worth of them to process. I got wise and gave it back to the client. There was a fair bit of money in it but not that much. The original task was to convert all the video from NTSC to PAL, that as it turned out was the easiest part.