This operation is divided in two steps : selecting streams and the check out advanced parameters.
Selecting streams to be processed and multiplexed.
The audio streams are at the left and subpicture streams at the right. Just check the one you want to be processed or demultiplexed (subpictures can only be demultiplexed and are not processed, you must use Subrip to do that).
The radio buttons in Audio Streams Groupbox select the streams wich are going to be multiplexed with Avi File. At the present time only two streams can be multiplexed even if you can process as many streams as you want (Nandub restrictions). The first column is for the default audio streams and the second column for secondary audio streams. If you want to prevent a stream from being multiplex uncheck and check it .
Advanced Audio parameters.
First choose between original (DVD) audio or a conversion to MP3.
If you choose original be carefull with MPA streams (you can see the type of the audio stream in Test Feature Combo Box), they cannot be multiplexed). Original audio streams take a lot of space, so you think about it.
For MP3 you got some optional parameters such as the Kbps, VBR (Variable Bit Rate) encoding. 96 kbps with VBR is a configuration i like.
You can test amplification of each streams with the Test Feature. Just Select the Stream and push Test. That way you can avoid difference of level between audio streams.