Relationship between Video and Audio formats

[Phil S]

I recently downloaded an AVI file from the web which I used SUPER C to encode to DVD compliant MPEG2. I then used VS10 to burn it to DVD.
Somewhere along the line the video lost the right hand audio channel which is in the original AVI but not in the VOB.

I suspect that I chose the wrong audio codec, or the wrong 2 or 6 channel setting in Super C but I can't be sure. (from AC3, MP2, MP3).

I'm not asking for an answer to this (although any hint would be welcome) but is their a good tutorial or explanation of Audio Codecs and the relationship with Vidoe formats that can be downloaded as I realise that I know very lttle about this.

[skier-hughes]

Have you kept all the intermediary files to see where it got lost?
I don't suspect codec, per say, but most likely a settings choice in one of the apps.

[Phil S]

It got lost in Super C. The AVI file has it, the resultant VOB does not and obviously the burned DVD has not.

I think I had some settings wrong like it was set to AC 3 audio when the original was MPEG Layer 3. Whether this would cause this I don't know, but I'm not overly concerened with this because the video is still watchable. I won't redo as it takes 4 hours to render.

What I really am looking for is some sort of detailed guide to Audio Codecs, what they do etc as I've realised I know little about this and so I know what I'm setting next time.

For instance, I believe that AC 3 is used for 5.1 digital but can MP3 do that too? What is MP2 and the difference with MP3. I'm just confused by audio formats when it comes to their use in video.

[skier-hughes]

CODEC
COmpression DECompression.

It is a utility used to compress the audio file. You need the same codec on the computer that compressed it to play it.

Taking any file and changing it to AC3 or MP3 will not cause it to loose it's stereo or 5.1 properties, UNLESS there is a fault in the app.

For future reference if yu are going to use super c again, I'd check that you didn't have a tick box for mono checked,a s this would be the most likely cause.

AC-3 can be stereo or 5.1. As for their use in video, it's like video compression. It's best to use the highest quality until the final rendering of the movie. If you have a dv-avi file then you wouldn't change it to mpeg1 for editing and tene hope for a high quality movie at the end, so don't compress the hell out of audio and expect the same.

Here's a comparison of codecs
http://wiki.hydrogenaudio.org/index.php ... comparison

Happy reading!!!!!!

Quick guide.
Work with losssless audio formats
Change to format required at time required.
Check settings of the apps you use that you don't change things you don't want to.