1. Browse to and open the media file.
There are two panes at the lower end of the MediaCoder window. Each pane has a number of tabs you can switch between. The left hand pane is for general settings, the right hand pane is for specific codec settings.
Since the video part of your flick already works there is no reason to convert that. To not convert the video, click on the Video tab in the left hand pane. Tick the box next to 'Copy video'. Most other options on the tab will now grey out, except Container. Keep the same container as in the original file (presumably AVI).
2. Click on the 'Audio' tab in the left hand pane. As encoder, pick LAME MP3 (I hope you have access to it in Linux - if not I guess you will be told so and will have to pick another option... only if so, I wouldn't know which one
). For Resample, choose Original. Channel: Stereo. Audio ID: 1. Gain: 0dB.
Make sure Copy Audio, External File and Normalize are not ticked.
3. On the right hand pane, click on the tab LAME MP3. Preset: Custom. Rate Mode: CBR. Channel: Auto. Bitrate: 128 Kbps (this is usually enough, but a little on the low side for clear dialogues). If the original audio bitrate is higher, choose the higher value.
4. Click on the tab 'Picture' on the left hand pane. Make sure that you set the frame rate for the video to the same value as the original. This is important because if you have a 23.976 frames per second frame rate, and the program sets a 25 fps frame rate for the re-encoded file, you will see the video stuttering, especially noticeable on panoramic shots. Also, subs and audio may go out of synch if the wrong frame rate is set.
That should be it as far as the media settings are concerned...
5. Browse to your desired Output Folder where you want to save the re-encoded file (at the top of the MediaCoder window) by pressing the ... button.
5. Press the 'Start' button. Wait.
6. When finished, use MediaInfo or Avinaptic to compare the audio and video settings of the re-encoded file with the original file. If everything goes as planned, your audio stream will now be converted to a constant bitrate mp3 which your DVD player supports.