what is multiplexing/demultiplexing?

[speedy726]

What exactly is multiplexing and demultiplexing and when would you use it? Is it when you join a video stream with an audio stream to make them one file? And what is the difference between Single Multiplex and Multiplex and the difference between Simply De-Multiplex and De-Multiplex? These options are offered in Tmpgenc, thats all I know.

[91BRAVO]

When I see the word multiplex I think compile

[Truman]

http://www.vcdhelp.com/faq.htm

[DVantrease]

I read the faq, but it didn't say when you would want to do this. Is it used for fixing sync problems or what?

[Truman]

Demultiplex is when you split a system stream to separate video and audio streams.
Multiplex is when you join the video file and audio file(s) to a system stream.
If you produced a invalid MPEG stream before, you have a chance to correct this by demux / remux, i.e. correct audio or video delay, muxrate, packet size.
Most people use to do audio and video seperately (I believe), because the best MPEG video encoder, i.e. TMPG and CCE do not have the best audio encoders. Then you have to multiplex (mux) video and audio to a readdy-to-author system stream.